utils.py

import threading
import os
import contextlib
import torch
import torch.nn as nn
from PIL import Image, ImageDraw, ImageFont, ExifTags
from PIL import __version__ as pil_version
from multiprocessing.pool import ThreadPool
import numpy as np
from itertools import repeat
import glob
import cv2
import tempfile
import hashlib
from pathlib import Path
import time
import torchvision
import math
import re
from typing import List, Union, Dict
import pkg_resources as pkg
from types import SimpleNamespace
from torch.utils.data import Dataset, DataLoader
from tqdm import tqdm
import random
import yaml
import logging.config
import sys
import pathlib
CURRENT_DIR = pathlib.Path(__file__).parent
sys.path.append(str(CURRENT_DIR))

LOGGING_NAME = 'ultralytics'
LOGGER = logging.getLogger(LOGGING_NAME) 
for fn in LOGGER.info, LOGGER.warning:
    setattr(LOGGER, fn.__name__, lambda x: fn(x))
IMG_FORMATS = "bmp", "dng", "jpeg", "jpg", "mpo", "png", "tif", "tiff", "webp", "pfm"  # include image suffixes
VID_FORMATS = "asf", "avi", "gif", "m4v", "mkv", "mov", "mp4", "mpeg", "mpg", "ts", "wmv"  # include video suffixes
TQDM_BAR_FORMAT = '{l_bar}{bar:10}{r_bar}'  # tqdm bar format
NUM_THREADS = min(8, os.cpu_count())
PIN_MEMORY = str(os.getenv("PIN_MEMORY", True)).lower() == "true"  # global pin_memory for dataloaders
_formats = ["xyxy", "xywh", "ltwh"]
CFG_FLOAT_KEYS = {'warmup_epochs', 'box', 'cls', 'dfl', 'degrees', 'shear'}
CFG_FRACTION_KEYS = {
    'dropout', 'iou', 'lr0', 'lrf', 'momentum', 'weight_decay', 'warmup_momentum', 'warmup_bias_lr', 'fl_gamma',
    'label_smoothing', 'hsv_h', 'hsv_s', 'hsv_v', 'translate', 'scale', 'perspective', 'flipud', 'fliplr', 'mosaic',
    'mixup', 'copy_paste', 'conf', 'iou'}
CFG_INT_KEYS = {
    'epochs', 'patience', 'batch', 'workers', 'seed', 'close_mosaic', 'mask_ratio', 'max_det', 'vid_stride',
    'line_thickness', 'workspace', 'nbs'}
CFG_BOOL_KEYS = {
    'save', 'exist_ok', 'pretrained', 'verbose', 'deterministic', 'single_cls', 'image_weights', 'rect', 'cos_lr',
    'overlap_mask', 'val', 'save_json', 'save_hybrid', 'half', 'dnn', 'plots', 'show', 'save_txt', 'save_conf',
    'save_crop', 'hide_labels', 'hide_conf', 'visualize', 'augment', 'agnostic_nms', 'retina_masks', 'boxes', 'keras',
    'optimize', 'int8', 'dynamic', 'simplify', 'nms', 'v5loader'}
# Get orientation exif tag
for orientation in ExifTags.TAGS.keys():
    if ExifTags.TAGS[orientation] == 'Orientation':
        break

def segments2boxes(segments):
    """
    It converts segment labels to box labels, i.e. (cls, xy1, xy2, ...) to (cls, xywh)

    Args:
      segments (list): list of segments, each segment is a list of points, each point is a list of x, y coordinates

    Returns:
      (np.ndarray): the xywh coordinates of the bounding boxes.
    """
    boxes = []
    for s in segments:
        x, y = s.T  # segment xy
        boxes.append([x.min(), y.min(), x.max(), y.max()])  # cls, xyxy
    return xyxy2xywh(np.array(boxes))  # cls, xywh


def check_version(
    current: str = "0.0.0",
    minimum: str = "0.0.0",
    name: str = "version ",
    pinned: bool = False,
    hard: bool = False,
    verbose: bool = False,
) -> bool:
    """
    Check current version against the required minimum version.

    Args:
        current (str): Current version.
        minimum (str): Required minimum version.
        name (str): Name to be used in warning message.
        pinned (bool): If True, versions must match exactly. If False, minimum version must be satisfied.
        hard (bool): If True, raise an AssertionError if the minimum version is not met.
        verbose (bool): If True, print warning message if minimum version is not met.

    Returns:
        bool: True if minimum version is met, False otherwise.
    """
    current, minimum = (pkg.parse_version(x) for x in (current, minimum))
    result = (current == minimum) if pinned else (current >= minimum)  # bool
    warning_message = f"WARNING ⚠️ {name}{minimum} is required by YOLOv8, but {name}{current} is currently installed"
    if verbose and not result:
        LOGGER.warning(warning_message)
    return result


TORCH_1_9 = check_version(torch.__version__, '1.9.0')


def smart_inference_mode():
    # Applies torch.inference_mode() decorator if torch>=1.9.0 else torch.no_grad() decorator
    def decorate(fn):
        return (torch.inference_mode if TORCH_1_9 else torch.no_grad)()(fn)

    return decorate


def box_iou(box1, box2, eps=1e-7):
    # https://github.com/pytorch/vision/blob/master/torchvision/ops/boxes.py
    """
    Return intersection-over-union (Jaccard index) of boxes.
    Both sets of boxes are expected to be in (x1, y1, x2, y2) format.
    Arguments:
        box1 (Tensor[N, 4])
        box2 (Tensor[M, 4])
    Returns:
        iou (Tensor[N, M]): the NxM matrix containing the pairwise
            IoU values for every element in boxes1 and boxes2
    """

    # inter(N,M) = (rb(N,M,2) - lt(N,M,2)).clamp(0).prod(2)
    (a1, a2), (b1, b2) = box1.unsqueeze(1).chunk(2, 2), box2.unsqueeze(0).chunk(2, 2)
    inter = (torch.min(a2, b2) - torch.max(a1, b1)).clamp(0).prod(2)

    # IoU = inter / (area1 + area2 - inter)
    return inter / ((a2 - a1).prod(2) + (b2 - b1).prod(2) - inter + eps)


class LoadImages:
    # YOLOv8 image/video dataloader, i.e. `yolo predict source=image.jpg/vid.mp4`
    def __init__(
        self, path, imgsz=640, stride=32, auto=True, transforms=None, vid_stride=1
    ):
        # *.txt file with img/vid/dir on each line
        if isinstance(path, str) and Path(path).suffix == ".txt":
            path = Path(path).read_text().rsplit()
        files = []
        for p in sorted(path) if isinstance(path, (list, tuple)) else [path]:
            p = str(Path(p).resolve())
            if "*" in p:
                files.extend(sorted(glob.glob(p, recursive=True)))  # glob
            elif os.path.isdir(p):
                files.extend(sorted(glob.glob(os.path.join(p, "*.*"))))  # dir
            elif os.path.isfile(p):
                files.append(p)  # files
            else:
                raise FileNotFoundError(f"{p} does not exist")
        # include image suffixes
        images = [x for x in files if x.split(".")[-1].lower() in IMG_FORMATS]
        videos = [x for x in files if x.split(".")[-1].lower() in VID_FORMATS]
        ni, nv = len(images), len(videos)

        self.imgsz = imgsz
        self.stride = stride
        self.files = images + videos
        self.nf = ni + nv  # number of files
        self.video_flag = [False] * ni + [True] * nv
        self.mode = "image"
        self.auto = auto
        self.transforms = transforms  # optional
        self.vid_stride = vid_stride  # video frame-rate stride
        self.bs = 1
        if any(videos):
            self.orientation = None  # rotation degrees
            self._new_video(videos[0])  # new video
        else:
            self.cap = None
        if self.nf == 0:
            raise FileNotFoundError(
                f"No images or videos found in {p}. "
                f"Supported formats are:\nimages: {IMG_FORMATS}\nvideos: {VID_FORMATS}"
            )

    def __iter__(self):
        self.count = 0
        return self

    def __next__(self):
        if self.count == self.nf:
            raise StopIteration
        path = self.files[self.count]

        if self.video_flag[self.count]:
            # Read video
            self.mode = "video"
            for _ in range(self.vid_stride):
                self.cap.grab()
            success, im0 = self.cap.retrieve()
            while not success:
                self.count += 1
                self.cap.release()
                if self.count == self.nf:  # last video
                    raise StopIteration
                path = self.files[self.count]
                self._new_video(path)
                success, im0 = self.cap.read()

            self.frame += 1
            s = f"video {self.count + 1}/{self.nf} ({self.frame}/{self.frames}) {path}: "

        else:
            # Read image
            self.count += 1
            im0 = cv2.imread(path)  # BGR
            if im0 is None:
                raise FileNotFoundError(f"Image Not Found {path}")
            s = f"image {self.count}/{self.nf} {path}: "

        if self.transforms:
            im = self.transforms(im0)  # transforms
        else:
            im = LetterBox(self.imgsz, self.auto, stride=self.stride)(image=im0)
            im = im.transpose((2, 0, 1))[::-1]  # HWC to CHW, BGR to RGB
            im = np.ascontiguousarray(im)  # contiguous

        return path, im, im0, self.cap, s

    def _new_video(self, path):
        # Create a new video capture object
        self.frame = 0
        self.cap = cv2.VideoCapture(path)
        self.frames = int(self.cap.get(cv2.CAP_PROP_FRAME_COUNT) / self.vid_stride)
        if hasattr(cv2, "CAP_PROP_ORIENTATION_META"):  # cv2<4.6.0 compatibility
            self.orientation = int(
                self.cap.get(cv2.CAP_PROP_ORIENTATION_META)
            )  # rotation degrees
            # Disable auto-orientation due to known issues in https://github.com/ultralytics/yolov5/issues/8493
            # self.cap.set(cv2.CAP_PROP_ORIENTATION_AUTO, 0)

    def _cv2_rotate(self, im):
        # Rotate a cv2 video manually
        if self.orientation == 0:
            return cv2.rotate(im, cv2.ROTATE_90_CLOCKWISE)
        elif self.orientation == 180:
            return cv2.rotate(im, cv2.ROTATE_90_COUNTERCLOCKWISE)
        elif self.orientation == 90:
            return cv2.rotate(im, cv2.ROTATE_180)
        return im

    def __len__(self):
        return self.nf  # number of files


class LetterBox:
    """Resize image and padding for detection, instance segmentation, pose"""

    def __init__(
        self, new_shape=(640, 640), auto=False, scaleFill=False, scaleup=True, stride=32
    ):
        self.new_shape = new_shape
        self.auto = auto
        self.scaleFill = scaleFill
        self.scaleup = scaleup
        self.stride = stride

    def __call__(self, labels=None, image=None):
        if labels is None:
            labels = {}
        img = labels.get("img") if image is None else image
        shape = img.shape[:2]  # current shape [height, width]
        new_shape = labels.pop("rect_shape", self.new_shape)
        if isinstance(new_shape, int):
            new_shape = (new_shape, new_shape)

        # Scale ratio (new / old)
        r = min(new_shape[0] / shape[0], new_shape[1] / shape[1])
        # only scale down, do not scale up (for better val mAP)
        if not self.scaleup:
            r = min(r, 1.0)

        # Compute padding
        ratio = r, r  # width, height ratios
        new_unpad = int(round(shape[1] * r)), int(round(shape[0] * r))
        dw, dh = new_shape[1] - new_unpad[0], new_shape[0] - new_unpad[1]  # wh padding
        if self.auto:  # minimum rectangle
            dw, dh = np.mod(dw, self.stride), np.mod(dh, self.stride)  # wh padding
        elif self.scaleFill:  # stretch
            dw, dh = 0.0, 0.0
            new_unpad = (new_shape[1], new_shape[0])
            ratio = (
                new_shape[1] / shape[1],
                new_shape[0] / shape[0],
            )  # width, height ratios

        dw /= 2  # divide padding into 2 sides
        dh /= 2
        if labels.get("ratio_pad"):
            labels["ratio_pad"] = (labels["ratio_pad"], (dw, dh))  # for evaluation

        if shape[::-1] != new_unpad:  # resize
            img = cv2.resize(img, new_unpad, interpolation=cv2.INTER_LINEAR)
        top, bottom = int(round(dh - 0.1)), int(round(dh + 0.1))
        left, right = int(round(dw - 0.1)), int(round(dw + 0.1))
        img = cv2.copyMakeBorder(
            img, top, bottom, left, right, cv2.BORDER_CONSTANT, value=(114, 114, 114)
        )  # add border

        if len(labels):
            labels = self._update_labels(labels, ratio, dw, dh)
            labels["img"] = img
            labels["resized_shape"] = new_shape
            return labels
        else:
            return img

    def _update_labels(self, labels, ratio, padw, padh):
        """Update labels"""
        labels["instances"].convert_bbox(format="xyxy")
        labels["instances"].denormalize(*labels["img"].shape[:2][::-1])
        labels["instances"].scale(*ratio)
        labels["instances"].add_padding(padw, padh)
        return labels


class Annotator:
    # YOLOv8 Annotator for train/val mosaics and jpgs and detect/hub inference annotations
    def __init__(
        self,
        im,
        line_width=None,
        font_size=None,
        font="Arial.ttf",
        pil=False,
        example="abc",
    ):
        assert (
            im.data.contiguous
        ), "Image not contiguous. Apply np.ascontiguousarray(im) to Annotator() input images."
        # non-latin labels, i.e. asian, arabic, cyrillic
        non_ascii = not is_ascii(example)
        self.pil = pil or non_ascii
        if self.pil:  # use PIL
            self.pil_9_2_0_check = check_version(
                pil_version, "9.2.0"
            )  # deprecation check
            self.im = im if isinstance(im, Image.Image) else Image.fromarray(im)
            self.draw = ImageDraw.Draw(self.im)
            self.font = ImageFont.load_default()
        else:  # use cv2
            self.im = im
        self.lw = line_width or max(round(sum(im.shape) / 2 * 0.003), 2)  # line width

    def box_label(
        self, box, label="", color=(128, 128, 128), txt_color=(255, 255, 255)
    ):
        # Add one xyxy box to image with label
        if isinstance(box, torch.Tensor):
            box = box.tolist()
        if self.pil or not is_ascii(label):
            self.draw.rectangle(box, width=self.lw, outline=color)  # box
            if label:
                if self.pil_9_2_0_check:
                    _, _, w, h = self.font.getbbox(label)  # text width, height (New)
                else:
                    w, h = self.font.getsize(
                        label
                    )  # text width, height (Old, deprecated in 9.2.0)
                outside = box[1] - h >= 0  # label fits outside box
                self.draw.rectangle(
                    (
                        box[0],
                        box[1] - h if outside else box[1],
                        box[0] + w + 1,
                        box[1] + 1 if outside else box[1] + h + 1,
                    ),
                    fill=color,
                )
                # self.draw.text((box[0], box[1]), label, fill=txt_color, font=self.font, anchor='ls')  # for PIL>8.0
                self.draw.text(
                    (box[0], box[1] - h if outside else box[1]),
                    label,
                    fill=txt_color,
                    font=self.font,
                )
        else:  # cv2
            p1, p2 = (int(box[0]), int(box[1])), (int(box[2]), int(box[3]))
            cv2.rectangle(
                self.im, p1, p2, color, thickness=self.lw, lineType=cv2.LINE_AA
            )
            if label:
                tf = max(self.lw - 1, 1)  # font thickness
                # text width, height
                w, h = cv2.getTextSize(label, 0, fontScale=self.lw / 3, thickness=tf)[0]
                outside = p1[1] - h >= 3
                p2 = p1[0] + w, p1[1] - h - 3 if outside else p1[1] + h + 3
                cv2.rectangle(self.im, p1, p2, color, -1, cv2.LINE_AA)  # filled
                cv2.putText(
                    self.im,
                    label,
                    (p1[0], p1[1] - 2 if outside else p1[1] + h + 2),
                    0,
                    self.lw / 3,
                    txt_color,
                    thickness=tf,
                    lineType=cv2.LINE_AA,
                )

    def rectangle(self, xy, fill=None, outline=None, width=1):
        # Add rectangle to image (PIL-only)
        self.draw.rectangle(xy, fill, outline, width)

    def text(self, xy, text, txt_color=(255, 255, 255), anchor="top"):
        # Add text to image (PIL-only)
        if anchor == "bottom":  # start y from font bottom
            w, h = self.font.getsize(text)  # text width, height
            xy[1] += 1 - h
        self.draw.text(xy, text, fill=txt_color, font=self.font)

    def fromarray(self, im):
        # Update self.im from a numpy array
        self.im = im if isinstance(im, Image.Image) else Image.fromarray(im)
        self.draw = ImageDraw.Draw(self.im)

    def result(self):
        # Return annotated image as array
        return np.asarray(self.im)


def non_max_suppression(
    prediction,
    conf_thres=0.25,
    iou_thres=0.45,
    classes=None,
    agnostic=False,
    multi_label=False,
    labels=(),
    max_det=300,
    nm=0,  # number of masks
):
    # Checks
    assert (
        0 <= conf_thres <= 1
    ), f"Invalid Confidence threshold {conf_thres}, valid values are between 0.0 and 1.0"
    assert (
        0 <= iou_thres <= 1
    ), f"Invalid IoU {iou_thres}, valid values are between 0.0 and 1.0"
    # YOLOv8 model in validation model, output = (inference_out, loss_out)
    if isinstance(prediction, (list, tuple)):
        prediction = prediction[0]  # select only inference output
    device = prediction.device
    mps = "mps" in device.type  # Apple MPS
    if mps:  # MPS not fully supported yet, convert tensors to CPU before NMS
        prediction = prediction.cpu()
    bs = prediction.shape[0]  # batch size
    nc = prediction.shape[1] - nm - 4  # number of classes
    mi = 4 + nc  # mask start index
    xc = prediction[:, 4:mi].amax(1) > conf_thres  # candidates

    # Settings
    # min_wh = 2  # (pixels) minimum box width and height
    max_wh = 7680  # (pixels) maximum box width and height
    max_nms = 30000  # maximum number of boxes into torchvision.ops.nms()
    time_limit = 0.5 + 0.05 * bs  # seconds to quit after
    redundant = True  # require redundant detections
    multi_label &= nc > 1  # multiple labels per box (adds 0.5ms/img)
    merge = False  # use merge-NMS

    t = time.time()
    output = [torch.zeros((0, 6 + nm), device=prediction.device)] * bs
    for xi, x in enumerate(prediction):  # image index, image inference
        # Apply constraints
        # x[((x[:, 2:4] < min_wh) | (x[:, 2:4] > max_wh)).any(1), 4] = 0  # width-height
        x = x.transpose(0, -1)[xc[xi]]  # confidence

        # Cat apriori labels if autolabelling
        if labels and len(labels[xi]):
            lb = labels[xi]
            v = torch.zeros((len(lb), nc + nm + 5), device=x.device)
            v[:, :4] = lb[:, 1:5]  # box
            v[range(len(lb)), lb[:, 0].long() + 4] = 1.0  # cls
            x = torch.cat((x, v), 0)

        # If none remain process next image
        if not x.shape[0]:
            continue

        # Detections matrix nx6 (xyxy, conf, cls)
        box, cls, mask = x.split((4, nc, nm), 1)
        # center_x, center_y, width, height) to (x1, y1, x2, y2)
        box = xywh2xyxy(box)
        if multi_label:
            i, j = (cls > conf_thres).nonzero(as_tuple=False).T
            x = torch.cat((box[i], x[i, 4 + j, None], j[:, None].float(), mask[i]), 1)
        else:  # best class only
            conf, j = cls.max(1, keepdim=True)
            x = torch.cat((box, conf, j.float(), mask), 1)[conf.view(-1) > conf_thres]

        # Filter by class
        if classes is not None:
            x = x[(x[:, 5:6] == torch.tensor(classes, device=x.device)).any(1)]

        # Check shape
        n = x.shape[0]  # number of boxes
        if not n:  # no boxes
            continue
        # sort by confidence and remove excess boxes
        x = x[x[:, 4].argsort(descending=True)[:max_nms]]

        # Batched NMS
        c = x[:, 5:6] * (0 if agnostic else max_wh)  # classes
        # boxes (offset by class), scores
        boxes, scores = x[:, :4] + c, x[:, 4]
        i = torchvision.ops.nms(boxes, scores, iou_thres)  # NMS
        i = i[:max_det]  # limit detections
        if merge and (1 < n < 3e3):  # Merge NMS (boxes merged using weighted mean)
            # update boxes as boxes(i,4) = weights(i,n) * boxes(n,4)
            iou = box_iou(boxes[i], boxes) > iou_thres  # iou matrix
            weights = iou * scores[None]  # box weights
            x[i, :4] = torch.mm(weights, x[:, :4]).float() / weights.sum(
                1, keepdim=True
            )  # merged boxes
            if redundant:
                i = i[iou.sum(1) > 1]  # require redundancy

        output[xi] = x[i]
        if mps:
            output[xi] = output[xi].to(device)
        if (time.time() - t) > time_limit:
            LOGGER.warning(f"WARNING ⚠️ NMS time limit {time_limit:.3f}s exceeded")
            break  # time limit exceeded

    return output


class Colors:
    # Ultralytics color palette https://ultralytics.com/
    def __init__(self):
        # hex = matplotlib.colors.TABLEAU_COLORS.values()
        hexs = (
            "FF3838",
            "FF9D97",
            "FF701F",
            "FFB21D",
            "CFD231",
            "48F90A",
            "92CC17",
            "3DDB86",
            "1A9334",
            "00D4BB",
            "2C99A8",
            "00C2FF",
            "344593",
            "6473FF",
            "0018EC",
            "8438FF",
            "520085",
            "CB38FF",
            "FF95C8",
            "FF37C7",
        )
        self.palette = [self.hex2rgb(f"#{c}") for c in hexs]
        self.n = len(self.palette)

    def __call__(self, i, bgr=False):
        c = self.palette[int(i) % self.n]
        return (c[2], c[1], c[0]) if bgr else c

    @staticmethod
    def hex2rgb(h):  # rgb order (PIL)
        return tuple(int(h[1 + i : 1 + i + 2], 16) for i in (0, 2, 4))


colors = Colors()  # create instance for 'from utils.plots import colors'


def threaded(func):
    # Multi-threads a target function and returns thread. Usage: @threaded decorator
    def wrapper(*args, **kwargs):
        thread = threading.Thread(target=func, args=args, kwargs=kwargs, daemon=True)
        thread.start()
        return thread

    return wrapper


def plot_images(
    images,
    batch_idx,
    cls,
    bboxes,
    masks=np.zeros(0, dtype=np.uint8),
    paths=None,
    fname="images.jpg",
    names=None,
):
    # Plot image grid with labels
    if isinstance(images, torch.Tensor):
        images = images.cpu().float().numpy()
    if isinstance(cls, torch.Tensor):
        cls = cls.cpu().numpy()
    if isinstance(bboxes, torch.Tensor):
        bboxes = bboxes.cpu().numpy()
    if isinstance(masks, torch.Tensor):
        masks = masks.cpu().numpy().astype(int)
    if isinstance(batch_idx, torch.Tensor):
        batch_idx = batch_idx.cpu().numpy()

    max_size = 1920  # max image size
    max_subplots = 16  # max image subplots, i.e. 4x4
    bs, _, h, w = images.shape  # batch size, _, height, width
    bs = min(bs, max_subplots)  # limit plot images
    ns = np.ceil(bs**0.5)  # number of subplots (square)
    if np.max(images[0]) <= 1:
        images *= 255  # de-normalise (optional)

    # Build Image
    mosaic = np.full((int(ns * h), int(ns * w), 3), 255, dtype=np.uint8)  # init
    for i, im in enumerate(images):
        if i == max_subplots:  # if last batch has fewer images than we expect
            break
        x, y = int(w * (i // ns)), int(h * (i % ns))  # block origin
        im = im.transpose(1, 2, 0)
        mosaic[y : y + h, x : x + w, :] = im

    # Resize (optional)
    scale = max_size / ns / max(h, w)
    if scale < 1:
        h = math.ceil(scale * h)
        w = math.ceil(scale * w)
        mosaic = cv2.resize(mosaic, tuple(int(x * ns) for x in (w, h)))

    # Annotate
    fs = int((h + w) * ns * 0.01)  # font size
    annotator = Annotator(
        mosaic, line_width=2, font_size=fs, pil=True, example=names
    )
    for i in range(i + 1):
        x, y = int(w * (i // ns)), int(h * (i % ns))  # block origin
        annotator.rectangle(
            [x, y, x + w, y + h], None, (255, 255, 255), width=2
        )  # borders
        if paths:
            annotator.text(
                # filenames
                (x + 5, y + 5 + h),
                text=Path(paths[i]).name[:40],
                txt_color=(220, 220, 220),
            )
        if len(cls) > 0:
            idx = batch_idx == i

            boxes = xywh2xyxy(bboxes[idx, :4]).T
            classes = cls[idx].astype("int")
            labels = bboxes.shape[1] == 4  # labels if no conf column
            # check for confidence presence (label vs pred)
            conf = None if labels else bboxes[idx, 4]

            if boxes.shape[1]:
                if boxes.max() <= 1.01:  # if normalized with tolerance 0.01
                    boxes[[0, 2]] *= w  # scale to pixels
                    boxes[[1, 3]] *= h
                elif scale < 1:  # absolute coords need scale if image scales
                    boxes *= scale
            boxes[[0, 2]] += x
            boxes[[1, 3]] += y
            for j, box in enumerate(boxes.T.tolist()):
                c = classes[j]
                color = colors(c)
                c = names[c] if names else c
                if labels or conf[j] > 0.25:  # 0.25 conf thresh
                    label = f"{c}" if labels else f"{c} {conf[j]:.1f}"
                    annotator.box_label(box, label, color=color)
    annotator.im.save(fname)  # save


def output_to_target(output, max_det=300):
    # Convert model output to target format [batch_id, class_id, x, y, w, h, conf] for plotting
    targets = []
    for i, o in enumerate(output):
        box, conf, cls = o[:max_det, :6].cpu().split((4, 1, 1), 1)
        j = torch.full((conf.shape[0], 1), i)
        targets.append(torch.cat((j, cls, xyxy2xywh(box), conf), 1))
    targets = torch.cat(targets, 0).numpy()
    return targets[:, 0], targets[:, 1], targets[:, 2:]


def is_ascii(s=""):
    # Is string composed of all ASCII (no UTF) characters? (note str().isascii() introduced in python 3.7)
    s = str(s)  # convert list, tuple, None, etc. to str
    return len(s.encode().decode("ascii", "ignore")) == len(s)


def xyxy2xywh(x):
    """
    Convert bounding box coordinates from (x1, y1, x2, y2) format to (x, y, width, height) format.

    Args:
        x (np.ndarray) or (torch.Tensor): The input bounding box coordinates in (x1, y1, x2, y2) format.
    Returns:
       y (np.ndarray) or (torch.Tensor): The bounding box coordinates in (x, y, width, height) format.
    """
    y = x.clone() if isinstance(x, torch.Tensor) else np.copy(x)
    y[..., 0] = (x[..., 0] + x[..., 2]) / 2  # x center
    y[..., 1] = (x[..., 1] + x[..., 3]) / 2  # y center
    y[..., 2] = x[..., 2] - x[..., 0]  # width
    y[..., 3] = x[..., 3] - x[..., 1]  # height
    return y


def xywh2xyxy(x):
    # Convert nx4 boxes from [x, y, w, h] to [x1, y1, x2, y2] where xy1=top-left, xy2=bottom-right
    y = x.clone() if isinstance(x, torch.Tensor) else np.copy(x)
    y[:, 0] = x[:, 0] - x[:, 2] / 2  # top left x
    y[:, 1] = x[:, 1] - x[:, 3] / 2  # top left y
    y[:, 2] = x[:, 0] + x[:, 2] / 2  # bottom right x
    y[:, 3] = x[:, 1] + x[:, 3] / 2  # bottom right y
    return y


def check_det_dataset(dataset, autodownload=True):
    # Download, check and/or unzip dataset if not found locally
    data = dataset
    # Download (optional)
    extract_dir = ''

    # Read yaml (optional)
    if isinstance(data, (str, Path)):
        data = yaml_load(data, append_filename=True)  # dictionary

    # Checks
    if isinstance(data['names'], (list, tuple)):  # old array format
        data['names'] = dict(enumerate(data['names']))  # convert to dict
    data['nc'] = len(data['names'])

    # Resolve paths
    path = Path(extract_dir or data.get('path') or Path(data.get('yaml_file', '')).parent)  # dataset root

    DATASETS_DIR = os.path.abspath('.')
    if not path.is_absolute():
        path = (DATASETS_DIR / path).resolve()
        data['path'] = path  # download scripts
    for k in 'train', 'val', 'test':
        if data.get(k):  # prepend path
            if isinstance(data[k], str):
                x = (path / data[k]).resolve()
                if not x.exists() and data[k].startswith('../'):
                    x = (path / data[k][3:]).resolve()
                data[k] = str(x)
            else:
                data[k] = [str((path / x).resolve()) for x in data[k]]

    # Parse yaml
    train, val, test, s = (data.get(x) for x in ('train', 'val', 'test', 'download'))
    if val:
        val = [Path(x).resolve() for x in (val if isinstance(val, list) else [val])]  # val path
        if not all(x.exists() for x in val):
            msg = f"\nDataset '{dataset}' not found ⚠️, missing paths %s" % [str(x) for x in val if not x.exists()]
            if s and autodownload:
                LOGGER.warning(msg)
            else:
                raise FileNotFoundError(msg)
            t = time.time()
            if s.startswith('bash '):  # bash script
                LOGGER.info(f'Running {s} ...')
                r = os.system(s)
            else:  # python script
                r = exec(s, {'yaml': data})  # return None
            dt = f'({round(time.time() - t, 1)}s)'
            s = f"success ✅ {dt}, saved to {colorstr('bold', DATASETS_DIR)}" if r in (0, None) else f"failure {dt} ❌"
            LOGGER.info(f"Dataset download {s}\n")

    return data  # dictionary


def yaml_load(file='data.yaml', append_filename=False):
    """
    Load YAML data from a file.

    Args:
        file (str, optional): File name. Default is 'data.yaml'.
        append_filename (bool): Add the YAML filename to the YAML dictionary. Default is False.

    Returns:
        dict: YAML data and file name.
    """
    with open(file, errors='ignore', encoding='utf-8') as f:
        # Add YAML filename to dict and return
        s = f.read()  # string
        if not s.isprintable():  # remove special characters
            s = re.sub(r'[^\x09\x0A\x0D\x20-\x7E\x85\xA0-\uD7FF\uE000-\uFFFD\U00010000-\U0010ffff]+', '', s)
        return {**yaml.safe_load(s), 'yaml_file': str(file)} if append_filename else yaml.safe_load(s)


class IterableSimpleNamespace(SimpleNamespace):
    """
    Iterable SimpleNamespace class to allow SimpleNamespace to be used with dict() and in for loops
    """

    def __iter__(self):
        return iter(vars(self).items())

    def __str__(self):
        return '\n'.join(f"{k}={v}" for k, v in vars(self).items())

    def get(self, key, default=None):
        return getattr(self, key, default)


def colorstr(*input):
    # Colors a string https://en.wikipedia.org/wiki/ANSI_escape_code, i.e.  colorstr('blue', 'hello world')
    *args, string = input if len(input) > 1 else ("blue", "bold", input[0])  # color arguments, string
    colors = {
        "black": "\033[30m",  # basic colors
        "red": "\033[31m",
        "green": "\033[32m",
        "yellow": "\033[33m",
        "blue": "\033[34m",
        "magenta": "\033[35m",
        "cyan": "\033[36m",
        "white": "\033[37m",
        "bright_black": "\033[90m",  # bright colors
        "bright_red": "\033[91m",
        "bright_green": "\033[92m",
        "bright_yellow": "\033[93m",
        "bright_blue": "\033[94m",
        "bright_magenta": "\033[95m",
        "bright_cyan": "\033[96m",
        "bright_white": "\033[97m",
        "end": "\033[0m",  # misc
        "bold": "\033[1m",
        "underline": "\033[4m"}
    return "".join(colors[x] for x in args) + f"{string}" + colors["end"]


def seed_worker(worker_id):
    # Set dataloader worker seed https://pytorch.org/docs/stable/notes/randomness.html#dataloader
    worker_seed = torch.initial_seed() % 2 ** 32
    np.random.seed(worker_seed)
    random.seed(worker_seed)


def build_dataloader(cfg, batch, img_path, stride=32, rect=False, names=None, rank=-1, mode="train"):
    assert mode in ["train", "val"]
    shuffle = mode == "train"
    if cfg.rect and shuffle:
        LOGGER.warning("WARNING ⚠️ 'rect=True' is incompatible with DataLoader shuffle, setting shuffle=False")
        shuffle = False
    dataset = YOLODataset(
        img_path=img_path,
        imgsz=cfg.imgsz,
        batch_size=batch,
        augment=mode == "train",  # augmentation
        hyp=cfg,  # TODO: probably add a get_hyps_from_cfg function
        rect=cfg.rect or rect,  # rectangular batches
        cache=cfg.cache or None,
        single_cls=cfg.single_cls or False,
        stride=int(stride),
        pad=0.0 if mode == "train" else 0.5,
        prefix=colorstr(f"{mode}: "),
        use_segments=cfg.task == "segment",
        use_keypoints=cfg.task == "keypoint",
        names=names)

    batch = min(batch, len(dataset))
    nd = torch.cuda.device_count()  # number of CUDA devices
    workers = cfg.workers if mode == "train" else cfg.workers * 2
    nw = min([os.cpu_count() // max(nd, 1), batch if batch > 1 else 0, workers])  # number of workers

    if rank == -1:
        sampler = None
    if cfg.image_weights or cfg.close_mosaic:
        loader = DataLoader
    generator = torch.Generator()
    generator.manual_seed(6148914691236517205)
    return loader(dataset=dataset,
                  batch_size=batch,
                  shuffle=shuffle and sampler is None,
                  num_workers=nw,
                  sampler=sampler,
                  pin_memory=PIN_MEMORY,
                  collate_fn=getattr(dataset, "collate_fn", None),
                  worker_init_fn=seed_worker,
                  generator=generator), dataset


class BaseDataset(Dataset):
    """Base Dataset.
    Args:
        img_path (str): image path.
        pipeline (dict): a dict of image transforms.
        label_path (str): label path, this can also be an ann_file or other custom label path.
    """

    def __init__(
        self,
        img_path,
        imgsz=640,
        cache=False,
        augment=True,
        hyp=None,
        prefix="",
        rect=False,
        batch_size=None,
        stride=32,
        pad=0.5,
        single_cls=False,
    ):
        super().__init__()
        self.img_path = img_path
        self.imgsz = imgsz
        self.augment = augment
        self.single_cls = single_cls
        self.prefix = prefix
        self.im_files = self.get_img_files(self.img_path)
        self.labels = self.get_labels()
        self.ni = len(self.labels)

        # rect stuff
        self.rect = rect
        self.batch_size = batch_size
        self.stride = stride
        self.pad = pad
        if self.rect:
            assert self.batch_size is not None
            self.set_rectangle()

        # cache stuff
        self.ims = [None] * self.ni
        self.npy_files = [Path(f).with_suffix(".npy") for f in self.im_files]
        if cache:
            self.cache_images(cache)

        # transforms
        self.transforms = self.build_transforms(hyp=hyp)

    def get_img_files(self, img_path):
        """Read image files."""
        try:
            f = []  # image files
            for p in img_path if isinstance(img_path, list) else [img_path]:
                p = Path(p)  # os-agnostic
                if p.is_dir():  # dir
                    f += glob.glob(str(p / "**" / "*.*"), recursive=True)
                    # f = list(p.rglob('*.*'))  # pathlib
                elif p.is_file():  # file
                    with open(p) as t:
                        t = t.read().strip().splitlines()
                        parent = str(p.parent) + os.sep
                        f += [x.replace("./", parent) if x.startswith("./") else x for x in t]  # local to global path
                        # f += [p.parent / x.lstrip(os.sep) for x in t]  # local to global path (pathlib)
                else:
                    raise FileNotFoundError(f"{self.prefix}{p} does not exist")
            im_files = sorted(x.replace("/", os.sep) for x in f if x.split(".")[-1].lower() in IMG_FORMATS)
            # self.img_files = sorted([x for x in f if x.suffix[1:].lower() in IMG_FORMATS])  # pathlib
            assert im_files, f"{self.prefix}No images found"
        except Exception as e:
            raise FileNotFoundError(f"{self.prefix}Error loading data from {img_path}\n") from e
        return im_files

    def load_image(self, i):
        # Loads 1 image from dataset index 'i', returns (im, resized hw)
        im, f, fn = self.ims[i], self.im_files[i], self.npy_files[i]
        if im is None:  # not cached in RAM
            if fn.exists():  # load npy
                im = np.load(fn)
            else:  # read image
                im = cv2.imread(f)  # BGR
                if im is None:
                    raise FileNotFoundError(f"Image Not Found {f}")
            h0, w0 = im.shape[:2]  # orig hw
            r = self.imgsz / max(h0, w0)  # ratio
            if r != 1:  # if sizes are not equal
                interp = cv2.INTER_LINEAR if (self.augment or r > 1) else cv2.INTER_AREA
                im = cv2.resize(im, (math.ceil(w0 * r), math.ceil(h0 * r)), interpolation=interp)
            return im, (h0, w0), im.shape[:2]  # im, hw_original, hw_resized
        return self.ims[i], self.im_hw0[i], self.im_hw[i]  # im, hw_original, hw_resized

    def cache_images(self, cache):
        # cache images to memory or disk
        gb = 0  # Gigabytes of cached images
        self.im_hw0, self.im_hw = [None] * self.ni, [None] * self.ni
        fcn = self.cache_images_to_disk if cache == "disk" else self.load_image
        with ThreadPool(NUM_THREADS) as pool:
            results = pool.imap(fcn, range(self.ni))
            pbar = tqdm(enumerate(results), total=self.ni, bar_format=TQDM_BAR_FORMAT)
            for i, x in pbar:
                if cache == "disk":
                    gb += self.npy_files[i].stat().st_size
                else:  # 'ram'
                    self.ims[i], self.im_hw0[i], self.im_hw[i] = x  # im, hw_orig, hw_resized = load_image(self, i)
                    gb += self.ims[i].nbytes
                pbar.desc = f"{self.prefix}Caching images ({gb / 1E9:.1f}GB {cache})"
            pbar.close()

    def cache_images_to_disk(self, i):
        # Saves an image as an *.npy file for faster loading
        f = self.npy_files[i]
        if not f.exists():
            np.save(f.as_posix(), cv2.imread(self.im_files[i]))

    def set_rectangle(self):
        bi = np.floor(np.arange(self.ni) / self.batch_size).astype(int)  # batch index
        nb = bi[-1] + 1  # number of batches

        s = np.array([x.pop("shape") for x in self.labels])  # hw
        ar = s[:, 0] / s[:, 1]  # aspect ratio
        irect = ar.argsort()
        self.im_files = [self.im_files[i] for i in irect]
        self.labels = [self.labels[i] for i in irect]
        ar = ar[irect]

        # Set training image shapes
        shapes = [[1, 1]] * nb
        for i in range(nb):
            ari = ar[bi == i]
            mini, maxi = ari.min(), ari.max()
            if maxi < 1:
                shapes[i] = [maxi, 1]
            elif mini > 1:
                shapes[i] = [1, 1 / mini]

        self.batch_shapes = np.ceil(np.array(shapes) * self.imgsz / self.stride + self.pad).astype(int) * self.stride
        self.batch = bi  # batch index of image

    def __getitem__(self, index):
        return self.transforms(self.get_label_info(index))

    def get_label_info(self, index):
        label = self.labels[index].copy()
        label.pop("shape", None)  # shape is for rect, remove it
        label["img"], label["ori_shape"], label["resized_shape"] = self.load_image(index)
        label["ratio_pad"] = (
            label["resized_shape"][0] / label["ori_shape"][0],
            label["resized_shape"][1] / label["ori_shape"][1],
        )  # for evaluation
        if self.rect:
            label["rect_shape"] = self.batch_shapes[self.batch[index]]
        label = self.update_labels_info(label)
        return label

    def __len__(self):
        return len(self.labels)

    def update_labels_info(self, label):
        """custom your label format here"""
        return label

    def build_transforms(self, hyp=None):
        """Users can custom augmentations here
        like:
            if self.augment:
                # training transforms
                return Compose([])
            else:
                # val transforms
                return Compose([])
        """
        raise NotImplementedError

    def get_labels(self):
        """Users can custom their own format here.
        Make sure your output is a list with each element like below:
            dict(
                im_file=im_file,
                shape=shape,  # format: (height, width)
                cls=cls,
                bboxes=bboxes, # xywh
                segments=segments,  # xy
                keypoints=keypoints, # xy
                normalized=True, # or False
                bbox_format="xyxy",  # or xywh, ltwh
            )
        """
        raise NotImplementedError


def img2label_paths(img_paths):
    # Define label paths as a function of image paths
    sa, sb = f"{os.sep}images{os.sep}", f"{os.sep}labels{os.sep}"  # /images/, /labels/ substrings
    return [sb.join(x.rsplit(sa, 1)).rsplit(".", 1)[0] + ".txt" for x in img_paths]


def get_hash(paths):
    # Returns a single hash value of a list of paths (files or dirs)
    size = sum(os.path.getsize(p) for p in paths if os.path.exists(p))  # sizes
    h = hashlib.md5(str(size).encode())  # hash sizes
    h.update("".join(paths).encode())  # hash paths
    return h.hexdigest()  # return hash


class Compose:

    def __init__(self, transforms):
        self.transforms = transforms

    def __call__(self, data):
        for t in self.transforms:
            data = t(data)
        return data

    def append(self, transform):
        self.transforms.append(transform)

    def tolist(self):
        return self.transforms

    def __repr__(self):
        format_string = f"{self.__class__.__name__}("
        for t in self.transforms:
            format_string += "\n"
            format_string += f"    {t}"
        format_string += "\n)"
        return format_string


class Format:

    def __init__(self,
                 bbox_format="xywh",
                 normalize=True,
                 return_mask=False,
                 return_keypoint=False,
                 mask_ratio=4,
                 mask_overlap=True,
                 batch_idx=True):
        self.bbox_format = bbox_format
        self.normalize = normalize
        self.return_mask = return_mask  # set False when training detection only
        self.return_keypoint = return_keypoint
        self.mask_ratio = mask_ratio
        self.mask_overlap = mask_overlap
        self.batch_idx = batch_idx  # keep the batch indexes

    def __call__(self, labels):
        img = labels.pop("img")
        h, w = img.shape[:2]
        cls = labels.pop("cls")
        instances = labels.pop("instances")
        instances.convert_bbox(format=self.bbox_format)
        instances.denormalize(w, h)
        nl = len(instances)

        if self.normalize:
            instances.normalize(w, h)
        labels["img"] = self._format_img(img)
        labels["cls"] = torch.from_numpy(cls) if nl else torch.zeros(nl)
        labels["bboxes"] = torch.from_numpy(instances.bboxes) if nl else torch.zeros((nl, 4))
        if self.return_keypoint:
            labels["keypoints"] = torch.from_numpy(instances.keypoints) if nl else torch.zeros((nl, 17, 2))
        # then we can use collate_fn
        if self.batch_idx:
            labels["batch_idx"] = torch.zeros(nl)
        return labels

    def _format_img(self, img):
        if len(img.shape) < 3:
            img = np.expand_dims(img, -1)
        img = np.ascontiguousarray(img.transpose(2, 0, 1)[::-1])
        img = torch.from_numpy(img)
        return img

class Bboxes:
    """Now only numpy is supported"""

    def __init__(self, bboxes, format="xyxy") -> None:
        assert format in _formats
        bboxes = bboxes[None, :] if bboxes.ndim == 1 else bboxes
        assert bboxes.ndim == 2
        assert bboxes.shape[1] == 4
        self.bboxes = bboxes
        self.format = format
        # self.normalized = normalized

    def convert(self, format):
        assert format in _formats
        if self.format == format:
            return
        elif self.format == "xyxy":
            if format == "xywh":
                bboxes = xyxy2xywh(self.bboxes)
        elif self.format == "xywh":
            if format == "xyxy":
                bboxes = xywh2xyxy(self.bboxes)
        self.bboxes = bboxes
        self.format = format

    def areas(self):
        self.convert("xyxy")
        return (self.bboxes[:, 2] - self.bboxes[:, 0]) * (self.bboxes[:, 3] - self.bboxes[:, 1])

    def mul(self, scale):
        """
        Args:
            scale (tuple | List | int): the scale for four coords.
        """
        assert isinstance(scale, (tuple, list))
        assert len(scale) == 4
        self.bboxes[:, 0] *= scale[0]
        self.bboxes[:, 1] *= scale[1]
        self.bboxes[:, 2] *= scale[2]
        self.bboxes[:, 3] *= scale[3]

    def add(self, offset):
        """
        Args:
            offset (tuple | List | int): the offset for four coords.
        """
        assert isinstance(offset, (tuple, list))
        assert len(offset) == 4
        self.bboxes[:, 0] += offset[0]
        self.bboxes[:, 1] += offset[1]
        self.bboxes[:, 2] += offset[2]
        self.bboxes[:, 3] += offset[3]

    def __len__(self):
        return len(self.bboxes)

    @classmethod
    def concatenate(cls, boxes_list: List["Bboxes"], axis=0) -> "Bboxes":
        """
        Concatenates a list of Boxes into a single Bboxes

        Arguments:
            boxes_list (list[Bboxes])

        Returns:
            Bboxes: the concatenated Boxes
        """
        assert isinstance(boxes_list, (list, tuple))
        if not boxes_list:
            return cls(np.empty(0))
        assert all(isinstance(box, Bboxes) for box in boxes_list)

        if len(boxes_list) == 1:
            return boxes_list[0]
        return cls(np.concatenate([b.bboxes for b in boxes_list], axis=axis))

    def __getitem__(self, index) -> "Bboxes":
        """
        Args:
            index: int, slice, or a BoolArray

        Returns:
            Bboxes: Create a new :class:`Bboxes` by indexing.
        """
        if isinstance(index, int):
            return Bboxes(self.bboxes[index].view(1, -1))
        b = self.bboxes[index]
        assert b.ndim == 2, f"Indexing on Bboxes with {index} failed to return a matrix!"
        return Bboxes(b)


def resample_segments(segments, n=1000):
    """
    Inputs a list of segments (n,2) and returns a list of segments (n,2) up-sampled to n points each.

    Args:
      segments (list): a list of (n,2) arrays, where n is the number of points in the segment.
      n (int): number of points to resample the segment to. Defaults to 1000

    Returns:
      segments (list): the resampled segments.
    """
    for i, s in enumerate(segments):
        s = np.concatenate((s, s[0:1, :]), axis=0)
        x = np.linspace(0, len(s) - 1, n)
        xp = np.arange(len(s))
        segments[i] = np.concatenate([np.interp(x, xp, s[:, i]) for i in range(2)]).reshape(2, -1).T  # segment xy
    return segments


class Instances:

    def __init__(self, bboxes, segments=None, keypoints=None, bbox_format="xywh", normalized=True) -> None:
        """
        Args:
            bboxes (ndarray): bboxes with shape [N, 4].
            segments (list | ndarray): segments.
            keypoints (ndarray): keypoints with shape [N, 17, 2].
        """
        if segments is None:
            segments = []
        self._bboxes = Bboxes(bboxes=bboxes, format=bbox_format)
        self.keypoints = keypoints
        self.normalized = normalized

        if len(segments) > 0:
            # list[np.array(1000, 2)] * num_samples
            segments = resample_segments(segments)
            # (N, 1000, 2)
            segments = np.stack(segments, axis=0)
        else:
            segments = np.zeros((0, 1000, 2), dtype=np.float32)
        self.segments = segments

    def convert_bbox(self, format):
        self._bboxes.convert(format=format)

    def bbox_areas(self):
        self._bboxes.areas()

    def scale(self, scale_w, scale_h, bbox_only=False):
        """this might be similar with denormalize func but without normalized sign"""
        self._bboxes.mul(scale=(scale_w, scale_h, scale_w, scale_h))
        if bbox_only:
            return
        self.segments[..., 0] *= scale_w
        self.segments[..., 1] *= scale_h
        if self.keypoints is not None:
            self.keypoints[..., 0] *= scale_w
            self.keypoints[..., 1] *= scale_h

    def denormalize(self, w, h):
        if not self.normalized:
            return
        self._bboxes.mul(scale=(w, h, w, h))
        self.segments[..., 0] *= w
        self.segments[..., 1] *= h
        if self.keypoints is not None:
            self.keypoints[..., 0] *= w
            self.keypoints[..., 1] *= h
        self.normalized = False

    def normalize(self, w, h):
        if self.normalized:
            return
        self._bboxes.mul(scale=(1 / w, 1 / h, 1 / w, 1 / h))
        self.segments[..., 0] /= w
        self.segments[..., 1] /= h
        if self.keypoints is not None:
            self.keypoints[..., 0] /= w
            self.keypoints[..., 1] /= h
        self.normalized = True

    def add_padding(self, padw, padh):
        # handle rect and mosaic situation
        assert not self.normalized, "you should add padding with absolute coordinates."
        self._bboxes.add(offset=(padw, padh, padw, padh))
        self.segments[..., 0] += padw
        self.segments[..., 1] += padh
        if self.keypoints is not None:
            self.keypoints[..., 0] += padw
            self.keypoints[..., 1] += padh

    def __getitem__(self, index) -> "Instances":
        """
        Args:
            index: int, slice, or a BoolArray

        Returns:
            Instances: Create a new :class:`Instances` by indexing.
        """
        segments = self.segments[index] if len(self.segments) else self.segments
        keypoints = self.keypoints[index] if self.keypoints is not None else None
        bboxes = self.bboxes[index]
        bbox_format = self._bboxes.format
        return Instances(
            bboxes=bboxes,
            segments=segments,
            keypoints=keypoints,
            bbox_format=bbox_format,
            normalized=self.normalized,
        )

    def flipud(self, h):
        if self._bboxes.format == "xyxy":
            y1 = self.bboxes[:, 1].copy()
            y2 = self.bboxes[:, 3].copy()
            self.bboxes[:, 1] = h - y2
            self.bboxes[:, 3] = h - y1
        else:
            self.bboxes[:, 1] = h - self.bboxes[:, 1]
        self.segments[..., 1] = h - self.segments[..., 1]
        if self.keypoints is not None:
            self.keypoints[..., 1] = h - self.keypoints[..., 1]

    def fliplr(self, w):
        if self._bboxes.format == "xyxy":
            x1 = self.bboxes[:, 0].copy()
            x2 = self.bboxes[:, 2].copy()
            self.bboxes[:, 0] = w - x2
            self.bboxes[:, 2] = w - x1
        else:
            self.bboxes[:, 0] = w - self.bboxes[:, 0]
        self.segments[..., 0] = w - self.segments[..., 0]
        if self.keypoints is not None:
            self.keypoints[..., 0] = w - self.keypoints[..., 0]

    def clip(self, w, h):
        ori_format = self._bboxes.format
        self.convert_bbox(format="xyxy")
        self.bboxes[:, [0, 2]] = self.bboxes[:, [0, 2]].clip(0, w)
        self.bboxes[:, [1, 3]] = self.bboxes[:, [1, 3]].clip(0, h)
        if ori_format != "xyxy":
            self.convert_bbox(format=ori_format)
        self.segments[..., 0] = self.segments[..., 0].clip(0, w)
        self.segments[..., 1] = self.segments[..., 1].clip(0, h)
        if self.keypoints is not None:
            self.keypoints[..., 0] = self.keypoints[..., 0].clip(0, w)
            self.keypoints[..., 1] = self.keypoints[..., 1].clip(0, h)

    def update(self, bboxes, segments=None, keypoints=None):
        new_bboxes = Bboxes(bboxes, format=self._bboxes.format)
        self._bboxes = new_bboxes
        if segments is not None:
            self.segments = segments
        if keypoints is not None:
            self.keypoints = keypoints

    def __len__(self):
        return len(self.bboxes)

    @classmethod
    def concatenate(cls, instances_list: List["Instances"], axis=0) -> "Instances":
        """
        Concatenates a list of Boxes into a single Bboxes

        Arguments:
            instances_list (list[Bboxes])
            axis

        Returns:
            Boxes: the concatenated Boxes
        """
        assert isinstance(instances_list, (list, tuple))
        if not instances_list:
            return cls(np.empty(0))
        assert all(isinstance(instance, Instances) for instance in instances_list)

        if len(instances_list) == 1:
            return instances_list[0]

        use_keypoint = instances_list[0].keypoints is not None
        bbox_format = instances_list[0]._bboxes.format
        normalized = instances_list[0].normalized

        cat_boxes = np.concatenate([ins.bboxes for ins in instances_list], axis=axis)
        cat_segments = np.concatenate([b.segments for b in instances_list], axis=axis)
        cat_keypoints = np.concatenate([b.keypoints for b in instances_list], axis=axis) if use_keypoint else None
        return cls(cat_boxes, cat_segments, cat_keypoints, bbox_format, normalized)

    @property
    def bboxes(self):
        return self._bboxes.bboxes


def is_dir_writeable(dir_path: Union[str, Path]) -> bool:
    """
    Check if a directory is writeable.

    Args:
        dir_path (str) or (Path): The path to the directory.

    Returns:
        bool: True if the directory is writeable, False otherwise.
    """
    try:
        with tempfile.TemporaryFile(dir=dir_path):
            pass
        return True
    except OSError:
        return False


class YOLODataset(BaseDataset):
    cache_version = '1.0.1'  # dataset labels *.cache version, >= 1.0.0 for YOLOv8
    rand_interp_methods = [cv2.INTER_NEAREST, cv2.INTER_LINEAR, cv2.INTER_CUBIC, cv2.INTER_AREA, cv2.INTER_LANCZOS4]
    """YOLO Dataset.
    Args:
        img_path (str): image path.
        prefix (str): prefix.
    """

    def __init__(self,
                 img_path,
                 imgsz=640,
                 cache=False,
                 augment=True,
                 hyp=None,
                 prefix="",
                 rect=False,
                 batch_size=None,
                 stride=32,
                 pad=0.0,
                 single_cls=False,
                 use_segments=False,
                 use_keypoints=False,
                 names=None):
        self.use_segments = use_segments
        self.use_keypoints = use_keypoints
        self.names = names
        assert not (self.use_segments and self.use_keypoints), "Can not use both segments and keypoints."
        super().__init__(img_path, imgsz, cache, augment, hyp, prefix, rect, batch_size, stride, pad, single_cls)

    def cache_labels(self, path=Path("./labels.cache")):
        # Cache dataset labels, check images and read shapes
        if path.exists():
            path.unlink()  # remove *.cache file if exists
        x = {"labels": []}
        nm, nf, ne, nc, msgs = 0, 0, 0, 0, []  # number missing, found, empty, corrupt, messages
        desc = f"{self.prefix}Scanning {path.parent / path.stem}..."
        total = len(self.im_files)
        with ThreadPool(NUM_THREADS) as pool:
            results = pool.imap(func=verify_image_label,
                                iterable=zip(self.im_files, self.label_files, repeat(self.prefix),
                                             repeat(self.use_keypoints), repeat(len(self.names))))
            pbar = tqdm(results, desc=desc, total=total, bar_format=TQDM_BAR_FORMAT)
            for im_file, lb, shape, segments, keypoint, nm_f, nf_f, ne_f, nc_f, msg in pbar:
                nm += nm_f
                nf += nf_f
                ne += ne_f
                nc += nc_f
                if im_file:
                    x["labels"].append(
                        dict(
                            im_file=im_file,
                            shape=shape,
                            cls=lb[:, 0:1],  # n, 1
                            bboxes=lb[:, 1:],  # n, 4
                            segments=segments,
                            keypoints=keypoint,
                            normalized=True,
                            bbox_format="xywh"))
                if msg:
                    msgs.append(msg)
                pbar.desc = f"{desc} {nf} images, {nm + ne} backgrounds, {nc} corrupt"
            pbar.close()

        if msgs:
            LOGGER.info("\n".join(msgs))
        x["hash"] = get_hash(self.label_files + self.im_files)
        x["results"] = nf, nm, ne, nc, len(self.im_files)
        x["msgs"] = msgs  # warnings
        x["version"] = self.cache_version  # cache version
        self.im_files = [lb["im_file"] for lb in x["labels"]]  # update im_files
        if is_dir_writeable(path.parent):
            np.save(str(path), x)  # save cache for next time
            path.with_suffix(".cache.npy").rename(path)  # remove .npy suffix
            LOGGER.info(f"{self.prefix}New cache created: {path}")
        else:
            LOGGER.warning(f"{self.prefix}WARNING ⚠️ Cache directory {path.parent} is not writeable")  # not writeable
        return x

    def get_labels(self):
        self.label_files = img2label_paths(self.im_files)
        cache_path = Path(self.label_files[0]).parent.with_suffix(".cache")
        try:
            cache, exists = np.load(str(cache_path), allow_pickle=True).item(), True  # load dict
            assert cache["version"] == self.cache_version  # matches current version
            assert cache["hash"] == get_hash(self.label_files + self.im_files)  # identical hash
        except (FileNotFoundError, AssertionError, AttributeError):
            cache, exists = self.cache_labels(cache_path), False  # run cache ops

        # Display cache
        nf, nm, ne, nc, n = cache.pop("results")  # found, missing, empty, corrupt, total
        if exists:
            d = f"Scanning {cache_path}... {nf} images, {nm + ne} backgrounds, {nc} corrupt"
            tqdm(None, desc=self.prefix + d, total=n, initial=n, bar_format=TQDM_BAR_FORMAT)  # display cache results
            if cache["msgs"]:
                LOGGER.info("\n".join(cache["msgs"]))  # display warnings

        # Read cache
        [cache.pop(k) for k in ("hash", "version", "msgs")]  # remove items
        labels = cache["labels"]

        # Check if the dataset is all boxes or all segments
        len_cls = sum(len(lb["cls"]) for lb in labels)
        len_boxes = sum(len(lb["bboxes"]) for lb in labels)
        len_segments = sum(len(lb["segments"]) for lb in labels)
        if len_segments and len_boxes != len_segments:
            LOGGER.warning(
                f"WARNING ⚠️ Box and segment counts should be equal, but got len(segments) = {len_segments}, "
                f"len(boxes) = {len_boxes}. To resolve this only boxes will be used and all segments will be removed. "
                "To avoid this please supply either a detect or segment dataset, not a detect-segment mixed dataset.")
            for lb in labels:
                lb["segments"] = []
        return labels

    # TODO: use hyp config to set all these augmentations
    def build_transforms(self, hyp=None):
        transforms = Compose([LetterBox(new_shape=(self.imgsz, self.imgsz), scaleup=False)])
        transforms.append(
            Format(bbox_format="xywh",
                   normalize=True,
                   return_mask=self.use_segments,
                   return_keypoint=self.use_keypoints,
                   batch_idx=True,
                   mask_ratio=hyp.mask_ratio,
                   mask_overlap=hyp.overlap_mask))
        return transforms

    def close_mosaic(self, hyp):
        hyp.mosaic = 0.0  # set mosaic ratio=0.0
        hyp.copy_paste = 0.0  # keep the same behavior as previous v8 close-mosaic
        hyp.mixup = 0.0  # keep the same behavior as previous v8 close-mosaic
        self.transforms = self.build_transforms(hyp)

    def update_labels_info(self, label):
        """custom your label format here"""
        # NOTE: cls is not with bboxes now, classification and semantic segmentation need an independent cls label
        # we can make it also support classification and semantic segmentation by add or remove some dict keys there.
        bboxes = label.pop("bboxes")
        segments = label.pop("segments")
        keypoints = label.pop("keypoints", None)
        bbox_format = label.pop("bbox_format")
        normalized = label.pop("normalized")
        label["instances"] = Instances(bboxes, segments, keypoints, bbox_format=bbox_format, normalized=normalized)
        return label

    @staticmethod
    def collate_fn(batch):
        new_batch = {}
        keys = batch[0].keys()
        values = list(zip(*[list(b.values()) for b in batch]))
        for i, k in enumerate(keys):
            value = values[i]
            if k == "img":
                value = torch.stack(value, 0)
            if k in ["masks", "keypoints", "bboxes", "cls"]:
                value = torch.cat(value, 0)
            new_batch[k] = value
        new_batch["batch_idx"] = list(new_batch["batch_idx"])
        for i in range(len(new_batch["batch_idx"])):
            new_batch["batch_idx"][i] += i  # add target image index for build_targets()
        new_batch["batch_idx"] = torch.cat(new_batch["batch_idx"], 0)
        return new_batch


class DFL(nn.Module):
    # Integral module of Distribution Focal Loss (DFL) proposed in Generalized Focal Loss https://ieeexplore.ieee.org/document/9792391
    def __init__(self, c1=16):
        super().__init__()
        self.conv = nn.Conv2d(c1, 1, 1, bias=False).requires_grad_(False)
        x = torch.arange(c1, dtype=torch.float)
        self.conv.weight.data[:] = nn.Parameter(x.view(1, c1, 1, 1))
        self.c1 = c1

    def forward(self, x):
        b, c, a = x.shape  # batch, channels, anchors
        return self.conv(x.view(b, 4, self.c1, a).transpose(2, 1).softmax(1)).view(
            b, 4, a
        )


def dist2bbox(distance, anchor_points, xywh=True, dim=-1):
    """Transform distance(ltrb) to box(xywh or xyxy)."""
    lt, rb = torch.split(distance, 2, dim)
    x1y1 = anchor_points - lt
    x2y2 = anchor_points + rb
    if xywh:
        c_xy = (x1y1 + x2y2) / 2
        wh = x2y2 - x1y1
        return torch.cat((c_xy, wh), dim)  # xywh bbox
    return torch.cat((x1y1, x2y2), dim)  # xyxy bbox


def post_process(x):
    dfl = DFL(16)
    anchors = torch.tensor(
        np.load(
            "./anchors.npy",
            allow_pickle=True,
        )
    )
    strides = torch.tensor(
        np.load(
            "./strides.npy",
            allow_pickle=True,
        )
    )
    box, cls = torch.cat([xi.view(x[0].shape[0], 144, -1) for xi in x], 2).split(
        (16 * 4, 80), 1
    )
    dbox = dist2bbox(dfl(box), anchors.unsqueeze(0), xywh=True, dim=1) * strides
    y = torch.cat((dbox, cls.sigmoid()), 1)
    return y, x


def smooth(y, f=0.05):
    # Box filter of fraction f
    nf = round(len(y) * f * 2) // 2 + 1  # number of filter elements (must be odd)
    p = np.ones(nf // 2)  # ones padding
    yp = np.concatenate((p * y[0], y, p * y[-1]), 0)  # y padded
    return np.convolve(yp, np.ones(nf) / nf, mode='valid')  # y-smoothed


def compute_ap(recall, precision):
    """ Compute the average precision, given the recall and precision curves
    # Arguments
        recall:    The recall curve (list)
        precision: The precision curve (list)
    # Returns
        Average precision, precision curve, recall curve
    """

    # Append sentinel values to beginning and end
    mrec = np.concatenate(([0.0], recall, [1.0]))
    mpre = np.concatenate(([1.0], precision, [0.0]))

    # Compute the precision envelope
    mpre = np.flip(np.maximum.accumulate(np.flip(mpre)))

    # Integrate area under curve
    method = 'interp'  # methods: 'continuous', 'interp'
    if method == 'interp':
        x = np.linspace(0, 1, 101)  # 101-point interp (COCO)
        ap = np.trapz(np.interp(x, mrec, mpre), x)  # integrate
    else:  # 'continuous'
        i = np.where(mrec[1:] != mrec[:-1])[0]  # points where x-axis (recall) changes
        ap = np.sum((mrec[i + 1] - mrec[i]) * mpre[i + 1])  # area under curve

    return ap, mpre, mrec


def ap_per_class(tp, conf, pred_cls, target_cls, plot=False, save_dir=Path(), names=(), eps=1e-16, prefix=""):
    """ Compute the average precision, given the recall and precision curves.
    Source: https://github.com/rafaelpadilla/Object-Detection-Metrics.
    # Arguments
        tp:  True positives (nparray, nx1 or nx10).
        conf:  Objectness value from 0-1 (nparray).
        pred_cls:  Predicted object classes (nparray).
        target_cls:  True object classes (nparray).
        plot:  Plot precision-recall curve at mAP@0.5
        save_dir:  Plot save directory
    # Returns
        The average precision as computed in py-faster-rcnn.
    """

    # Sort by objectness
    i = np.argsort(-conf)
    tp, conf, pred_cls = tp[i], conf[i], pred_cls[i]

    # Find unique classes
    unique_classes, nt = np.unique(target_cls, return_counts=True)
    nc = unique_classes.shape[0]  # number of classes, number of detections

    # Create Precision-Recall curve and compute AP for each class
    px, py = np.linspace(0, 1, 1000), []  # for plotting
    ap, p, r = np.zeros((nc, tp.shape[1])), np.zeros((nc, 1000)), np.zeros((nc, 1000))
    for ci, c in enumerate(unique_classes):
        i = pred_cls == c
        n_l = nt[ci]  # number of labels
        n_p = i.sum()  # number of predictions
        if n_p == 0 or n_l == 0:
            continue

        # Accumulate FPs and TPs
        fpc = (1 - tp[i]).cumsum(0)
        tpc = tp[i].cumsum(0)

        # Recall
        recall = tpc / (n_l + eps)  # recall curve
        r[ci] = np.interp(-px, -conf[i], recall[:, 0], left=0)  # negative x, xp because xp decreases

        # Precision
        precision = tpc / (tpc + fpc)  # precision curve
        p[ci] = np.interp(-px, -conf[i], precision[:, 0], left=1)  # p at pr_score

        # AP from recall-precision curve
        for j in range(tp.shape[1]):
            ap[ci, j], mpre, mrec = compute_ap(recall[:, j], precision[:, j])
            if plot and j == 0:
                py.append(np.interp(px, mrec, mpre))  # precision at mAP@0.5

    # Compute F1 (harmonic mean of precision and recall)
    f1 = 2 * p * r / (p + r + eps)
    names = [v for k, v in names.items() if k in unique_classes]  # list: only classes that have data
    names = dict(enumerate(names))  # to dict

    i = smooth(f1.mean(0), 0.1).argmax()  # max F1 index
    p, r, f1 = p[:, i], r[:, i], f1[:, i]
    tp = (r * nt).round()  # true positives
    fp = (tp / (p + eps) - tp).round()  # false positives
    return tp, fp, p, r, f1, ap, unique_classes.astype(int)


class Metric:

    def __init__(self) -> None:
        self.p = []  # (nc, )
        self.r = []  # (nc, )
        self.f1 = []  # (nc, )
        self.all_ap = []  # (nc, 10)
        self.ap_class_index = []  # (nc, )
        self.nc = 0

    @property
    def ap50(self):
        """AP@0.5 of all classes.
        Return:
            (nc, ) or [].
        """
        return self.all_ap[:, 0] if len(self.all_ap) else []

    @property
    def ap(self):
        """AP@0.5:0.95
        Return:
            (nc, ) or [].
        """
        return self.all_ap.mean(1) if len(self.all_ap) else []

    @property
    def mp(self):
        """mean precision of all classes.
        Return:
            float.
        """
        return self.p.mean() if len(self.p) else 0.0

    @property
    def mr(self):
        """mean recall of all classes.
        Return:
            float.
        """
        return self.r.mean() if len(self.r) else 0.0

    @property
    def map50(self):
        """Mean AP@0.5 of all classes.
        Return:
            float.
        """
        return self.all_ap[:, 0].mean() if len(self.all_ap) else 0.0

    @property
    def map75(self):
        """Mean AP@0.75 of all classes.
        Return:
            float.
        """
        return self.all_ap[:, 5].mean() if len(self.all_ap) else 0.0

    @property
    def map(self):
        """Mean AP@0.5:0.95 of all classes.
        Return:
            float.
        """
        return self.all_ap.mean() if len(self.all_ap) else 0.0

    def mean_results(self):
        """Mean of results, return mp, mr, map50, map"""
        return [self.mp, self.mr, self.map50, self.map]

    def class_result(self, i):
        """class-aware result, return p[i], r[i], ap50[i], ap[i]"""
        return self.p[i], self.r[i], self.ap50[i], self.ap[i]

    @property
    def maps(self):
        """mAP of each class"""
        maps = np.zeros(self.nc) + self.map
        for i, c in enumerate(self.ap_class_index):
            maps[c] = self.ap[i]
        return maps

    def fitness(self):
        # Model fitness as a weighted combination of metrics
        w = [0.0, 0.0, 0.1, 0.9]  # weights for [P, R, mAP@0.5, mAP@0.5:0.95]
        return (np.array(self.mean_results()) * w).sum()

    def update(self, results):
        """
        Args:
            results: tuple(p, r, ap, f1, ap_class)
        """
        self.p, self.r, self.f1, self.all_ap, self.ap_class_index = results


class DetMetrics:

    def __init__(self, save_dir=Path("."), plot=False, names=()) -> None:
        self.save_dir = save_dir
        self.plot = plot
        self.names = names
        self.box = Metric()

    def process(self, tp, conf, pred_cls, target_cls):
        results = ap_per_class(tp, conf, pred_cls, target_cls, plot=self.plot, save_dir=self.save_dir,
                               names=self.names)[2:]
        self.box.nc = len(self.names)
        self.box.update(results)

    @property
    def keys(self):
        return ["metrics/precision(B)", "metrics/recall(B)", "metrics/mAP50(B)", "metrics/mAP50-95(B)"]

    def mean_results(self):
        return self.box.mean_results()

    def class_result(self, i):
        return self.box.class_result(i)

    @property
    def maps(self):
        return self.box.maps

    @property
    def fitness(self):
        return self.box.fitness()

    @property
    def ap_class_index(self):
        return self.box.ap_class_index

    @property
    def results_dict(self):
        return dict(zip(self.keys + ["fitness"], self.mean_results() + [self.fitness]))


def increment_path(path, exist_ok=False, sep='', mkdir=False):
    """
    Increments a file or directory path, i.e. runs/exp --> runs/exp{sep}2, runs/exp{sep}3, ... etc.

    If the path exists and exist_ok is not set to True, the path will be incremented by appending a number and sep to
    the end of the path. If the path is a file, the file extension will be preserved. If the path is a directory, the
    number will be appended directly to the end of the path. If mkdir is set to True, the path will be created as a
    directory if it does not already exist.

    Args:
    path (str or pathlib.Path): Path to increment.
    exist_ok (bool, optional): If True, the path will not be incremented and will be returned as-is. Defaults to False.
    sep (str, optional): Separator to use between the path and the incrementation number. Defaults to an empty string.
    mkdir (bool, optional): If True, the path will be created as a directory if it does not exist. Defaults to False.

    Returns:
    pathlib.Path: Incremented path.
    """
    path = Path(path)  # os-agnostic
    if path.exists() and not exist_ok:
        path, suffix = (path.with_suffix(''), path.suffix) if path.is_file() else (path, '')

        # Method 1
        for n in range(2, 9999):
            p = f'{path}{sep}{n}{suffix}'  # increment path
            if not os.path.exists(p):  #
                break
        path = Path(p)

    if mkdir:
        path.mkdir(parents=True, exist_ok=True)  # make directory

    return path


def cfg2dict(cfg):
    """
    Convert a configuration object to a dictionary.

    This function converts a configuration object to a dictionary, whether it is a file path, a string, or a SimpleNamespace object.

    Inputs:
        cfg (str) or (Path) or (SimpleNamespace): Configuration object to be converted to a dictionary.

    Returns:
        cfg (dict): Configuration object in dictionary format.
    """
    if isinstance(cfg, (str, Path)):
        cfg = yaml_load(cfg)  # load dict
    elif isinstance(cfg, SimpleNamespace):
        cfg = vars(cfg)  # convert to dict
    return cfg


def get_cfg(cfg: Union[str, Path, Dict, SimpleNamespace] = None, overrides: Dict = None):
    """
    Load and merge configuration data from a file or dictionary.

    Args:
        cfg (str) or (Path) or (Dict) or (SimpleNamespace): Configuration data.
        overrides (str) or (Dict), optional: Overrides in the form of a file name or a dictionary. Default is None.

    Returns:
        (SimpleNamespace): Training arguments namespace.
    """
    cfg = cfg2dict(cfg)

    # Merge overrides
    if overrides:
        overrides = cfg2dict(overrides)
        cfg = {**cfg, **overrides}  # merge cfg and overrides dicts (prefer overrides)

    # Special handling for numeric project/names
    for k in 'project', 'name':
        if k in cfg and isinstance(cfg[k], (int, float)):
            cfg[k] = str(cfg[k])

    # Type and Value checks
    for k, v in cfg.items():
        if v is not None:  # None values may be from optional args
            if k in CFG_FLOAT_KEYS and not isinstance(v, (int, float)):
                raise TypeError(f"'{k}={v}' is of invalid type {type(v).__name__}. "
                                f"Valid '{k}' types are int (i.e. '{k}=0') or float (i.e. '{k}=0.5')")
            elif k in CFG_FRACTION_KEYS:
                if not isinstance(v, (int, float)):
                    raise TypeError(f"'{k}={v}' is of invalid type {type(v).__name__}. "
                                    f"Valid '{k}' types are int (i.e. '{k}=0') or float (i.e. '{k}=0.5')")
                if not (0.0 <= v <= 1.0):
                    raise ValueError(f"'{k}={v}' is an invalid value. "
                                     f"Valid '{k}' values are between 0.0 and 1.0.")
            elif k in CFG_INT_KEYS and not isinstance(v, int):
                raise TypeError(f"'{k}={v}' is of invalid type {type(v).__name__}. "
                                f"'{k}' must be an int (i.e. '{k}=0')")
            elif k in CFG_BOOL_KEYS and not isinstance(v, bool):
                raise TypeError(f"'{k}={v}' is of invalid type {type(v).__name__}. "
                                f"'{k}' must be a bool (i.e. '{k}=True' or '{k}=False')")

    # Return instance
    return IterableSimpleNamespace(**cfg)


def clip_boxes(boxes, shape):
    """
    It takes a list of bounding boxes and a shape (height, width) and clips the bounding boxes to the
    shape

    Args:
      boxes (torch.Tensor): the bounding boxes to clip
      shape (tuple): the shape of the image
    """
    if isinstance(boxes, torch.Tensor):  # faster individually
        boxes[..., 0].clamp_(0, shape[1])  # x1
        boxes[..., 1].clamp_(0, shape[0])  # y1
        boxes[..., 2].clamp_(0, shape[1])  # x2
        boxes[..., 3].clamp_(0, shape[0])  # y2
    else:  # np.array (faster grouped)
        boxes[..., [0, 2]] = boxes[..., [0, 2]].clip(0, shape[1])  # x1, x2
        boxes[..., [1, 3]] = boxes[..., [1, 3]].clip(0, shape[0])  # y1, y2


def scale_boxes(img1_shape, boxes, img0_shape, ratio_pad=None):
    """
    Rescales bounding boxes (in the format of xyxy) from the shape of the image they were originally specified in
    (img1_shape) to the shape of a different image (img0_shape).

    Args:
      img1_shape (tuple): The shape of the image that the bounding boxes are for, in the format of (height, width).
      boxes (torch.Tensor): the bounding boxes of the objects in the image, in the format of (x1, y1, x2, y2)
      img0_shape (tuple): the shape of the target image, in the format of (height, width).
      ratio_pad (tuple): a tuple of (ratio, pad) for scaling the boxes. If not provided, the ratio and pad will be
                         calculated based on the size difference between the two images.

    Returns:
      boxes (torch.Tensor): The scaled bounding boxes, in the format of (x1, y1, x2, y2)
    """
    if ratio_pad is None:  # calculate from img0_shape
        gain = min(img1_shape[0] / img0_shape[0], img1_shape[1] / img0_shape[1])  # gain  = old / new
        pad = (img1_shape[1] - img0_shape[1] * gain) / 2, (img1_shape[0] - img0_shape[0] * gain) / 2  # wh padding
    else:
        gain = ratio_pad[0][0]
        pad = ratio_pad[1]

    boxes[..., [0, 2]] -= pad[0]  # x padding
    boxes[..., [1, 3]] -= pad[1]  # y padding
    boxes[..., :4] /= gain
    clip_boxes(boxes, img0_shape)
    return boxes


def exif_size(img):
    # Returns exif-corrected PIL size
    s = img.size  # (width, height)
    with contextlib.suppress(Exception):
        rotation = dict(img._getexif().items())[orientation]
        if rotation in [6, 8]:  # rotation 270 or 90
            s = (s[1], s[0])
    return s


def verify_image_label(args):
    # Verify one image-label pair
    im_file, lb_file, prefix, keypoint, num_cls = args
    # number (missing, found, empty, corrupt), message, segments, keypoints
    nm, nf, ne, nc, msg, segments, keypoints = 0, 0, 0, 0, "", [], None
    try:
        # verify images
        im = Image.open(im_file)
        im.verify()  # PIL verify
        shape = exif_size(im)  # image size
        shape = (shape[1], shape[0])  # hw
        assert (shape[0] > 9) & (shape[1] > 9), f"image size {shape} <10 pixels"
        assert im.format.lower() in IMG_FORMATS, f"invalid image format {im.format}"
        if im.format.lower() in ("jpg", "jpeg"):
            with open(im_file, "rb") as f:
                f.seek(-2, 2)
        
        # verify labels
        if os.path.isfile(lb_file):
            nf = 1  # label found
            with open(lb_file) as f:
                lb = [x.split() for x in f.read().strip().splitlines() if len(x)]
                if any(len(x) > 6 for x in lb) and (not keypoint):  # is segment
                    classes = np.array([x[0] for x in lb], dtype=np.float32)
                    segments = [np.array(x[1:], dtype=np.float32).reshape(-1, 2) for x in lb]  # (cls, xy1...)
                    lb = np.concatenate((classes.reshape(-1, 1), segments2boxes(segments)), 1)  # (cls, xywh)
                lb = np.array(lb, dtype=np.float32)
            nl = len(lb)
            if nl:
                if keypoint:
                    assert lb.shape[1] == 56, "labels require 56 columns each"
                    assert (lb[:, 5::3] <= 1).all(), "non-normalized or out of bounds coordinate labels"
                    assert (lb[:, 6::3] <= 1).all(), "non-normalized or out of bounds coordinate labels"
                    kpts = np.zeros((lb.shape[0], 39))
                    for i in range(len(lb)):
                        kpt = np.delete(lb[i, 5:], np.arange(2, lb.shape[1] - 5, 3))  # remove occlusion param from GT
                        kpts[i] = np.hstack((lb[i, :5], kpt))
                    lb = kpts
                    assert lb.shape[1] == 39, "labels require 39 columns each after removing occlusion parameter"
                else:
                    assert lb.shape[1] == 5, f"labels require 5 columns, {lb.shape[1]} columns detected"
                    assert (lb[:, 1:] <= 1).all(), \
                        f"non-normalized or out of bounds coordinates {lb[:, 1:][lb[:, 1:] > 1]}"
                # All labels
                max_cls = int(lb[:, 0].max())  # max label count
                assert max_cls <= num_cls, \
                    f'Label class {max_cls} exceeds dataset class count {num_cls}. ' \
                    f'Possible class labels are 0-{num_cls - 1}'
                assert (lb >= 0).all(), f"negative label values {lb[lb < 0]}"
                _, i = np.unique(lb, axis=0, return_index=True)
                if len(i) < nl:  # duplicate row check
                    lb = lb[i]  # remove duplicates
                    if segments:
                        segments = [segments[x] for x in i]
                    msg = f"{prefix}WARNING ⚠️ {im_file}: {nl - len(i)} duplicate labels removed"
            else:
                ne = 1  # label empty
                lb = np.zeros((0, 39), dtype=np.float32) if keypoint else np.zeros((0, 5), dtype=np.float32)
        else:
            nm = 1  # label missing
            lb = np.zeros((0, 39), dtype=np.float32) if keypoint else np.zeros((0, 5), dtype=np.float32)
        if keypoint:
            keypoints = lb[:, 5:].reshape(-1, 17, 2)
        lb = lb[:, :5]
        return im_file, lb, shape, segments, keypoints, nm, nf, ne, nc, msg
    except Exception as e:
        nc = 1
        msg = f"{prefix}WARNING ⚠️ {im_file}: ignoring corrupt image/label: {e}"
        return [None, None, None, None, None, nm, nf, ne, nc, msg]