import cv2 import math import numpy as np import random import torch from scipy import special from scipy.stats import multivariate_normal from torchvision.transforms.functional import rgb_to_grayscale # -------------------------------------------------------------------- # # --------------------------- blur kernels --------------------------- # # -------------------------------------------------------------------- # # --------------------------- util functions --------------------------- # def sigma_matrix2(sig_x, sig_y, theta): """Calculate the rotated sigma matrix (two dimensional matrix). Args: sig_x (float): sig_y (float): theta (float): Radian measurement. Returns: ndarray: Rotated sigma matrix. """ d_matrix = np.array([[sig_x**2, 0], [0, sig_y**2]]) u_matrix = np.array([[np.cos(theta), -np.sin(theta)], [np.sin(theta), np.cos(theta)]]) return np.dot(u_matrix, np.dot(d_matrix, u_matrix.T)) def mesh_grid(kernel_size): """Generate the mesh grid, centering at zero. Args: kernel_size (int): Returns: xy (ndarray): with the shape (kernel_size, kernel_size, 2) xx (ndarray): with the shape (kernel_size, kernel_size) yy (ndarray): with the shape (kernel_size, kernel_size) """ ax = np.arange(-kernel_size // 2 + 1., kernel_size // 2 + 1.) xx, yy = np.meshgrid(ax, ax) xy = np.hstack((xx.reshape((kernel_size * kernel_size, 1)), yy.reshape(kernel_size * kernel_size, 1))).reshape(kernel_size, kernel_size, 2) return xy, xx, yy def pdf2(sigma_matrix, grid): """Calculate PDF of the bivariate Gaussian distribution. Args: sigma_matrix (ndarray): with the shape (2, 2) grid (ndarray): generated by :func:`mesh_grid`, with the shape (K, K, 2), K is the kernel size. Returns: kernel (ndarrray): un-normalized kernel. """ inverse_sigma = np.linalg.inv(sigma_matrix) kernel = np.exp(-0.5 * np.sum(np.dot(grid, inverse_sigma) * grid, 2)) return kernel def cdf2(d_matrix, grid): """Calculate the CDF of the standard bivariate Gaussian distribution. Used in skewed Gaussian distribution. Args: d_matrix (ndarrasy): skew matrix. grid (ndarray): generated by :func:`mesh_grid`, with the shape (K, K, 2), K is the kernel size. Returns: cdf (ndarray): skewed cdf. """ rv = multivariate_normal([0, 0], [[1, 0], [0, 1]]) grid = np.dot(grid, d_matrix) cdf = rv.cdf(grid) return cdf def bivariate_Gaussian(kernel_size, sig_x, sig_y, theta, grid=None, isotropic=True): """Generate a bivariate isotropic or anisotropic Gaussian kernel. In the isotropic mode, only `sig_x` is used. `sig_y` and `theta` is ignored. Args: kernel_size (int): sig_x (float): sig_y (float): theta (float): Radian measurement. grid (ndarray, optional): generated by :func:`mesh_grid`, with the shape (K, K, 2), K is the kernel size. Default: None isotropic (bool): Returns: kernel (ndarray): normalized kernel. """ if grid is None: grid, _, _ = mesh_grid(kernel_size) if isotropic: sigma_matrix = np.array([[sig_x**2, 0], [0, sig_x**2]]) else: sigma_matrix = sigma_matrix2(sig_x, sig_y, theta) kernel = pdf2(sigma_matrix, grid) kernel = kernel / np.sum(kernel) return kernel def bivariate_generalized_Gaussian(kernel_size, sig_x, sig_y, theta, beta, grid=None, isotropic=True): """Generate a bivariate generalized Gaussian kernel. ``Paper: Parameter Estimation For Multivariate Generalized Gaussian Distributions`` In the isotropic mode, only `sig_x` is used. `sig_y` and `theta` is ignored. Args: kernel_size (int): sig_x (float): sig_y (float): theta (float): Radian measurement. beta (float): shape parameter, beta = 1 is the normal distribution. grid (ndarray, optional): generated by :func:`mesh_grid`, with the shape (K, K, 2), K is the kernel size. Default: None Returns: kernel (ndarray): normalized kernel. """ if grid is None: grid, _, _ = mesh_grid(kernel_size) if isotropic: sigma_matrix = np.array([[sig_x**2, 0], [0, sig_x**2]]) else: sigma_matrix = sigma_matrix2(sig_x, sig_y, theta) inverse_sigma = np.linalg.inv(sigma_matrix) kernel = np.exp(-0.5 * np.power(np.sum(np.dot(grid, inverse_sigma) * grid, 2), beta)) kernel = kernel / np.sum(kernel) return kernel def bivariate_plateau(kernel_size, sig_x, sig_y, theta, beta, grid=None, isotropic=True): """Generate a plateau-like anisotropic kernel. 1 / (1+x^(beta)) Reference: https://stats.stackexchange.com/questions/203629/is-there-a-plateau-shaped-distribution In the isotropic mode, only `sig_x` is used. `sig_y` and `theta` is ignored. Args: kernel_size (int): sig_x (float): sig_y (float): theta (float): Radian measurement. beta (float): shape parameter, beta = 1 is the normal distribution. grid (ndarray, optional): generated by :func:`mesh_grid`, with the shape (K, K, 2), K is the kernel size. Default: None Returns: kernel (ndarray): normalized kernel. """ if grid is None: grid, _, _ = mesh_grid(kernel_size) if isotropic: sigma_matrix = np.array([[sig_x**2, 0], [0, sig_x**2]]) else: sigma_matrix = sigma_matrix2(sig_x, sig_y, theta) inverse_sigma = np.linalg.inv(sigma_matrix) kernel = np.reciprocal(np.power(np.sum(np.dot(grid, inverse_sigma) * grid, 2), beta) + 1) kernel = kernel / np.sum(kernel) return kernel def random_bivariate_Gaussian(kernel_size, sigma_x_range, sigma_y_range, rotation_range, noise_range=None, isotropic=True): """Randomly generate bivariate isotropic or anisotropic Gaussian kernels. In the isotropic mode, only `sigma_x_range` is used. `sigma_y_range` and `rotation_range` is ignored. Args: kernel_size (int): sigma_x_range (tuple): [0.6, 5] sigma_y_range (tuple): [0.6, 5] rotation range (tuple): [-math.pi, math.pi] noise_range(tuple, optional): multiplicative kernel noise, [0.75, 1.25]. Default: None Returns: kernel (ndarray): """ assert kernel_size % 2 == 1, 'Kernel size must be an odd number.' assert sigma_x_range[0] < sigma_x_range[1], 'Wrong sigma_x_range.' sigma_x = np.random.uniform(sigma_x_range[0], sigma_x_range[1]) if isotropic is False: assert sigma_y_range[0] < sigma_y_range[1], 'Wrong sigma_y_range.' assert rotation_range[0] < rotation_range[1], 'Wrong rotation_range.' sigma_y = np.random.uniform(sigma_y_range[0], sigma_y_range[1]) rotation = np.random.uniform(rotation_range[0], rotation_range[1]) else: sigma_y = sigma_x rotation = 0 kernel = bivariate_Gaussian(kernel_size, sigma_x, sigma_y, rotation, isotropic=isotropic) # add multiplicative noise if noise_range is not None: assert noise_range[0] < noise_range[1], 'Wrong noise range.' noise = np.random.uniform(noise_range[0], noise_range[1], size=kernel.shape) kernel = kernel * noise kernel = kernel / np.sum(kernel) return kernel def random_bivariate_generalized_Gaussian(kernel_size, sigma_x_range, sigma_y_range, rotation_range, beta_range, noise_range=None, isotropic=True): """Randomly generate bivariate generalized Gaussian kernels. In the isotropic mode, only `sigma_x_range` is used. `sigma_y_range` and `rotation_range` is ignored. Args: kernel_size (int): sigma_x_range (tuple): [0.6, 5] sigma_y_range (tuple): [0.6, 5] rotation range (tuple): [-math.pi, math.pi] beta_range (tuple): [0.5, 8] noise_range(tuple, optional): multiplicative kernel noise, [0.75, 1.25]. Default: None Returns: kernel (ndarray): """ assert kernel_size % 2 == 1, 'Kernel size must be an odd number.' assert sigma_x_range[0] < sigma_x_range[1], 'Wrong sigma_x_range.' sigma_x = np.random.uniform(sigma_x_range[0], sigma_x_range[1]) if isotropic is False: assert sigma_y_range[0] < sigma_y_range[1], 'Wrong sigma_y_range.' assert rotation_range[0] < rotation_range[1], 'Wrong rotation_range.' sigma_y = np.random.uniform(sigma_y_range[0], sigma_y_range[1]) rotation = np.random.uniform(rotation_range[0], rotation_range[1]) else: sigma_y = sigma_x rotation = 0 # assume beta_range[0] < 1 < beta_range[1] if np.random.uniform() < 0.5: beta = np.random.uniform(beta_range[0], 1) else: beta = np.random.uniform(1, beta_range[1]) kernel = bivariate_generalized_Gaussian(kernel_size, sigma_x, sigma_y, rotation, beta, isotropic=isotropic) # add multiplicative noise if noise_range is not None: assert noise_range[0] < noise_range[1], 'Wrong noise range.' noise = np.random.uniform(noise_range[0], noise_range[1], size=kernel.shape) kernel = kernel * noise kernel = kernel / np.sum(kernel) return kernel def random_bivariate_plateau(kernel_size, sigma_x_range, sigma_y_range, rotation_range, beta_range, noise_range=None, isotropic=True): """Randomly generate bivariate plateau kernels. In the isotropic mode, only `sigma_x_range` is used. `sigma_y_range` and `rotation_range` is ignored. Args: kernel_size (int): sigma_x_range (tuple): [0.6, 5] sigma_y_range (tuple): [0.6, 5] rotation range (tuple): [-math.pi/2, math.pi/2] beta_range (tuple): [1, 4] noise_range(tuple, optional): multiplicative kernel noise, [0.75, 1.25]. Default: None Returns: kernel (ndarray): """ assert kernel_size % 2 == 1, 'Kernel size must be an odd number.' assert sigma_x_range[0] < sigma_x_range[1], 'Wrong sigma_x_range.' sigma_x = np.random.uniform(sigma_x_range[0], sigma_x_range[1]) if isotropic is False: assert sigma_y_range[0] < sigma_y_range[1], 'Wrong sigma_y_range.' assert rotation_range[0] < rotation_range[1], 'Wrong rotation_range.' sigma_y = np.random.uniform(sigma_y_range[0], sigma_y_range[1]) rotation = np.random.uniform(rotation_range[0], rotation_range[1]) else: sigma_y = sigma_x rotation = 0 # TODO: this may be not proper if np.random.uniform() < 0.5: beta = np.random.uniform(beta_range[0], 1) else: beta = np.random.uniform(1, beta_range[1]) kernel = bivariate_plateau(kernel_size, sigma_x, sigma_y, rotation, beta, isotropic=isotropic) # add multiplicative noise if noise_range is not None: assert noise_range[0] < noise_range[1], 'Wrong noise range.' noise = np.random.uniform(noise_range[0], noise_range[1], size=kernel.shape) kernel = kernel * noise kernel = kernel / np.sum(kernel) return kernel def random_mixed_kernels(kernel_list, kernel_prob, kernel_size=21, sigma_x_range=(0.6, 5), sigma_y_range=(0.6, 5), rotation_range=(-math.pi, math.pi), betag_range=(0.5, 8), betap_range=(0.5, 8), noise_range=None): """Randomly generate mixed kernels. Args: kernel_list (tuple): a list name of kernel types, support ['iso', 'aniso', 'skew', 'generalized', 'plateau_iso', 'plateau_aniso'] kernel_prob (tuple): corresponding kernel probability for each kernel type kernel_size (int): sigma_x_range (tuple): [0.6, 5] sigma_y_range (tuple): [0.6, 5] rotation range (tuple): [-math.pi, math.pi] beta_range (tuple): [0.5, 8] noise_range(tuple, optional): multiplicative kernel noise, [0.75, 1.25]. Default: None Returns: kernel (ndarray): """ kernel_type = random.choices(kernel_list, kernel_prob)[0] if kernel_type == 'iso': kernel = random_bivariate_Gaussian( kernel_size, sigma_x_range, sigma_y_range, rotation_range, noise_range=noise_range, isotropic=True) elif kernel_type == 'aniso': kernel = random_bivariate_Gaussian( kernel_size, sigma_x_range, sigma_y_range, rotation_range, noise_range=noise_range, isotropic=False) elif kernel_type == 'generalized_iso': kernel = random_bivariate_generalized_Gaussian( kernel_size, sigma_x_range, sigma_y_range, rotation_range, betag_range, noise_range=noise_range, isotropic=True) elif kernel_type == 'generalized_aniso': kernel = random_bivariate_generalized_Gaussian( kernel_size, sigma_x_range, sigma_y_range, rotation_range, betag_range, noise_range=noise_range, isotropic=False) elif kernel_type == 'plateau_iso': kernel = random_bivariate_plateau( kernel_size, sigma_x_range, sigma_y_range, rotation_range, betap_range, noise_range=None, isotropic=True) elif kernel_type == 'plateau_aniso': kernel = random_bivariate_plateau( kernel_size, sigma_x_range, sigma_y_range, rotation_range, betap_range, noise_range=None, isotropic=False) return kernel np.seterr(divide='ignore', invalid='ignore') def circular_lowpass_kernel(cutoff, kernel_size, pad_to=0): """2D sinc filter Reference: https://dsp.stackexchange.com/questions/58301/2-d-circularly-symmetric-low-pass-filter Args: cutoff (float): cutoff frequency in radians (pi is max) kernel_size (int): horizontal and vertical size, must be odd. pad_to (int): pad kernel size to desired size, must be odd or zero. """ assert kernel_size % 2 == 1, 'Kernel size must be an odd number.' kernel = np.fromfunction( lambda x, y: cutoff * special.j1(cutoff * np.sqrt( (x - (kernel_size - 1) / 2)**2 + (y - (kernel_size - 1) / 2)**2)) / (2 * np.pi * np.sqrt( (x - (kernel_size - 1) / 2)**2 + (y - (kernel_size - 1) / 2)**2)), [kernel_size, kernel_size]) kernel[(kernel_size - 1) // 2, (kernel_size - 1) // 2] = cutoff**2 / (4 * np.pi) kernel = kernel / np.sum(kernel) if pad_to > kernel_size: pad_size = (pad_to - kernel_size) // 2 kernel = np.pad(kernel, ((pad_size, pad_size), (pad_size, pad_size))) return kernel # ------------------------------------------------------------- # # --------------------------- noise --------------------------- # # ------------------------------------------------------------- # # ----------------------- Gaussian Noise ----------------------- # def generate_gaussian_noise(img, sigma=10, gray_noise=False): """Generate Gaussian noise. Args: img (Numpy array): Input image, shape (h, w, c), range [0, 1], float32. sigma (float): Noise scale (measured in range 255). Default: 10. Returns: (Numpy array): Returned noisy image, shape (h, w, c), range[0, 1], float32. """ if gray_noise: noise = np.float32(np.random.randn(*(img.shape[0:2]))) * sigma / 255. noise = np.expand_dims(noise, axis=2).repeat(3, axis=2) else: noise = np.float32(np.random.randn(*(img.shape))) * sigma / 255. return noise def add_gaussian_noise(img, sigma=10, clip=True, rounds=False, gray_noise=False): """Add Gaussian noise. Args: img (Numpy array): Input image, shape (h, w, c), range [0, 1], float32. sigma (float): Noise scale (measured in range 255). Default: 10. Returns: (Numpy array): Returned noisy image, shape (h, w, c), range[0, 1], float32. """ noise = generate_gaussian_noise(img, sigma, gray_noise) out = img + noise if clip and rounds: out = np.clip((out * 255.0).round(), 0, 255) / 255. elif clip: out = np.clip(out, 0, 1) elif rounds: out = (out * 255.0).round() / 255. return out def generate_gaussian_noise_pt(img, sigma=10, gray_noise=0): """Add Gaussian noise (PyTorch version). Args: img (Tensor): Shape (b, c, h, w), range[0, 1], float32. scale (float | Tensor): Noise scale. Default: 1.0. Returns: (Tensor): Returned noisy image, shape (b, c, h, w), range[0, 1], float32. """ b, _, h, w = img.size() if not isinstance(sigma, (float, int)): sigma = sigma.view(img.size(0), 1, 1, 1) if isinstance(gray_noise, (float, int)): cal_gray_noise = gray_noise > 0 else: gray_noise = gray_noise.view(b, 1, 1, 1) cal_gray_noise = torch.sum(gray_noise) > 0 if cal_gray_noise: noise_gray = torch.randn(*img.size()[2:4], dtype=img.dtype, device=img.device) * sigma / 255. noise_gray = noise_gray.view(b, 1, h, w) # always calculate color noise noise = torch.randn(*img.size(), dtype=img.dtype, device=img.device) * sigma / 255. if cal_gray_noise: noise = noise * (1 - gray_noise) + noise_gray * gray_noise return noise def add_gaussian_noise_pt(img, sigma=10, gray_noise=0, clip=True, rounds=False): """Add Gaussian noise (PyTorch version). Args: img (Tensor): Shape (b, c, h, w), range[0, 1], float32. scale (float | Tensor): Noise scale. Default: 1.0. Returns: (Tensor): Returned noisy image, shape (b, c, h, w), range[0, 1], float32. """ noise = generate_gaussian_noise_pt(img, sigma, gray_noise) out = img + noise if clip and rounds: out = torch.clamp((out * 255.0).round(), 0, 255) / 255. elif clip: out = torch.clamp(out, 0, 1) elif rounds: out = (out * 255.0).round() / 255. return out # ----------------------- Random Gaussian Noise ----------------------- # def random_generate_gaussian_noise(img, sigma_range=(0, 10), gray_prob=0): sigma = np.random.uniform(sigma_range[0], sigma_range[1]) if np.random.uniform() < gray_prob: gray_noise = True else: gray_noise = False return generate_gaussian_noise(img, sigma, gray_noise) def random_add_gaussian_noise(img, sigma_range=(0, 1.0), gray_prob=0, clip=True, rounds=False): noise = random_generate_gaussian_noise(img, sigma_range, gray_prob) out = img + noise if clip and rounds: out = np.clip((out * 255.0).round(), 0, 255) / 255. elif clip: out = np.clip(out, 0, 1) elif rounds: out = (out * 255.0).round() / 255. return out def random_generate_gaussian_noise_pt(img, sigma_range=(0, 10), gray_prob=0): sigma = torch.rand( img.size(0), dtype=img.dtype, device=img.device) * (sigma_range[1] - sigma_range[0]) + sigma_range[0] gray_noise = torch.rand(img.size(0), dtype=img.dtype, device=img.device) gray_noise = (gray_noise < gray_prob).float() return generate_gaussian_noise_pt(img, sigma, gray_noise) def random_add_gaussian_noise_pt(img, sigma_range=(0, 1.0), gray_prob=0, clip=True, rounds=False): noise = random_generate_gaussian_noise_pt(img, sigma_range, gray_prob) out = img + noise if clip and rounds: out = torch.clamp((out * 255.0).round(), 0, 255) / 255. elif clip: out = torch.clamp(out, 0, 1) elif rounds: out = (out * 255.0).round() / 255. return out # ----------------------- Poisson (Shot) Noise ----------------------- # def generate_poisson_noise(img, scale=1.0, gray_noise=False): """Generate poisson noise. Reference: https://github.com/scikit-image/scikit-image/blob/main/skimage/util/noise.py#L37-L219 Args: img (Numpy array): Input image, shape (h, w, c), range [0, 1], float32. scale (float): Noise scale. Default: 1.0. gray_noise (bool): Whether generate gray noise. Default: False. Returns: (Numpy array): Returned noisy image, shape (h, w, c), range[0, 1], float32. """ if gray_noise: img = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY) # round and clip image for counting vals correctly img = np.clip((img * 255.0).round(), 0, 255) / 255. vals = len(np.unique(img)) vals = 2**np.ceil(np.log2(vals)) out = np.float32(np.random.poisson(img * vals) / float(vals)) noise = out - img if gray_noise: noise = np.repeat(noise[:, :, np.newaxis], 3, axis=2) return noise * scale def add_poisson_noise(img, scale=1.0, clip=True, rounds=False, gray_noise=False): """Add poisson noise. Args: img (Numpy array): Input image, shape (h, w, c), range [0, 1], float32. scale (float): Noise scale. Default: 1.0. gray_noise (bool): Whether generate gray noise. Default: False. Returns: (Numpy array): Returned noisy image, shape (h, w, c), range[0, 1], float32. """ noise = generate_poisson_noise(img, scale, gray_noise) out = img + noise if clip and rounds: out = np.clip((out * 255.0).round(), 0, 255) / 255. elif clip: out = np.clip(out, 0, 1) elif rounds: out = (out * 255.0).round() / 255. return out def generate_poisson_noise_pt(img, scale=1.0, gray_noise=0): """Generate a batch of poisson noise (PyTorch version) Args: img (Tensor): Input image, shape (b, c, h, w), range [0, 1], float32. scale (float | Tensor): Noise scale. Number or Tensor with shape (b). Default: 1.0. gray_noise (float | Tensor): 0-1 number or Tensor with shape (b). 0 for False, 1 for True. Default: 0. Returns: (Tensor): Returned noisy image, shape (b, c, h, w), range[0, 1], float32. """ b, _, h, w = img.size() if isinstance(gray_noise, (float, int)): cal_gray_noise = gray_noise > 0 else: gray_noise = gray_noise.view(b, 1, 1, 1) cal_gray_noise = torch.sum(gray_noise) > 0 if cal_gray_noise: img_gray = rgb_to_grayscale(img, num_output_channels=1) # round and clip image for counting vals correctly img_gray = torch.clamp((img_gray * 255.0).round(), 0, 255) / 255. # use for-loop to get the unique values for each sample vals_list = [len(torch.unique(img_gray[i, :, :, :])) for i in range(b)] vals_list = [2**np.ceil(np.log2(vals)) for vals in vals_list] vals = img_gray.new_tensor(vals_list).view(b, 1, 1, 1) out = torch.poisson(img_gray * vals) / vals noise_gray = out - img_gray noise_gray = noise_gray.expand(b, 3, h, w) # always calculate color noise # round and clip image for counting vals correctly img = torch.clamp((img * 255.0).round(), 0, 255) / 255. # use for-loop to get the unique values for each sample vals_list = [len(torch.unique(img[i, :, :, :])) for i in range(b)] vals_list = [2**np.ceil(np.log2(vals)) for vals in vals_list] vals = img.new_tensor(vals_list).view(b, 1, 1, 1) out = torch.poisson(img * vals) / vals noise = out - img if cal_gray_noise: noise = noise * (1 - gray_noise) + noise_gray * gray_noise if not isinstance(scale, (float, int)): scale = scale.view(b, 1, 1, 1) return noise * scale def add_poisson_noise_pt(img, scale=1.0, clip=True, rounds=False, gray_noise=0): """Add poisson noise to a batch of images (PyTorch version). Args: img (Tensor): Input image, shape (b, c, h, w), range [0, 1], float32. scale (float | Tensor): Noise scale. Number or Tensor with shape (b). Default: 1.0. gray_noise (float | Tensor): 0-1 number or Tensor with shape (b). 0 for False, 1 for True. Default: 0. Returns: (Tensor): Returned noisy image, shape (b, c, h, w), range[0, 1], float32. """ noise = generate_poisson_noise_pt(img, scale, gray_noise) out = img + noise if clip and rounds: out = torch.clamp((out * 255.0).round(), 0, 255) / 255. elif clip: out = torch.clamp(out, 0, 1) elif rounds: out = (out * 255.0).round() / 255. return out # ----------------------- Random Poisson (Shot) Noise ----------------------- # def random_generate_poisson_noise(img, scale_range=(0, 1.0), gray_prob=0): scale = np.random.uniform(scale_range[0], scale_range[1]) if np.random.uniform() < gray_prob: gray_noise = True else: gray_noise = False return generate_poisson_noise(img, scale, gray_noise) def random_add_poisson_noise(img, scale_range=(0, 1.0), gray_prob=0, clip=True, rounds=False): noise = random_generate_poisson_noise(img, scale_range, gray_prob) out = img + noise if clip and rounds: out = np.clip((out * 255.0).round(), 0, 255) / 255. elif clip: out = np.clip(out, 0, 1) elif rounds: out = (out * 255.0).round() / 255. return out def random_generate_poisson_noise_pt(img, scale_range=(0, 1.0), gray_prob=0): scale = torch.rand( img.size(0), dtype=img.dtype, device=img.device) * (scale_range[1] - scale_range[0]) + scale_range[0] gray_noise = torch.rand(img.size(0), dtype=img.dtype, device=img.device) gray_noise = (gray_noise < gray_prob).float() return generate_poisson_noise_pt(img, scale, gray_noise) def random_add_poisson_noise_pt(img, scale_range=(0, 1.0), gray_prob=0, clip=True, rounds=False): noise = random_generate_poisson_noise_pt(img, scale_range, gray_prob) out = img + noise if clip and rounds: out = torch.clamp((out * 255.0).round(), 0, 255) / 255. elif clip: out = torch.clamp(out, 0, 1) elif rounds: out = (out * 255.0).round() / 255. return out # ------------------------------------------------------------------------ # # --------------------------- JPEG compression --------------------------- # # ------------------------------------------------------------------------ # def add_jpg_compression(img, quality=90): """Add JPG compression artifacts. Args: img (Numpy array): Input image, shape (h, w, c), range [0, 1], float32. quality (float): JPG compression quality. 0 for lowest quality, 100 for best quality. Default: 90. Returns: (Numpy array): Returned image after JPG, shape (h, w, c), range[0, 1], float32. """ img = np.clip(img, 0, 1) encode_param = [int(cv2.IMWRITE_JPEG_QUALITY), quality] _, encimg = cv2.imencode('.jpg', img * 255., encode_param) img = np.float32(cv2.imdecode(encimg, 1)) / 255. return img def random_add_jpg_compression(img, quality_range=(90, 100)): """Randomly add JPG compression artifacts. Args: img (Numpy array): Input image, shape (h, w, c), range [0, 1], float32. quality_range (tuple[float] | list[float]): JPG compression quality range. 0 for lowest quality, 100 for best quality. Default: (90, 100). Returns: (Numpy array): Returned image after JPG, shape (h, w, c), range[0, 1], float32. """ quality = np.random.uniform(quality_range[0], quality_range[1]) return add_jpg_compression(img, quality)