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''' |
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python by: youngjung uh, Clova ML, Naver |
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contact: youngjung.uh@navercorp.com |
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date: 17 Dec 2018 |
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------------------------------------------------------------------- |
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---- below comment came from the original (readFlowFile.m) ------- |
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---- below comment came from the original (writeFlowFile.m) ------- |
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------------------------------------------------------------------- |
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readFlowFile read a flow file FILENAME into 2-band image IMG |
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writeFlowFile writes a 2-band image IMG into flow file FILENAME |
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According to the c++ source code of Daniel Scharstein |
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Contact: schar@middlebury.edu |
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Author: Deqing Sun, Department of Computer Science, Brown University |
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Contact: dqsun@cs.brown.edu |
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$Date: 2007-10-31 15:36:40 (Wed, 31 Oct 2006) $ |
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Copyright 2007, Deqing Sun. |
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All Rights Reserved |
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Permission to use, copy, modify, and distribute this software and its |
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documentation for any purpose other than its incorporation into a |
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commercial product is hereby granted without fee, provided that the |
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above copyright notice appear in all copies and that both that |
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copyright notice and this permission notice appear in supporting |
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documentation, and that the name of the author and Brown University not be used in |
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advertising or publicity pertaining to distribution of the software |
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without specific, written prior permission. |
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THE AUTHOR AND BROWN UNIVERSITY DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, |
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INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR ANY |
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PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR OR BROWN UNIVERSITY BE LIABLE FOR |
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ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
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ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
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OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
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''' |
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import os |
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import numpy as np |
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from struct import pack, unpack |
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def readFlowFile(fname): |
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''' |
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args |
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fname (str) |
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return |
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flow (numpy array) numpy array of shape (height, width, 2) |
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''' |
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TAG_FLOAT = 202021.25 |
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ext = os.path.splitext(fname)[1] |
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assert len(ext) > 0, ('readFlowFile: extension required in fname %s' % fname) |
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assert ext == '.flo', exit('readFlowFile: fname %s should have extension ''.flo''' % fname) |
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try: |
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fid = open(fname, 'rb') |
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except IOError: |
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print('readFlowFile: could not open %s', fname) |
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tag = unpack('f', fid.read(4))[0] |
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width = unpack('i', fid.read(4))[0] |
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height = unpack('i', fid.read(4))[0] |
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assert tag == TAG_FLOAT, ('readFlowFile(%s): wrong tag (possibly due to big-endian machine?)' % fname) |
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assert 0 < width and width < 100000, ('readFlowFile(%s): illegal width %d' % (fname, width)) |
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assert 0 < height and height < 100000, ('readFlowFile(%s): illegal height %d' % (fname, height)) |
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nBands = 2 |
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flow = np.fromfile(fid, np.float32) |
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flow = flow.reshape(height, width, nBands) |
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fid.close() |
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return flow |
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def writeFlowFile(img, fname): |
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TAG_STRING = 'PIEH' |
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ext = os.path.splitext(fname)[1] |
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assert len(ext) > 0, ('writeFlowFile: extension required in fname %s' % fname) |
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assert ext == '.flo', exit('writeFlowFile: fname %s should have extension ''.flo''', fname) |
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height, width, nBands = img.shape |
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assert nBands == 2, 'writeFlowFile: image must have two bands' |
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try: |
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fid = open(fname, 'wb') |
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except IOError: |
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print('writeFlowFile: could not open %s', fname) |
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fid.write(bytes(TAG_STRING, 'utf-8')) |
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fid.write(pack('i', width)) |
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fid.write(pack('i', height)) |
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tmp = np.zeros((height, width*nBands), np.float32) |
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tmp[:, np.arange(width) * nBands] = img[:, :, 0] |
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tmp[:, np.arange(width) * nBands + 1] = np.squeeze(img[:, :, 1]) |
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fid.write(bytes(tmp)) |
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fid.close() |
