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Open Source Computer Vision Library
https://opencv.org/
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38 lines
944 B
38 lines
944 B
#!/usr/bin/env python |
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''' |
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Texture flow direction estimation. |
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Sample shows how cv2.cornerEigenValsAndVecs function can be used |
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to estimate image texture flow direction. |
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Usage: |
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texture_flow.py [<image>] |
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''' |
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import numpy as np |
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import cv2 |
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if __name__ == '__main__': |
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import sys |
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try: fn = sys.argv[1] |
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except: fn = 'data/starry_night.jpg' |
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img = cv2.imread(fn) |
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gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY) |
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h, w = img.shape[:2] |
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eigen = cv2.cornerEigenValsAndVecs(gray, 15, 3) |
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eigen = eigen.reshape(h, w, 3, 2) # [[e1, e2], v1, v2] |
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flow = eigen[:,:,2] |
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vis = img.copy() |
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vis[:] = (192 + np.uint32(vis)) / 2 |
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d = 12 |
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points = np.dstack( np.mgrid[d/2:w:d, d/2:h:d] ).reshape(-1, 2) |
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for x, y in points: |
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vx, vy = np.int32(flow[y, x]*d) |
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cv2.line(vis, (x-vx, y-vy), (x+vx, y+vy), (0, 0, 0), 1, cv2.CV_AA) |
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cv2.imshow('input', img) |
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cv2.imshow('flow', vis) |
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cv2.waitKey()
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