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Optical flow python

Trewqy Zebra answered on September 14, 2022 Popularity 7/10 Helpfulness 2/10

answer Optical flow python

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Optical flow python

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1 #!/usr/bin/env python
    2 
    3 '''
    4 Lucas-Kanade tracker
    5 ====================
    6 
    7 Lucas-Kanade sparse optical flow demo. Uses goodFeaturesToTrack
    8 for track initialization and back-tracking for match verification
    9 between frames.
   10 
   11 Usage
   12 -----
   13 lk_track.py [<video_source>]
   14 
   15 
   16 Keys
   17 ----
   18 ESC - exit
   19 '''
   20 
   21 # Python 2/3 compatibility
   22 from __future__ import print_function
   23 
   24 import numpy as np
   25 import cv2 as cv
   26 
   27 import video
   28 from common import anorm2, draw_str
   29 
   30 lk_params = dict( winSize  = (15, 15),
   31                   maxLevel = 2,
   32                   criteria = (cv.TERM_CRITERIA_EPS | cv.TERM_CRITERIA_COUNT, 10, 0.03))
   33 
   34 feature_params = dict( maxCorners = 500,
   35                        qualityLevel = 0.3,
   36                        minDistance = 7,
   37                        blockSize = 7 )
   38 
   39 class App:
   40     def __init__(self, video_src):
   41         self.track_len = 10
   42         self.detect_interval = 5
   43         self.tracks = []
   44         self.cam = video.create_capture(video_src)
   45         self.frame_idx = 0
   46 
   47     def run(self):
   48         while True:
   49             _ret, frame = self.cam.read()
   50             frame_gray = cv.cvtColor(frame, cv.COLOR_BGR2GRAY)
   51             vis = frame.copy()
   52 
   53             if len(self.tracks) > 0:
   54                 img0, img1 = self.prev_gray, frame_gray
   55                 p0 = np.float32([tr[-1] for tr in self.tracks]).reshape(-1, 1, 2)
   56                 p1, _st, _err = cv.calcOpticalFlowPyrLK(img0, img1, p0, None, **lk_params)
   57                 p0r, _st, _err = cv.calcOpticalFlowPyrLK(img1, img0, p1, None, **lk_params)
   58                 d = abs(p0-p0r).reshape(-1, 2).max(-1)
   59                 good = d < 1
   60                 new_tracks = []
   61                 for tr, (x, y), good_flag in zip(self.tracks, p1.reshape(-1, 2), good):
   62                     if not good_flag:
   63                         continue
   64                     tr.append((x, y))
   65                     if len(tr) > self.track_len:
   66                         del tr[0]
   67                     new_tracks.append(tr)
   68                     cv.circle(vis, (int(x), int(y)), 2, (0, 255, 0), -1)
   69                 self.tracks = new_tracks
   70                 cv.polylines(vis, [np.int32(tr) for tr in self.tracks], False, (0, 255, 0))
   71                 draw_str(vis, (20, 20), 'track count: %d' % len(self.tracks))
   72 
   73             if self.frame_idx % self.detect_interval == 0:
   74                 mask = np.zeros_like(frame_gray)
   75                 mask[:] = 255
   76                 for x, y in [np.int32(tr[-1]) for tr in self.tracks]:
   77                     cv.circle(mask, (x, y), 5, 0, -1)
   78                 p = cv.goodFeaturesToTrack(frame_gray, mask = mask, **feature_params)
   79                 if p is not None:
   80                     for x, y in np.float32(p).reshape(-1, 2):
   81                         self.tracks.append([(x, y)])
   82 
   83 
   84             self.frame_idx += 1
   85             self.prev_gray = frame_gray
   86             cv.imshow('lk_track', vis)
   87 
   88             ch = cv.waitKey(1)
   89             if ch == 27:
   90                 break
   91 
   92 def main():
   93     import sys
   94     try:
   95         video_src = sys.argv[1]
   96     except:
   97         video_src = 0
   98 
   99     App(video_src).run()
  100     print('Done')
  101 
  102 
  103 if __name__ == '__main__':
  104     print(__doc__)
  105     main()
  106     cv.destroyAllWindows()

Popularity 7/10 Helpfulness 2/10 Language python

Source: fossies.org

Tags: flow python

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Contributed on Sep 14 2022

Trewqy Zebra

0 Answers Avg Quality 2/10

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Optical flow python

Comment

1 #!/usr/bin/env python
    2 
    3 '''
    4 Lucas-Kanade tracker
    5 ====================
    6 
    7 Lucas-Kanade sparse optical flow demo. Uses goodFeaturesToTrack
    8 for track initialization and back-tracking for match verification
    9 between frames.
   10 
   11 Usage
   12 -----
   13 lk_track.py [<video_source>]
   14 
   15 
   16 Keys
   17 ----
   18 ESC - exit
   19 '''
   20 
   21 # Python 2/3 compatibility
   22 from __future__ import print_function
   23 
   24 import numpy as np
   25 import cv2 as cv
   26 
   27 import video
   28 from common import anorm2, draw_str
   29 
   30 lk_params = dict( winSize  = (15, 15),
   31                   maxLevel = 2,
   32                   criteria = (cv.TERM_CRITERIA_EPS | cv.TERM_CRITERIA_COUNT, 10, 0.03))
   33 
   34 feature_params = dict( maxCorners = 500,
   35                        qualityLevel = 0.3,
   36                        minDistance = 7,
   37                        blockSize = 7 )
   38 
   39 class App:
   40     def __init__(self, video_src):
   41         self.track_len = 10
   42         self.detect_interval = 5
   43         self.tracks = []
   44         self.cam = video.create_capture(video_src)
   45         self.frame_idx = 0
   46 
   47     def run(self):
   48         while True:
   49             _ret, frame = self.cam.read()
   50             frame_gray = cv.cvtColor(frame, cv.COLOR_BGR2GRAY)
   51             vis = frame.copy()
   52 
   53             if len(self.tracks) > 0:
   54                 img0, img1 = self.prev_gray, frame_gray
   55                 p0 = np.float32([tr[-1] for tr in self.tracks]).reshape(-1, 1, 2)
   56                 p1, _st, _err = cv.calcOpticalFlowPyrLK(img0, img1, p0, None, **lk_params)
   57                 p0r, _st, _err = cv.calcOpticalFlowPyrLK(img1, img0, p1, None, **lk_params)
   58                 d = abs(p0-p0r).reshape(-1, 2).max(-1)
   59                 good = d < 1
   60                 new_tracks = []
   61                 for tr, (x, y), good_flag in zip(self.tracks, p1.reshape(-1, 2), good):
   62                     if not good_flag:
   63                         continue
   64                     tr.append((x, y))
   65                     if len(tr) > self.track_len:
   66                         del tr[0]
   67                     new_tracks.append(tr)
   68                     cv.circle(vis, (int(x), int(y)), 2, (0, 255, 0), -1)
   69                 self.tracks = new_tracks
   70                 cv.polylines(vis, [np.int32(tr) for tr in self.tracks], False, (0, 255, 0))
   71                 draw_str(vis, (20, 20), 'track count: %d' % len(self.tracks))
   72 
   73             if self.frame_idx % self.detect_interval == 0:
   74                 mask = np.zeros_like(frame_gray)
   75                 mask[:] = 255
   76                 for x, y in [np.int32(tr[-1]) for tr in self.tracks]:
   77                     cv.circle(mask, (x, y), 5, 0, -1)
   78                 p = cv.goodFeaturesToTrack(frame_gray, mask = mask, **feature_params)
   79                 if p is not None:
   80                     for x, y in np.float32(p).reshape(-1, 2):
   81                         self.tracks.append([(x, y)])
   82 
   83 
   84             self.frame_idx += 1
   85             self.prev_gray = frame_gray
   86             cv.imshow('lk_track', vis)
   87 
   88             ch = cv.waitKey(1)
   89             if ch == 27:
   90                 break
   91 
   92 def main():
   93     import sys
   94     try:
   95         video_src = sys.argv[1]
   96     except:
   97         video_src = 0
   98 
   99     App(video_src).run()
  100     print('Done')
  101 
  102 
  103 if __name__ == '__main__':
  104     print(__doc__)
  105     main()
  106     cv.destroyAllWindows()

Popularity 7/10 Helpfulness 1/10 Language python

Source: fossies.org

Tags: python flow

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Contributed on Sep 14 2022

Trewqy Zebra

0 Answers Avg Quality 2/10

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