| #!/usr/bin/env python |
| |
| import numpy as np |
| import cv2 |
| import video |
| |
| help_message = ''' |
| USAGE: opt_flow.py [<video_source>] |
| |
| Keys: |
| 1 - toggle HSV flow visualization |
| 2 - toggle glitch |
| |
| ''' |
| |
| def draw_flow(img, flow, step=16): |
| h, w = img.shape[:2] |
| y, x = np.mgrid[step/2:h:step, step/2:w:step].reshape(2,-1) |
| fx, fy = flow[y,x].T |
| lines = np.vstack([x, y, x+fx, y+fy]).T.reshape(-1, 2, 2) |
| lines = np.int32(lines + 0.5) |
| vis = cv2.cvtColor(img, cv2.COLOR_GRAY2BGR) |
| cv2.polylines(vis, lines, 0, (0, 255, 0)) |
| for (x1, y1), (x2, y2) in lines: |
| cv2.circle(vis, (x1, y1), 1, (0, 255, 0), -1) |
| return vis |
| |
| def draw_hsv(flow): |
| h, w = flow.shape[:2] |
| fx, fy = flow[:,:,0], flow[:,:,1] |
| ang = np.arctan2(fy, fx) + np.pi |
| v = np.sqrt(fx*fx+fy*fy) |
| hsv = np.zeros((h, w, 3), np.uint8) |
| hsv[...,0] = ang*(180/np.pi/2) |
| hsv[...,1] = 255 |
| hsv[...,2] = np.minimum(v*4, 255) |
| bgr = cv2.cvtColor(hsv, cv2.COLOR_HSV2BGR) |
| return bgr |
| |
| def warp_flow(img, flow): |
| h, w = flow.shape[:2] |
| flow = -flow |
| flow[:,:,0] += np.arange(w) |
| flow[:,:,1] += np.arange(h)[:,np.newaxis] |
| res = cv2.remap(img, flow, None, cv2.INTER_LINEAR) |
| return res |
| |
| if __name__ == '__main__': |
| import sys |
| print help_message |
| try: |
| fn = sys.argv[1] |
| except: |
| fn = 0 |
| |
| cam = video.create_capture(fn) |
| ret, prev = cam.read() |
| prevgray = cv2.cvtColor(prev, cv2.COLOR_BGR2GRAY) |
| show_hsv = False |
| show_glitch = False |
| cur_glitch = prev.copy() |
| |
| while True: |
| ret, img = cam.read() |
| gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY) |
| flow = cv2.calcOpticalFlowFarneback(prevgray, gray, None, 0.5, 3, 15, 3, 5, 1.2, 0) |
| prevgray = gray |
| |
| cv2.imshow('flow', draw_flow(gray, flow)) |
| if show_hsv: |
| cv2.imshow('flow HSV', draw_hsv(flow)) |
| if show_glitch: |
| cur_glitch = warp_flow(cur_glitch, flow) |
| cv2.imshow('glitch', cur_glitch) |
| |
| ch = 0xFF & cv2.waitKey(5) |
| if ch == 27: |
| break |
| if ch == ord('1'): |
| show_hsv = not show_hsv |
| print 'HSV flow visualization is', ['off', 'on'][show_hsv] |
| if ch == ord('2'): |
| show_glitch = not show_glitch |
| if show_glitch: |
| cur_glitch = img.copy() |
| print 'glitch is', ['off', 'on'][show_glitch] |
| cv2.destroyAllWindows() |
