可以在opt_flow.py的draw_flow
功能得到光流矢量(綠色箭頭)。這是我會怎麼做:
#!/usr/bin/env python
'''
example to show optical flow
USAGE: opt_flow.py [<video_source>]
Keys:
1 - toggle HSV flow visualization
2 - toggle glitch
Keys:
ESC - exit
'''
# Python 2/3 compatibility
from __future__ import print_function
import numpy as np
import math
import cv2
import video
def draw_flow(img, flow, step=16):
global arrows
h, w = img.shape[:2]
y, x = np.mgrid[step/2:h:step, step/2:w:step].reshape(2,-1).astype(int)
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:
arrows.append([x1,y1, math.sqrt((x2-x1)*(x2-x1) + (y2-y1)*(y2-y1))])
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(__doc__)
try:
fn = sys.argv[1]
except IndexError:
fn = 0
arrows = []
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
arrows.clear()
finalImg = draw_flow(gray,flow)
print(arrows)
cv2.imshow('flow', finalImg)
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 = 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()
在上面的代碼中,我保存的光流矢量(始點座標和向量長度)在全球變量arrows
像這樣:
arrows.append([x1,y1, math.sqrt((x2-x1)*(x2-x1) + (y2-y1)*(y2-y1))])
與(x1, y1)
箭頭的起點和(x2, y2)
箭頭的終點。
希望它有幫助。
首先,非常感謝你@Elouarn,這就是我想要的。我嘗試了python shell,我可以看到所有的數據出來(雖然它很重)。因爲我是編程新手,所以我可能會用更多的東西來打擾你。首先:我想要這些值,以便稍後在不同的庫(如PyOpenGL)中調用它,問題是如何分別調用每個值? arrow.x1或arrow.length ...等等。 –
要分別訪問每個值,可以用'for'循環遍歷'arrows'數組。要僅打印'x1',您可以在箭頭中使用'for [x1,y1,length]:print(x1)'或'爲arrow中的箭頭:print(箭頭[0])'。希望這是你要求的!如果我的回答對你有幫助,請考慮接受它:) –
謝謝,這又是我正在尋找的。現在我的第二個問題:如果我想在openGL中使用這些值,例如,我會說例如通過箭頭[0]組織所有這些對象的X值或者使用箭頭[3]的Z值... ...我對嗎? (對不起,我是新來的,我剛剛看到了接受的答案部分,我現在這樣做了)非常感謝你:) –