光流法python代码

以下是一个简单的光流法的 Python 代码示例：

import cv2

cap = cv2.VideoCapture(0)

# 获取第一帧
ret, frame1 = cap.read()

# 转换为灰度图像
prvs = cv2.cvtColor(frame1,cv2.COLOR_BGR2GRAY)

# 创建 HSV 图像以便绘制光流
hsv = np.zeros_like(frame1)
hsv[...,1] = 255

while(1):
    ret, frame2 = cap.read()
    next = cv2.cvtColor(frame2,cv2.COLOR_BGR2GRAY)

    # 计算光流
    flow = cv2.calcOpticalFlowFarneback(prvs,next,None,0.5,3,15,3,5,1.2,0)

    # 绘制光流
    mag, ang = cv2.cartToPolar(flow[...,0], flow[...,1])
    hsv[...,0] = ang*180/np.pi/2
    hsv[...,2] = cv2.normalize(mag,None,0,255,cv2.NORM_MINMAX)
    bgr = cv2.cvtColor(hsv,cv2.COLOR_HSV2BGR)

    cv2.imshow('frame2',bgr)
    k = cv2.waitKey(30) & 0xff
    if k == 27:
        break

    # 更新前一帧
    prvs = next

cap.release()
cv2.destroyAllWindows()