OpenCV: 光流法python代码

https://blog.csdn.net/weixin_42284380/article/details/151273480

可以直接跑：

import cv2
import numpy as np
 
cap = cv2.VideoCapture('../test-1920X1080.mp4')
 
# 获取第一帧并检测特征点
ret, old_frame = cap.read()
old_gray = cv2.cvtColor(old_frame, cv2.COLOR_BGR2GRAY)
p0 = cv2.goodFeaturesToTrack(old_gray, maxCorners=100, qualityLevel=0.3, minDistance=7)
 
# 创建随机颜色用于轨迹绘制
color = np.random.randint(0, 255, (100, 3))
 
# 用于保存特征点轨迹
trajectory = [[] for _ in range(len(p0))]
 
while True:
    ret, frame = cap.read()
    if not ret:
        break
    frame_gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
 
    # 计算光流
    p1, st, err = cv2.calcOpticalFlowPyrLK(old_gray, frame_gray, p0, None)
 
    # 选择良好匹配点
    good_new = p1[st == 1]
    good_old = p0[st == 1]
 
    # 更新轨迹
    for i, (new, old) in enumerate(zip(good_new, good_old)):
        a, b = new.ravel()
        trajectory[i].append((int(a), int(b)))
 
        # 绘制轨迹
        for j in range(1, len(trajectory[i])):
            cv2.line(frame, trajectory[i][j-1], trajectory[i][j], color[i].tolist(), 2)
 
    # 显示结果
    cv2.imshow('Frame', frame)
 
    # 更新前一帧和特征点
    old_gray = frame_gray.copy()
    p0 = good_new.reshape(-1, 1, 2)
 
    if cv2.waitKey(30) & 0xff == 27:
        break
 
cap.release()
cv2.destroyAllWindows()