Python写一个视频车速识别代码

你好，我可以回答这个问题。以下是 Python 编写视频车速识别代码的示例：

import cv2

# 读取视频文件
cap = cv2.VideoCapture('video.mp4')

# 获取视频帧率
fps = cap.get(cv2.CAP_PROP_FPS)

# 定义车速检测函数
def detect_speed(frame1, frame2):
    # 将两帧图像转换为灰度图像
    gray1 = cv2.cvtColor(frame1, cv2.COLOR_BGR2GRAY)
    gray2 = cv2.cvtColor(frame2, cv2.COLOR_BGR2GRAY)

    # 计算两帧图像的差异
    diff = cv2.absdiff(gray1, gray2)

    # 对差异图像进行二值化处理
    thresh = cv2.threshold(diff, 25, 255, cv2.THRESH_BINARY)[1]

    # 对二值化图像进行膨胀操作
    kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (5, 5))
    dilate = cv2.dilate(thresh, kernel, iterations=3)

    # 计算车速
    contours, hierarchy = cv2.findContours(dilate, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
    for contour in contours:
        if cv2.contourArea(contour) > 1000:
            x, y, w, h = cv2.boundingRect(contour)
            cv2.rectangle(frame1, (x, y), (x + w, y + h), (0, 0, 255), 2)
            speed = w * fps / 1000 * 3.6
            cv2.putText(frame1, "Speed: {:.2f} km/h".format(speed), (x, y - 10), cv2.FONT_HERSHEY_SIMPLEX, 0.5, (0, 0, 255), 2)

    return frame1

# 读取视频帧
ret, frame1 = cap.read()
ret, frame2 = cap.read()

# 循环处理视频帧
while cap.isOpened():
    # 检测车速
    result = detect_speed(frame1, frame2)

    # 显示结果
    cv2.imshow('result', result)

    # 读取下一帧
    frame1 = frame2
    ret, frame2 = cap.read()

    # 按下 q 键退出循环
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# 释放资源
cap.release()
cv2.destroyAllWindows()

希望这个示例能够帮助你实现视频车速识别功能。