为什么这个运动检测代码不起作用？

Question

我对opencv很陌生。我使用OpenCV 2.4.10 C++来检测运动，使用连续帧之间的差异。下面给出了我使用的代码。它的问题是，即使有运动发生，它也没有运动。就是说，diff窗口总是黑色的。你知道吗

#include "opencv2/objdetect/objdetect.hpp"
#include "opencv2/video/video.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"

#include <iostream>
#include <stdio.h>

using namespace std;
using namespace cv;
Mat diffImage(Mat t0,Mat t1,Mat t2)
{
  Mat d1,d2,motion;
  absdiff(t2, t1, d1);
  absdiff(t1, t0, d2);
  bitwise_and(d1, d2, motion);
  return motion;
}
int main()
{
    VideoCapture capture(0);
    Mat frame,prev_frame,next_frame,pbwf,bwf,nbwf;
    //capture.open( 0 );
    if ( ! capture.isOpened() ) { printf("--(!)Error opening video capture\n"); return -1; }

    capture.read(prev_frame);
    capture.read(frame);
    capture.read(next_frame);
    cvtColor(prev_frame, pbwf, cv::COLOR_BGR2GRAY);
    cvtColor(frame, bwf, CV_RGB2GRAY);
    cvtColor(next_frame, nbwf, cv::COLOR_BGR2GRAY);
    while(1)
    {
        imshow("diff",diffImage(pbwf,bwf,nbwf));
        imshow("pnwf",pbwf);
        imshow("bnwf",bwf);
        imshow("nbwf",nbwf);
        //prev_frame=frame;
       //frame=next_frame;
       pbwf=bwf;
       bwf=nbwf;
        capture.read(next_frame);
        cvtColor(next_frame, nbwf, cv::COLOR_BGR2GRAY);
        char c=waitKey(5);
        if((char)c==27)
            break;
    } 
    return 0;
}

类似的python脚本运行良好，正如预期的那样。你知道吗

import cv2

def diffImg(t0, t1, t2):
  d1 = cv2.absdiff(t2, t1)
  d2 = cv2.absdiff(t1, t0)
  return cv2.bitwise_and(d1, d2)

cam = cv2.VideoCapture(0)

winName = "Movement Indicator"
cv2.namedWindow(winName, cv2.CV_WINDOW_AUTOSIZE)

# Read three images first:
t_minus = cv2.cvtColor(cam.read()[1], cv2.COLOR_RGB2GRAY)
t = cv2.cvtColor(cam.read()[1], cv2.COLOR_RGB2GRAY)
t_plus = cv2.cvtColor(cam.read()[1], cv2.COLOR_RGB2GRAY)

while True:
  cv2.imshow( winName, diffImg(t_minus, t, t_plus) )

  # Read next image
  t_minus = t
  t = t_plus
  t_plus = cv2.cvtColor(cam.read()[1], cv2.COLOR_RGB2GRAY)

  key = cv2.waitKey(10)
  if key == 27:
    cv2.destroyWindow(winName)
    break

print "Goodbye"

谁能告诉我为什么会这样。谢谢

Answer 1

一个潜在的问题是，在Python代码中总是使用COLOR_RGB2GRAY转换，但在C代码中，这种转换和COLOR_BGR2GRAY混合使用。尝试将C代码中的所有颜色转换更改为COLOR_RGB2GRAY，看看是否有任何变化。你知道吗