C++ OpenCV直方图不'；t更新，尽管有新的视频数据

我试图为来自单通道黑白视频流的每一帧计算一个直方图。最后，我将把这些直方图的投影反馈给OpenCV的camshift函数

这是我的密码：

#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/opencv.hpp"
#include "opencv2/core/core.hpp"
#include <iostream>
#include <vector>

using namespace std;
using namespace cv;

int main(int argc, char* argv[]) {

    Mat frame, back, fore, hist, image, v_hist;
    BackgroundSubtractorMOG2 bgs;
    vector<vector<Point> > contours;
    vector<Vec4i> hierarchy;

    int bins = 8; 
    int histSize[] = { bins };
    float range[] = { 0, 255 }; //values will range from 0 to 256
    const float* histRange = { range };
    bool uniform = true, accumulate = true;

    VideoCapture cap(0);
    if (!cap.isOpened()) {
        cout << "Cannot open the video cam" << endl;
        return -1;
    }

    namedWindow("histogram",CV_WINDOW_AUTOSIZE);
    namedWindow("Foreground",CV_WINDOW_AUTOSIZE);

    for (;;) {
        if (!cap.read(frame)){
            cout << "No frame" << endl;
            break;
        }

        frame.copyTo(image);

        //***start mask computation***
        bgs.operator()(image, fore);
        bgs.getBackgroundImage(back);

        findContours(fore, contours, hierarchy, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_SIMPLE);

        int idx = 0;
        for( ; idx >= 0; idx = hierarchy[idx][0] ){
            Scalar color( 255, 255, 255 );
            drawContours( fore, contours, idx, color, CV_FILLED, 8, hierarchy );
        }

        erode(fore, fore, Mat());
        erode(fore, fore, Mat());
        dilate(fore, fore, Mat());
        dilate(fore, fore, Mat());
        //****end mask computation****

        calcHist( &fore, 1, 0, Mat(), v_hist, 1, histSize, &histRange, uniform, accumulate);

        int hist_w = 512; int hist_h = 400;
        int bin_w = cvRound( (double) hist_w/ (*histSize) );

        Mat histImage( hist_h, hist_w, CV_8UC3, Scalar(0, 0, 0) );

        normalize( v_hist, v_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );

        //draw histogram
        for (int i = 1; i < *histSize; i++)
            line ( histImage, 
            Point(bin_w*(i-1), hist_h - cvRound(v_hist.at<float>(i-1)) ),
            Point( bin_w*(i), hist_h - cvRound(v_hist.at<float>(i)) ),
            Scalar( 255, 255, 255), 2, 8, 0  );

        if(!histImage.empty()) imshow("histogram", histImage);

        if(!fore.empty()) imshow("Foreground", fore);


        if (waitKey(30) >= 0) break;

    }
    return 0;
}

#包括“opencv2/highgui/highgui.hpp”
#包括“opencv2/imgproc/imgproc.hpp”
#包括“opencv2/opencv.hpp”
#包括“opencv2/core/core.hpp”
#包括
#包括
使用名称空间std；
使用名称空间cv；
int main（int argc，char*argv[]）{
垫子框架，背部，前部，历史，图像，v_历史；
背景：MOG2 bgs；
矢量等值线；
向量层次；
int bins=8；
int histSize[]={bins}；
浮点范围[]={0，255}；//值的范围为0到256
常量浮点*histRange={range}；
布尔均匀=真，累加=真；
视频捕获上限（0）；
如果（！cap.isOpened（））{
cout虽然我还没有找到绘制的直方图没有更新的确切原因，但我已经做了一些测试，现在我确信直方图在不同帧之间发生了变化

以下是我在以前的程序中添加的代码：

//new declarations
Mat last_hist;
bool first = true;

//code is the same, leading up to...
normalize( v_hist, v_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );

if (!first){
    eq = std::equal( v_hist.begin<uchar>(), v_hist.end<uchar>(), last_hist.begin<uchar>() );
    if (eq)
        cout << "hists equal" << endl;
    else
        cout << "hists not equal" << endl;
}
else
    first = false;

//draw histogram
for (int i = 1; i < *histSize; i++)
//...

if(!frame.empty())imshow("Frame", frame);
v_hist.copyTo(last_hist);

if (waitKey(30) >= 0) break;
//from here to end is the same

//新声明
最后一次；
bool first=true；
//代码是相同的，导致。。。
规范化（v_hist，v_hist，0，histImage.rows，NORM_MINMAX，-1，Mat（））；
如果（！第一个）{
eq=std:：equal（v_hist.begin（）、v_hist.end（）、last_hist.begin（））；
if（eq）
库特