C++使用opencv實現彩色直方圖計算

在學習opencv的時候，跑opencv官網例程的源碼出現了一個問題：

0x000007FEE09A532C (opencv_world310.dll) (XXX.exe 中)處有未經處理的異常:  0xC0000005:  讀取位置 0xFFFFFFFFFFFFFFFF 時發生訪問衝突。

查了很久才發現原來是庫的問題！！源碼如下：

#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgcodecs.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include <iostream>
#include <stdio.h>

using namespace std;
using namespace cv;
int main()
{
	Mat src, dst;
	src = imread("photo.jpg");
	if (src.empty())
	{
		return -1;
	}
	vector<Mat> bgr_planes;
	split(src, bgr_planes);
	int histSize = 256;
	float range[] = { 0, 256 };
	const float* histRange = { range };
	bool uniform = true; bool accumulate = false;
	Mat b_hist, g_hist, r_hist;
	calcHist(&bgr_planes[0], 1, 0, Mat(), b_hist, 1, &histSize, &histRange, uniform, accumulate);
	calcHist(&bgr_planes[1], 1, 0, Mat(), g_hist, 1, &histSize, &histRange, uniform, accumulate);
	calcHist(&bgr_planes[2], 1, 0, Mat(), r_hist, 1, &histSize, &histRange, uniform, accumulate);
	// Draw the histograms for B, G and R
	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(b_hist, b_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat());
	normalize(g_hist, g_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat());
	normalize(r_hist, r_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat());
	for (int i = 1; i < histSize; i++)
	{
		line(histImage, Point(bin_w*(i - 1), hist_h - cvRound(b_hist.at<float>(i - 1))),
			Point(bin_w*(i), hist_h - cvRound(b_hist.at<float>(i))),
			Scalar(255, 0, 0), 2, 8, 0);
		line(histImage, Point(bin_w*(i - 1), hist_h - cvRound(g_hist.at<float>(i - 1))),
			Point(bin_w*(i), hist_h - cvRound(g_hist.at<float>(i))),
			Scalar(0, 255, 0), 2, 8, 0);
		line(histImage, Point(bin_w*(i - 1), hist_h - cvRound(r_hist.at<float>(i - 1))),
			Point(bin_w*(i), hist_h - cvRound(r_hist.at<float>(i))),
			Scalar(0, 0, 255), 2, 8, 0);
	}
	namedWindow("calcHist Demo", WINDOW_AUTOSIZE);
	imshow("calcHist Demo", histImage);
	waitKey(0);
	return 0;
}

其實問題主要就是出在了opencv_world310.dll這個地方，因爲我是在debug模式下運行的，這個庫是release下的庫，因此引用了之後是有問題的。當時我配置的時候是兩個路徑都加在裏面，如圖：

出錯的時候直接用的第一個opencv_world310.lib，而沒有去用第二個帶d的。於是我把第一刪了，只留了第二個。在debug模式下運行，問題終於解決，成功輸出直方圖。