【OpenCV】显示HSV模型中H分量的颜色直方图

环境

• VS2015
• OpenCV3.2
  
  • 配置OpenCV请参考 Visual Studio 2015配置OpenCV环境

代码

#include "stdafx.h"
#include 
#include 
#include 
#include 

using namespace cv;
using namespace std;

/* @brief 得到H分量的直方图图像
@param src 输入图像
@param histimg 输出颜色直方图
@return void 返回值为空
*/
void getHistImg(const Mat src, Mat &histimg) {
    Mat hue, hist;

    int hsize = 16;//直方图bin的个数
    float hranges[] = { 0,180 };
    const float* phranges = hranges;

    int ch[] = { 0, 0 };
    hue.create(src.size(), src.depth());
    mixChannels(&src, 1, &hue, 1, ch, 1);//得到H分量

    calcHist(&hue, 1, 0, Mat(), hist, 1, &hsize, &phranges);

    normalize(hist, hist, 0, 255, NORM_MINMAX);

    histimg = Scalar::all(0);
    int binW = histimg.cols / hsize;
    Mat buf(1, hsize, CV_8UC3);
    for (int i = 0; i < hsize; i++)
        buf.at(i) = Vec3b(saturate_cast(i*180. / hsize), 255, 255);
    cvtColor(buf, buf, COLOR_HSV2BGR);

    for (int i = 0; i < hsize; i++)
    {
        int val = saturate_cast<int>(hist.at<float>(i)*histimg.rows / 255);
        rectangle(histimg, Point(i*binW, histimg.rows),
            Point((i + 1)*binW, histimg.rows - val),
            Scalar(buf.at(i)), -1, 8);
    }
}

int main(void)
{
    Mat src, histimg = Mat::zeros(540, 540, CV_8UC3);

    // 载入图片
    src = imread("../Da_Yuan.jpg");
    if (!src.data)
    {
        cout << "load image failed" << endl;
        return -1;
    }

    // 调用
    getHistImg(src, histimg);

    imshow("histImage", histimg);
    imshow("srcImage", src);

    waitKey(0);
    return 0;
}

结果