OpenCV -混淆使用calchrist

OpenCV - Confusion using calcHist

本文关键字：calchrist OpenCV      更新时间：2023-10-16

我已经多次阅读calcHist()的文档，但我认为我对OpenCV的缺乏经验和生锈的编程技能完全阻碍了我理解它。

我希望在HSV图像(Hue，或通道[0])的一个通道中计算像素，用于分割目的，使用10个近似颜色的箱子，根据类似的东西(让我们以此为例，我从网络上偷走了范围-流，省略紫红色似乎是错误的):

红色:0-19 &330 - 360红黄(RY): 20-49黄色:50 - 69年YG: 70 - 84绿色:85 - 170GB: 171 - 191蓝色:192 - 264英国石油(BP): 265 - 289紫色:290 - 329

等等…

那么如何使用calchrist呢?

我最远到:

#include <opencv2/opencv.hpp>
#include <vector>
#include <opencv2/highgui/highgui.hpp>
#include <iostream>
using namespace std;
using namespace cv;
int main(int argc, char *argv[])
{
    Mat scene, sceneHSV, dest, histo;
    int numImages = 1, histChannel[] = {0}, dims = 1, histSize[] = {10};
    float redRange[] = {0, 10};
    float roRange[] = {10, 25};
    float orangeRange[] = {25, 35};
    float oyRange[] = {35, 42};
    float yellowRange[] = {42, 85};
    float ygRange[] = {85, 96};
    float greenRange[] = {96, 132};
    float gbRange[] = {132, 145};
    float blueRange[] = {145, 160};
    float bpRange[] = {160, 165};
    float purpleRange[] = {165, 180};
    const float* ranges[] = {redRange, roRange, orangeRange, oyRange, yellowRange, ygRange, greenRange, gbRange, blueRange, bpRange, purpleRange};
    vector<Mat> channels;
    scene = imread("Apple.jpg", 1);
    if (scene.data == NULL)
    {
        cout<<"FAIL"<<endl;
        cin.get();
    }
    cvtColor(scene, sceneHSV, CV_BGR2HSV);
    dilate(sceneHSV, sceneHSV, Mat(), Point(-1, -1), 1, BORDER_CONSTANT, 1);
    pyrMeanShiftFiltering(sceneHSV, dest, 2, 50, 3);
    split(sceneHSV, channels); 
    calcHist(&scene, 1, histChannel, Mat(), histo, dims, histSize, ranges, false, false); 
    cout<<histo<<endl;
    waitKey(0);
    return 0;
}

现在什么?在这种情况下，calchrist的参数会是什么样子?输出的直方图会是什么样子?仅仅是一个充满整型数的1x9数组?

非常感谢。

我从这里修改了代码

你可能还想看一下cvtColor的文档

请注意，我没有尝试编译或运行这段代码，所以我不能保证它会工作。但无论如何，它可能是一个有用的参考。

Mat hist;
int nimages = 1; // Only 1 image, that is the Mat scene.
int channels[] = {0} // Index for hue channel
int dims = 1 // Only 1 channel, the hue channel
int histSize[] = {9} // 9 bins, 1 each for Red, RY, Yellow, YG etc.
float hranges[] = { 0, 180 }; // hue varies from 0 to 179, see cvtColor
const float *ranges[] = {hranges};
// Compute the histogram.
calcHist(&scene, 
nimages, 
channels, 
Mat(), // No mask
hist, dims, histSize, ranges, uniform=true)
// Now hist will contain the counts in each bin.
// Lets just print out the values. Note that you can output Mat using std::cout
cout << "Histogram: " << endl << hist << endl;
// To access the individual bins, you can either iterate over them
// or use hist.at<uchar>(i, j); Note that one of the index should be 0
// because hist is 1D histogram. Print out hist.rows and hist.cols to see if hist is a N x 1 or 1 x N matrix.
/*
MatIterator_<uchar> it, end;
int binIndex = 0;
for( it = hist.begin<uchar>(), end = hist.end<uchar>(); it != end; ++it)
{
  printf("Count in %d bin: %dn", binIndex, *it);
  ++binIndex;
}
*/
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