Question

我已多次阅读calcHist（）的文档，但我认为我对OpenCV的经验不足以及生锈的编程技巧完全阻止我理解它。

我正在考虑计算HSV图像（Hue或channel [0]）的一个通道中的像素以进行分割，使用10个接近颜色的区域（根据类似的东西）（让我用这个作为例子，我偷了网络上的范围 - fwiw，省略紫红色似乎是错误的：

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

等等......

那么我如何使用calcHist做到这一点？

我到目前为止：

#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;
}

现在怎样？在这种情况下，calcHist的参数会是什么样的，输出直方图是什么样的？只是一个完整的1x9阵列？

非常感谢。

Answer 1

我修改了here

中的代码

您可能还想查看cvtColor here

的文档

请注意，我没有尝试编译或运行此代码，因此我不保证它会起作用。但是，它可能有用作参考。

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: %d\n", binIndex, *it);
  ++binIndex;
}
*/

OpenCV - 使用calcHist进行混淆

1 个答案: