Question

我正在使用上面的代码从灰度图像计算直方图;它工作正常。

cv::Mat imgSrc = cv::imread("Image.jpg", cv::IMREAD_UNCHANGED);
cv::Mat histogram; //Array for the histogram
int channels[] = {0}; 
int binNumArray[] = {256}; 
float intensityRanges[] = { 0, 256 }; 
const float* ranges[] = { intensityRanges };
cv::calcHist( &imgSrc, 1, channels, cv::noArray(), histogram, 1,     binNumArray, ranges, true, false) ;

在Kaehler＆amp; amp; Bradski他们称之为老式的C风格阵列＆＃34;并且他们说新风格将使用STL矢量模板，并且使用cv :: InputArrayOfArrays给出用于计算直方图的图像阵列。但是，如果我尝试通过以下方式替换通道数组：

std :: vector channels {0};

给出了编译错误。所以我的问题是： 1.如何定义＆＃39; channel＆＃39; binNumArray＆＃39;，＆＃39; intensityRanges＆＃39;的数组？使用向量？ 2.如何使用cv :: InputArrayOfArrays定义输入图像数组？

Answer 1

此示例同时显示"old" approach和"new" approach，因此您可以了解其中的区别。它基于OpenCV documentation中的示例。

＆＃34; new＆＃34; 方法只是一个方便的包装器，内部调用＆＃34; old＆＃34; 。

#include <opencv2\opencv.hpp>
#include <vector>
using namespace cv;
using namespace std;


int main()
{
    Mat3b src = imread("path_to_image");
    Mat3b hsv;
    cvtColor(src, hsv, CV_BGR2HSV);

    Mat hist;
    Mat hist2;
    {
        // Quantize the hue to 30 levels
        // and the saturation to 32 levels
        int hbins = 30, sbins = 32;
        int histSize[] = { hbins, sbins };
        // hue varies from 0 to 179, see cvtColor
        float hranges[] = { 0, 180 };
        // saturation varies from 0 (black-gray-white) to
        // 255 (pure spectrum color)
        float sranges[] = { 0, 256 };
        const float* ranges[] = { hranges, sranges };

        // we compute the histogram from the 0-th and 1-st channels
        int channels[] = { 0, 1 };
        calcHist(&hsv, 1, channels, Mat(), // do not use mask
            hist, 2, histSize, ranges,
            true, // the histogram is uniform
            false);
    }

    {
        // Quantize the hue to 30 levels
        // and the saturation to 32 levels
        vector<int> histSize = { 30, 32 };
        // hue varies from 0 to 179, see cvtColor
        // saturation varies from 0 (black-gray-white) to
        // 255 (pure spectrum color)
        vector<float> ranges = { 0, 180, 0, 256 };
        // we compute the histogram from the 0-th and 1-st channels
        vector<int> channels = { 0, 1 };

        vector<Mat> mats = { hsv };
        calcHist(mats, channels, Mat(), // do not use mask
            hist2, histSize, ranges,
            /*true, // the histogram is uniform, this is ALWAYS true*/
            false);
    }
    return 0;
}

如何使用向量设置OpenCV3 calcHist（）的参数？

1 个答案: