c++ - 在 C++ 中实现 matlab hist()

Question

这是我要实现的代码行

kb = [];
    for k = 1:length(nRef)
        for n=1:length(dCmpInd{k})
            x = [centroid(nRef{k}, 1), centroid(dCmpInd{k}(n),1)];
            y = [centroid(nRef{k}, 2), centroid(dCmpInd{k}(n),2)];

            [x,ind] = sort(x);
            y = y(ind);
            kb = [kb diff(y) / diff(x)];
        end
    end

    theta = (atan(kb));

    [N, X] = hist(abs(theta),2);

这是我的 C++ 代码:

 std::vector<double> kb;
    std::vector<double> theta;
    for (int k = 0; k < nRef.size(); k++)
    {
        for (int n = 0; n < dCmpInd[k].size(); n++)
        {
            double x1 = centroids[nRef[k]].m_X; double x2 = centroids[dCmpInd[k][n]].m_X;
            double y1 = centroids[nRef[k]].m_Y; double y2 = centroids[dCmpInd[k][n]].m_Y;
            if (x1 <x2)
            {
                double tempdiff = (y2-y1)/(x2-x1);              
                kb.push_back(tempdiff);
                theta.push_back(abs(atan(tempdiff)));
            }
            else
            {
                double tempdiff = (y1-y2)/(x1-x2);
                kb.push_back(tempdiff);
                theta.push_back(abs(atan(tempdiff)));
            }
        }
    }

有没有快速实现的方法:

[N,X] = hist(theta,2);

我也可以使用 openCV 2.4.10，但 calcHist() 并不完全相同，我需要创建 2 个分箱。

我的输入是一维数组:

0.00598881028540019 1.56120677124307    0.00598881028540019 0.00669537049433832 1.37723800334516    1.37723800334516    1.36424594043624    1.56120677124307    0.0152220988707370

输出是:

X= 0.394793300524817    1.17240228100365
 N = 4 5

Answer 1

calcHist 工作正常。尝试以下选择 histSize 和 range 的方法。希望能帮助到你 !。

float ary[9] = { 0.00598881028540019, 1.56120677124307,0.00598881028540019, 0.00669537049433832,1.37723800334516, 1.37723800334516, 1.36424594043624,1.56120677124307, 0.0152220988707370 };
cv::Mat srcMat = cv::Mat(1, 9, CV_32FC1, ary);
int histSize = 2;
float range[] = { 0.0, 2.0 };
const float* histRange = { range };
bool uniform = true;
bool accumulate = false;
cv::Mat histOut;
cv::calcHist(&srcMat, 1, 0, Mat(),histOut, 1, &histSize, &histRange, uniform, accumulate);
cout << histOut << endl;