在OpenCV中使用calcHist（）函数的参数列表错误

Question

I'm trying to use the following code:

    cv::MatND hist;
    cv::Mat image = cv::imread("image.bmp");
    float *range = new float[33];
    int histSize = 32;
    int channel = 0;
    for (int i = 0; i < 33; ++i)
        range[i] = (float)6602.0 + 21*i;
    float **ranges = &range;
    cv::calcHist(&frame.get<0>(), 1, &channel, cv::Mat(), hist, 1, &histSize, ranges, false, false);

The image is grayscale, so I'm using the zeroth channel to get the histogram, I know the range is uniform but I wanted to know my boundaries exactly, and the image is CV_16U type (in the original code the image is read from a camera, but that's too long to include here)

My problem is that at compilation I get the following errors:

    error C2665: 'cv::calcHist' : none of the 3 overloads could convert all the argument types
    C:\opencv\build_x64\include\opencv2/imgproc/imgproc.hpp(670): could be 'void     cv::calcHist(const cv::Mat *,int,const int *,cv::InputArray,cv::OutputArray,int,const int *,const float **,bool,bool)'
    C:\opencv\build_x64\include\opencv2/imgproc/imgproc.hpp(676): or 'void cv::calcHist(const cv::Mat *,int,const int *,cv::InputArray,cv::SparseMat &,int,const int *,const float **,bool,bool)'
    while trying to match the argument list '(cv::Mat *, int, int *, cv::Mat, cv::MatND, int, int *, float **, bool, bool)'

I know its kind of silly, but I'm about to go crazy. Any help is appreciated. PS: I'm using opencv 2.4.2 on Microsoft Visual C++ express in 64-bit environment.

Best,

Baris

Answer 1

If your OpenCV version is newer than 2.3, which seems to be the case, you should know that cv::Mat and cv::MatND are combined.

But about the error, as in the new OpenCV cv::Mat can have any number of dimensions, they have changed the definition, as you can see here :

C++: void calcHist(const Mat* images, int nimages, const int* channels, InputArray mask, OutputArray hist, int dims, const int* histSize, const float** ranges, bool uniform=true, bool accumulate=false )
C++: void calcHist(const Mat* images, int nimages, const int* channels, InputArray mask, SparseMat& hist, int dims, const int* histSize, const float** ranges, bool uniform=true, bool accumulate=false )

You can also see in the brand new tutorial here , a simple cv::Mat would do the trick:

cv::Mat hist;

Using the new documentation would help you clear these things up, unfortunately most of the tutorials and codes available are based on the old OpenCV which has undertaken big changes to get to the current version.