'OpenCV C# iterate Mat object like C++

I'm trying to follow a tutorial of OpenCV which is written in C++ but I need to write it in C#. This works quite ok so far. As I'm not a C++ developer and not. familiar with the language I came to a point now where I struggle a bit and where I'm not sure if what I did is the equivalent to the C++ version.

This is the code in C++

vector<Point> pointsOfInterest;
Mat_<uchar>::iterator itMask = mask.begin<uchar>();
Mat_<uchar>::iterator end = mask.end<uchar>();
for( ; itMask!=end; ++itMask)
    if(*itMask==255)
        pointsOfInterest.push_back(itMask.pos());

What I read here is a loop, that iterates over the whole Mat and checks if the value at position is 255 and if so, it adds the point to the end of the pointsOfInterest list.

So I guess this means every x,y pixel in the Mat is checked for the value. My equivalent in C# looks like this:

List<Point> pointsOfInterest = new List<Point>();
for(int x = 0;x<mask.Cols;x++)
{
    for(int y=0;y<mask.Rows; y++)
    {
        if (mask.At<int>(x, y) == 255)
            pointsOfInterest.Add(new Point(x, y));
    }
}

but the result I'm getting is not as expected that's why I wonder if this part is really correct? Sometimes the mask.At throws a NullPointer as well which is strange. I'm also wondering that the C++ just iterates a one dimensional array (I think at least) meanwhile C# would need 2-Dimensions.

Can someone confirm that it is the same or does someone know what is wrong and needs to be adjusted?

c++sharpc++opencvmatrix


Solution 1:[1]

I have also found out that changing the x and y, for the img.At(y,x) , will solve the exception and you will get the points in your list.

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