How to access image Data from a RGB image (3channel image) in opencv

Question

I am trying to take the imageData of image in this where w= width of image and h = height of image

for (int i = x; i < x+h; i++) //height of frame pixels
{
          


        

Answer 1

There are quite a few methods to do this (the link provided by jeff7 is very useful).

My preferred method to access image data is the cvPtr2D method. You'll want something like:

for(int x = 0; x < width; ++x)
{
    for(int y = 0; y < height; ++y)
    {
        uchar* ptr = cvPtr2D(img, y, x, NULL);
        // blue channel can now be accessed with ptr[0]
        // green channel can now be accessed with ptr[1]
        // red channel can now be accessed with ptr[2]
    }
}

(img is an IplImage* in the above code)

Not sure if this is the most efficient way of doing this etc. but I find it the easiest and simplest way of doing it.

You can find documentation for this method here.