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

See good explanation here on multiple methods for accessing pixels in an IplImage in OpenCV.

From the code you've posted your problem lies in your position variable, you'd want something like int pos = i*w*Channels + j*Channels, then you can access the RGB pixels at

unsigned char r = data->imageData[pos];

unsigned char g = data->imageData[pos+1];

unsigned char b = data->imageData[pos+2];

(assuming RGB, but on some platforms I think it can be stored BGR).