colored image to greyscale image using CUDA parallel processing

Question

I am trying to solve a problem in which i am supposed to change a colour image to a greyscale image. For this purpose i am using CUDA parallel approach.

The kerne code i

Answer 1

the calculation of absolute x & y image positions is perfect. but when u need to access that particular pixel in the coloured image , shouldn't you u use the following code??

uchar4 rgba = rgbaImage[absolute_image_position_x + (absolute_image_position_y * numCols)];

I thought so, when comparing it to a code you'd write to execute the same problem in serial code. Please let me know :)