https://dev.to/sandeepbalachandran/machine-learning-convolution-with-color-images-2p41

create 3 color images from RGB bmp. R color one image,G two image , B three image.

numImgs = 3
cudnnSetTensor4dDescriptor,[input_descriptor],CUDNN_TENSOR_NHWC,CUDNN_DATA_FLOAT,\
                                   numImgs,3,[image.rows],[image.cols]
cudnnSetTensor4dDescriptor,[out_descriptor],CUDNN_TENSOR_NHWC,CUDNN_DATA_FLOAT,\
                                   numImgs,3,[image.rows],[image.cols]

copyGPUToMem 
mix 3 imgs to one rgb
save bmp colored
