for s in range (0, hist.shape[1]):
            for i in range (0, hist.shape[0], 2):                        
                #if green
                if hist[i,s] > hist[i+1,s]:
                    histimg[i,s,1] = (hist[i,s] - hist[i+1,s])

                #red
                else:
                    histimg[i,s,2] = hist[i+1,s] - hist[i,s]