Compute image histogram

histogram.py

def histogram(img_channel):
        #hist, _ = np.histogram(im_channele, bins = 256, range = (0, 256))
        hist = np.array([0] * 256)

        height = len(img_channel)
        width = len(img_channel[0])
        for row in range(height):
                for col in range(width):
                        hist[img_channel[row, col]] += 1

        return hist