The log transformation is very useful when we need to compress or stretch a certain range of gray-levels in an image; for example, in order to display the Fourier spectrum (where the DC component value is much higher than the others, so that without the log transform the other frequency components almost always cannot even be seen). The point transformation function for a log transform is of the general form,
, where c is a constant.
Let's implement the histogram for the color channels of the input image:
def plot_image(image, title=''): pylab.title(title, size=20), pylab.imshow(image) pylab.axis('off') # comment this line if ...
