why we should use gray scale for image processing

Question

I think this can be a stupid question but after read a lot and search a lot about image processing every example I see about image processing uses gray scale to work

I u

Answer 1

As explained by John Zhang:

luminance is by far more important in distinguishing visual features

John also gives an excellent suggestion to illustrate this property: take a given image and separate the luminance plane from the chrominance planes.

To do so you can use ImageMagick separate operator that extracts the current contents of each channel as a gray-scale image:

convert myimage.gif -colorspace YCbCr -separate sep_YCbCr_%d.gif

Here's what it gives on a sample image (top-left: original color image, top-right: luminance plane, bottom row: chrominance planes):