Convertin colors to more simple colors in an image.

[googleelgoog]

Hi all,

I am developing a project and I need your advices.

We are manufacturing marble. Some people take photographs of marbles with digital camera and send it to us.

Until now, we open all images and write which kind of marble.
Every marble has its own characteristic.

For example one's characteristic is

white background and black vessels on it

the other's

orange background and grey vessels on it.

Now I trying to recognize marble kind with visual basic.

This will my future steps,

1.(which I don't know how to do it) Convert all colors to an most approximate simple color. For example
Lightskyblue= blue
Lightsteelblue= blue
.
.
.
Lightyellow = yellow
Wheat= yellow
.
.
.

How can I do it with rgb or hex values. (Or it is possible to use color palettes?)

2. (I can do it) Count every color in new image. Then sort them in most repetition in descending order. Then pick 2 or 3 top colors to define which kind of marble.


Could you please help, or have different advices?

Thank in advance.