save image with a long colormap

Hi all,

I'd like to know how to save an image in matlab with colormap. For example, when I write:

imwrite(Matrix,jet,'name.png')

The image is saved with the colormap jet. So far, so good. Now say I want a longer colormap, e.g.: [jet,flipud(jet),0 0 0]. When I type:

imwrite(Matrix,[jet,flipud(jet),0 0 0],'name.png')

It returns an error massage.

Note that when I type:

colormap([jet,flipud(jet),0 0 0])

The figure is displayed with the colormap [jet,flipud(jet),0 0 0], so there's nothing wrong with the colormap. I guess it's "imwrite" that makes the troubles.

Any ideas how to solve that?

Thanks in advance!

P.S. The matrix I want to save doesn't necessarily contain integers. Usually, its elements are of type float or double.

Answer 1

[Image Analyst]

Color maps can only be 256 rows long. If you want more than that you'll have to use an RGB image, not an indexed one.

To remove a colormap from the displayed image, use a colormap of gray

colormap(gray(256));