MATLAB Central Newsreader - blue and white Logical image

blue and white Logical image

Henry Bourne — Sat, 17 Jan 2009 18:10:03 -0500

Hi guys,

I have a logical array representing an image. this was created from an rgb array using im2bw with a classification threshold set.

The logical result is correct, but when I show it on an axis (using image()) in my GUI it appears blue and white, not black and white as I'd like.

If I run the program in debug mode, and manually enter the im2bw and image() lines it appears black and white... I'm not sure what's going on!

Can anyone offer some advice? I'm using 7.6.0 R2008a. Have built the gui using the guide utility.

Thanks very much.

Re: blue and white Logical image

Sadik — Sat, 17 Jan 2009 20:56:02 -0500

"Henry Bourne" <henrybourne.remove_-_this@mac.com> wrote in message <gkt6tr$9tv$1@fred.mathworks.com>...
> Hi guys,
>
> I have a logical array representing an image. this was created from an rgb array using im2bw with a classification threshold set.
>
> The logical result is correct, but when I show it on an axis (using image()) in my GUI it appears blue and white, not black and white as I'd like.
>
> If I run the program in debug mode, and manually enter the im2bw and image() lines it appears black and white... I'm not sure what's going on!
>
> Can anyone offer some advice? I'm using 7.6.0 R2008a. Have built the gui using the guide utility.
>
> Thanks very much.

I don't know exactly but maybe you could try playing with the colormap of the figure like the following:

colormap(gray)

Because I had the same problem and the zero values were shown with dark blue.

Hope it helps.

Re: blue and white Logical image

Henry Bourne — Sun, 18 Jan 2009 01:04:02 -0500

> I don't know exactly but maybe you could try playing with the colormap of the figure like the following:
>
> colormap(gray)
>
> Because I had the same problem and the zero values were shown with dark blue.
>
> Hope it helps.

Figured it out.

It displays in black and white if I use imshow() instead of image(). Not entirely sure of the specifics why... But it works!

Thanks!