Figure display issue 'colormap(gray)'

Hi

I have created a figure by using following code. The figure attached here. I have chose colormap(gray) and surprised why the background gray color in subplot(1,3,3) is different.

figure(1),
subplot(1,3,1);
imagesc(Shot);
color=caxis; caxis(color*.005); 
colormap(gray);

subplot(1,3,2);
imagesc(Shot0);
color=caxis; caxis(color*.005); 
colormap(gray);

subplot(1,3,3);
imagesc(Shot_sub);
color=caxis; %caxis(color*.005); 
colormap(gray);

Answer 1

[Walter Roberson]

You are not doing the caxis(color*.005) in the last one.

When you do imagesc(), caxis should automatically become the range of values present in the data.

When you caxis() 0.005 times that range, you really restrict the range of mapping. If your data is positive, much of the data will turn white, unless your distribution is badly skewed (a possibility.)

In the last of the plots, you do not restrict the range to 1/200 of the value of the data, so if the data is positive, it is not going to be brightened as much as the others.

[Nisar Ahmed]

Hi Roberson,

Thank for the detail answer. See in the attached figure, when I added caxis(color*.005) in the last one how it appears (far from actual figure) but the background color still dark. How I can overcome this issue?

Please see another attached figure.

[Image Analyst]

Perhaps you would want to use imadjust() to make the image more pleasing for display.

[Walter Roberson]

Can you attach the image data for testing?

[Nisar Ahmed]

Hi Roberson,

I tried to upload data but faild as I am using tp plot a data with extention .rss.

[Shot_sub] = (ReadRSS('Pshot_sub.rss'))

[Walter Roberson]

can you attach the rss file? you will need to zip it up and attach the zip

[Nisar Ahmed]

I tried to zip it but again size is around 12 MB (gearter than 5 MB size limit) so unable to load.

[Walter Roberson]

put it up on dropbox and post the link?