How to save image?

I have a set of image data which is 256x256 matrix. I display the image data using the code below;

load topomatrix;
figure;
imshow(topomatrix,'displayrange',[]);
colormap('jet');

Now, I want to save the image with full display range and colormap, anyone know how to do it, is it using IMWRITE?

imwrite(topomatrix, 'topo.jpg');

Does anyone know how to do it, thank in advance!!!

Answer 1

[Image Analyst]

You'll need to scale it and convert it to an 8 bit RGB image.

image8Bit = uint8(255 * mat2gray(topomatrix));
jetMap = jet(256);
imshow(image8bit);
colormap(jetMap);
rgbImageToSave = ind2rgb(image8Bit, jetMap);
imwrite(rgbImageToSave, 'rgbImage.png'); % Save as PNG to avoid jpeg artifacts.

[TAY]

Thank you for your help it works well. Thanks

[TAY]

hi, i have apply caxis to the colormap but when I save the image it still appear to be the same before I apply the caxis function, may I know how to solve this problem? Thank you.

[Jane]

What do we do if we have a 3d matrix instead?

[Image Analyst]

If it has 3 planes/slices then you can use imwrite(). It will just consider it a color image. If you have more planes/slices, then either save each 2-D image separately or save the 3-D image into a .mat file.