Saving a true color image

I created a true color image using values for RGB:

    R = 1;
    G = 0.3301;
    B = 0.9;
    truecolor_image = cat(3, R, G, B);
    filt_image = image(truecolor_image);

Now when I try to have Matlab save this image:

imwrite(filt_image, 'Filter Color.png');

All I get is a blank white pixel. Even after re-sizing to a 300 by 300 pixel image, the figure is still white and blank. How do I save this color image?

Answer 1

[Matz Johansson Bergström]

When you are calling image it returns a handle, which is a float value that you can use to modify the image in the plot window after you display it. For instance

handl = image(truecolor_image)
set(handl, 'cdata', 200)

What you are doing is writing this handle, which is a float, to a file. You want to write the actual matrix to the file. So, it is sufficient to write:

imwrite(truecolor_image, 'Filter Color.png');

[Michael]

Nice that worked well. Now would I be able to put text on top of the truecolor_image and then still save it in the same manner as well?

[Image Analyst]

No. Not unless you used the textInserter method of the Computer Vision System Toolbox. Otherwise, use export_fig.