Obtaining the maxvalue on a dicom colormap programatically

while using

    [dicom_data,color_map] = dicomread('dicomfile.dcm');

I get this as color_map:

    []

and running max(color_map) return the same.

If I examine the the image via the colormap editor I can find that the ColorDataMax is 3627 on one dicom image and 2627 on another.

new_colormap = gray(3627)

works fine on one image and

new_colormap = gray(2627)

on the other, but I want to expand the colormap programmatically without losing info, so I need to know what's the top gray value on each colormap.

How can I do this?

Answer 1

[Image Analyst]

The max gray levels are 3627 and 2627. But I don't know what your plans are for new_colormap. You can't have more than 256 gray levels if you want to display the image and use a gray scale colormap.

[Antonio]

http://imageshack.us/photo/my-images/802/gray3627.png/

http://imageshack.us/photo/my-images/198/gray256.png/

Sorry, I may have phrased this ambiguously,I know the top levels are those, but I got them via the colormap editor. I want to know how to get them via the program, that means, without using the colormap editor.

Also, I don't understand what you say about the 256 gray levels. Using gray(256) as a colormap damages my image, but using gray(3627) does not (in the case of the image with that top intensity).

[Image Analyst]

You can get the max and min this way:

minValue = min(dicom_data(:));
maxValue = max(dicom_data(:));

Depends on how you're displaying the image (like if you're using [] or not in imshow) -- but use whatever colormap works for you.