Setting Image Contrast Window Auto

Hello every one,

i am trying to edit the intensity or you could say the Viewing Window of a image, i am aiming to have it be done automatically rather than opening the IMTOOLS then pressing on the contrast and setting the window numbers manually. is that possible ??

thanks every one :)

Answer 1

[Sarah Wait Zaranek]

imshow will let you specify high and low when you view the image. Syntax here:

imshow(I,[low high])

If you would like to convert a matrix to a grayscale image, you can use the following.

I = mat2gray(A, [amin amax])

If you want to determine an appropriate range of that grayscale image, one of the following may be used.

• contrast will create a new gray colormap, cmap, that has an approximately equal intensity distribution. See code below.

load clown;
cmap = contrast(X);
image(X); 
colormap(cmap);

• stretchlim will find the limits to adjust (stretch) your contrast. Then you can use imadjust to adjust your image. See code below.

I = imread('pout.tif');
J = imadjust(I,stretchlim(I),[]);
imshow(I), figure, imshow(J)

• histeq will enhance contrast using histogram equalization. See code below.

I = imread('tire.tif');
J = histeq(I);
imshow(I)
figure, imshow(J)

[Amjed]

Hello sarah, ummmm well its not like that unfortunately>> you see the second step is sort off what i am want but i need to adjust the window of my data since its a MATRIX IMAGE filled with numbers ....lets say for example the data are between the -3 to 13 ... i want to have my window set between 0 to 15 .. i can do that manual with the contrast tool but i wanna have it as a code to do it automatically for me for a specific matrix

[Amjed]

I FOUND IT !! :P ... its imshow(I ,[low high]) THAT what i was looking for!! thanks anyways Sarah :)

[Brett Shoelson]

Amjed,

You understand that IMSHOW(I,[LOW, HIGH]) just modifies the display of the data, not the data itself, right? BTW, if you want automatic scaling of the display, try IMSHOW(I,[]) (empty square brackets).

Brett

[Sarah Wait Zaranek]

Thanks, Brett -- see my new answer above.

[Amjed]

SARAH.. your new answer is perfect i used the mat2gray code.. and it worked perfectly thaaaaaaaaaaaaaanks alot :) and yes imshow is a bad move since i couldnt extract it to the workspace also

[Sarah Wait Zaranek]

Great. I love that you can edit and improve the answers from feedback. Thanks for your clarification.