MagickContrastStretchImage question

The MagickWand interface is a new high-level C API interface to ImageMagick core methods. We discourage the use of the core methods and encourage the use of this API instead. Post MagickWand questions, bug reports, and suggestions to this forum.
Locked
sideralarts
Posts: 1
Joined: 2013-03-07T17:15:14-07:00
Authentication code: 6789

MagickContrastStretchImage question

Post by sideralarts »

Greetings,

I am trying to contrast correct a greyscale image to get some details to appear a little sharper. Currently I create my wand and give it the following command:

Code: Select all

MagickContrastStretchImage(image_wand, 0.8, 0.9);
The reason I am posting here is no matter what values I give for the black point and the white point the image never seems to change. When I run

Code: Select all

MagickGetImageChannelRange(image_wand, GrayChannel,&min, &max);
I get that the minimum is 0 and the maximum is 65535. The image I am giving it is a .jpg and I am outputting the contrast into another .jpg file without changing any other setting in my program.

My question is am I using the function correctly? I am having a hard time getting values to give my any change at all, so any advice would be appreciated.

Locked