Photoshop's Auto-Levels,Contrasts / Picasa's feeling lucky

Question

would anyone be aware of a good library (free or not) to do the equivalent of Photoshop's auto contrats/levels or Picasa's feeling luckly?

I am trying to correct pictures automatically in a batch.

I tried AForge.net, which is pretty cool but gives some disastrous results (sample below)

Before: http://cmichel.net/so/before.jpg

After (Aforge): http://cmichel.net/so/After-Aforge.jpg

Best regards

Answer 1

The automatic contrast improvement is frequently done by Histogram Equalization (AKA Histogram Normalization). (usually its done on grayscale images or the Intensity channel of an HSI color model)

Keep in mind, while this is in general a good means of improving contrast, it doesnt always work. It has better performance if you did Local Histogram Eq on some images.

Decent PPT slides on topic:

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=2&ved=0CCoQFjAB&url=http%3A%2F%2Fwww.cs.bgu.ac.il%2F~klara%2FATCS111%2FIntensity%2520Transformation%2520and%2520Spatial%2520Filtering%2520-Gonzales%2520Chapter%25203.1-3.3.ppt&ei=loB0T_yPMcro0QGN7PX_Ag&usg=AFQjCNEKzlqkIsnHqTmY8xkgLBfDLplE-w&sig2=C6CrU9nWuKCXif0V8KayQg