Is there a a function/code which can make the darker bits darker and the lighter bits lighter?

just a random image I found on google. Is it possible to make the black parts (crack) darker and the background (concrete) lighter?

Answer 1

[Matz Johansson Bergström]

If you have the image processing toolbox you can use imcontrast. http://www.mathworks.se/help/images/ref/imcontrast.html

Answer 2

[Iain]

Yup.

Calculate the difference from the image's mid level (128 probably, but this depends on how you're dealing with the image), and multiply it by a number greater than 1. Add that difference back to the mid level.

[Duncan]

do you have any links or info about doing this?

thanks

[Iain]

 Adjusted_Contrast = (Image - meanlevel) * scale;
 Adjusted_Image = meanlevel + Adjusted_Contrast;

You need to change data types & values of mean level & scale, as you need.

Answer 3

[Image Analyst]

You can use imadjust() or just pass in the range you want to see into imshow().