CPS Dots Extraction

This demo allows the user to extract the CPS dots ("tracking dots", "yellow dots") from a color laser print-out or copy. Not all color laser printers and copiers produce these patterns. After processing, a binary image is returned. If that shows many small dots in repetitive pattern, the printer used to generate the submitted output produces CPS codes.
More information CPS codes (a.k.a. tracking dots, yellow dots) can be found on the website of the Electronic Frontier Foundation

For further details please refer to:

J. van Beusekom: Optical Document Security in High Volume Office Environments, PhD Thesis


You can either submit an image through the form interface, or you can submit it programmatically through HTTP.

Form Interface

File (max. 50MByte):

Resolution [dpi]

If you do not have an image at hand or want to try some of our images, try one of these (note that results are cached, so this is faster than using a new image):

Programmatic Interface

To submit your image programmatically, you can simply POST to this URL; the image should be a parameter named "imagefile".

From the command line, you can do this using:

curl -D header.out -F 'imagefile=@input.png;type=image/png;resolution=300' http://demo-madm.dfki.uni-kl.de/line-orientation/index.php > output.png

You can also do this easily using the HTTP implementation in your favorite programming language (C#, Python, Java, Perl, etc.).