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.
CPS Dots Extraction
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
- Please make sure that the file is not larger than 20MByte!
- Please use PNG files as input and do not conver the scanned file into JPEG format (JPEG artifacts may destroy the tiny yellow dots)
- Using a resolution of 600 dpi results in clearly visible dots (do not use less than 300dpi)
- Depending on the size of the page, processing may take up to a minute.
You can either submit an image through the form interface, or you can
submit it programmatically through HTTP.
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):
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 'email@example.com;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.).