... But how? Which technical possibilities are there at all to filter
images of naked people? We are at the Technical University in
Aachen. Thomas Deselaers and Daniel Keysers have developed a software
that analyzes images for special features. T.D.: "This is the image
that shall be analyzed now. And if we now look at the positions in the
image with high probability of being skin, we can see that large
portions of the image are very bright, that is, many pixels are
probably showing skin. Then we can furthermore analyze the texture in
the image. Then the contrast. You can see that here we have a possible
approach to detect shapes." The color values; contours in relation to
each other; absolute values that the pixels can be examined for. For
example, if the program detects a specific ratio of skin color in the
image, it raises an alarm. A built-in filter could then block the
corresponding images. An example: The two researchers enter the term
"Julia" for a search in their database. First without filter. Result:
the selection also shows two adult images. Then they switch on the
nudity filter. And behold: the two images are gone in the new result.
DK: "This system is also not tailored for large databases; if you see
that for example Google offers almost one billion images and here the
largest amount of images we worked on was about 30,000; still there
are large obstacles that need to be overcome."