NCJ Number
171643
Date Published
1990
Length
232 pages
Annotation
This technical report describes computer enhancement of photographs.
Abstract
Because photographic evidence of a crime may require some restoration or enhancement before positive forensic information can be extracted, researchers have developed and applied computer-based procedures that can be used to reduce distortions. These procedures, which have been verified using both simulated and real forensic photographic evidence, have yielded very successful results when images are blurred because of relative motion or out-of-focus. In those cases all the information is in the image, but improperly arranged or scrambled. Excellent results can also be obtained in the enhancement of poor contrast images. This research project did not address the enhancement of images with poor spatial resolution or the restoration of video sequences. The article recommends research into the restoration of video sequences as recorded by surveillance cameras. This capability would be very useful because of the poor quality characteristic of many such systems used in banks, hotels and other buildings. Figures, appendixes, references