Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!pikes!bscott From: bscott@pikes.Colorado.EDU (Ben M Scott) Newsgroups: comp.sys.amiga Subject: Re: Manipulation of Courtroom Evidence Summary: You can frame your neighbor with Digi-View! Keywords: video graphics computer alter evidence Message-ID: <3290@pikes.Colorado.EDU> Date: 16 Feb 90 10:41:33 GMT References: <102034@pyramid.pyramid.com> <4240@jhunix.HCF.JHU.EDU> Reply-To: bscott@pikes.Colorado.EDU (Ben M Scott) Organization: University of Colorado, Denver Lines: 39 In article <4240@jhunix.HCF.JHU.EDU> barrett@jhunix.UUCP (Dan Barrett) writes: >In article <102034@pyramid.pyramid.com> wniren@pyrtech (Walter Nirenberg) writes: >>...the impact of recent computer >>graphics technology advances on the use of video and photographs as >>courtroom evidence. As many of you may know, it has been possible >>over the past few years to manipulate photographs and videos at >>a bit-level using new generations of graphics computers. The results > > I own a Commodore Amiga, and indeed it is possible to retouch photos >on screen. Right now, the screen resolution of the Amiga (approx. 750 x 480 >pixels in 4096 simultaneous colors) can display stunning pictures, but I >don't know how you would get an altered screen picture back onto a photograph. >You could photograph the screen, but that might result in a great loss of Use the Polaroid Palette, a high-quality color output device that converts screen output to film or possibly slides. About $2500, but good quality. Also, there are commercial houses which will do a similar job, many even can accept Amiga-Format disks or IFF files. A very very good picture, say a Dynamic Hires/SHAM/whatever that other format from ASDG is that also offers the same thing, COULD pass for a photograph. Especially if it was digitized carefully, or scanned. However, it would not stand up to expert scrutiny; if there was any suspicion that the photo was bogus the first real close examination would clearly show it to be computer generated or re-generated. There are VERY expensive systems that, coupled with relatively low-quality film, COULD theoretically make 'perfect' pictures, but you'd need full 32-bit color (4 billion shades) and at least 2048x2048 res and VERY VERY careful digitizing to really make an undetectable picture. And this is BEFORE changes; if you went around moving things and swapping faces, it'd be almost impossible. Videotape evidence, however, would be another story. Since individual video frames are of much lower quality (the imperfections average out at 30 FPS) than a photo, changes carefully made with a good genlock could probably go undetected. And though altering photos is an old trick, not so many would suspect the relatively new technology of videotape as being altered. THERE is the danger. . <<<>>>