Donald James Lynn, was an image analyst at the Jet Propulsion Laboratory in Pasadena, California.
An excerpt from the British Society for the Turin Shroud Newsletter by historian Ian Wilson reads:
Back in 1976 Don Lynn and his colleague Jean Lorre were employed at the Image Processing Laboratory of the Jet Propulsion Laboratory, Pasadena. At that time they were working on analysing and enhancing the images that the Viking Lander mission had been sending back from the surface of Mars. Because the techniques they were using seemed applicable to the Shroud, they were approached by the then still embryonic STURP project, leading to Don taking up a strong interest in the Shroud that would never wane. The Jet Propulsion Laboratory allowed Don and his colleague to use the Laboratory's equipment for Shroud research, just so long as the work was done in their own time. Despite intense pressure of work on the Mars images, within months Don became a participant at the Shroud conference held in Albuquerque, New Mexico, March 1977. His special contribution to Shroud studies was to show, via the then very new method of digitizing photographic images, that the Shroud's image has none of the directionality, such as left and right-hand brush-strokes, readily evident whenever paintings are studied by the same methods. Comments by him during a discussion filmed at the time of that same conference formed part of a key scene in the closing moments of David Rolfe's 1977 Shroud documentary, "The Silent Witness." He and his wife Patti attended the recent Orvieto Congress in Italy and went on to Turin to view the Shroud together.
An article at a NASA website, "How Image Enhancement May Explain Past Events" is very informative.