ARMY FOREIGN SCIENCE AND TECHNOLOGY CENTER CHARLOTTESVILLE VA
In many types of photography the image recorded on the film was not produced by rays which all pass through a common focal point. Causes of this phenomenon include the use of focal plane shutters in aerial photography from high speed aircraft, various types of lenses, scanning procedures in radar imaging, etc. The use of linear congruence constructions permits these images to be treated mathematically without introducing distortions based on the assumption of a common focal point. Author
Trans. of Geodeziya i Kartografiya (USSR) n6 p57-63 1971, by Eric Peabody.