Method of modifying slide transparencies so as to provide uniform illumination in angular projection
US4455067A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 29, 1980 |
| Grant date | Jun 19, 1984 |
| Priority date | — |
| Expiry date | Jul 29, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B21/001
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Photography, particularly, a method of modifying slide transparencies so as to eliminate distortion and to provide uniform illumination in oblique projection, for example, upon rear view screens. The method of modifying slide transparencies includes supporting the object to be photographed at an angle with respect to the optical path of the camera; selectively illuminating the object to be photographed such that the portion farthest from the camera receives the greatest portion of the light with the rest of the object being gradually and continuously less illuminated so the portion nearest the camera receives the least light; and, taking a picture of the object, such that the transparency defines the object being photographed in trapezoidal form with the wider base being the least illuminated and the narrow apex being the greatest illuminated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.