The Use of Logarithmic and Density Units for Pixels
The use of logarithmic representation for pixel data may provide maximum flexibility in several areas. The logarithmic representation seems to be an optimum coding for digital brightness representation and also allows easy conversion to and from the linear brightness domain, which is necessary for proper spatial filtering. The ability to provide latitude by simply “sliding” up and down the logarithmic curve can also provide the crucial capability to print-up or print-down or color-correct scenes after initial capture. Density units are a natural analogy to logarithmic units for digital input scanning of motion-picture film. The film itself, however, will have introduced a toe and shoulder to the dark and light parts of the image. The natural relationship between film density and logarithmic units, as well as the ability to provide latitude and correction capabilities, makes the logarithmic pixel representation a significant candidate for high-definition television (HDTV) and computer graphics.
- Print ISSN
- 0036-1682
- Published
- 1991-10
- Content type
- Original Research
- DOI
- 10.5594/J02429