Part of the encoding process in compatable color television is
transformationof the RGB signals from the camera into a two dimensional
color space diagram with coordinates of chrominance and luminance. This is
also used in JPEG encoding. The spectral sensitivity of the camera,
projector, and eye are all different and internal compensations are
necessary to produce a satisfactory image. The range of colors that can be
reproduced in a display will depend on how deep into the red one can go
without losing brightness; same with green and blue. LCD and DLP displays
use filters with white light sources. CRTs are limited by what phosphors
will do, as are the plasma displays [which are arrays of tiny fluorescent
lamps]. Lasers produce pure colors, but there may also be limitations in how
red the red, greeen the green and blue the blue. The purity of each color
does not in itself guarantee fidelity or richness of the color display,
unless the source colors map into the extremes of the chrominance-luminance
space. One-paragraph articles about laser illuminators don't give all the
relevant data.
Mike Carrell
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As Hoyte Stearns pointed out, upcoming DLP projection televisions will use
an array of lasers instead of a bright light and color wheel. See:
http://www.technologyreview.com/NanoTech/17651/
". . . the main advantage that lasers offer over traditional projection is
an increased richness in colors, says Mooradian. The color of light
produced by a laser is, by definition, spectrally narrow, varying less
than one nanometer on either side of the peak wavelength. . . ."
The lasers should last longer than white lights, too.
- Jed
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