Consumer demand for high image quality from LCoS based front projection systems requires that manufacturers closely control a number of different image parameters. These include display brightness, brightness uniformity, contrast ratio (sequential black and white, and checkerboard), color, color uniformity, focus uniformity, and gamma. For three channel color systems, other critical factors are convergence, color balancing and gamma correction. Detection and quantification of blemishes and pixel level defects may also be important.

Some of this testing has traditionally been performed using either fixed arrays of detectors, or by scanning a single spot photometer/colorimeter over the image area. However, neither of these techniques fully meets the needs of display manufacturers. For instance, the primary downside of a scanned spot photometer/colorimeter is slow measurement speed. And detector arrays, usually arranged in ANSI 9 or 13 point configurations, cannot adequately measure focus uniformity, or identify image blemishes and pixel defects. Also, a separate system must be used for testing each size of display produced.

Radiant Imaging offers two products specifically intended for projection system testing. The Radiant Imaging PM-PTS™ is a comprehensive, turnkey solution for measuring front projection display output parameters and identifying display defects. The PM-PTS™ consists of a PM Series™ Imaging Colorimeter mated to a specialized projection test software suite. This software controls the pattern displayed on the projector, and performs measurement and analysis of the measurement. This enables testing and calibration to be fully automated. Most importantly, the PM-PTS™ utilizes a calibration light source to map the characteristics of the projection screen or display surface, and then remove these screen related factors from the projected image prior to analysis.

The Radiant Imaging PM-DCB™ is an automated system for performing color balancing and gamma correction. It enables correction of both color and brightness variations within a display image, and allows separate corrections to be performed at different display brightness levels. Gamma correction balances the output of each color channel to ensure that displayed brightness levels match the desired gamma curve. It also allows the color temperature of the source to be corrected and maintained at any output brightness level.