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Stray light compensation in small area contrast measurements of projection displays



Paul A. Boynton, Edward F. Kelley


The accurate measurement of small area black levels is important in projection display characterization. For example, techniques can be used to determine resolution of projection systems by measuring the contrast of alternating grill patterns or fully-modulated sine waves of various spatial frequencies. Unfortunately, the measurement of the contrast of these patterns may be influenced by stray light, either from ambient and reflected light in the environment, or from veiling glare scatter in the lens of the light-measuring device. Such stray-light corruption can lead to large errors in contrast determination, providing an inaccurate characterization of the projector. For large-area measurements, various techniques have been employed, including the use of frustums and masks, to minimize such unwanted effects and provide a more accurate measurement. With some modifications, these same tools may be used for small-area measurements with similar results. The design, construction, and implementation of these tools will be discussed. Results will be shown comparing small-area contrast measurements of projection systems, including resolution determination, with and without stray light compensation, for different measurement instrumentation.
Proceedings Title
Proc. Intl. Soc. for Optical Engineering (SPIE)
Conference Dates
January 23-24, 2002
Conference Location
San Jose, CA, USA
Conference Title
Projection Display VIII


projection displays, replica mask, resolution, small area contrast, stray light, display measurement


Boynton, P. and Kelley, E. (2002), Stray light compensation in small area contrast measurements of projection displays, Proc. Intl. Soc. for Optical Engineering (SPIE), San Jose, CA, USA, [online], (Accessed April 13, 2024)
Created January 22, 2002, Updated October 12, 2021