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NIST Stray Light Elimination Tube Prototype



Paul A. Boynton, Edward F. Kelley


Electronic projection displays involve the projection of an image, usually through a lens system, onto a viewing screen. Metrics such as light output, contrast, non-uniformity, and color gamut are used to describe the resultant image quality. although standards exist which define the methodology for these measurements, the accuracy of measuring the light output of projection display systems can be compromised by the conditions of the viewing room. Room lights directly illuminating the screen and the reflection of these light sources off of walls, floors, furniture, and other objects. Additionally, back-reflections from the projection screen must be considered. The stray-light components can contribute to the measured value, providing erroneous results. A stray-light elimination tube (SLET) was developed to remove such contamination so that the user can better evaluate the performance of the projection system independent of ambient light conditions. This report describes the design of the first prototype SLET, developed and built in June 1998, and includes some remarks about possible improvements.
NIST Interagency/Internal Report (NISTIR) - 6861
Report Number


display metrology, projection display measurements, stray light


Boynton, P. and Kelley, E. (2002), NIST Stray Light Elimination Tube Prototype, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online],, (Accessed June 16, 2024)


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Created February 28, 2002, Updated October 12, 2021