Development of an Accurate and Repeatable Measurement Method for Speckle in Laser Illuminated Projectors

With the emergence of lasers as a replacement for xenon arc lamps in ultra-high brightness digital projection applications, it is desirable to preserve the best possible image. Speckle is one aspect of image quality that has been fundamentally difficult to measure, due the unique physical characteristics of coherent light and the absence of a single focal plane for the speckle image. In this paper, the success criteria for a speckle measurement method are identified, and industry work to date is surveyed. The challenges of measuring low values of speckle are identified as: a large number of variables; system interaction among variables; and noise. The concept of Uniform Field Contrast Ratio (UFCR) is introduced to distinguish between Speckle Contrast Ratio (SCR) and contrast due to non-speckle noise sources that can affect SCR measurement. We expect that ultimately two different measurement methods will be needed: one optimized for low noise, and one optimized for commercial cinema installations.

Published

2014-10

Content type

Original Research

Keywords

Speckle, measurement, laser, projector, projection, illumination, SCR, UFCR

DOI

10.5594/M001585

ISBN

978-1-61482-954-6