Speckle evaluation in laser display: From speckle contrast to speckle influence degree

Speckle contrast (SC) is universally used to evaluate speckle in laser display, which has virtues of briefness in calculating and definitude in physical meaning. But the results characterized by SC is usually inconsistent with human visual perception. In this study, an alternative framework for speckle evaluation, speckle influence degree (SID), is developed. It considers the effects of SC, sampling rate, and image resolution on perceived speckle by human eyes. Theoretical analysis is firstly conducted. Then, speckle images of different sampling rate, SC, and image resolution are generated and calculated. Finally, SID is shown to be a more comprehensive metric that could characterize the influence of sampling rate and image resolution and that is better matched with subjective perception of human eyes than SC.