Spearheading the speckle measurement guidelines
Since 2008, Barco has been at the forefront of laser projection development. Early on, we realized that speckle1 would be a roadblock to the adoption of laser technology in projection. With our very first high-brightness prototypes, we – together with Brussels University (VUB) – performed user testing in a cinema environment to better understand the human perception limits of laser speckle and their impact on image quality.
Curious about the results? Read the full report here.
In addition to developing patented de-speckling technologies for our projectors, we also developed an early speckle measurement procedure that rigorously quantifies laser speckle, linked to what people actually perceive in a theater setting. As a result, an objective2 speckle measurement procedure was developed in collaboration with Brussels University (VUB).
We are happy to conclude that – after a two-year effort – the LIPA Speckle Metrology Working Group (SMWG) has converged on a proposal that is very close to the original Barco-VUB procedure. This is a great recognition of the foresight of our experts who have been working on this challenge for several years now.
To be continued
But this is just the beginning. Now that there’s a speckle measurement ‘Recommended practice’ (RP) for laser projection systems in place, various industry bodies can use it to evaluate different projectors and screens, to set acceptability limits. In cooperation with the VUB, Barco contributed to the first in-depth study that links speckle measurement to user preference. One of the early Barco laser projector prototypes was used for this research and we can tell you, our projectors have only gotten better since then.
1 Speckle is the shimmering effect that you’ve seen every time you use a laser pointer. From a technical perspective, speckle is an interference pattern that occurs when coherent light is scattered off an optically rough surface, such as a screen. Since laser beams consist of coherent light, they will usually exhibit speckle. It is observed as visible ‘noise’ on a uniform area of the scene and decreases the perceived contrast of the pictures; is most visible on uniform, bright scene elements. Speckle is more visible when the viewer moves their head back and forth.
2 In this case, ‘objective’ means that the measured number corresponds to how humans perceive the speckle, and that it can be reproduced for different setups, and be used as a performance measurement for different projection and screen systems.