Speckle disturbance limit in laser-based cinema projection systems.

Guy Verschaffelt,An Jacobs,Wendy Van Den Broeck,Youri Meuret,Stijn Roelandt,Hugo Thienpont,Bram Lievens,Katriina Kilpi,Peter Janssens

doi:10.1038/srep14105

Guy Verschaffelt, An Jacobs + Show 7 more

Open Access

https://doi.org/10.1038/srep14105

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Abstract

In a multi-disciplinary effort, we investigate the level of speckle that can be tolerated in a laser cinema projector based on a quality of experience experiment with movie clips shown to a test audience in a real-life movie theatre setting. We identify a speckle disturbance threshold by statistically analyzing the observers’ responses for different values of the amount of speckle, which was monitored using a well-defined speckle measurement method. The analysis shows that the speckle perception of a human observer is not only dependent on the objectively measured amount of speckle, but it is also strongly influenced by the image content. The speckle disturbance limit for movies turns out to be substantially larger than that for still images, and hence is easier to attain.

Highlights

In a multi-disciplinary effort, we investigate the level of speckle that can be tolerated in a laser cinema projector based on a quality of experience experiment with movie clips shown to a test audience in a real-life movie theatre setting
Due to the limitations of arc lamps[1] currently used in high-end projectors, the luminance or brightness of projected cinema images is considered by many people as being too dark[2], especially for 3D cinema projection where a considerable amount of light is lost because of the filtering involved in creating separate views for each eye
We will group the participants into 4 different blocks when we perform statistical analysis of the responses. This grouping is illustrated in Fig. 1: Block 1 corresponds to all the participants seated in rows 3 to 5, Block 2 is the collection of all persons seated in rows 6 to 8, etc

Summary

Introduction

In a multi-disciplinary effort, we investigate the level of speckle that can be tolerated in a laser cinema projector based on a quality of experience experiment with movie clips shown to a test audience in a real-life movie theatre setting. Due to the limitations of arc lamps[1] currently used in high-end projectors, the luminance or brightness of projected cinema images is considered by many people as being too dark[2], especially for 3D cinema projection where a considerable amount of light is lost because of the filtering involved in creating separate views for each eye. Laser display technology is widely considered as the most promising technology for high-lumen future projection applications[2] These sources can combine a high lumen output with a very low étendue, which leads to a high optical efficiency in the projector[5]. There exist several techniques that can be used to reduce the amount of speckle[9,10,11] These techniques are based on the superposition of (partly) uncorrelated speckle patterns, which are usually generated using wavelength decorrelation, spatial decorrelation, angular decorrelation, screen movement, polarization scrambling or any combination thereof 7.

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