Reducing Cinema Projectors Power Consumption Using Global Dimming and Image Statistics

Global Dimming techniques are being employed to boost the power efficiency of digital cinema projectors. Global Dimming of a display's light source leads to power savings and improves the black level in scenes with limited bright features. Depending on the implementation, it can faithfully reproduce any content or trade accuracy for increased power savings. This article simulates the expected power savings of Global Dimming in cinema under various scenarios. Numerical findings suggest an average of ~20% power savings when faithfully reproducing content, which can drastically increase to ~55% if the top 1% of content is clipped or tone mapped. Combining limited tone-mapping with refreshing dimming only at shot intersections is promising, offering significant power savings while maintaining artifact-free rendering. However, implementing this approach faces several workflow and distribution hurdles. Combining Global Dimming and Lightsteering HDR technology, where light can be used much more efficiently, could lead to significant power savings for exhibitors.