Projector Tone Map Adjustment for Luminance Matching
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Solution Overview
Problem
Projectors face challenges in performing HDR displays with absolute luminance due to varying projection surface luminance, leading to unnecessary light emission and reduced light source life, as existing solutions do not account for the relationship between maximum image data luminance and projection surface luminance.
Innovation Solution
A projector system that includes a spatial light modulator, tone map unit, projection lens, luminance acquiring unit, and control unit, which adjusts the tone map and light source output based on the projection surface's maximum luminance to match the input video data's maximum luminance, reducing light emission when the projection surface luminance exceeds the image data's maximum luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the projector emits light at maximum intensity to ensure HDR display quality, then the luminance display quality is improved, but the light source life is reduced
Solution Approach 1:
The system dynamically adjusts the light source intensity parameter based on the actual projection surface luminance characteristics. By changing the operating parameters of the light source according to measured conditions rather than maintaining fixed maximum intensity, the system achieves optimal display quality while reducing unnecessary light emission that would otherwise shorten light source life.
Solution Approach 2:
The system incorporates a feedback mechanism where the luminance acquiring unit measures the actual projection surface luminance and feeds this information back to the control unit. The control unit then adjusts the light source intensity accordingly, creating a closed-loop control system that prevents excessive light emission and extends light source life while maintaining display quality.
2Device complexity
If the projector uses a fixed tone map for HDR display, then the processing simplicity is maintained, but the adaptability to varying projection situations is reduced
Solution Approach 1:
The system transitions from a static fixed tone map approach to a dynamic adaptive tone map generation approach. The tone map is no longer fixed but is generated in real-time based on measured projection surface luminance characteristics, allowing the system to adapt to varying projection situations such as different screen types, projection distances, and environmental conditions.
Solution Approach 2:
The system changes the parameters of the tone map based on measured projection conditions. By adjusting tone map parameters according to the actual luminance characteristics of the projection surface, the system achieves adaptability to different projection situations while maintaining reasonable processing complexity through algorithmic generation rather than exhaustive lookup tables.
3Device complexity
If the projector does not adjust light output based on projection surface luminance, then the device complexity is reduced, but the energy efficiency is worsened
Solution Approach 1:
The system implements a feedback control mechanism where the luminance acquiring unit continuously monitors the projection surface luminance and feeds this information to the control unit. This feedback loop enables the projector to adjust its light output in real-time, preventing energy waste from excessive light emission while maintaining relatively simple device architecture through efficient control algorithms.
Solution Approach 2:
The system enables the projector to self-adjust its light output based on measured conditions without requiring complex external control systems. The luminance acquiring unit and control unit work together to automatically optimize light emission, allowing the device to serve itself in optimizing energy efficiency while maintaining manageable device complexity.
Data Source
AI summary
A projector includes a light source; a spatial light modulator; a signal processing unit that includes a tone map unit that performs a luminance gradation conversion of an input video data according to a tone map indicating a relationship of an output luminance with respect to an input luminance; a luminance acquiring unit that obtains a maximum luminance of a projection surface of the modulated light; and a control unit that controls an amount of light of the light source and sets the tone map. When the maximum luminance of the projection surface is equal to or greater than a first threshold value indicating a maximum luminance of the input video data, the control unit sets, to the tone map unit, a tone map in which a maximum value of the output luminance is set to be the first threshold value.