Projector Light Source Control via Vertical Sync Signal Synchronization
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Solution Overview
Problem
Existing projector systems face delays in light source control due to asynchronous processing of image signal input, leading to suboptimal control of luminance distribution, especially during rapid changes in image scenes, which requires large-scale memory for frame buffering.
Innovation Solution
Implementing an image input unit that synchronizes with vertical synchronizing signals to calculate and transmit the ratio of input and output resolutions, average luminance levels, and adjusted histogram data to the light source control unit, allowing for real-time light source control without the need for large-scale memory by synchronizing image input information with subsequent vertical synchronizing signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If asynchronous processing of image signal input is used, then device complexity is reduced, but light source control timing accuracy deteriorates
Solution Approach 1:
The patent applies preliminary action by calculating and storing image input information (average luminance level and luminance distribution) in advance during the vertical synchronizing signal period, before the actual image signal processing begins. This allows the light source control unit to immediately use pre-computed data when needed, eliminating processing delays without requiring complex real-time computation during image display.
2Reliability
If large-scale memory is used for frame buffering, then light source control accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts only the essential image input information (average luminance level and luminance distribution histogram) needed for light source control, rather than buffering entire frames. By taking out only these specific parameters and transmitting them asynchronously to the light source control unit, the system achieves accurate control without requiring large-scale frame buffer memory.
3Productivity
If real-time light source control is implemented, then responsiveness to scene changes is improved, but processing complexity increases
Solution Approach 1:
The system performs preliminary calculation of average luminance level and luminance distribution during the vertical synchronizing signal interval, before the image signal processing starts. This pre-computation enables real-time light source control responsiveness without adding complexity to the main image processing pipeline, as the heavy computation is completed in advance during idle periods.
Solution Approach 2:
The patent implements feedback by continuously monitoring image input information and dynamically adjusting light source output based on detected luminance characteristics. The light source control unit receives ongoing feedback about scene brightness and automatically modulates light intensity to maintain optimal display conditions, improving responsiveness without requiring complex manual intervention.
Data Source
AI summary
A projector includes: an image input unit that, upon the input of a first image signal synchronized with a vertical synchronizing signal, sends image input information; a resolution conversion output unit that converts the first image signal to a second image signal that indicates an image with a prescribed resolution and supplies the result as output; a light source unit that is provided with a light source and an image-forming element that uses illumination light from the light source to generate image light; a light source control unit that uses the image input information to control the light quantity of the light source; and an image-forming element drive unit that drives the image-forming element on the basis of the second image signal. The image input unit sends image input information synchronized with a second vertical synchronizing signal that follows the first vertical synchronizing signal.