Projector Sync Signaling for Flicker-Free Image Capture
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Solution Overview
Problem
Existing projectors face issues with screen flickering and color discoloration when capturing projected images due to synchronization challenges between the projector and external image capturing devices, particularly in DLP technology, which causes the 'rainbow effect' and color misalignment.
Innovation Solution
A method for synchronizing peripheral devices by generating a synchronization signal based on the refresh rate of the image signal, transmitted via wired or wireless interfaces to external image capturing devices, ensuring the capturing device operates at the same frequency as the projector, thus aligning color and reducing flickering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If DLP technology with color wheel is used to achieve high brightness and color separation, then image brightness and color quality are improved, but screen flickering and color discoloration occur when captured by external devices
Solution Approach 1:
The patent implements a feedback mechanism where the projector detects the refresh rate of the input signal and automatically generates a corresponding synchronization signal. This closed-loop approach ensures that the color wheel rotation speed matches the display refresh rate, eliminating flickering and color separation issues during capture while maintaining high brightness output.
Solution Approach 2:
The patent dynamically adjusts the rotation speed parameter of the color wheel based on the detected refresh rate of the input signal. By changing this critical parameter in real-time, the system synchronizes the color separation process with the display refresh cycle, preventing the rainbow effect and ensuring accurate color capture without sacrificing brightness.
2Speed
If the color wheel rotates rapidly to achieve high refresh rates, then image refresh speed is improved, but the rainbow effect and color separation become more noticeable
Solution Approach 1:
The system uses feedback from the input signal's refresh rate to control the color wheel's rotation speed. This ensures that the color wheel completes exactly one full rotation (through all three primary colors) during each display refresh cycle, preventing partial color displays that cause the rainbow effect while maintaining the required refresh rate.
Solution Approach 2:
The patent implements periodic synchronization where the color wheel's rotation period is precisely matched to the display refresh period. This periodic alignment ensures that each refresh cycle displays complete color information in the correct sequence, eliminating the rainbow effect while preserving high refresh rates for smooth image display.
3Device complexity
If no synchronization signal is provided to external capturing devices, then device complexity is reduced, but screen flickering and color instability occur during image capture
Solution Approach 1:
The patent introduces a synchronization signal as an intermediary between the projector and external capturing devices. This additional signal acts as a timing reference that helps capturing devices synchronize their readout with the projector's color wheel rotation and display refresh, eliminating flickering and color instability without requiring complex modifications to either device.
Data Source
AI summary
A method for synchronizing peripheral devices of a projector includes the projector receiving an image signal from an image output device to project an image, the projector generating a synchronization signal, the projector outputting the synchronization signal to an external image capturing device via a wired interface or a wireless interface, and the external image capturing device capturing the image projected by the projector according to the synchronization signal. The image signal has a refresh rate, and the frequency of the synchronization signal is generated according to the refresh rate.