Dual Exposure Control Circuit for Imaging Systems
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Solution Overview
Problem
Conventional auto exposure control systems in imaging systems face challenges in harmoniously adjusting exposure time and gain, leading to issues like motion blur and noise, particularly with the introduction of white pixels which can cause over-exposure and unpredictable distortions.
Innovation Solution
A dual exposure control circuit and method that individually control the exposure time and gain of RGB and white pixel arrays using a computing unit, compensator, and decision circuit to determine compensation coefficients and control signals based on luminance levels, operating in normal or low light modes to prevent over-exposure and enhance image brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If exposure time is increased to improve Signal-to-Noise Ratio, then noise is reduced, but motion blur increases
Solution Approach 1:
The patent segments the pixel array into RGB pixel arrays and white pixel arrays with independent exposure control. By controlling exposure time and gain separately for different pixel types, the system can optimize exposure parameters for each array independently, resolving the contradiction between SNR and motion blur by allowing shorter exposure times for RGB pixels while using white pixels for low-light enhancement.
Solution Approach 2:
The patent applies local quality by providing different exposure control characteristics to different regions of the pixel array. RGB pixel arrays and white pixel arrays have independent exposure time and gain control, allowing each region to be optimized for its specific function - RGB pixels for color information with controlled exposure, and white pixels for high sensitivity in low-light conditions.
2Illumination intensity
If gain is increased to improve image brightness, then luminance is enhanced, but noise increases
Solution Approach 1:
The patent segments the gain control into separate channels for RGB and white pixel arrays. By independently controlling gain for each array type, the system can apply higher gain to white pixel arrays to enhance brightness in low-light conditions while keeping gain controlled for RGB arrays to minimize noise introduction.
Solution Approach 2:
The patent implements local quality through differentiated gain control - white pixel arrays receive higher gain multiplication to boost brightness in low-light scenarios, while RGB pixel arrays maintain controlled gain to preserve signal quality and minimize noise, allowing each region to optimize for its specific performance requirements.
3Use of energy by moving object
If white pixels are introduced to enhance sensitivity, then light sensitivity is improved, but over-exposure occurs
Solution Approach 1:
The patent segments the exposure control into independent channels for white pixel arrays and RGB pixel arrays. By controlling exposure time and gain separately for white pixels, the system can maximize their light sensitivity and energy collection capability while preventing over-exposure through independent parameter adjustment, allowing white pixels to contribute effectively to low-light performance without causing distortion.
Solution Approach 2:
The patent applies local quality by providing specialized exposure control for white pixel arrays - higher exposure time and gain parameters tailored to their high sensitivity characteristics. This localized optimization allows white pixels to achieve maximum light collection efficiency while preventing over-exposure through controlled parameter application specific to each pixel type's properties.
4Measurement precision
If exposure time is increased to improve SNR, then noise is reduced, but frame rate is limited
Solution Approach 1:
The patent segments the exposure control strategy by applying different exposure time parameters to different pixel arrays. RGB pixel arrays use shorter exposure times to maintain high frame rates, while white pixel arrays use longer exposure times to improve SNR in low-light conditions. This segmentation allows the system to optimize both frame rate and SNR simultaneously by leveraging the complementary strengths of different pixel types.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for precise adjustment of exposure parameters, reducing noise and motion blur while maintaining image quality by preventing over-exposure of white pixels, thereby improving the Signal-to-Noise Ratio (SNR) and overall image brightness.
Implementation Method 1
a photoelectrical device for transforming the received photon into an electrical signal
Data Source
AI summary
A dual-exposure control circuit of an imaging system includes an RGB pixel array and a white pixel array. The dual-exposure control circuit is arranged to determine EGPs for the RGB pixel array and the white pixel array, and compensate RGB data sensed by the RGB pixel array based on the determined EGP.