Dynamic Clipper Control for Image Smear Reduction
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Solution Overview
Problem
Conventional image pickup apparatuses face challenges in reducing smear phenomena, especially under varying lighting conditions, which affect image quality and dynamic range, with existing solutions either inadequately correcting smear or reducing the dynamic range.
Innovation Solution
An image pickup apparatus that includes a clipper to limit output voltage, a gain upper limit setter, and a controller to determine and respond to smear conditions, activating or deactivating the clipper to manage output voltage and gain accordingly, thereby reducing smear and expanding dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a gain is increased for shooting at night to increase sensitivity, then sensitivity is improved, but smear component is amplified causing deterioration in image quality
Solution Approach 1:
The patent implements dynamic control of the clipper's clipping level based on shooting conditions. The control unit adjusts the clipping threshold adaptively - setting a lower clipping level when high-brightness subjects are detected to suppress smear, and raising or disabling the clipping level when shooting in low-illuminance conditions to maintain sensitivity. This dynamic adjustment resolves the contradiction by making the system flexible rather than fixed.
2Object-affected harmful factors
If a clipper is used to suppress smear phenomenon, then smear is reduced, but dynamic range of image pickup signals is reduced
Solution Approach 1:
The control unit dynamically adjusts the clipping level based on scene brightness analysis. When a high-brightness photographic subject is detected, the clipper activates with an appropriate clipping level to suppress smear. When shooting in low-illuminance conditions without high-brightness subjects, the clipper is deactivated or set to a higher level, preserving the full dynamic range. This conditional dynamic control resolves the contradiction between smear suppression and dynamic range preservation.
3Object-affected harmful factors
If conventional smear correction techniques are applied, then smear is partially suppressed, but image quality deteriorates under various shooting conditions
Solution Approach 1:
The patent employs dynamic control of the clipper based on real-time analysis of shooting conditions. The control unit determines whether high-brightness subjects are present and adjusts the clipping level accordingly. This dynamic adaptation ensures optimal performance across diverse shooting scenarios - suppressing smear when necessary while maintaining image quality and avoiding artifacts in other conditions, thereby resolving the reliability issue.
Solution Approach 2:
The invention changes the operational parameters of the clipper dynamically. By adjusting the clipping threshold level based on scene characteristics (presence of high-brightness subjects, illuminance conditions), the system adapts to different shooting scenarios. This parameter change approach allows the same hardware to optimally handle both smear-prone high-brightness scenes and low-illuminance scenes without quality deterioration.
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
The solution effectively reduces smear phenomena during high-brightness shooting and enhances sensitivity and dynamic range in low-illuminance conditions, improving image quality by dynamically adjusting settings based on shooting conditions.
Implementation Method 1
Each image pickup element includes a photoelectric converter PD
Data Source
AI summary
An image pickup apparatus configured to output an image signal based on an optical signal photoelectrically converted by an image pickup element provided with two-dimensionally arranged pixels includes: a clipper configured to limit output voltage of the image signal based on the optical signal; a gain upper limit setter configured to set a gain upper limit to be applied to the optical signal; a determiner configured to determine whether or not a condition to cause occurrence of a smear in a shot image is satisfied; and a controller configured to limit an output voltage of the optical signal by using the clipper when the determiner determines that the condition to cause occurrence of the smear is satisfied, and to inactivate limitation of the output voltage of the optical signal by using the clipper when the determiner determines that the condition to cause occurrence of the smear is not satisfied.