Imaging Apparatus White Balance Gain Adjustment for High ISO Noise
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Solution Overview
Problem
Conventional imaging apparatuses struggle to reproduce accurate colors when using high sensitivity ISO settings like ISO6400 or ISO12800 due to noise issues and fixed white balance gain calculations based on standard ISO sensitivity, leading to unsuitable color reproduction.
Innovation Solution
An imaging apparatus that includes an imaging sensor, a gain setting unit to adjust output signal amplification gain based on ISO sensitivity, and a determination unit to calculate white balance gain for correction, allowing for dynamic white balance adjustment according to ISO sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high sensitivity ISO is used to amplify image information, then the output signal amplification gain increases, but the noise component influence becomes strong and color reproduction becomes inaccurate
Solution Approach 1:
The patent changes the parameter of white balance gain based on the output signal amplification gain (ISO sensitivity). By dynamically adjusting the white balance gain according to the amplification gain, the system compensates for color shifts that occur at high ISO settings, thereby maintaining accurate color reproduction even when noise influence increases.
2Device complexity
If white balance gain is calculated based on predetermined ISO sensitivity, then the calculation is simple, but color reproduction becomes unsuitable when actual ISO sensitivity differs from predetermined value
Solution Approach 1:
The patent transitions from a static white balance gain calculation (based on fixed predetermined ISO) to a dynamic calculation where the white balance gain is determined according to the actual output signal amplification gain. This allows the white balance correction to adapt to different ISO settings, improving color reproduction accuracy without significantly increasing system complexity.
3Power
If high sensitivity ISO such as ISO6400 or ISO12800 is used, then the image information amplification is sufficient for low light conditions, but the noise problem deteriorates color reproduction
Solution Approach 1:
The patent implements a feedback mechanism where the white balance gain is determined based on the output signal amplification gain. The determination unit receives the amplification gain value and adjusts the white balance gain accordingly, creating a closed-loop system that compensates for high ISO color shifts and maintains reliable color reproduction even at ISO6400 or ISO12800.
Data Source
AI summary
An imaging apparatus includes an imaging sensor operable to capture a subject image and output image information, a gain setting unit operable to set a value of an output signal amplification gain according to a value of ISO sensitivity for amplifying the image information output from the imaging sensor, a determination unit operable to determine a value of white balance gain to be used for white balance correction according to the value of the output signal amplification gain set by the gain setting unit, and a white balance correcting unit operable to perform white balance correction on the image information output from the imaging sensor based on the value of the output signal amplification gain set by the setting unit and the value of the white balance gain determined by the determination unit.