Imaging Element Phase-Difference Pixel Correction
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Solution Overview
Problem
Existing imaging devices face challenges in improving image quality due to insufficient correction of output signals from phase-difference detecting pixels, which are crucial for brightness signals, especially near the edges of the light receiving surface, leading to noise increase and reduced image quality when using gain correction.
Innovation Solution
The imaging element is designed with a specific arrangement of phase-difference detecting pixels and imaging pixels on the light receiving surface, where pairs of phase-difference detecting pixels are positioned eccentrically to each other, allowing for gain correction that balances signal levels and minimizes noise, while interpolation correction is used for other pixels, maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gain correction is applied to phase-difference detecting pixels near the edge of the light receiving surface, then signal level balance is improved, but noise increases and image quality deteriorates
Solution Approach 1:
The patent applies different correction methods to different regions of the light receiving surface. Specifically, gain correction is applied to phase-difference detecting pixels in the central region where it effectively balances signal levels, while interpolation correction is applied to pixels near the edges where gain correction would excessively amplify noise. This spatially differentiated approach optimizes image quality across the entire sensor surface.
2Object-affected harmful factors
If interpolation correction is used for phase-difference detecting pixels, then noise is reduced, but image quality deteriorates due to using signals from different positions
Solution Approach 1:
The patent selectively applies interpolation correction only to phase-difference detecting pixels located near the edges of the light receiving surface, where noise is the primary concern. For central region pixels, gain correction is used instead to maintain signal level balance. This localized application strategy minimizes the negative impact on image quality while effectively reducing noise in edge regions.
3Measurement precision
If the photoelectric conversion area of phase-difference detecting pixels is made smaller to detect phase difference, then phase difference detection capability is improved, but the pixels become insufficient for generating captured image data
Solution Approach 1:
The patent designs phase-difference detecting pixels that serve dual functions: their eccentric photoelectric conversion areas enable precise phase difference detection, while their output signals are utilized through correction processes (gain or interpolation correction) to contribute to captured image data generation. This multi-functional design allows the same pixel structure to fulfill both phase detection and imaging requirements.
Solution Approach 2:
The patent introduces correction processes as intermediary steps between the phase-difference detecting pixels and the captured image data generation. Gain correction multiplies pixel signals by appropriate factors to balance signal levels, while interpolation correction uses signals from multiple pixels to reconstruct pixel values. These intermediary processing steps bridge the gap between the limited photoelectric conversion area and the requirement for sufficient imaging data.
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 configuration enhances the quality of captured images by effectively correcting output signals from phase-difference detecting pixels, particularly those contributing to brightness signals, thereby improving image fidelity and reducing noise.
Implementation Method 1
a plurality of pixels which photoelectrically converts light rays having different colors
Data Source
AI summary
An imaging element has plural pixels which photoelectrically convert light rays having different colors, and has a light receiving surface on which the plural pixels are arranged in two dimensions according to a regular pattern, the plural pixels include first pixels that output signals each having a first color component which most contribute to obtainment of brightness signals, and second pixels that output signals having color components other than the first color component, the first pixels and the second pixels are as defined herein, and a pair row is formed on the light receiving surface as defined herein.