Solid-State Image Sensor Dynamic Range Expansion via Multi-Size Pixel Synthesis
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Solution Overview
Problem
Conventional solid-state image sensors using a Bayer array face issues with unnatural color and brightness changes near the incident light threshold due to differing pixel sensitivities and interpolation of non-target color information, leading to false colors and degradation of image quality, which limits their dynamic range expansion.
Innovation Solution
A solid-state image sensor with a pixel unit featuring output pixels of multiple sizes arranged in specific patterns, where signal processing units synthesize pixel signals from multiple output pixels of the same color with different sizes, selecting and multiplying signals based on incident light amounts to expand the dynamic range while minimizing image quality degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If pixel signals are switched at a specific incident light amount to expand dynamic range, then the dynamic range is improved, but unnatural color and brightness changes occur in spatial and temporal directions
Solution Approach 1:
The pixel array is segmented into multiple regions with different pixel sizes (first pixels with larger light-receiving area, second pixels with smaller light-receiving area). This segmentation allows different pixel types to be used in different lighting conditions, expanding dynamic range while maintaining image quality consistency through appropriate signal selection and combination.
Solution Approach 2:
Different regions of the pixel array are assigned different pixel sizes and characteristics. The first pixels with larger light-receiving area are used for low-light conditions, while second pixels with smaller light-receiving area are used for high-light conditions. This local quality differentiation enables optimal performance across varying light conditions without causing unnatural transitions.
2Loss of information
If color information is interpolated from peripheral pixels in Bayer array, then missing color information is obtained, but false color artifacts occur
Solution Approach 1:
The pixel array is divided into multiple regions with different pixel sizes and color filter arrangements. This segmentation provides multiple sources of color information that can be selectively used or combined, reducing reliance on interpolation from peripheral pixels and minimizing false color artifacts while maintaining complete color information.
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 expands the dynamic range while suppressing image quality degradation by selectively using pixel signals based on incident light levels, reducing unnatural color or brightness changes and false colors, thereby improving image fidelity.
Implementation Method 1
unit pixels respectively including light-receiving elements
Data Source
AI summary
The present technology relates to a solid-state image sensor and an electronic device that can expand a dynamic range while suppressing degradation of image quality.A solid-state image sensor includes a pixel unit in which basic pattern pixel groups are arranged, each of the basic pattern pixel groups having output pixels of a plurality of colors arranged according to a predetermined pattern, the output pixel being a pixel based on an output unit of a pixel signal, the output pixel of at least one color among the output pixels having three or more types of sizes, and a signal processing unit configured to perform synthesis processing for a plurality of the pixel signals from a plurality of the output pixels having a same color and different sizes. The present technology can be applied to, for example, a CMOS image sensor.