Color Filter Array Sub-Pixel Segmentation for Image Sensor Dynamic Range
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Solution Overview
Problem
Conventional image sensing devices have a limited dynamic range, which restricts their ability to capture a broader range of luminance differences in image information, leading to inadequate identification of image details at higher luminous flux levels.
Innovation Solution
A color filter array is developed by dividing each pixel into sub-pixels, allowing the accumulation of pixel values from these sub-pixels to generate output data that is below a saturated threshold, thereby increasing the dynamic range of the image sensing device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the maximum luminous flux LFmax is increased to broaden the luminous flux range, then the dynamic range of the image sensing device is improved, but the luminance differences in the image information become greater making it harder to identify image details
Solution Approach 1:
The patent divides each pixel into multiple sub-pixels (e.g., 2×2 or 3×3 grid), where each sub-pixel captures luminous flux independently. This segmentation allows the system to accumulate pixel values from multiple sub-pixels to extend the effective dynamic range while maintaining fine luminance differentiation through the accumulated data from individual sub-pixel responses.
2Measurement precision
If the minimum luminous flux LFmin is reduced to capture lower luminance, then the dynamic range is improved, but the maximum luminous flux LFmax must be maintained to avoid saturation
Solution Approach 1:
The patent accumulates pixel values from multiple sub-pixels, where each sub-pixel may individually saturate at high luminous flux levels. By combining partial responses from multiple sub-pixels, the system effectively extends the linear detection range beyond what a single pixel could achieve, allowing detection of both low and high luminance without complete saturation.
3Device complexity
If conventional pixels are used without subdivision, then the device structure is simple, but the dynamic range is limited and cannot capture broader luminance differences
Solution Approach 1:
The patent transitions from a single-value pixel output to a multi-value pixel output by dividing each pixel into multiple sub-pixels. This dimensional change from 1D (single value) to 2D (multiple values per pixel location) enables the system to represent a broader range of luminance values through accumulation, effectively increasing dynamic range while maintaining spatial resolution.
Data Source
AI summary
A color filter array for an image sensing device includes a plurality of pixels, for generating a plurality of pixel data of an image; and a control unit, for controlling the plurality of pixels; wherein each of the plurality of pixels is divided into a plurality of sub-pixels; wherein the pixel data outputted by each of the plurality of pixels is generated based on at least one pixel value of the plurality of sub-pixels and the outputted pixel data is smaller than a saturated threshold; wherein at least one pixel in the plurality of pixels has a mixed color by having different sub-pixel colors in the plurality of sub-pixels.