Color Filter Array Design for Single-Sensor Imaging Resolution
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Solution Overview
Problem
Existing color imaging apparatuses with single image sensors face challenges in obtaining accurate color information due to resolution loss and artifacts like 'false color' during demosaicing, and struggle with efficient data compression and transmission.
Innovation Solution
An imaging apparatus with a color filter having different optical transmittances for each pixel and wavelength range, and a transmission data compression circuit that compresses signals based on similarity between pixels, ensuring equal sensitivity and luminance across pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only one image sensor is used to reduce size and cost, then device complexity is reduced, but measurement precision of color information deteriorates due to resolution loss and false color artifacts during demosaicing
Solution Approach 1:
The color filter array is segmented into multiple types (first, second, third color filter types) with different optical characteristics. Each pixel is assigned a specific color filter type, creating a segmented filtering system that captures diverse spectral information across the sensor array, enabling accurate color reconstruction without traditional demosaicing losses
Solution Approach 2:
Different regions of the color filter array have different optical transmittance characteristics tailored to local needs. The first, second, and third color filter types have distinct transmittance profiles for different wavelength ranges, allowing each pixel to capture optimized spectral information for its specific position and function
2Loss of information
If optical filter elements are arranged in a random color pattern to capture color information, then color data is obtained, but resolution decreases and false color artifacts occur during demosaicing
Solution Approach 1:
The color filter array is pre-configured with a specific non-random pattern where pixels of the same color filter type are strategically positioned. This preliminary arrangement ensures that sufficient color information is captured across the array, enabling accurate color reconstruction and eliminating the need for traditional demosaicing operations that cause resolution loss and false color artifacts
3Measurement precision
If a color filter with different optical transmittances for each pixel and wavelength range is used, then color information accuracy is improved, but device complexity increases
Solution Approach 1:
The color filter array uses a finite set of three color filter types that can be universally applied across all pixels. Each filter type serves multiple functions: capturing specific wavelength ranges, providing spectral diversity, and enabling accurate color reconstruction. This universal approach simplifies manufacturing while maintaining high color information accuracy
Solution Approach 2:
The invention changes the optical transmittance parameters of the color filters to achieve different spectral responses. By adjusting the transmittance characteristics of the first, second, and third color filter types across different wavelength ranges, the system captures accurate color information without requiring complex per-pixel customization
4Loss of information
If data from all pixels is transmitted without compression, then complete information is transmitted, but transmission speed decreases and memory space increases
Solution Approach 1:
The transmission data compression circuit extracts and transmits only the essential color information and pixel data required for image reconstruction. By identifying and removing redundant information, the system maintains complete color information accuracy while significantly reducing data volume for transmission and storage
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 approach allows for more accurate color information capture and efficient data compression, reducing artifacts and improving image resolution while maintaining efficient data transmission.
Implementation Method 1
an imaging device that includes a plurality of pixels and that converts the optical signal formed on the plurality of pixels into an electrical signal
Data Source
AI summary
An imaging apparatus includes an imaging optical system that forms an optical signal, an imaging device that includes a plurality of pixels and that converts the optical signal formed on the plurality of pixels into an electrical signal, a color filter that is arranged between the imaging optical system and the imaging device and that has a different optical transmittance for each of the plurality of pixels and each of a plurality of wavelength ranges, and a transmission data compression circuit that compresses the electrical signal obtained by the imaging device. The sum of products of an optical transmittance group relating to a plurality of optical transmittances of the color filter for each of the plurality of pixels in the plurality of wavelength ranges and coefficients common to the plurality of pixels is the same between the plurality of pixels.