Color Filter with Spatially Varying Transmittance for Single-Sensor Imaging
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Solution Overview
Problem
Existing color imaging apparatuses using a single image sensor face challenges in obtaining accurate wavelength information for red, green, and blue colors, leading to degraded image resolution and artifacts like false colors due to limited capability in capturing simultaneous wavelength information from each pixel.
Innovation Solution
The implementation of an imaging apparatus with a color filter that has varying light transmittance based on pixel positions and wavelength bands, combined with the compressed sensing technique for in-pixel addition and reconstruction, allows for the generation of a color image with resolution equivalent to that of a three-chip image sensor using only one image sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single image sensor is used to reduce size and cost, then device complexity and cost are reduced, but the ability to obtain accurate wavelength information for R, G, and B is degraded
Solution Approach 1:
The color filter is divided into multiple regions with different transmittance characteristics for different wavelength bands. Each region captures specific wavelength information, allowing a single sensor to obtain R, G, and B wavelength data that would normally require multiple sensors. This segmentation of the filter function enables spectral information separation while using one sensor array.
Solution Approach 2:
Different regions of the color filter are assigned different transmittance properties tailored to specific wavelength bands. The filter has spatially varying optical characteristics where certain areas transmit red wavelengths, others transmit green, and others transmit blue, allowing each pixel location to capture specific color information locally.
2Ease of operation
If demosaicing is performed to obtain wavelength information for all pixels, then color image can be generated from single sensor, but image resolution degrades and false color artifacts occur
Solution Approach 1:
The color filter is pre-configured with multiple transmittance patterns that capture different wavelength combinations before the imaging process. By encoding wavelength information in the filter structure itself, the system performs spectral sampling in advance, allowing reconstruction algorithms to recover full-color information without requiring post-capture demosaicing operations that degrade resolution.
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 effectively suppresses the degradation of image resolution and occurrence of artifacts, enabling the production of high-quality color images with improved fidelity and reduced false colors.
Implementation Method 1
a color filter that is located between the image-forming optical system and the imaging device and has a light transmittance which differs according to positions on the color filter corresponding to the plurality of pixels and according to a plurality of wavelength bands
Implementation Method 2
an imaging device that includes a plurality of pixels, receives, with the plurality of pixels, the optical signals used to form the image, and converts the optical signals into electric signals
Data Source
AI summary
An imaging apparatus includes an image-forming optical system that forms an image by using optical signals; an imaging device that includes a plurality of pixels, receives, with the plurality of pixels, the optical signals used to form the image, and converts the optical signals into electric signals; and a color filter that is located between the image-forming optical system and the imaging device and has a light transmittance which differs according to positions on the color filter corresponding to the plurality of pixels and according to a plurality of wavelength bands.