Panchromatic and Color Pixel Sensor Array for Low Light Imaging
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Solution Overview
Problem
Existing electronic image sensors face reduced light sensitivity due to color filters, which limits their ability to capture high-resolution color images in low light conditions, and existing solutions either increase noise or require complex and costly systems with reduced light efficiency.
Innovation Solution
The method involves processing digital images by forming a high-resolution digital panchromatic image and a lower-resolution digital color image, allowing for improved final image quality under varying lighting conditions by intermixing panchromatic and color pixels, with panchromatic pixels having wider spectral sensitivity and color pixels being adjusted for equal sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If color filters are applied to all pixels to enable color imaging, then color information is captured, but light sensitivity is reduced
Solution Approach 1:
The image sensor array is segmented into two distinct types of pixels: color pixels with color filters and panchromatic pixels without filters. This segmentation allows each pixel type to serve its specialized function, with color pixels capturing chromatic information and panchromatic pixels capturing luminance information with high sensitivity, thereby resolving the contradiction between color information capture and light sensitivity.
Solution Approach 2:
Different regions of the image sensor have different qualities: color pixels in certain locations provide color information while panchromatic pixels in other locations provide high-light-sensitivity monochrome information. This local differentiation of pixel qualities allows the system to simultaneously achieve color imaging capability and high light sensitivity where needed.
2Illumination intensity
If panchromatic pixels are used to increase light sensitivity, then photographic speed improves, but color information is lost at those pixel locations
Solution Approach 1:
The sensor is divided into color pixels and panchromatic pixels, with panchromatic pixels strategically positioned to provide high-light-sensitivity monochrome information while color pixels provide color information. This segmentation allows the system to recover color information through interpolation from surrounding color pixels while maintaining high photographic speed from the panchromatic pixels.
Solution Approach 2:
The processing system acts as an intermediary that combines information from both pixel types. It uses the high-resolution monochrome data from panchromatic pixels and the color information from color pixels to generate a final color image, mediating between the two data sources to produce output that has both high photographic speed and complete color information.
3Illumination intensity
If gain is applied to color pixels to match sensitivity with monochrome pixels, then sensitivity is improved, but noise increases
Solution Approach 1:
By segmenting the sensor into separate color and panchromatic pixel arrays, the system eliminates the need for gain adjustment. Color pixels and panchromatic pixels are read out and processed separately, with the panchromatic pixels providing the sensitivity reference. This segmentation prevents noise amplification that would occur if gain were applied to color pixels to match monochrome sensitivity.
Solution Approach 2:
The system creates a copy of the image data from panchromatic pixels (which have high sensitivity and low noise) and uses it to inform the processing of color pixel data. This copying approach allows the system to leverage the high-quality monochrome signal to improve overall image quality without introducing noise through gain amplification of the color pixel signals.
4Illumination intensity
If a two-sensor system with beam splitter is used to separate color and monochrome imaging, then light sensitivity is improved, but system complexity and cost increase
Solution Approach 1:
Instead of using separate sensors and a beam splitter, this invention merges color and monochrome sensing capabilities into a single integrated image sensor array. The sensor combines color pixels with color filters and panchromatic pixels without filters in one array, eliminating the need for separate sensors and complex optical switching components.
Solution Approach 2:
The single image sensor array performs multiple functions simultaneously: color pixels capture color information while panchromatic pixels capture high-sensitivity monochrome information. This multi-functionality in a single sensor replaces the need for separate specialized sensors and a beam splitter, reducing system complexity and cost while maintaining improved light sensitivity.
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 enhances image quality in low light conditions by increasing the sensitivity of color pixels to match panchromatic sensitivity, reducing noise, and simplifying the system while maintaining high-resolution color image capture.
Implementation Method 1
an electronic image sensor to create an electronic representation of a visual image
Implementation Method 2
a pattern of filters is typically fabricated on the pattern of pixels, with different filter materials being used to make individual pixels sensitive to only a portion of the visible light spectrum
Data Source
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Figure 4A~5
AI summary
A method for forming a final digital color image includes capturing an image using an image sensor having panchromatic pixels and color pixels corresponding to at least two color photoresponses; providing from the captured image a digital panchromatic image and an intermediate digital color image; and using the digital panchromatic image and the intermediate digital color image to provide the final digital color image.