Bimodal Image Sensor with Segmented Pixel Matrix for Day Night Vision
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Solution Overview
Problem
Image acquisition devices face challenges in operating effectively in both day and night vision conditions with a good signal-to-noise ratio due to limitations in current color filter arrays and infrared sensitivity.
Innovation Solution
An image acquisition device with a matrix of elementary filters comprising primary color filters, panchromatic filters, and infrared filters, where panchromatic filters represent at least 50% of the filters, and processing means to calculate luminance and interpolate images based on illumination conditions to form monochrome, color, and infrared images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an infrared filter is added to block infrared radiation, then noise is reduced in daytime vision, but the sensor cannot detect infrared radiation for night vision
Solution Approach 1:
The sensor matrix is segmented into different pixel types: color pixels with primary color filters (R, G, B), infrared pixels without color filters, and panchromatic pixels. This segmentation allows different regions to perform different functions - color pixels for daytime color imaging and infrared pixels for night vision, resolving the contradiction between noise reduction and dual vision capability
Solution Approach 2:
The sensor is designed with multi-functionality by incorporating both color pixels and infrared pixels in the same matrix. The infrared pixels can detect infrared radiation for night vision while color pixels operate during daytime, making the sensor universally capable of both day and night operations without requiring separate sensors or filters
2Measurement precision
If the sensor operates in daytime vision mode, then color image quality is good, but infrared radiation causes high noise levels
Solution Approach 1:
The harmful infrared radiation is extracted and isolated to specific infrared pixels that are spatially separated from color pixels. By assigning dedicated infrared detection capability to specific pixels rather than having all pixels sensitive to infrared, the noise from infrared radiation is contained and can be processed separately, maintaining color image quality while accounting for infrared presence
3Reliability
If panchromatic pixels are used to improve low light sensitivity, then luminance signal is enhanced, but color information is lost in those pixels
Solution Approach 1:
The patent merges the advantages of different pixel types by combining panchromatic pixels (for sensitivity) with color pixels (for color information). The panchromatic pixels provide enhanced luminance signal in low light conditions, while surrounding color pixels capture color information. During image processing, the luminance data from panchromatic pixels is combined with color data from adjacent color pixels, achieving both sensitivity and color preservation
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
Enables the device to operate in varying lighting conditions with improved signal-to-noise ratio by determining illumination levels and adjusting image formation accordingly, enhancing image quality and sensitivity.
Implementation Method 1
a sensor (CCD or CMOS) consisting of a matrix of photosensitive elementary sensors also called pixels
Implementation Method 2
infrared pixels for night vision
Implementation Method 3
primary color filters, a primary color filter transmitting only a primary color
Data Source
Figure 1
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Figure 3A
AI summary
The invention concerns an image acquisition device comprising a sensor consisting of a matrix of light-sensitive pixels, and a matrix of elementary filters covering the sensor. The pixels can be of three different types: panchromatic pixels, primary colour pixels and infrared pixels. In low illumination conditions, the device provides a monochromatic image from the panchromatic pixels, and in high illumination conditions, a colour image with a high signal to noise ratio, by combining the primary colour images and subtracting the infrared image.