Image Sensor Color Filter Array for Single-Shot HDR Capture
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Solution Overview
Problem
Conventional image sensors struggle to capture high-dynamic range images in high-illumination or low-illumination environments due to limitations in dynamic range, requiring multiple exposures and resulting in user inconvenience and potential image blurriness.
Innovation Solution
An apparatus and method utilizing a filter module with wide-band, narrow-band, and all-pass filters to process optical signals, applying different weights to generate high-dynamic range images from a single exposure, improving sensitivity and image quality without the need for expensive HDR sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional image sensors with color filter arrays are used in high-illumination or low-illumination environments, then color images can be captured, but the dynamic range is limited causing loss of information in shadows or highlights
Solution Approach 1:
The color filter array is segmented into multiple types of filters (first color filters, second color filters, and third color filters) with different spectral characteristics. This segmentation allows different filter regions to capture different portions of the light spectrum, enabling the sensor to handle a wider dynamic range by selectively capturing information in various illumination conditions without requiring multiple exposures.
2Loss of information
If HDR image sensors are used to accurately capture images in high-illumination or low-illumination environments, then image quality improves, but the cost and complexity increase making them unsuitable for consumer products
Solution Approach 1:
The image sensor is designed with multi-functionality by incorporating three types of color filters that can operate under various illumination conditions. The sensor can function as both a standard color image sensor and an HDR-capable sensor by utilizing different filter combinations, eliminating the need for specialized expensive HDR sensors while maintaining consumer product affordability and simplicity.
Solution Approach 2:
The invention changes the spectral parameters of the color filters by using filters with different bandwidths and center wavelengths. The first color filters have narrower bandwidths for precise color separation, while the second and third color filters have broader bandwidths to capture more light in low-illumination and highlight conditions. This parameter variation allows a single sensor to achieve HDR capability without increased complexity.
3Loss of information
If multiple images with different exposure amounts are captured to create HDR images, then HDR quality improves, but user convenience deteriorates due to the need for long holding time and potential for hand shake
Solution Approach 1:
The invention merges multiple filtering functions into a single exposure capture. By incorporating first color filters, second color filters, and third color filters in the color filter array, the sensor simultaneously captures information that would normally require multiple exposures with different exposure times. This combining of functions into one shot eliminates the need for users to hold the device steady during multiple captures, thereby maintaining ease of operation while achieving HDR quality.
4Illumination intensity
If long exposure is used to capture dark areas, then visibility in shadows improves, but information is lost in bright areas due to saturation
Solution Approach 1:
Different regions of the color filter array have different local qualities optimized for specific conditions. The second color filters with broader bandwidths are strategically positioned to capture more light in low-illumination areas, while the first color filters with narrower bandwidths are used in regions where color precision is needed. This local optimization allows the sensor to capture shadow details without causing highlight saturation, as each filter region processes light according to its specific characteristics.
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 generation of high-quality HDR images from a single exposure, enhancing user convenience and image sensitivity while avoiding the costs and complexities associated with traditional HDR image capture methods.
Implementation Method 1
a wide-band filter area that allows transmission of optical signals within a wavelength band corresponding to a complementary color of a predetermined color
Implementation Method 2
a narrow-band filter area that allows transmission of optical signals within a wavelength band corresponding to the predetermined color
Implementation Method 3
an all-pass filter area that allows transmission of optical signals in all wavelength bands
Data Source
AI summary
An apparatus, method, and medium for generating an image is provided. The apparatus includes an optical module, a filter module which includes a wide-band filter area that allows transmission of optical signals within a wavelength band corresponding to a color of a predetermined color, a narrow-band filter area that allows transmission of optical signals within a wavelength band corresponding to the predetermined color, and an all-pass filter area that allows transmission of optical signals in all wavelength bands, and an image generation module which generates an image by processing optical signals that transmit through the filter module, wherein the image generation module applies different weights to optical signals according to which of the wide-band filter area, the narrow-band filter area, and the all-pass filter area the optical signals respectively transmit through.