Spectral Imaging System Using Color Filter Array Coding
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Solution Overview
Problem
Current spectral imaging techniques face challenges in efficiently reconstructing spectral information of objects with high spatial resolution and light efficiency, often requiring complex setups and prior knowledge of the scene, while trading off spectral information with spatial resolution.
Innovation Solution
A novel spectral imaging system that applies optical coding to input light fields using a coder unit and imaging lens module, allowing for the reconstruction of spectral data through a detector array, which can operate in both static and dynamic modes with controllable transmittance functions, enabling single-snapshot or multi-frame spectral reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If compressed sensing techniques are used to acquire HS snapshot images, then spectral information is obtained, but the system complexity increases and light efficiency decreases
Solution Approach 1:
The patent introduces a color filter array as an intermediary element between the lens and sensor. This CFA acts as a mediator that encodes spectral information into spatial patterns that can be captured in a single snapshot, avoiding the need for complex compressed sensing hardware while still enabling spectral reconstruction through computational algorithms.
Solution Approach 2:
The patent replaces mechanical spectral scanning systems (whiskbroom, pushbroom) with a static color filter array combined with computational reconstruction. This substitution eliminates moving parts and complex optical mechanisms while achieving the same spectral imaging goal through a simpler, snapshot-based approach.
2Loss of information
If polychromatic sensors with color filter arrays are used, then spectral information is captured, but spatial resolution is degraded
Solution Approach 1:
The patent segments the spectral information capture across multiple pixels through the color filter array pattern. Each pixel captures a specific spectral band, and by combining information from multiple pixels, the system reconstructs both spectral and spatial data, effectively distributing the spectral measurement task across the sensor array to preserve spatial resolution.
Solution Approach 2:
The patent transforms the spectral measurement problem from a spatial dimension issue to a spectral dimension solution. By using the color filter array to encode spectral information and applying computational reconstruction algorithms, the system recovers spatial resolution that would otherwise be lost, effectively trading spectral encoding for spatial recovery through mathematical processing.
3Loss of information
If integral field spectroscopic systems are used, then spectral information is obtained, but spatial resolution is traded off for spectral bands
Solution Approach 1:
The patent inverts the traditional approach by placing the color filter array at the sensor plane rather than using complex optical elements in the optical path to separate spectral bands. This inversion allows the use of standard camera sensors with modified filter arrays, achieving spectral imaging without the spatial resolution degradation associated with integral field spectroscopy optical elements.
4Productivity
If 2D grating is used to form multiple multispectral sub-images, then fast hyperspectral cube acquisition is achieved, but spatial resolution is low and system integration is difficult
Solution Approach 1:
The patent makes the system universally compatible with standard camera platforms by using a color filter array that can be integrated into existing camera sensors. This approach maintains the fast snapshot acquisition capability while improving spatial resolution and eliminating the need for specialized, non-integrable optical elements like 2D gratings.
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
The system effectively reconstructs spectral data with improved spatial resolution and light efficiency, allowing for the distinction between different objects or features based on their spectra, and can be integrated into common cameras, offering a technologically simple solution for spectral imaging.
Implementation Method 1
an optical unit configured and operable for applying a predetermined coding to an input light field while creating an optical image thereof
Implementation Method 2
a detector having a pixel array... for receiving and processing image data indicative of light detected by the pixel array
Data Source
AI summary
An imaging system and method are presents for use in reconstructing spectral data of an object. The imaging system comprises: an optical unit; a pixel array of a detector; and a data processor for receiving and processing image data indicative of light detected by the pixel array and generating reconstructed spectral data of the object being imaged. The optical unit is configured and operable for applying a predetermined coding to an input light field while creating an optical image thereof on a detection plane defined by the pixel array. Therefore, the image data is a function of the predetermined coding and a spectrum of the object to be determined.