Integral Field Spectral Imager With Superpixel Homogenization
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Solution Overview
Problem
Chip-scale spectral imagers suffer from undersampling issues due to mosaic designs, leading to erroneous spectral variations and spatial information loss, which conventional demosaicing algorithms often fail to address, especially in scenes with high spatial frequency content.
Innovation Solution
An integral field spectral imager with a superpixel array, optical homogenizers, and spectral filters configured to spatially and spectrally filter electromagnetic radiation, eliminating the need for spatial filters and allowing for more flexible integration with external optics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a mosaic imager design is used, then spectral filtering is achieved at each pixel, but spectral data accuracy deteriorates due to undersampling and spatial information is lost
Solution Approach 1:
The image sensor is divided into superpixels, where each superpixel contains multiple pixels (e.g., 2x2, 3x3, or 4x4 arrangements). Each pixel within a superpixel is assigned a different spectral filter, creating a localized spectral sampling pattern that can be computationally reconstructed to achieve full spectral information without the undersampling problems of traditional mosaic designs.
Solution Approach 2:
The patent transitions from traditional 2D spatial-mosaic sampling to a 3D approach by combining spatial superpixel structures with spectral filtering dimensions. This multi-dimensional sampling strategy allows simultaneous capture of spatial, spectral, and superpixel-position information, enabling accurate spectral reconstruction through computational methods.
2Measurement precision
If demosaicing algorithms are used to address undersampling, then spectral data can be reconstructed, but spatial artifacts are introduced that corrupt subsequent analysis
Solution Approach 1:
The patent introduces superpixels as an intermediary structure between individual pixels and the final spectral image. Each superpixel acts as a local sampling unit with its own set of spectrally-filtered pixels, providing redundant spatial information that enables artifact-free spectral reconstruction without corrupting the original spatial content.
Solution Approach 2:
The patent changes the sampling parameter structure by organizing pixels into superpixel groups with specific geometric arrangements (2x2, 3x3, 4x4). This parameter change in spatial organization, combined with spectral filter assignment, creates a sampling pattern that avoids the aliasing and artifact problems of traditional mosaic demosaicing while maintaining spectral accuracy.
3Loss of information
If spatial filters (antialiasing filters) are used to reduce artifacts, then spatial information is preserved, but integration with external optics becomes less flexible
Solution Approach 1:
The patent extracts the spatial filtering function from the optical path and relocates it to the computational domain. By using superpixel-based spectral sampling with multiple pixels per superpixel, the system inherently provides redundant spatial information that eliminates the need for physical antialiasing filters, thereby maintaining optics integration flexibility while preserving spatial information.
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 imager provides improved spectral data accuracy and reduced spatial artifacts, enhancing machine perception capabilities while maintaining spatial information without the need for antialiasing filters and enabling faster optics integration.
Implementation Method 1
Each optical homogenizer is configured to spatially homogenize the received electromagnetic radiation
Implementation Method 2
Each spectral filter is configured to spectrally filter the spatially homogenized electromagnetic radiation differently from one another
Data Source
AI summary
An integral field spectral imager has a plurality of optical homogenizers. Each optical homogenizer is in-register with a corresponding different superpixel in a superpixel array and is configured to spatially homogenize incident EMR and to pass the spatially homogenized EMR to a spectral filter in an array of spectral filters, thence to the in-register, corresponding different superpixel. Baffles are included to maximize confinement of the spatially homogenized EMR passed by a single optical homogenizer to the in-register, corresponding different superpixel so as to minimize crosstalk between superpixels. Optical homogenizers and baffles are designed to produce a pattern of homogenized EMR on a superpixel, regardless of where incident EMR is received on an optical homogenizer. Methods for using embodiments of the spectral imager in a variety of spectral bands in the EMR spectrum enable determining spectral information about incident EMR.