Hyperpixels: Pixel Filter Arrays of Multivariate Optical Elements for Optimized Spectral Imaging

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Williams, Calum, Cousins, Richard, Mellor, Christopher J., Bohndiek, Sarah E., Gordon, George S. D.
Format: Preprint
Published: 2024
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866916175583117312
author Williams, Calum
Cousins, Richard
Mellor, Christopher J.
Bohndiek, Sarah E.
Gordon, George S. D.
author_facet Williams, Calum
Cousins, Richard
Mellor, Christopher J.
Bohndiek, Sarah E.
Gordon, George S. D.
contents We introduce the concept of `hyperpixels' in which each element of a pixel filter array (suitable for CMOS image sensor integration) has a spectral transmission tailored to a target spectral component expected in application-specific scenes. These are analogous to arrays of multivariate optical elements that could be used for sensing specific analytes. Spectral tailoring is achieved by engineering the heights of multiple sub-pixel Fabry-Perot resonators that cover each pixel area. We first present a design approach for hyperpixels, based on a matched filter concept and, as an exemplar, design a set of 4 hyperpixels tailored to optimally discriminate between 4 spectral reflectance targets. Next, we fabricate repeating 2x2 pixel filter arrays of these designs, alongside repeating 2x2 arrays of an optimal bandpass filters, perform both spectral and imaging characterization. Experimentally measured hyperpixel transmission spectra show a 2.4x reduction in unmixing matrix condition number (p=0.031) compared to the optimal band-pass set. Imaging experiments using the filter arrays with a monochrome sensor achieve a 3.47x reduction in unmixing matrix condition number (p=0.020) compared to the optimal band-pass set. This demonstrates the utility of the hyperpixel approach and shows its superiority even over the optimal bandpass case. We expect that with further improvements in design and fabrication processes increased performance may be obtained. Because the hyperpixels are straightforward to customize, fabricate and can be placed atop monochrome sensors, this approach is highly versatile and could be adapted to a wide range of real-time imaging applications which are limited by low SNR including micro-endoscopy, capsule endoscopy, industrial inspection and machine vision.
format Preprint
id arxiv_https___arxiv_org_abs_2403_16901
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Hyperpixels: Pixel Filter Arrays of Multivariate Optical Elements for Optimized Spectral Imaging
Williams, Calum
Cousins, Richard
Mellor, Christopher J.
Bohndiek, Sarah E.
Gordon, George S. D.
Optics
Image and Video Processing
We introduce the concept of `hyperpixels' in which each element of a pixel filter array (suitable for CMOS image sensor integration) has a spectral transmission tailored to a target spectral component expected in application-specific scenes. These are analogous to arrays of multivariate optical elements that could be used for sensing specific analytes. Spectral tailoring is achieved by engineering the heights of multiple sub-pixel Fabry-Perot resonators that cover each pixel area. We first present a design approach for hyperpixels, based on a matched filter concept and, as an exemplar, design a set of 4 hyperpixels tailored to optimally discriminate between 4 spectral reflectance targets. Next, we fabricate repeating 2x2 pixel filter arrays of these designs, alongside repeating 2x2 arrays of an optimal bandpass filters, perform both spectral and imaging characterization. Experimentally measured hyperpixel transmission spectra show a 2.4x reduction in unmixing matrix condition number (p=0.031) compared to the optimal band-pass set. Imaging experiments using the filter arrays with a monochrome sensor achieve a 3.47x reduction in unmixing matrix condition number (p=0.020) compared to the optimal band-pass set. This demonstrates the utility of the hyperpixel approach and shows its superiority even over the optimal bandpass case. We expect that with further improvements in design and fabrication processes increased performance may be obtained. Because the hyperpixels are straightforward to customize, fabricate and can be placed atop monochrome sensors, this approach is highly versatile and could be adapted to a wide range of real-time imaging applications which are limited by low SNR including micro-endoscopy, capsule endoscopy, industrial inspection and machine vision.
title Hyperpixels: Pixel Filter Arrays of Multivariate Optical Elements for Optimized Spectral Imaging
topic Optics
Image and Video Processing
url https://arxiv.org/abs/2403.16901