Subpixel Equalization for Sequencing Image Crosstalk Attenuation
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Solution Overview
Problem
Existing DNA sequencing systems face challenges in accurately distinguishing true light signals from adjacent wells due to spatial crosstalk, leading to sequencing errors and reduced base calling accuracy.
Innovation Solution
Implementing an equalization-based approach using lookup tables (LUTs) to attenuate spatial crosstalk by training an equalizer with least squares estimation, maximizing the signal-to-noise ratio through coefficient learning and applying these coefficients to pixel intensities for improved base calling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a CCD camera is positioned directly adjacent to the fiber-optic faceplate to detect light signals, then detection sensitivity is improved, but spatial crosstalk between adjacent wells increases
Solution Approach 1:
The patent introduces an intermediary computational model (point spread function and equalization algorithm) between the CCD camera and the final image interpretation. This mathematical intermediary processes the raw pixel data to separate true well signals from crosstalk, allowing the camera to remain in direct contact with the faceplate while eliminating the harmful crosstalk effect through computational means.
Solution Approach 2:
The patent replaces mechanical or physical separation methods with a computational signal processing approach. Instead of physically moving the camera away from the faceplate or using optical isolation, the system uses digital image processing algorithms to substitute for the mechanical separation, achieving crosstalk reduction without sacrificing detection sensitivity.
2Productivity
If the density of analytes is increased to improve productivity, then sequencing throughput is improved, but spatial crosstalk between adjacent analytes increases
Solution Approach 1:
The patent changes the parameter of signal processing from direct intensity measurement to equalized intensity measurement using pre-computed lookup tables. By transforming how pixel intensities are interpreted through mathematical equalization, the system can handle higher analyte densities where crosstalk is more severe, effectively allowing increased productivity without being limited by crosstalk interference.
3Speed
If traditional image processing methods are used to analyze sequencing images, then processing speed is maintained, but base calling accuracy deteriorates due to uncorrected spatial crosstalk
Solution Approach 1:
The patent performs preliminary action by pre-computing the point spread function and generating equalization lookup tables before actual sequencing image analysis. This pre-processing step creates ready-to-use correction parameters that can be quickly applied during sequencing, maintaining processing speed while significantly improving base calling accuracy through crosstalk correction.
Data Source
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AI summary
The technology disclosed attenuates spatial crosstalk from sequencing images for base calling. In particular, the technology disclosed accesses an image whose pixels depict intensity emissions from a target cluster and intensity emissions from additional adjacent clusters. The pixels include a center pixel that contains a center of the target cluster. Each pixel in the pixels is divisible into a plurality of subpixels. Depending upon a particular subpixel, in a plurality of subpixels of the center pixel, which contains the center of the target cluster, the technology disclosed selects, from a bank of subpixel lookup tables, a subpixel lookup table that corresponds to the particular subpixel. The selected subpixel lookup table contains pixel coefficients that are configured to maximizes a signal-to-noise ratio. The technology disclosed element-wise multiplies the pixel coefficients with the pixels and determines a weighted sum.