SPD Array Persistence Filtering for False Positive Suppression
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Solution Overview
Problem
High-speed imaging systems using single-photon detectors face challenges in distinguishing between genuine photon detections and false positives caused by thermal noise and ambient light, leading to reduced accuracy and increased false positives, which limits their ability to achieve high voxel rates with minimal errors.
Innovation Solution
Implementing a persistence condition where detection signals must be consistently positive across multiple observation windows to confirm genuine photon incidences, filtering out false positives and ensuring only confirmed detections are processed, while also considering coincidence conditions to verify spatially clustered photon incidents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If single-photon detectors (SPDs) are used to increase photosensitivity for detecting low photon densities, then detection speed and resolution are improved, but false positives increase due to thermal noise and ambient light
Solution Approach 1:
The system performs preliminary actions by recording detection signals over multiple observation windows before making a final determination. The persistence condition requires that a detection signal must be positive in at least M out of N observation windows to be considered a genuine detection, filtering out random false positives from thermal noise and ambient light
Solution Approach 2:
The system uses feedback by comparing detection signals across multiple observation windows and applying persistence conditions. The evaluation circuit continuously monitors detection signals and uses historical data from previous windows to determine whether a current detection is genuine or a false positive, creating a feedback loop that improves detection reliability
2Productivity
If the processing time per voxel is reduced to achieve high voxel rates (tens or hundreds of millions per second), then imaging speed is improved, but detection accuracy decreases due to limited photon capture time
Solution Approach 1:
The system applies periodic action by using multiple observation windows to evaluate detection signals. Instead of making a single determination per voxel, the system periodically samples the detection signal across N observation windows and applies persistence conditions (requiring M positive detections out of N windows), enabling high-speed processing while maintaining accuracy through temporal sampling
Solution Approach 2:
The evaluation circuit performs preliminary evaluation of detection signals across multiple observation windows before final image reconstruction. This preliminary action filters out false positives early in the processing pipeline, allowing high voxel rates to be achieved without sacrificing detection accuracy
3Measurement precision
If sensor arrays have increasingly more separate detectors (pixels) to improve spatial resolution, then resolution is improved, but computing power requirements increase and photosensitivity decreases due to smaller pixel size
Solution Approach 1:
The persistence filtering is performed as a preliminary action at the detector level before data is sent to the central processing unit. Each detector element independently applies persistence conditions to its own detection signals, filtering out false positives locally. This reduces the computing burden on central processors while maintaining high spatial resolution across large sensor arrays
Solution Approach 2:
The system segments the detection and processing function by distributing evaluation circuits across multiple detector elements. Each detector element independently evaluates its own detection signals using persistence conditions, dividing the overall processing task into many small independent units. This segmentation reduces the computing power requirement for the central system while maintaining high spatial resolution
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
This approach significantly reduces false positives, enhances detection accuracy, and allows for higher voxel rates by confirming genuine photon detections, thereby improving the overall performance and reliability of high-speed imaging systems.
Implementation Method 1
capturing photons on a plurality of single photon detectors (SPD), preferably single photon avalanche detectors (SPAD), which generate a detection signal
Data Source
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AI summary
The present invention relates to a system, detector element and method for high-speed imaging with SPD arrays, and a calibration routine for SPD arrays.