PSD-FPA Optical Sensor for Weapons Fire Detection
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Solution Overview
Problem
Existing optical systems for detecting and classifying weapons fire lack effectiveness in detection and false alarm rejection, and fail to cover the entire area of interest with combined passive and active illumination capabilities.
Innovation Solution
A new optical event detection system utilizing Position Sensing Detector Focal Plane Arrays (PSD-FPA) with advanced processing techniques for high-speed operation, including background subtraction, dual-gain switchover, and signature analysis, to accurately detect and classify weapons fire and other optical events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional imaging focal plane arrays are used for event detection, then the system can detect optical events, but the detection accuracy and false alarm rejection are insufficient
Solution Approach 1:
The system segments the detection task into multiple spectral bands by using multiple PSD-FPA sensors, each sensitive to different wavelength ranges. This segmentation allows the system to analyze events across different spectral characteristics, improving both detection accuracy and false alarm rejection by comparing multi-spectral signatures rather than relying on a single broad-spectrum detector.
Solution Approach 2:
The invention changes the operating parameters of the focal plane array by using PSD-FPA sensors that can operate at high frame rates (9000-12000 fps) and by implementing dual-gain modes. These parameter changes enable the system to capture fast transient events with high temporal resolution while adjusting gain settings to optimize signal-to-noise ratio for different event intensities, thereby improving detection precision and reducing false alarms.
2Measurement precision
If the system operates at high-speed data rates to detect fast artifacts, then accurate weapon detection is improved, but the complexity of signal processing increases
Solution Approach 1:
The system performs preliminary action by implementing background subtraction and initial event detection at the sensor level and in early processing stages. By pre-processing the high-speed data streams to identify potential events and remove background clutter before full analysis, the system reduces the complexity of subsequent processing while maintaining accurate weapon detection capability.
Solution Approach 2:
The invention implements dynamic processing where the system adapts its processing complexity based on detected events. During normal operation, processing is minimized, but when potential weapon events are detected, the system dynamically increases processing intensity and complexity. This dynamic approach allows high-speed operation with accurate detection while managing overall system complexity.
3Adaptability or versatility
If passive illumination only is used, then the system operates silently, but coverage and detection capability are limited
Solution Approach 1:
The system achieves universality by designing the optical sensor module to perform both passive detection and active illumination functions. The same PSD-FPA sensors can operate in passive mode to detect naturally occurring optical events or in active mode when illuminated by an external laser source. This multi-functionality expands detection capability across different operational scenarios without requiring completely separate sensor systems.
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 achieves accurate weapon detection, classification, and false alarm rejection with high-speed operation and precise location of optical phenomena, enabling effective detection of various types of weapons and events across the entire area of interest.
Implementation Method 1
an optical sensor module and an electronic control module... an optical lens sub-system focuses light onto one or more PSD-FPA(s)... which generate electronic signals
Data Source
AI summary
An event detection and classification system uses a new type of optical sensing component, a Position Sensing Detector Focal Plane Array (PSD-FPA). The PSD-FPA provides for high-speed operation that allows for accurate sensing of fast artifacts that are unique to weapons fire and enables precise location of optical phenomenon. The system detects and classifies events, particularly weapons fire, and rejects false alarms. An optical lens sub-system focuses light onto a PSD-FPA, which senses the photons and generates electrical signals associated with individual elements of the PSD-FPA. These signals are processed to identify and classify weapons-related or other events. Background subtraction, variable gain, time-intensity and time-location correlation, digital filtering, Fourier analysis, and wavelet analysis are all used to successfully classify the events while rejecting false alarms.