Analyzing reflectance based color changes in sensing applications
Inventors
Malanoski, Anthony P. • White, Brandy J. • Erickson, Jeffrey S. • Stenger, David A.
Assignees
Government Of United States, As Presented By Secretary Of Navy • US Department of Navy
Publication Number
US-10900891-B2
Publication Date
2021-01-26
Expiration Date
2037-05-27
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Abstract
Systems and methods are provided for identification of a detection event relevant in applications focused on real-time or near real-time reporting in a continuous monitoring application. A controller collects data from a plurality of sensors and compares recent data to background data to determine whether an event has occurred. A system in accordance with an embodiment of the present disclosure is considered to have detected an event of interest when at least a specified minimum number of sensors report a detection event at the same time.
Core Innovation
The invention provides systems and methods for identification of a detection event relevant in real-time or near real-time reporting in continuous monitoring applications using color sensor devices. A controller gathers color data from multiple sensors, generates multiple sliding data windows (background, active, and snap windows), and compares recent data to background data to determine whether an event has occurred. This is accomplished by analyzing the reflected color changes from indicator materials, especially porphyrin and metalloporphyrin indicators, which respond differentially across classes of targets.
The core problem addressed by the invention is the need for a flexible chemical sensing platform that can scale in size, cost, and power consumption to support distributed wireless sensor networks, particularly in portable or autonomous applications. Existing colorimetric sensing methods often rely on post-exposure image capture requiring extensive computation and are unsuitable for real-time, low-power, or portable sensor systems. The invention overcomes this by employing reflectance-based color measurement without image capture and by using algorithms that analyze color data onboard to report detection events with minimal false positives and efficient processing.
Claims Coverage
The patent includes three independent claims covering a sensor system, a method for detecting events, and a sensing device, each incorporating novel features related to data windows and event detection using multiple color sensors and indicators.
Use of multiple sliding data windows for event detection
The system generates background, active, and snap sliding windows of gathered color sensor data, where each successive window is a subset of the previous, progressively smaller, allowing real-time comparison of current and recent data to background data.
Multi-sensor and multi-indicator event determination
An event is determined to have occurred only if at least two or a specified minimum number of color sensor devices detect a potential event simultaneously, thereby reducing false positives and improving reliability.
Response threshold determination using standard deviation and slope techniques
Response thresholds for each color sensor device are determined based on gathered data using either a standard deviation technique or a slope based technique. The slope based technique involves calculation of threshold angles, slope values, and r2 values over data windows and compares angles via cosine values to detect changes.
Integration of differential indicators for target class identification
The sensor devices include an array of differentially responsive indicators across classes of targets (including porphyrins and metalloporphyrins), enabling semi-specific detection and potential target classification based on unique colorimetric signatures recorded by the RGB sensors.
Use of LED pulsing synchronized with RGB sensors for color measurement
The sensor devices use LEDs pulsed during measurement intervals to illuminate the indicators, with RGB sensors capturing color data without image-based processing, minimizing power consumption and processing demands.
The claims collectively cover a sensor system, method, and device that utilize a multi-window, multi-sensor approach with configurable thresholds determined via standard deviation or slope analysis to detect environmental changes through reflectance-based color sensing of differential indicators, specifically addressing real-time event detection with reduced false positives in an autonomous or portable context.
Stated Advantages
Provides real-time or near real-time detection of chemical or environmental targets with minimal false responses by combining multiple color channels (RGB) and multiple indicator array elements.
Automatically adjusts to the overall intensity of collected data, enabling adaptability to different device variations and indicator behaviors.
Enables use with low power, portable, and autonomous devices by employing simple functions compatible with microcontrollers capable of performing limited floating-point operations.
Reduces power consumption and computational load by eliminating the need for image capture and processing, using reflectance-based color sensors and pulsed LEDs.
Facilitates scalability and flexibility for distributed wireless sensor networks through a system that can be adapted in size, cost, and power consumption.
Documented Applications
Real-time detection of threats using autonomous or portable sensor systems.
Long-term, autonomous environmental monitoring both indoors and outdoors.
Wearable sensor applications.
Air quality monitoring.
Potential use with unmanned ground vehicles or unmanned systems requiring onboard data analysis.
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