Target-Based Smoke Detection Using IR Contrast
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Solution Overview
Problem
Conventional smoke detectors are impractical for large areas with high ceilings due to their point sensor design, requiring numerous installations and being costly and difficult to maintain, with beam-based detectors suffering from limited sensitivity and alignment issues.
Innovation Solution
A patterned target system using infrared radiation, comprising regions with IR absorption dye and reflective surfaces, processed by a camera and processor to detect smoke, allowing for simple installation and minimal maintenance, and functioning effectively under various light conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional point sensor smoke detectors are used, then detection is achieved in small local areas, but large numbers of detectors are needed for large areas
Solution Approach 1:
The patent transitions from point-based detection to area-based detection by using a camera to capture images of a target pattern. This dimensional change allows a single detector to monitor a large area by detecting smoke-induced contrast changes across the entire field of view, eliminating the need for multiple point sensors.
2Area of stationary object
If beam-based smoke detectors are used, then detection is possible in large areas, but precise alignment between emitter and receiver is required
Solution Approach 1:
The patent replaces the mechanical alignment system of beam-based detectors with an optical imaging system. Instead of requiring precise alignment between emitter and receiver, the system uses a camera to capture images of a target pattern, detecting smoke through contrast changes. This substitution eliminates alignment complexity while maintaining large area coverage.
3Ease of manufacture
If target-based smoke detection is used, then installation is simplified, but target contrast quality affects detection performance
Solution Approach 1:
The patent employs a target pattern with specific color properties that maximize contrast under various lighting conditions. The target uses colors that provide strong contrast in the visible spectrum and are sensitive to smoke-induced scattering, ensuring high measurement precision while maintaining installation simplicity.
4Device complexity
If low cost cameras are used, then system cost is reduced, but image quality degrades under low light conditions
Solution Approach 1:
The patent uses an active illuminator that periodically emits light to illuminate the target pattern. This periodic illumination ensures consistent image quality under various ambient light conditions, allowing the use of low-cost cameras while maintaining high measurement precision through controlled lighting rather than relying on ambient light.
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 provides cost-effective and robust smoke detection across large areas with reduced maintenance, immune to noise and false detections, and capable of detecting smoke under different light conditions without relying on precise alignment.
Implementation Method 1
The target contains a pattern comprising regions with IR absorption dye and reflective surface regions
Implementation Method 2
The target contains a pattern comprising regions with IR absorption dye and reflective surface regions
Implementation Method 3
A smoke detector includes a camera which responds to infra-red radiant energy
Implementation Method 4
Target-based smoke detection systems rely on the reduction in contrast of an observed target
Implementation Method 5
Target-based smoke detection systems rely on the reduction in contrast of an observed target
Data Source
AI summary
A smoke detector includes processing circuitry coupled to a camera. The field-of-view of the camera contains one or more targets, each having spatial indicia thereon. At least a portion of one of the targets is coated, at least in part, by an infra-red absorbing dye. The dye produces visually discernable dark areas on the coated target(s).