Fire Detection via Temporal Coherence Analysis of Video Brightness
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Solution Overview
Problem
Existing fire detection systems are limited in their ability to detect fires independently of the type of combustibles being consumed and often require direct line of sight, leading to performance limitations and increased costs due to sensitivity issues and obstruction problems.
Innovation Solution
A method involving the capture and analysis of digitized video images to compute temporal coherence factors, identifying regions with flickering patterns indicative of flames, which can detect fires across an entire monitored area and beyond direct line of sight using CCTV surveillance systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spectral sensors are used to detect fire at specific wavelengths, then detection reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies a single standard video camera sensor to detect multiple types of fires across different fuel sources by analyzing temporal coherence patterns rather than relying on fuel-specific spectral sensors. This universal approach eliminates the need for multiple specialized sensors while maintaining detection reliability across various combustion types.
Solution Approach 2:
Instead of using expensive spectral sensors that directly detect combustion wavelengths, the patent uses a standard video camera to capture visual images and computationally analyzes the temporal coherence patterns of brightness variations. This copying approach replaces physical spectral sensing with computational analysis of visual data, reducing hardware complexity and cost.
2Measurement precision
If sensors are placed close to the monitored area to maintain high sensitivity, then detection precision is improved, but the monitored area size is limited
Solution Approach 1:
The patent transitions from spatial proximity (physical distance) to temporal dimensionality by analyzing the time-varying brightness patterns across the entire video frame. By computing temporal coherence factors between pixels over time, the system maintains detection precision while monitoring large areas remotely, as the analysis occurs in the temporal domain rather than requiring close physical proximity to the fire source.
3Measurement precision
If direct line of sight is required for fire detection, then detection precision is improved, but adaptability to obstructions is reduced
Solution Approach 1:
The patent uses reflected light patterns as an intermediary to detect fires. Instead of requiring direct line of sight to the flame, the system captures light reflections from surfaces (walls, floors, objects) that have been illuminated by the fire. These reflected patterns maintain the temporal coherence characteristics of the fire source, allowing the system to detect fires through obstructions by analyzing the coherence of reflected light patterns rather than requiring direct visual access to the flame.
4Adaptability or versatility
If multiple spectral sensors are used to detect different fuel types, then adaptability is improved, but device complexity and cost increase
Solution Approach 1:
The patent employs a single video camera sensor that can detect temporal coherence patterns characteristic of fires from various fuel types (natural gas, oil, methanol, etc.). By analyzing the temporal variations in brightness across the entire monitored area and computing coherence factors, the system achieves universal fire detection capability without requiring multiple fuel-specific sensors, thereby reducing device complexity and cost while maintaining adaptability.
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 enhances fire detection reliability and sensitivity uniformly across a monitored area, reducing false alarms and costs by identifying flame reflections through computational analysis of brightness patterns, enabling early detection and notification within industrial, commercial, and residential settings.
Implementation Method 1
a video camera, capable of converting the captured images into two-dimensional bitmaps
Implementation Method 2
directly measuring the light that is radiated by a fire
Data Source
AI summary
The present invention provides a method and apparatus for detecting fire in a monitored area even if the flames are hidden behind obstructing objects. The steps of this method include: (a) detecting and capturing, at a prescribed frequency, video images of the monitored area, (b) converting the captured images into two-dimensional bitmaps of the temporally varying brightness values observed in the captured images, wherein the spatial resolution of this bitmap is determined by the number of pixels comprising the bitmaps, (c) specifying for any two of the pixels in the bitmaps a temporal coherence factor whose magnitude is a measure over a prescribed time of the similarities observed in the temporal variations of the brightness values being captured at each of the bitmap's pixels, (d) computing this temporal coherence factors for each of the prescribed set of pixels in the captured images, and (e) analyzing the computed temporal coherence factors to identify those sets of pixels that have temporal coherence factors whose values are above a prescribed threshold value, wherein this prescribed threshold value is set so as to identify those pixels that correspond to regions of the monitored area whose temporal variations in brightness indicate that the source of this brightness is a fire in the monitored area.