Thermal Image Reflection Detection Using Cross-Sensor Mapping
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Solution Overview
Problem
Thermal cameras suffer from reflections which can be annoying to human viewers and cause false detections in automated analytics, necessitating a method to detect and compensate for reflections in thermal images.
Innovation Solution
A method involving a thermal image sensor and a visible light, near-infrared, or short-wave infrared sensor with overlapping fields of view, using coordinate mapping and image analysis to identify reflections, followed by compensation techniques such as interpolation, background data, or gradient-based correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If thermal cameras are used for monitoring in low light scenarios and large areas, then coverage and security monitoring capability are improved, but reflections occur causing false detections and viewer confusion
Solution Approach 1:
The patent introduces a visible light camera as an intermediary device to detect reflections in thermal images. The visible light camera captures reflections that occur in the thermal image, and through coordinate mapping and image processing, identifies reflection regions in the thermal image to remove or correct them, thereby improving detection accuracy while maintaining wide coverage
Solution Approach 2:
The system uses the visible light camera to provide feedback about reflection conditions in the thermal image. By continuously monitoring for reflections and adjusting the thermal image accordingly, the system maintains reliable detection across large coverage areas despite the presence of reflective surfaces
2Reliability
If a second thermal camera is added to detect and compensate for reflections, then reflection detection capability is improved, but system cost and complexity increase significantly
Solution Approach 1:
Instead of using a second thermal camera, the patent uses a visible light camera to create a copy or representation of the reflection conditions. The visible light image serves as a reference to identify and correct reflections in the thermal image, achieving reflection detection without the high cost and complexity of a second thermal camera
Solution Approach 2:
The visible light camera acts as an intermediary that bridges the gap between thermal and visible spectra. It detects reflections that affect the thermal image without requiring a second thermal sensor, thereby reducing system complexity while maintaining reliable reflection detection capability
Data Source
AI summary
A method of detecting a reflection in a first thermal image captured by a thermal image sensor and, a second image is captured by a visible light sensor, near infrared sensor, or short-wave infrared sensor having a field of view which overlaps a field of view of the thermal image. A relationship between coordinates in the thermal image and the second image is determined. A first object is detected in a first position in the thermal image. A candidate image area in a second position in the second image is analysed to determine if an object equivalent to the first object is present, the second position corresponding to the first position according to the relationship between the coordinates in the thermal image and the second image. In response to a determination that there is no equivalent object in candidate image area, it is determined that first object is a reflection.