Wide-Angle Thermal Imaging for Accurate Indoor Position Detection
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Solution Overview
Problem
Existing thermal imagers with wide-angle lenses provide distorted images, making it difficult to accurately determine the position of people in a monitored space, which complicates building management tasks such as occupancy tracking, power consumption adjustment, and fire protection device installation.
Innovation Solution
A method involving a thermal imager with a wide-angle lens that applies a wide-angle correction function to compensate for image deformation, using normalization, metric, and angular correction factors to determine the actual position of a person in a space, and a home automation sensor equipped with such a thermal imager for precise position detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a wide-angle lens is used in the thermal imager, then the field of view is increased allowing a larger area to be monitored, but the image becomes distorted making position determination inaccurate
Solution Approach 1:
The patent applies a wide-angle correction function that transforms the distorted polar coordinates (r, θ) obtained from the wide-angle lens into corrected Cartesian coordinates (x, y). This parameter transformation compensates for the optical distortion while preserving the expanded field of view, allowing accurate position determination across the entire monitored area.
2Measurement precision
If image distortion correction is applied to the entire thermal image, then position accuracy is improved, but computational complexity and processing time increase
Solution Approach 1:
Instead of correcting the entire thermal image, the patent extracts only the region of interest (the person) from the deformed image, determines its polar coordinates, applies the correction function to transform these coordinates into accurate position information, and uses this corrected position data for building management purposes. This selective approach maintains accuracy while minimizing computational overhead.
3Area of stationary object
If the thermal imager is installed at height to optimize monitoring coverage, then the monitored area is increased, but the distortion in the thermal image increases
Solution Approach 1:
The patent introduces a wide-angle correction function as an intermediary mathematical transformation between the distorted polar coordinates captured by the high-mounted thermal imager and the desired Cartesian position coordinates. This correction function acts as a mediator that eliminates the distortion effect while preserving the advantage of high installation position for expanded coverage.
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
Enables accurate determination of person positions for improved building management, including precise occupancy tracking, reduced over-counting, and efficient power consumption adjustments, while maintaining low computational requirements.
Implementation Method 1
a thermal imager capable of sensing the infrared radiation emitted by the bodies present in the space and of creating thermal images of the space based on this sensed radiation
Data Source
AI summary
A method for obtaining the position of a person in a space of a building via a thermal imager including a wide-angle lens, the method including: acquiring, with the thermal imager, through its wide-angle lens, a deformed thermal image of a scene including the person, the deformed thermal image including a hot zone corresponding to the person present in the scene; extracting a region of interest corresponding to the person from the deformed thermal image using an algorithm; determining the position of the region of interest by identifying the polar coordinates distance r and angle θ of the centre of the region of interest in a polar coordinate system the origin of which is at the centre of the deformed thermal image; and obtaining the actual position of the person by applying a wide-angle correction function to the distance r.