Thermal Image Processing with Intensity-Based Ghost Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Thermal cameras suffer from ghost images caused by internal reflections, which are difficult to distinguish from actual objects and can obscure other objects of interest, and existing methods to suppress these reflections often require additional optical elements, complicating manufacture and reducing image quality.
Innovation Solution
A method for thermal image processing that suppresses ghost images by analyzing the frequency distribution of pixel intensities to determine if a hot object peak is separated from the thermal background by an intensity threshold, and adjusts pixel intensities to suppress the ghost image based on this analysis without adding optical elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If antireflective coatings are applied to reduce internal reflections, then ghost image suppression is improved, but the sensitivity of the thermal camera in the wavelength range is reduced
Solution Approach 1:
The patent replaces the optical/physical approach (antireflective coatings) with a computational/image processing approach. By analyzing pixel intensity frequency distributions and identifying characteristic patterns of ghost images, the system suppresses ghost images through digital processing rather than optical modifications, thereby maintaining full thermal sensitivity while eliminating the harmful reflections.
2Object-affected harmful factors
If curved protective windows or filters are added to defocus or attenuate reflected radiation, then ghost image suppression is improved, but device complexity and manufacturing costs increase
Solution Approach 1:
The patent substitutes complex optical elements (curved windows, specialized filters) with a computational algorithm that processes the thermal image data. The method identifies ghost images through frequency distribution analysis and suppresses them through pixel intensity adjustment, eliminating the need for additional optical components and simplifying the overall device architecture.
Solution Approach 2:
The thermal camera system performs ghost image suppression using its own captured thermal data without requiring external optical modifications. The processing unit utilizes the frequency distribution information already present in the thermal image to identify and suppress ghost images, making the system self-sufficient and avoiding additional hardware requirements.
3Object-affected harmful factors
If additional optical elements are introduced to reduce reflections, then ghost image suppression is improved, but image quality is degraded in situations without ghost images
Solution Approach 1:
The patent implements a dynamic, conditional ghost image suppression approach. The processing unit continuously analyzes the frequency distribution of pixel intensities and only applies suppression when characteristic ghost image patterns are detected. This dynamic adaptation allows the system to maintain optimal image quality in normal conditions while effectively suppressing ghost images when they occur, without the constant degradation caused by fixed optical modifications.
Solution Approach 2:
The method changes the processing parameters (pixel intensity values) selectively based on the detected presence of ghost images. By analyzing the frequency distribution and identifying peaks characteristic of ghost images, the system adjusts only the affected pixel intensities while leaving the rest of the image unchanged, thereby maintaining overall image quality while suppressing ghost artifacts.
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 method effectively suppresses ghost images, improving image quality and reducing false alarms, while being computationally efficient and adaptable to varying thermal dynamics without complicating the camera's manufacture.
Implementation Method 1
thermal camera is used to monitor temperature for early fire detection and/or detecting over-heating of objects
Implementation Method 2
ghost image of the hot object, which is caused by internal reflections of radiation from the hot object in the thermal camera
Data Source
Figure 1~4
Figure 2a~2c
Figure 3a~3c
AI summary
According to an aspect, there is provided a method for thermal image processing, the method comprising: obtaining a thermal image acquired by a thermal camera and depicting a scene; obtaining a frequency distribution based on pixel intensities of the thermal image; processing the frequency distribution to determine whether the frequency distribution comprises a peak, caused by a hot object in the scene, which is separated from a thermal background of the scene by more than an intensity threshold; and in response to determining that the frequency distribution comprises the peak which is separated from the thermal background by more than the intensity threshold, processing the thermal image to suppress a ghost image of the hot object in the thermal image, wherein the ghost image is caused by internal reflections of radiation from the hot object in the thermal camera, and wherein the processing of the thermal image comprises: estimating a location of ghost image pixels forming the ghost image; and suppressing the ghost image in the thermal image by adjusting intensities of the ghost image pixels.