Thermal Camera Detector Sensitivity Correction via Iterative Weighted Averaging

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing thermal imaging camera technologies face challenges in correcting non-uniform sensitivity of detector elements, leading to noise and errors in thermal image generation, particularly due to the absence of a shutter mechanism which disrupts real-time image display and requires extensive memory and computing resources for effective noise reduction.

Innovation Solution

A method that corrects non-uniform sensitivity by iteratively updating background frames with a weighted average of new and existing data, allowing for real-time image correction with minimal computing effort, reducing the influence of data deviations and long-term drift, and enabling continuous image frame correction without the need for frequent shutter phases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a shutter mechanism is used to correct non-uniform sensitivity, then measurement precision is improved, but device complexity and loss of time increase due to disrupted real-time image display

Engineering Contradiction:

Improvecorrection accuracyVSAvoidshutter mechanism

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the background frame data from the actual image sequence and processes it separately through iterative correction algorithms. By separating the background subtraction function from the main imaging path, the shutter mechanism becomes unnecessary while maintaining correction precision.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical shutter system with computational methods. Iterative background frame processing and numerical correction algorithms substitute for the physical shutter, eliminating moving parts while achieving the same correction objective.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a shutter mechanism is used to correct non-uniform sensitivity, then measurement precision is improved, but productivity decreases due to interrupted real-time image display

Engineering Contradiction:

Improvecorrection accuracyVSAvoidreal-time imaging speed

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent enables continuous background frame processing alongside real-time image acquisition. The iterative correction algorithm processes background data in the background, ensuring that useful imaging action continues without interruption while correction precision is maintained.

Inventive Principle:

Principle #20Continuity of useful action

3Measurement precision

If extensive memory and computing resources are used for noise reduction, then measurement precision is improved, but use of energy and device complexity increase

Engineering Contradiction:

Improvenoise reduction qualityVSAvoidcomputing energy

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies iterative correction with weighted averaging that processes only the necessary portion of background data with appropriate weighting factors. This partial processing approach achieves sufficient noise reduction without requiring exhaustive computation of all possible correction parameters.

Inventive Principle:

Principle #16Partial or excessive action

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 significantly improves imaging quality by reducing noise and maintaining real-time image display, expanding the application of thermal imaging cameras in time-critical scenarios while minimizing memory and computing requirements.

Implementation Method 1

a thermal image can be generated particularly in the medium and far infrared range by a matrix of temperature-sensitive resistors (detector elements), such as a matrix-shaped arrangement of microbolometers

Methodology Applied

Scientific EffectInfrared detection: Photoelectric Effect

Implementation Method 2

The individual detector elements of the FPA's are usually subjected to a bias voltage and then allow a temperature-dependent current

Methodology Applied

Scientific EffectThermoresistive effect: Thermo-resistive Effect

Data Source

PatentEP2393286B1Method and device for correcting non-uniform sensitivity of detector elements of thermal image cameras

Publication Date: 2015.01.28 ESW

Figure 1
Figure 2
Figure 3

AI summary

Method and apparatus for correcting inconsistent sensitivity of detector elements in thermal imaging cameras, wherein, during shutter phases with the beam path of the thermal imaging camera closed, background frames are acquired from an internal reference, the changes between the background frames of the shutter phases are registered, and an updated background frame is generated which is used to correct at least one image frame, characterized in that the updated background frame is generated from at least one newly acquired background frame and a background frame to be updated by multiplying the data of each pixel of the newly acquired background frame by a first factor and adding it to the data of each pixel of the background frame to be updated, multiplied by a second factor.where the first factor is a value between zero and one, and the second factor is the difference between one and the first factor, thus providing the data of each pixel of the updated background frame as an accumulated weighted average.