Microbolometer Array Correction via Common Scalar Parameters
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Solution Overview
Problem
Infrared camera sensor arrays face significant non-uniformity issues, leading to suboptimal image quality due to variations in pixel responses, which existing correction methods often address through cumbersome and power-intensive methods like shutters and Peltier devices, or computationally heavy processing that sacrifices detail.
Innovation Solution
A method that calculates common correction parameters to minimize differences between adjacent sensor elements, allowing for concurrent correction during image capture without the need for shutters or Peltier devices, using scale and offset factors to stabilize image quality across the array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a shutter is used to create uniform illumination for correction, then the 1pt table can be regularly updated, but the image is obscured for a period of time and reliability decreases due to moving parts
Solution Approach 1:
The patent removes the shutter component entirely from the system. Instead of using a mechanical shutter to create uniform illumination, the invention uses the existing non-uniform pixel responses to calculate correction factors, thereby eliminating the reliability issues associated with moving parts while maintaining correction accuracy
Solution Approach 2:
The patent replaces the mechanical shutter system with a computational approach. Rather than physically blocking radiation to create uniform illumination, the system uses mathematical algorithms to analyze pixel responses and calculate correction factors, substituting mechanical action with computational processing
2Measurement precision
If a shutter is used for regular correction updates, then correction accuracy is maintained, but power consumption increases
Solution Approach 1:
The patent eliminates the shutter mechanism that requires power to operate. By removing this component entirely and using computational methods instead, the system reduces power consumption while maintaining the ability to perform correction updates
Solution Approach 2:
The mechanical shutter operation is replaced with computational processing that consumes significantly less power. The system uses the natural variation in pixel responses during normal operation to calculate correction factors, eliminating the need for power-intensive mechanical movement
3Stability of the object's composition
If Peltier devices are used to stabilise array temperature, then temperature stability is improved, but cost and power consumption increase
Solution Approach 1:
The patent replaces the thermal management system (Peltier devices) with a computational correction approach. By calculating and applying correction factors that account for temperature-induced non-uniformities, the system maintains image quality without the high power consumption and cost of active thermal control
Solution Approach 2:
The patent changes the approach from controlling physical parameters (temperature) to correcting output parameters (pixel responses). Instead of actively stabilizing temperature, the system measures pixel responses under varying conditions and calculates correction factors that compensate for temperature effects
4Measurement precision
If complex computational methods are used to correct non-uniformity, then image quality improves, but processing load and computational cost increase
Solution Approach 1:
The patent applies local correction factors to each pixel based on its specific response characteristics. By analyzing and correcting each pixel's non-uniformity individually using simple comparative measurements, the system achieves high image quality without requiring complex global processing
Solution Approach 2:
The patent uses minimal computational action - simply comparing pixel responses and applying basic correction factors - rather than employing complex iterative algorithms. This partial approach achieves sufficient correction without excessive processing load
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 reduces the need for moving parts, power consumption, and computational load, enabling continuous operation with improved image stability and reduced component costs, while maintaining high image quality by directly correcting non-uniformities from image data.
Implementation Method 1
Infrared cameras measure infrared radiation (heat) incident upon a sensing array
Implementation Method 2
Each pixel consists of a thermally isolated 'bridge' of resistive material that is heated by incident radiation. The resistance of the bridge varies with its temperature
Implementation Method 3
Typically this is achieved by the use of one or more Peltier devices
Data Source
AI summary
A microbolometer comprises an array of sensor elements or 'pixels' each individually responsive to generate an output indicative of the intensity of infrared radiation incident thereupon. In practice there are significant non-uniformities in the response of each pixel and further processing of the outputs must take place to generate an accurate image. These non-uniformities are dealt with by means of individual correction factors to be applied to the outputs of each pixel in the image. Commonly, the correction used provides a constant offset (Ipt) and a linear gain correction (2pt). As the optimal values of these corrections drifts over time it is still necessary to provide further correction. In the present invention this is achieved by calculating one or more common scalar correction parameters that when applied to all of the individual correction factors before they are used to correct the output of the sensor elements will minimise the differences between the corrected outputs of adjacent sensor elements in the array when summed over a particular selection of sensor elements in the array.