Bolometer Array Image Correction via Electrical Resistance Calculation
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Solution Overview
Problem
Existing methods for correcting nonuniformities in images captured by bolometer arrays are either costly, require mechanical parts, or are computationally intensive and tedious to implement, failing to effectively address the pixelization and columnar effects in raw images.
Innovation Solution
A method that calculates the electrical resistances of active and blind bolometers at ambient temperature using reference measurements and activation energy, allowing for the determination of actual scene temperatures and correction of raw images without mechanical parts or extensive automation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mechanical shutter is used to correct nonuniformities by collecting reference images, then image correction is achieved, but device complexity and cost increase due to mechanical parts and motorization
Solution Approach 1:
The patent replaces the mechanical shutter system with a computational method. Instead of using physical components to block and measure reference images, the invention uses algorithmic processing of electrical resistance data from bolometers to correct nonuniformities. This substitution eliminates mechanical parts while achieving the same correction objective through mathematical operations on sensor data.
Solution Approach 2:
The patent creates a computational model (copy) of the reference measurement process. Rather than physically capturing reference images with a shutter, the system calculates equivalent reference data by measuring electrical resistances at known temperatures and using these to derive correction factors. This computational copy replaces the physical reference imaging process.
2Measurement precision
If reference measurements are taken at various temperatures with all bolometers closed, then temperature response characterization is achieved, but manufacturing time and cost increase
Solution Approach 1:
The patent performs preliminary characterization during the manufacturing process by measuring electrical resistances at two fixed temperatures (liquid nitrogen temperature and ambient temperature). These preliminary measurements establish the temperature response characteristics that are then used for correction during operation, eliminating the need for time-consuming reference measurements at multiple temperatures during calibration.
Solution Approach 2:
The patent changes the approach from measuring multiple temperature parameters to measuring electrical resistance parameters at fixed temperatures. By measuring resistance at two known temperatures and using the known temperature response model, the system derives correction factors without requiring actual thermal imaging at various temperatures, thus reducing calibration time.
3Measurement precision
If calibration tables are stored in memory space, then temperature correction is enabled, but manufacturing cost increases
Solution Approach 1:
The patent extracts the essential correction information from complex calibration tables and represents it through simple electrical resistance measurements at two temperatures. By taking out only the necessary data (resistance values at known temperatures) and using a mathematical model to derive correction factors, the system eliminates the need for large memory storage while maintaining correction accuracy.
Solution Approach 2:
The patent replaces expensive, large-capacity memory storage with a computational approach that uses minimal stored data (electrical resistance values). The correction is performed through real-time calculation rather than lookup in large calibration tables, effectively using a cheaper, more efficient solution that reduces manufacturing costs.
4Measurement precision
If complex algorithms are used to correct image nonuniformity, then correction capability is achieved, but computational requirements and cost increase
Solution Approach 1:
The patent changes the correction approach from complex image-space algorithms to simple electrical resistance parameter measurements. By working in the electrical domain rather than the image domain, the system uses straightforward resistance ratio calculations instead of computationally intensive image processing algorithms, reducing computational requirements while achieving the same correction goal.
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 simplifies image processing by eliminating the need for mechanical parts and automation, effectively correcting pixelization and columnar effects in images, resulting in a more cost-effective and efficient image correction process.
Implementation Method 1
When they are exposed to a scene with a view to acquiring an image, these bolometers, which are sensitive to the temperature of the scene, see their electrical resistance vary. In other words, the current flowing through each of the bolometers is dependent on the temperature of the scene, but also on the ambient temperature.
Data Source
AI summary
A method for processing a raw image characterized by raw measurements Sp(i,j) that are associated with active bolometers Bpix_(i,j) of an imager, which bolometers are arranged in a matrix array, the imager being at an ambient temperature Tamb and furthermore comprising blind bolometers Bb_(k), the method, which is executed by a computer that is provided with a memory, comprising the following steps:a) a step of calculating the electrical resistances RTc(i,j) and RTc(k), at the temperature Tamb, of the active and blind bolometers, respectively, from their respective electrical resistances RTr(i,j) and RTr(k) at a reference temperature Tr, said resistances being stored in the memory;b) a step of determining the temperatures Tsc(i,j) actually measured by each of the active bolometers Bpix_(i,j) from the electrical resistances calculated in step a) and from the raw measurements Sp(i,j).