Focal Plane Array Gain Normalization Without Thermoelectric Cooling
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Solution Overview
Problem
Focal plane arrays in imaging systems face challenges in producing accurate image data due to varying temperature, as system gain is not constant and conventional methods require temperature control using thermoelectric cooling.
Innovation Solution
A method to normalize focal plane array system gain by determining temperature and calculating gain using empirically derived coefficients, allowing for temperature-independent image data production without temperature control, using a temperature sensor and module to apply the calculated gain to the output of the focal plane array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermoelectric cooling is used to control FPA temperature, then system gain stability is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent extracts the temperature control function from the imaging system by removing thermoelectric cooling devices. Instead of actively controlling temperature, the system measures temperature variations and compensates for their effects through gain normalization calculations, thereby eliminating complex temperature control hardware while maintaining system gain stability.
Solution Approach 2:
The patent changes the approach from controlling the temperature parameter to controlling the system gain parameter. By measuring temperature and using it to calculate appropriate gain values through empirical coefficients, the system compensates for temperature-induced gain variations without actually controlling the temperature, thus resolving the contradiction between stability and complexity.
2Reliability
If thermoelectric cooling is used to control FPA temperature, then system gain stability is improved, but power consumption increases
Solution Approach 1:
The patent removes the power-consuming thermoelectric cooling devices from the system. By replacing active temperature control with passive temperature measurement and computational gain normalization, the system eliminates the high power consumption associated with thermoelectric cooling while maintaining system gain stability through software-based compensation.
Solution Approach 2:
The patent replaces the mechanical/thermal system (thermoelectric cooling) with an electronic/computational system (temperature sensing and gain calculation). This substitution eliminates the need for power-intensive active cooling while achieving the same goal of gain stability through mathematical compensation based on measured temperature variations.
3Reliability
If temperature control devices are used, then system gain stability is improved, but hardware size increases
Solution Approach 1:
The patent extracts and removes the bulky temperature control hardware (thermoelectric cooling devices) from the system. By relying on temperature measurement and computational compensation instead of active control, the system achieves gain stability with minimal additional hardware, thereby reducing overall system size.
4Device complexity
If empirical gain normalization is used, then device complexity is reduced, but measurement precision requirements increase
Solution Approach 1:
The patent implements a feedback mechanism where temperature measurements are continuously used to adjust system gain values. The measured temperature feeds into gain normalization calculations that compensate for temperature-induced variations, creating a closed-loop system that maintains gain stability through continuous measurement and adjustment without requiring complex active control.
Data Source
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AI summary
A method of normalizing FPA system gain for varying temperature includes determining an FPA temperature and calculating an FPA system gain as a function of the FPA temperature, system gain for the FPA at a reference temperature, and empirically derived coefficients. The method also includes applying the FPA system gain at the FPA temperature to condition output of the FPA to produce temperature independent image data. An imaging system includes a focal plane array (FPA) (102). A temperature sensor (106) is operatively connected to measure temperature of the FPA. A module (112) is operatively connected to the FPA and temperature sensor to calculate FPA system gain for the FPA as described above, and to apply the FPA system gain to condition output of the FPA to produce temperature independent image data. There need be no temperature control device, such as a thermoelectric cooling device, connected for temperature control of the FPA.