Thermal Imager Shutter Calibration for Microbolometer Accuracy
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Solution Overview
Problem
Microbolometer arrays in thermal imaging systems, used in applications like small satellites, face challenges with non-uniform responses to infrared radiation, leading to decreased measurement accuracy and the need for frequent calibration due to environmental changes and radiation exposure, which complicates temperature measurement and requires additional components for calibration, limiting their feasibility in space applications.
Innovation Solution
A thermal imaging system with a shutter assembly that acts as a controllable blackbody radiation source, allowing for calibration by adjusting its temperature and using it to generate reference temperature data for correcting measurement errors, thereby enabling accurate temperature measurements without additional components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If microbolometer arrays are used for thermal imaging, then power consumption is reduced and compact design is enabled, but measurement accuracy decreases due to nonuniform responses
Solution Approach 1:
The patent applies parameter changes by varying the temperature of the shutter assembly to multiple known values (e.g., 293K, 313K, 333K) during calibration. This allows the system to characterize the microbolometer array's response at different temperature conditions, compensating for nonuniform responses and improving measurement accuracy while maintaining the low-power advantage of uncooled microbolometers
2Measurement precision
If calibration is performed using extra components like flaps with blackbody emitters, then measurement accuracy is improved, but device complexity increases and observation surface is limited
Solution Approach 1:
The shutter assembly serves multiple functions: it acts as both the calibration target (emitting blackbody radiation at controlled temperatures) and the mechanical shutter for protecting the detector. This eliminates the need for separate calibration components, reducing device complexity while maintaining accurate temperature measurement capability
Solution Approach 2:
The shutter assembly performs self-calibration by serving as its own blackbody source. By controlling its own temperature to known values and measuring its emitted radiation, the system calibrates the microbolometer array without requiring external calibration equipment, simplifying the overall system design
3Measurement precision
If frequent calibration is performed to compensate for environmental changes, then measurement accuracy is maintained, but loss of time increases
Solution Approach 1:
The system performs calibration at periodic intervals or when triggered by specific conditions (e.g., temperature thresholds, eclipse transitions). The shutter assembly rapidly cycles through predefined temperature points, enabling quick calibration cycles that minimize time loss while maintaining accuracy under changing environmental conditions
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
The system provides a simple and accurate calibration mechanism for microbolometer arrays, allowing continuous temperature measurements with minimal stabilization, improving measurement precision and reducing the need for extra components, thus enhancing the feasibility of thermal imaging systems for space applications.
Implementation Method 1
A thermal imaging system with a shutter assembly that acts as a controllable blackbody radiation source
Implementation Method 2
an infrared sensing module comprising a plurality of infrared detectors, each configured to receive the infrared radiation from the object
Data Source
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Figure 3(a)~3(b)
AI summary
This application relates to a method and an imaging system for providing an infrared image of an object. The system comprises an optical element configured to capture infrared radiation from the object. The system also comprises an infrared sensing module and a processing unit. The infrared sensing module comprises a plurality of infrared detectors, each configured to receive the infrared radiation from the object after passage through the optical element and generate a measurement signal from the received infrared radiation. The processing unit is coupled to the infrared sensing module and configured to convert the measurement signals into temperature data associated with the object for providing the infrared image. In addition, the system comprises a shutter assembly disposed between the infrared sensing module and the optical element. The shutter assembly is configured to selectively pass the infrared radiation from the object through to the infrared sensing module. The shutter assembly comprises a temperature controller configured to adjust a temperature of the shutter assembly. The proposed method and system provide a simple calibration mechanism for an infrared imaging system.