Infrared Imager Calibration for Dark Current Noise Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Infrared imaging systems face instability and fixed pattern noise due to non-uniformity issues, particularly in thermal infrared detectors operating at higher temperatures, which affect the effectiveness of factory-calibrated gain and offset maps.
Innovation Solution
A two-source calibration method using two different temperature sources and integration times is performed at the factory, followed by a single-source calibration in the field to update non-uniformity correction terms, incorporating dark current correction and integration time adjustments to stabilize detector performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If factory calibration with gain and offset maps is performed, then initial non-uniformity correction is achieved, but instability and fixed pattern noise persist during operation at higher temperatures
Solution Approach 1:
The patent performs a two-source calibration at the factory before the detector is deployed, capturing images at two different temperatures to pre-determine dark current characteristics. This preliminary action establishes a baseline that compensates for temperature-dependent dark current variations during later single-source field calibration, preventing instability rather than just correcting it afterward.
Solution Approach 2:
The patent changes the operational parameters by using two different integration times during the factory two-source calibration process. By capturing images with both short and long integration times at different temperatures, the system characterizes dark current behavior across multiple parameter states, enabling more robust correction that remains stable across varying operating conditions.
2Ease of operation
If single-source calibration is performed in the field, then calibration simplicity is improved, but accuracy is reduced due to inability to separate dark current from signal
Solution Approach 1:
The patent performs a two-source calibration at the factory before the detector is deployed, capturing images at two different temperatures to pre-determine dark current characteristics. This preliminary action establishes a baseline that compensates for temperature-dependent dark current variations during later single-source field calibration, preventing instability rather than just correcting it afterward.
Solution Approach 2:
The patent segments the calibration process into two distinct phases: a comprehensive two-source calibration performed at the factory to establish dark current characteristics, and a simpler single-source calibration performed in the field for updates. This segmentation allows the complex dark current separation to be done once under controlled conditions, while field calibration maintains simplicity without sacrificing accuracy.
3Measurement precision
If two-source calibration with different integration times is performed, then dark current correction accuracy is improved, but calibration complexity increases
Solution Approach 1:
The patent segments the calibration process into two distinct phases: a comprehensive two-source calibration performed at the factory to establish dark current characteristics, and a simpler single-source calibration performed in the field for updates. This segmentation allows the complex dark current separation to be done once under controlled conditions, while field calibration maintains simplicity without sacrificing accuracy.
Solution Approach 2:
The patent performs a two-source calibration at the factory before the detector is deployed, capturing images at two different temperatures to pre-determine dark current characteristics. This preliminary action establishes a baseline that compensates for temperature-dependent dark current variations during later single-source field calibration, preventing instability rather than just correcting it afterward.
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 mitigates instability and enhances the accuracy of non-uniformity correction, ensuring effective gain and offset map updates even with a single temperature source, improving image quality and reducing noise in infrared imaging systems.
Implementation Method 1
As an example, a plurality of sensors may be provided in an image detector array to detect electromagnetic (EM) radiation at desired wavelengths. In some cases, such as for infrared imaging... The infrared imager is configured to capture a first set of infrared images of a reference object
Implementation Method 2
The logic device is configured to determine a dark current correction map based on the second set of infrared images... determining a dark current correction map based on the second set of infrared images
Implementation Method 3
The logic device is further configured to generate a non-uniformity correction map based on the dark current correction map... generating a non-uniformity correction map based on the dark current correction map
Data Source
AI summary
Techniques for facilitating non-uniformity correction calibrations are provided. In one example, an infrared imaging system includes an infrared imager and a logic device. The infrared imager is configured to capture a first set of infrared images of a reference object using a first integration time. The infrared imager is further configured to capture a second set of infrared images of the reference object using a second integration time different from the first integration time. The logic device is configured to determine a dark current correction map based on the second set of infrared images. The logic device is further configured to generate a non-uniformity correction map based on the dark current correction map. Related devices and methods are also provided.