CORRECTION OF NON-UNIFORMITY OF RESPONSE IN SENSOR ARRAYS
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Abstract
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 (1pt) 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.
36 Citations
76 Claims
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1-53. -53. (canceled)
- 54. A method of calculating one or more common correction parameters for a set of individual correction parameters for sensor elements in a sensor array operable to capture an image by determining the one or more common correction parameters that when applied the individual correction parameters for each sensor element in the sensor array 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, where the common correction parameters are determined by calculating the common correction parameters that will minimise the sum of the squares of the differences between the corrected outputs of adjacent sensor elements.
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72. An apparatus comprising:
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a sensor array having a plurality of sensor elements; and a processing unit connected thereto, wherein the processing unit is operable calculate one or more common correction parameters for a set of individual correction parameters for sensor elements in the sensor array operable to capture an image by determining the one or more common correction parameters that when applied the individual correction parameters for each sensor element in the sensor array 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, where the common correction parameters are determined by calculating the common correction parameters that will minimise the sum of the squares of the differences between the corrected outputs of adjacent sensor elements. - View Dependent Claims (73, 74, 75, 76)
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Specification