Error smoothing through global source non-uniformity correction

Abstract

A method of determining a temperature of an element in a scene includes providing a set of targets each characterized by a target temperature and measuring pixel output values for pixels in a detector array for the targets in the set of targets. Measuring pixel output values is performed at a plurality of detector temperatures. The method also includes mapping each pixel output value to one of a plurality of constant values, each of the plurality of constant values being associated with one of the target temperatures, assembling a scene temperature profile using the mapped pixel output values, and obtaining an image of the scene including the element, wherein the element is associated with a pixel of the detector array. The method further includes determining a pixel value associated with the element and computing the temperature of the element using the scene temperature profile.

What is claimed is: 
     
         1 . A method of determining a temperature of an element in a scene, the method comprising:
 providing a set of targets each characterized by a target temperature;   measuring pixel output values for pixels in a detector array for the targets in the set of targets, wherein measuring pixel output values is performed at a plurality of detector temperatures;   mapping each pixel output value to one of a plurality of constant values, each of the plurality of constant values being associated with one of the target temperatures;   assembling a scene temperature profile using the mapped pixel output values;   obtaining an image of the scene including the element, wherein the element is associated with a pixel of the detector array;   determining a pixel value associated with the element; and   computing the temperature of the element using the scene temperature profile.   
     
     
         2 . The method of  claim 1  wherein the set of targets comprise two targets. 
     
     
         3 . The method of  claim 1  wherein the plurality of detector temperatures comprise five or more temperatures. 
     
     
         4 . The method of  claim 1  wherein the scene temperature profile includes temperature data as a function of detector output data and is stored in a lookup table. 
     
     
         5 . The method of  claim 4  wherein the detector output data is post-NUC output data. 
     
     
         6 . The method of  claim 1  wherein determining a pixel value associated with the element comprises:
 measuring a number of counts associated with the pixel; and 
 computing a NUC-adjusted number of counts using factory calibration data collected using a shutter and operational calibration data collected using the shutter.