Error smoothing through global source non-uniformity correction

A method of performing non-uniformity correction for an imaging system, the method comprising:

• receiving image data from a detector;
• retrieving, from a memory, a set of stored factory calibration reference data comprising stored correction coefficients, a cold reference frame acquired with a cold target at a first temperature, a hot reference frame acquired with a hot target at a second temperature, and a reference frame acquired with a shutter closed;
• acquiring an operational calibration reference frame;
• computing, using a data processor, updated correction coefficients based on the stored correction coefficients, the cold reference frame acquired with the cold target at the first temperature, the hot reference frame acquired with the hot target at the second temperature, the operational calibration reference frame, and the reference frame acquired with the shutter closed;
• computing, using the data processor, a non-uniformity correction based on the updated correction coefficients and a gain calculated by:
• Gain
• =
• meanHot
• -
• meanCold
• nHot
• -
• nCold
• ,
• where meanHot is a mean pixel output for the hot reference frame and meanCold is a mean pixel output for the cold reference frame, nCold is a pixel value in the cold reference frame, and nHot is a pixel value in the hot reference frame;
• determining, that a platform is moving;
• updating the non-uniformity correction based on motion of the platform;
• forming a corrected image by applying the updated non-uniformity correction to the image data;
• and
• outputting the corrected image.

A method of performing non-uniformity correction, the method comprising:

• receiving image data from a detector;
• retrieving, from a memory, a set of stored factory calibration reference data comprising stored correction coefficients, a cold reference frame acquired with a cold target at a first temperature, a hot reference frame acquired with a hot target at a second temperature, and a reference frame acquired with a shutter closed;
• acquiring an operational calibration reference frame;
• computing, using a data processor, updated correction coefficients by (i) a comparison of the operational calibration reference frame with the reference frame acquired with the shutter closed, (ii) the stored correction coefficients, and (iii) a gain calculated from the cold reference frame acquired with the cold target at the first temperature and the hot reference frame acquired with the hot target at the second temperature;
• computing, using the data processor, a non-uniformity correction based on the updated correction coefficients;
• forming a corrected image by applying the non-uniformity correction to the image data;
• and
• outputting the corrected image.