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<title>Nonuniformity correction for improved registration and high-resolution image reconstruction in IR imagery</title>

1999; SPIE; Volume: 3808; Linguagem: Inglês

10.1117/12.365831

1996-756X

Ernest E. Armstrong, Majeed M. Hayat, Russell C. Hardie, Sergio Torres, Brian J. Yasuda,

CCD and CMOS Imaging Sensors

It is well known that non-uniformity noise in focal-plane array (FPA) sensors, which is due to the pixel-to-pixel variation in the detectors' responses, can considerably degrade the quality of images since it results in a fixed pattern that is superimposed on the true scene. This paper addresses the benefits of non-uniformity correction (NUC) pre- processing on the performance of a number of existing post- processing algorithms. The post-processing applications considered are image registration (motion compensation) and high-resolution image reconstruction from a sequence of blurred and undersampled images. The accuracy of motion estimation in the presence of non-uniformity noise is investigated in terms of the standard deviation of the gain and the offset of the FPA detectors. Two recently reported scene-based NUC techniques are employed to pre-process the FPA output prior post-processing. The first NUC technique is based on the assumption that all pixels experience the same range of irradiance over a sufficiently long sequence of frames (constant-range assumption), and the second NUC technique is registration-based and can be used recursively. It is shown that NUC improves the accuracy of registration, and consequently, enhances the benefit of high-resolution reconstruction. It is also shown that under cases of severe non-uniformity noise, a recursive application of the registration-based NUC may further improve the accuracy of registration and high-resolution image reconstruction. The results are illustrated using real and simulated data.