Image restoration of infrared focal plane array

Abstract

Imaging system mentioned in this work is made up of a cryogenic infrared focal array (IR FPA). Images acquired from such system always have degradations due to diffraction and aberration in the optical system, atmospheric degradation source, relative motion between the camera and the original scene, integral sampling of the detector arrays, defocusing and so on. Restoration is essential to an infrared imaging system. The degradation model based on a convolution product is presented, and a restoration method based on a modified Wiener filter is proposed. Newton-Raphson method is used in the optimal parameter search procedure. The model is based on the uniform detectors assumption, but in practical applications such assumption cannot be satisfied. So a pre-process is needed to correct the nonuniformity to meet the assumption. Blind pixels compensation is also included in the pre-process procedure. Moreover, to avoid the ringing that may be created by Wiener filter, a boundary expansion method is applied before restoration procedure. To assess the restoration effect, we select image definition as the measurement criteria, and the calculation results show that the restored images have much higher definition than the degraded image. The restoration procedure is applied to an Oriental Pearl infrared image.