Research On The Method For Non-uniformity Correction Of Infrared Focal Plane Based On Optical Defocus

The staring infrared imaging system plays an important action in military filed and civilian field, because of its simplicity, compactness in structure, high sensitivity and low power depletion. The non-uniformity of infrared focal plane greatly limits the infrared image quality, and therefore the non-uniformity must be corrected. As a key of staring infrared imaging system, the non-uniformity correction technology is mainly researched in this paper. Firstly, the characteristics of infrared images are described and the reason to the non-uniformity is analyzed. Secondly, several popular non-uniformity algorithms are evaluated. Then the merits and defects of each algorithm are presented. Lastly, the non-uniformity correction method based on optical defocus is discussed. The diffraction effects are neglected when the system is defocusing seriously and point spread function is the geometric projection of the system exit pupil in the image plane. If each point in the scene is defocused a spot that can cover the whole detector, the irradiance in the detector will be absolutely uniform. The non-uniformity can be corrected by the one point correction or the one point correction + two point correction with the uniform irradiance.