Visual Enhancement and Non-Uniformity Elimination (VENUE)

Many focal plane array sensors have a common problem due to nonuniformities in each image pixel, caused by variation in properties of individual detector elements, nonuniform gains and offsets, and parameters drifting over time. This results in frame-to-frame fixed pattern noise (FPN) in image data, which affects the ability to detect and classify targets. The problem becomes worse when dealing with polarization because of the image processing involved in generating the polarization images. Most of the factory correction approaches are inadequate due to the drift of pixel response over time. Mechanical correction in the field is often cumbersome, impractical, and inadequate to accommodate changing scene conditions. Scene-based nonuniformity correction (SBNUC) methods can work continuously without blocking the optical path and have no moving parts to break; however, they typically depend on the motion of the scene. To address these challenges, Charles River Analytics proposes Visual Enhancement and Non-Uniformity Elimination (VENUE) software to compensate for noise in infrared polarimetric microgrid sensors. VENUE applies SBNUC to individual polarized orientations before the degree of linear polarization image is constructed using an algorithm that combines detection and correction techniques.