Aliasing and blurring in microscanned imagery

Electro-optic staring sensors, which sample a scene with pixels of finite size, generate images that are affected by aliasing and blurring caused by the sampling process. One potential method to reduce the effects of sampling is microscanning. In the microscan process, multiple images of the scene are generated. Between each successive image, the location of the image on the detector array is moved a fraction of a pixel. The set of images produced in the microscan process are then combined to form a single image. We present an analytical model of the microscan process. The model shows that the microscan process can significantly reduce aliasing in the reconstructed image, and that the process does not blur the image beyond the blur caused by the finite pixel aperture. The model also shows that factors such as the blur produced by the imaging optics and the fill factor of the detector array affect the reduction in aliasing produced by microscanning. We present a quantitative description of the effect of microscanning for selected cases of fill factor, optics blur, and number of microscan steps. We also present images produced by computer simulation which qualitatively verify the reduction in aliasing associated with the microscan process.