Modeling the Target Acquisition Performance of Staring Array Imagers.

摘要

The sampling limitations associated with staring array imagers cause an aliased signal that corrupts the image. The aliased signal is a function of pre-sample blur, sampling frequency, and post-blur or image reconstruction. Papers in the literature have quantified aliasing and sample artifacts. However, the affect of these artifacts on target acquisition has not been quantified. That is, the relationship between the amount of aliasing or such display artifacts as visible raster and the target acquisition task performance of a human observer has not been established. In this paper, we provide a description of current efforts at the Night Vision and Electronic Sensors Directorate (NVESD) to quantify the relationship between the sampling artifacts generated by a sampled imager and target acquisition performance using that sensor. Based on perception experiments performed at NVESD, the MTF Squeeze model was developed. The degraded performance due to under-sampling is modeled as an increase in system blur or, equivalently, a contraction or squeeze in the MTF. An improvement to the non-sampled linear systems performance model includes calculation of the sample-corrupted signal, calculation of the MTF squeeze, and the elimination of the half-sample rate spatial frequency limit. The MTF Squeeze technique is applied to two other sampling experiments and is shown to agree with their findings.