Resolved target detection in clutter using correlated, dual-band imagery

Larry B Stotts

doi:10.1117/1.oe.54.10.103109

Abstract

This paper develops a log-likelihood ratio test statistic for resolved target detection in dual-band imagery because the previous work indicates that most of the processing gains come from processing just two bands. Simple, closed-form equations for the closed-form probabilities of false alarm and detection are given. A computer simulation validates the theory. A constant false alarm rate version of the theory is applied to real available multiband data with quasi-resolved target sets and fixed clutter noise. The results show very reasonable performance in target detectability using three sets of correlated dual-band images. Finally, this paper shows that the resolved target detection problem depends on the weighted difference between the dual-band target contrasts. The theoretical development reaffirms that the signal-to-noise ratio or contrast-to-noise ratio is approximately the weighted difference squared, divided by the normalized total image noise variance.

Highlights

One of the most challenging problems is detecting dim targets in complex optical images
The constant false alarm rate (CFAR) probability of the detection curve for a perfect matched filter (MF) and Qfa 1⁄4 10−5 is included in these two figures to better illustrate the effects of the numbers of pixel observations and bands, K and M, on Qd
This paper developed a log-likelihood ratio test statistic for resolved target detection in dual-band imagery because previous work indicates that most of the processing gains come from processing just two bands

Summary

Introduction

One of the most challenging problems is detecting dim targets in complex optical images. The paper investigates resolved target detection hypothesis testing using highly correlated two-color imagery to obtain large signal processing gains to reduce clutter and extract the target’s location if it is present. It extends the classical approach development of Stotts and Hoff to dual-band target detection. The resulting approach provided simple expressions for the test statistic and the probabilities of false alarm and detection, unlike the normal quadratic detector that requires very complicated computation of these last two entities, even using either Monte Carlo simulations or numerical methods.32 This approach reconfirms that the electrical SNR is related to the Weber contrast and the normalized noise variance, as shown by Stott and Hoff.. Stotts: Resolved target detection in clutter using correlated, dual-band imagery

Background and Motivation for Two-Band Only Optical Detection Strategy

Theory Validations from Computer Simulation Results

Assumptions Sensitivity

Application of Theory to Real Data

Summary