David Maker (Photon Research Associates, Inc.)
Keywords: NROC, Non-Resolved Object Characterization
Abstract:
This technique incorporates Horizontal and Vertical (H&V) polarization hyperspectral techniques in the infrared for target discrimination. Normally polarization provides an impediment to target discrimination because of the uncertainties in polarized background illumination. Here the polarization provides a definite aid in target discrimination even if the spectrum and intensity of the target and background are the same. In that regard negative images are approximately equivalent to taking the stretched reciprocal of Fresnel coefficient terms. Note in the emissive Fresnel coefficients there is a difference numerator (e.g., A-B ? f(?n,i)?cosi-ncosi) instead of A+B) emissive that ends up in these two denominators if the image is negative. In the near infrared (2-5 microns) we also need an additional ROI V and image H polarization components negative image correlation because of strong surface roughness wavelength angular i dependence and the often weak wavelength dependence of n. These two difference denominators created in this way then have many more possibilities of zeros and higher correlation between emissive ROI and emissive target elements in the image. The main application here is in discriminating thermally thick (emissive) from thermally thin (reflective) targets even given the same spectrum and intensity. The technique has already been tested on ground targets and shown to work and could discriminate balloons from RVs as well since balloons are reflective and RVs emissive in the near infrared.
This method allows accurate appraisal of whether such targets are thermally thick.
Date of Conference: September 10-14, 2006
Track: Non-Resolved Object Characterization