SUMMARY PROBLEMInvestigate a weighted-difference signal-processing algorithm for detecting ground targetr by using dual-band IR data. RESULTSThree variations of the algorithm were evaluated: (1) simple difference; (2) minimum noise; and (3) maximum SNR. The theoretical performance was compared to measured performance for two scenes collected by the NASA TIMS sensor over a rural area near Adelaide, Australia, and over a wooded area near the Redstone Arsenal. The theoretical and measured results agreed extremely.well. For a given correlation coefficient and color ratio, the amount of signal-to-noise ratio gain can be predicted. However, target input SNRs and color ratios can vary considera-iy. For the targets and scenes evaluated here, the typical gains achieved ranged from a few dB loss (targets without color) to a maximum of approximately 20 dB. Accession For NTIS GRA&I DTIC TAB

An experiment involving the production and measurement of chemical vapors released from two volatile liquid solvents and a toxic gas was conducted on December 9, 1992 at a remote site near Sacramento, California. During this experiment, measured quantities of liquid diethyl ether and acetone and hydrogen chloride gas were released under controlled conditions inside a mobile home type structure. Vapor concentrations of the two solvents and the gas were measured both inside and outside the structure with a variety of techniques. Measurement equipment included a Bruel & Kjaer Type 1302 multi-gas monitor, Miran Foxboro 1BX portable ambient air analyzer, and Microtip photoionization detectors. Supporting meteorology data was also collected. Chemical vapor and meteorological measurements have been correlated and present a limited understanding of plume dynamics for this particular release scenario and difficult weather conditions. These experiments were carried out under high humidity conditions just after heavy rain. The data has been plotted to show the concentration dispersion over the period of chemical vapor presence for the known release quantities and exhaust rates. Typical concentrations measured were less than 1 ppm for diethyl ether and HCL and from 0.5 to 5 ppm for acetone at a distance of ten to twenty meters from the release point. The results of this experiment provide a quantitative description of low-concentration hazardous chemical releases which can be used to validate chemical plume models as well as determine the necessity, viability, and sensitivity of remote sensing detection concepts.