<title>Range-gated imaging for near-field target identification</title>

Abstract

The combination of two complementary technologies developed independently at Los Alamos National Laboratory (LANL) and Sandia National Laboratory (SNL) has demonstrated feasibility of target detection and image capture in a highly light-scattering medium. The technique uses a compact SNL developed Photoconductive Semiconductor Switch/Laser Diode Array (PCSS/LDA) for short-range (distances of 8 to 10 m) large Field-Of-View (FOV) target illumination. Generation of a time-correlated echo signal is accomplished using a photodiode. The return image signal is recorded with a high- speed shuttered Micro-Channel-Plate Image Intensifier (MCPII), designed by LANL and manufactured by Philips Photonics. The MCPII is gated using a high-frequency impedance-matching microstrip design to produce 150 to 200 ps duration optical exposures. The ultra fast shuttering produces depth resolution of a few inches along the optic axis between the MCPII and the target, producing enhanced target images effectively deconvolved from noise components from the scattering medium in the FOV. The images from the MCPII are recorded with an RS-170 Charge-Coupled-Device camera and a Big Sky, Beam Code, PC-based digitizer frame grabber and analysis package. Laser pulse data were obtained by the system but jitter problems and spectral mismatches between diode spectral emission wavelength and MCPII photocathode spectral sensitivity prevented the capture of fast gating imaging with this demonstration system. Continued development of the system is underway.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.