The Design of the Synchronization Control Circuit Based on CPLD for the Range-gated Laser Imaging System

摘要

Some missions such as search and rescue (SAR) and general surveillance must work in low-light-level and low visibility conditions to find and identify targets. Passive night vision systems can't provide sufficient resolution and adequate contrast in low-light-level conditions. Some of the deficiencies can be overcome by the addition of a pulsed laser illuminator synchronized to a gated camera. Range gating can eliminate most of the light backscattered by aerosols and is immune to some extent to blooming effects specific to highly sensitive cameras. The synchronization control technique is one of the most key techniques in the range-gated imaging system. Conventional control circuits are composed of discrete components and Medium Scale Integration (MSI) and Small Scale Integration (SSI), which have bad reliability and poor ability of anti-interference. On the basis of analyzing the performance requirement to the synchronization control of the range-gated imaging system, a new synchronization control circuit based on CPLD is presented. The circuit based on CPLD is very compact and flexible and has high reliability and strong ability of anti-interference. The synchronization control circuit based on CPLD can provide a wide selection of gate widths, pulse widths and delays. The image resolution of range-gated imaging system can be improved by conveniently adjusting the pulse delay and the pulse width.