It describes the current major principles and algorithms on printing monitor and audit tech-niques,including API hook,driver hook,virtual printer and queue polling.

Base on the research of virtual printer technology,the virtual printer system provides abundant secondary exploitation interface according to COM standard,in order to conveniently use virtual printer in third party system.

In the process of optoelectronic theodolite real-time interactive simulation,the high frame virtual image distortion can t be avoided because of the limit of hardware process capability.

Based on the related parameter transformation from virtual image to virtual sound environment,the integration of virtual image and virtual sound field was investigated in this paper.