3-D Imaging of Partly Concealed Targets by Laser Radar

摘要

Imaging laser radar can provide the capability of high resolution 3- D imaging at long ranges. In contrast to conventional passive imaging systems, such as CCD and infrared (IR) techniques, laser radar provides both intensity and range information which adds an extra dimension to the image. Furthermore, laser radar has the ability to penetrate sparse obstructions, such as foliage and camouflage nets, which enables detection and recognition of partly concealed objects. 3-D laser radar can also be employed to see through windows and to create 3-D images of objects inside a building. We demonstrate that this is possible even through curtains or with Venetian blinds down. Also, disturbing reflexes, particularly in shaded glass, that can reduce the performance of passive sensors, presents no obstacle for the laser radar to image through windows. This capacity can, e.g., be of use in urban applications. Although we use a commercial scanning 3-D laser radar (ILRIS 3-D from Optech Inc.), with a rather low data rate, the collected data indicate the type of information that can be obtained with a staring 3-D flash imaging laser radar. Such systems will provide the capability of high resolution 3-D imaging at long ranges with cm-resolution at full video rate. This will also make it possible to image dynamic scenes. In this paper we will give examples of 3-D data from targets that are partly concealed in vegetation or under camouflage nets, as well as behind windows, and discuss how the data can be used.