Applications of Tunable Lasers to Laser Radar and 3D Imaging

摘要

This report demonstrates the remote sensing of a scattering object's size, shape,and surface properties using techniques based on the wavelength dependence of laser speckle. Originally, these techniques were motivated by applications of laser radar to target discrimination in ballistic missile defense. More recently, the emphasis has shifted to industrial applications of 3D imaging involving machine vision and dimensional metrology. Consequently, the report addresses a wide range of techniques and potential applications. For applications to target discrimination, the capability of obtaining high-resolution measurements of the target's range-resolved laser radar cross section is emphasized. Submillimeter range resolutions are demonstrated in the laboratory. The analytical background is also included for predicting and understanding target signatures based on knowledge of the target's shape and the scattering properties of its surface materials. Two approaches to high-resolution 3D imaging are considered that have many potential industrial applications. The first approach is an extension of the technique for measuring range-resolved laser radar cross section. The second approach relies on the wavelength dependence of laser speckle to provide range information and conventional optical imaging to provide lateral information. These techniques are analyzed theoretically and demonstrated in the laboratory. Together, they cover object sizes ranging from millimeters to meters.