ABSTRACT
A novel approach to segmentation of laser radar range images is presented. The approach is based on modeling horizontal and vertical scans of the terrain as piecewise-constant or piecewise-linear functions. The approach uses adaptive estimation based on Kalman filtering techniques. The performance of the segmentation algorithm is evaluated by application to laser range measurements. We also discuss how the output from the segmentation algorithm can be used for, e.g., object detection.
ABSTRACT
To understand the fundamental limit of performance with a given laser radar system, the phase noise of a testbed laser radar has been investigated. Apart from the phase noise in the transmitter laser and the local oscillator laser, additional phase noise was introduced by vibrations caused by fans in power supplies and cooling systems. The stability of the mechanical structure of the platform was also found to be of great importance. Furthermore, a model for the signal variations from diffuse targets has been developed. This model takes into account the stray light, the speckle decorrelation, and Doppler shift due to moving targets.
ABSTRACT
Measurements of signal amplitude distributions with a FM-cw CO2 laser radar have been made against various targets in both imaging and staring modes. Data show good agreement with theoretical distributions. From the measurements conclusions are drawn about the atmospheric- as well as target-induced effects. Beam wandering effects are shown to be of importance in the staring mode.
ABSTRACT
Experimentally verified signal amplitude distributions from a coherent CO2 laser radar have been used to derive radar performance for atmospheric remote sensing and hard target detection. Different target types include man-made diffuse, semirough, and glint targets as well as terrain backgrounds. The results, given as gas concentration accuracy and probability of detection, respectively, show the importance of including beam wandering especially for glint targets. It is shown how Doppler sensing and range gating improve target detection against terrain background.
