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We propose a ground target recognition method based on 3D laser radar data. The method handles general 3D scattered data. It is based on the fact that manmade objects of complex shape can be decomposed to a set of rectangles. The ground target recognition method consists of four steps; 3D size and orientation estimation, target segmentation into parts of approximately rectangular shape, identification of segments that represent the targets functional/main parts and target matching with CAD models. The core in this approach is rectangle estimation. The performance of the rectangle estimation method is evaluated statistically using Monte Carlo simulations. A case study on tank recognition is shown, where 3D data from four fundamentally different types of laser radar systems are used. Although the approach is tested on rather few examples, we believe that the approach is promising.Keywords: Rectangle estimation, laser radar, automatic target recognition 1 Ground target recognition using rectangle estimation Christina Grönwall, Fredrik Gustafsson, Mille Millnert Abstract-We propose a ground target recognition method based on 3D laser radar data. The method handles general 3D scattered data. It is based on the fact that man-made objects of complex shape can be decomposed to a set of rectangles. The ground target recognition method consists of four steps; 3D size and orientation estimation, target segmentation into parts of approximately rectangular shape, identi cation of segments that represent the target's functional/main parts and target matching with CAD models.The core in this approach is rectangle estimation. The performance of the rectangle estimation method is evaluated statistically using Monte Carlo simulations. A case study on tank recognition is shown, where 3D data from four fundamentally different types of laser radar systems are used. Although the approach is tested on rather few examples, we believe that the approach is promising.

Tel: +46 13 31 80 00, Fax +45 13 33 16 65 1 Abstract A C02-ladar system is used for measurements. The signal from the system is a sinusoidal FMmodulated multi-component signal. To extract the modulating frequencies time-frequency representations, e.g., the Wigner-Ville distribution (WVD) and the Choi-Williams distribution (CWD) are used. The estimation method is applied both to simulated and real data. Estimation of the vibration frequencies is shown to be feasible even for low SNR, e.g., -4 dB.

A coherent laser radar system based on semiconductor laser technology has been designed and built. The compact design and the absence of adjustments makes the system mechanically robust and easy to use. The present system has an output power of 50 mW and a line width of 280 kHz (HWHM). The laser radar system has been used in vibrometry measurements. For vibrometry of moving objects, adaptive signal processing is required in order to obtain the vibration signature. Especially for unresolved objects, interference between di erent vibrating parts will complicate the analysis. Modelbased estimation techniques are used to obtain the parameters which determine the dynamics of the re ecting object. Key words: coherent laser radar, vibrometry, modelbased signal processing 2 INTRODUCTION Coherent laser radar (CLR) systems have been investigated over several decades primarily for military applications. In order to receive a more general industrial acceptance, compact, robust, cost-e ective systems and more general signal processing tools must be developed. Semiconductor laser technology can achieve both high power and narrow line width without using external cavity designs. This allows the design of very compact systems without any m o vable parts such as pzt-elements. A critical feature is the tolerance designing, allowing for laser welding of the interferometric block. The design is also compatible with distributed ber sensor systems. The compact design and the absence of adjustments makes the system mechanically robust and easy to use. Semiconductor lasers can easily be broadband frequency modulated, and various applications can be addressed by making use of this property. For range/Doppler measurements, chirping or frequency shift keying can be applied. If necessary, a frequency shifted signal can, be obtained by using ,e.g., an acousto-optic modulator. CLR