Signal processing, image registration, and visualization of FLASH lidar data

Microscanning is an effective technique for re-of the scene. One particular system that collects 3-D images ducing aliasing and increasing resolution in 2D images pro-is a FLASH LADAR imager [1], [2], [3], [4]. One drawback duced by non-coherent imaging systems. Both the aliasing of this readout technology is that it has not been miniaturized reduction and resolution enhancement are accomplished by to the same degree other image acquisition devices have, such increasing the effective spatial sampling interval through subas traditional silicon CCD (Charge Coupled Device) arrays. pixel movements of the field of view on the detector array.As a consequence ofthis the pixel pitches in FLASH LADAR In this paper the authors examine (using both simulated and imaging arrays are much larger than other imaging systems. real data) the application of microscanning on 3D coherent Large pixel pitches make it difficult to sample the scene at the imagery (with application to 2D coherent imagery). The ap-diffraction limit of the imaging system. This undersampling plication of Inverse filtering techniques are also examined to of the image produces a loss of spatial resolution. resolve difficulties associated with blurring by the detector and optical systems. The effects of blurring by the detec-Microscanning has been proposed as a method for attaintor and optical system decrease image resolution when miing diffraction-limited spatial resolution from imaging syscroscanning is attempted at sub-pixel movements of less than tems whose spatial sampling is inadequate to achieve the half the detector width. A discrete filter is designed using diffraction-limit [5], [6]. Application ofmicro-scanning techthe MTF of the imaging system. This filter is then applied niques to 3-D LADAR imaging systems imparts technical to images collected with a 128x128x20 FLASH 3D LADAR challenges not encountered in the 2-D micro-scanning probsystem. The authors also investigate the difficulties that arise lem. Chief among these problems is the fact that each 3-D when the MTF of the system is not well characterized and image cube will phase with the target differently than others when image registration errors and a low signal to noise ratio due to the fact that the time the FLASH LADAR imager beare present in the system. gins recording data depending on when the returning pulse exceeds some predetermined threshold. This means that the

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FLASH lidar data collections in terrestrial and ocean environments

Gelbart

Weber

Bybee-Driscoll

et al. 2003

SPIE Proceedings

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Two separate data collections using Arete Associates' FLASH lidar are presented. The hardware and the experimental arrangements are discussed. An airborne data collection over military targets in clear and obscuring camouflage environments provided high-resolution three-dimensional images for combat identification purposes. In the second field test, the sensor was suspended from a crane above the ocean surface to acquire FLASH imagery of anti-landing mines and obstacles in the highly turbid surf zone environment over a wide range of surf zone conditions.

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Signal processing, image registration, and visualization of FLASH lidar data

Cited by 5 publications

References 11 publications

Active Time-of-Flight 3D Imaging Systems for Medium-Range Applications

Active Time-of-Flight 3D Imaging Systems for Medium-Range Applications

The Application of Inverse Filters to 3D Microscanning of LADAR Imagery

FLASH lidar data collections in terrestrial and ocean environments

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