Abstract: An imaging lidar system is presented which is adapted to decrease the backscattering at the receiver when a target is viewed in reflection and to increase the backscattered reflection when the target is viewed in obscuration by operating the airborne lidar imaging system bistatically in the former case, and monostatically in the latter case. In accordance with a first embodiment of the present invention, a retractible prism and remote reflecting mirror are used to direct the laser transmitter beam downward. The reflecting mirror is offset so that there is a finite angle between the transmitter optical path and the path of the light reflected back into the CCD framing camera. The angle can be varied by moving the reflecting mirror along a track or rail with the appropriate adjustment to the mirror so that the transmitter beam is completely captured and directed downward to illuminate the area viewed by the camera.

Abstract: A new and improved laser light beam homogenizer for transforming a laser beam with spatially inhomogeneous intensity into a beam with a more nearly spatially uniform intensity pattern is presented. The light beam is diverged by a lens and presented to an integrator. The integrator transforms the beam into a beam with a more uniform illumination. The uniform illumination beam is then impinged on control optics to limit the divergence of the uniform beam and control higher order distortion in the system. This beam may then be illuminated at a predetermined distance by a projecting optic lens. The laser light beam homogenizer of this invention is particularly well suited for use in an imaging lidar system.

Abstract: Imaging devices often obtain images of a scene in which portions of the scene are obscured by particles that are interposed between the scene and the camera such as those images obtained when looking through falling snow or through particles stirred up by water currents in an underwater domain. An improved system for reducing the effects of those particles on reconstructed images of a scene consists of obtaining a number of images of a scene and replacing missing elements of the scene, which elements are ones obscured by the particles, with corresponding elements of the scene obtained from previous or following images in which those particular elements of the scene are visible. In this manner, a reconstructed image of the scene can be obtained in which the effects of the particles on the image is greatly reduced.