In a laser beam X-Y scanning system for use, as for example, in turbid media such as sea water; the laser light reflected from objects is received by an image receiving device or detector such as a photomultiplier tube (PMT). The intensity level of the reflected light is maintained at an intensity level within the dynamic range of the image receiving device by controlling the effective intensity of the laser beam by varying the density of a plurality of series positioned variable neutral density filters positioned between the laser beam generator and the object to be illuminated or the illuminated object and the image receiving device. The light density of each filter is determined by real time environmental conditions and the instantaneous position of the laser light source relative to the object from which the laser light is reflected to the image receiver. The density of each of the plurality of filters is controlled by a computer.
A device for a motor vehicle includes at least one laser sensor. The laser sensor includes a device configured to sweep a scanning area with at least one laser beam emitted by the laser sensor and a power supply device for the laser sensor. In a method for operating a laser sensor in a scanning area with at least one laser beam, the power of the laser beam emitted by the laser sensor is varied in accordance with its direction of radiation.
An electronic distance measuring device that measures a distance from the electronic distance measuring device to an objective station. The electronic distance measuring device includes a radiation source for emitting frequency-modulated radiation towards a reflector disposed at the objective station, and a detector for detecting radiation reflected by the reflector. The distance of the objective station from the electronic distance measuring device is then calculated in accordance with the detected radiation. At least one radiation attenuating filter is positioned in a radiation path between the radiation source and the detector. The radiation attenuating filter is inclined with respect to a main axis of the radiation path so as to prevent incidence on the detector of an irregular reflection of the radiation by the attenuating filter.
A system for enhancing underwater visibility is described that uses left and right alternately chopped laser illumination, filtered wide baseline stereo imaging and specular reflectors for deblurring the images. Two stereo images are compared to determine the pattern of backscattered light and the resultant backscatter pattern is subtracted from the images. Inverse point spread filtering based on the fusion of the specular reflector pattern is next performed to further improve the images, and stereoscopic is display for enhanced visibility in turbid and murky mediums. The invention has broad application for underwater exploration and search and recovery operations, and is especially useful for detection and removal of underwater mine hazards.
A laser scanner for optically scanning and measuring an environment comprises a light transmitter having a predetermined transmission power for emitting a light beam. The emitted light beam is reflected at a measurement point in the environment. The reflected light beam is received with a certain intensity by a receiver. The transmission power is adjustable as a function of the intensity of the reflected light beam. Furthermore, a gray-scale value of the measurement point is determined as a function of the transmission power adjusted.
A rangefinder according to the present invention includes light source section, camera section, distance-measuring sensor, exposure controller and shutter. The light source section projects light onto an object for 3D imaging purposes. The camera section receives the light that was emitted from the light source section and then reflected from the object. The distance-measuring sensor estimates an approximate distance to the object. Based on the approximate distance, the exposure controller controls the optical output power of the light source section and/or the open/closed states of the shutter. The rangefinder can control the intensity of the projected light even if the object is on the move. As a result, the rangefinder can obtain highly precise information about the 3D location of the object.
