Senising on uavs for mapping and obstacle avoidance

Abstract

Structured light approaches utilize a laser to project features, which are then captured with a camera. By knowing the disparity between the laser emitter and the camera, the system can triangulate to find the range. Four, 185 degree field-of-view cameras provide overlapping views over nearly the whole unit sphere. The cameras are separated from each other to provide parallax. A near-infrared laser projection unit sends light out into the environment, which is reflected and viewed by the cameras. The laser projection system will create vertical lines, while the cameras will be displaced from each other horizontally. This relative shift of the lines, as viewed by different cameras, enables the lines to be triangulated in 3D space. At each point in time, a vertical stripe of the world will be triangulated. Over time, the laser line will be rotated over all yaw angles to provide full a 360 degree range.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
         1 . A sensing device for UAVs, comprising:
 a UAV;   a structured light sensor;
 the structured light sensor configured to use the size of the quadrotor, in order to provide a disparity requirement; and 
   a computer or microprocessor to process the structured light sensor information; and   the computer or microprocessor sending the structured light sensor information to one or more recipients.   
     
     
         2 . The sensing device for UAVs of  claim 1 , wherein the processing is used for obstacle avoidance. 
     
     
         3 . The sensing device for UAVs of  claim 1 , wherein the processing is used for mapping the surroundings. 
     
     
         4 . The sensing device for UAVs of  claim 1 , wherein the UAV is a quadrotor. 
     
     
         5 . The sensing device for UAVs of  claim 1 , wherein
 the structured light sensor is rotated; and   the rotation is accomplished by a mechanism on the vehicle.   
     
     
         6 . The sensing device for UAVs of  claim 1 , wherein
 the structured light sensor is rotated; and   the rotation is accomplished by moving the body of the vehicle.   
     
     
         7 . The sensing device for UAVs of  claim 1 , wherein
 the structured light sensor is rotated; and   the rotation is accomplished by at least one of a mechanism on the vehicle and moving the body of the vehicle, or a combination of the two.   
     
     
         8 . The sensing device for UAVs of  claim 1 , wherein
 multiple lines are used, one horizontal line and one vertical line, to increase the coverage.   
     
     
         9 . The sensing device for UAVs of  claim 1 , further comprising
 a time-of-flight sensor.   
     
     
         10 . A sensing device for UAVs, comprising
 a quadrotor;   one or more line time-of-flight sensors;   a computer or microprocessor to process range information; and   the computer or microprocessor sending the range information to one or more recipients.   
     
     
         11 . The sensing device for UAVs of  claim 10 , wherein the processing is used for obstacle avoidance. 
     
     
         12 . The sensing device for UAVs of  claim 10 , wherein the processing is used for mapping the surroundings. 
     
     
         13 . The sensing device for UAVs of  claim 10 , wherein
 the line time-of-flight sensor is rotated; and   the rotation is accomplished by a mechanism on the vehicle.   
     
     
         14 . The sensing device for UAVs of  claim 10 , wherein
 the line time-of-flight sensor is rotated; and   the rotation is accomplished by moving the body of the vehicle.   
     
     
         15 . The sensing device for UAVs of  claim 10 , wherein
 the line time-of-flight sensor is rotated; and   the rotation is accomplished by at least one of a mechanism on the vehicle and moving the body of the vehicle, or a combination of the two.   
     
     
         16 . The sensing device for UAVs of  claim 10 , further comprising
 a structured light sensor.   
     
     
         17 . The sensing device for UAVs of  claim 16 , wherein
 multiple lines are used, one horizontal line and one vertical line, to increase the coverage.   
     
     
         18 . The sensing device for UAVs of  claim 10 , wherein the UAV is a quadrotor. 
     
     
         19 . A sensing device for UAVs, comprising:
 a plurality of fisheye cameras;
 the cameras are separated from each other to provide parallax; 
 four, 185 degree field-of-view cameras provide overlapping views over nearly the whole unit sphere; 
   a plurality of laser line scanners;
 the near-infrared laser projection unit sends light out into the environment, which is reflected and viewed by the cameras; 
   the laser projection system creates vertical lines, while the cameras will be displaced from each other horizontally’
 this relative shift (stereo disparity) of the lines, as viewed by different cameras, enables the lines to be triangulated in 3D space; 
   at each point in time, a vertical stripe of the world will be triangulated;   over time, the laser line will be rotated over all yaw angles to provide full 360 degree range sensing capabilities;   the two laser line projectors are used to create a line that can then be sensed with the omnidirectional cameras;   each imager is composed of a camera module, a spectral filter, and a wide-angle compound lens;   an optical bandpass filter can be installed to attenuate incoming ambient light;   if no filter is installed, the imaging system can be used as a visible light imager to provide full 360 degree RGB imagery in addition to point clouds;   a laser projection unit consists of
 a solid-state laser diode, 
 laser pulsing circuitry, 
 aspheric collimation lens, 
 beam splitter, 
 small rotating mirror, and 
 laser line lens; 
   the laser circuitry pulses the laser while also providing a frame trigger to each imager;   the laser light is collimated into a beam using a small aspheric lens directly in front of the laser;   the laser beam is then split into an upward and downward beam;   each beam is reflected off a small rotating mirror coupled to a laser line lens;   the upward beam creates a laser line that extends from horizontal to positive 80 degrees pitch;   the downward beam creates a laser line that extends from horizontal to negative 80 degrees pitch;   the structured light sensor will be able to measure 360 degrees horizontally and 160 degrees vertically;   at each point in time, the sensor will generate approximately 2080 vertical range measurements;   each imager capturing approximately 180 images/second, the sensor will be able to generate over 370 k points per second;   the yaw scan rate can be varied, depending upon the current mission needs;   the sensor can be operated with a fine yaw resolution and slow scan rate, providing detailed scans of the environment; or, the sensor can be operated with a faster yaw rate, providing faster updates at a coarser rate; and   since this device relies on triangulation, the range accuracy will be dependent on range.   
     
     
         20 . The sensing device for UAVs of  claim 19 , comprising:
 a UAV;   one or more range sensors that are used to sense the surrounding environment;   a time-of-flight line sensor to perform the same task as shown with the structured light sensor; and   a vertical sensing plan aligned with the direction of travel.