Optical Sensing a Distance from a Range Sensing Apparatus and Method

Abstract

A method and a system for determining horizontal velocity of a construction vehicle and a distance from a range sensing apparatus to a surface is provided. In an embodiment, a plurality of video images of the surface generated by a video camera is received, an angular velocity is calculated by video processing, a distance from each of a plurality of laser rangefinders to the surface is measured, and linear horizontal velocity is calculated from angular velocity and distances.

1 . A sensing unit to determine a horizontal velocity of a construction vehicle and a distance from the construction vehicle to a surface, the sensing unit comprising:
 a plurality of laser rangefinders; and   a video camera.   
     
     
         2 . The sensing unit of  claim 1  further comprising:
 a memory communicatively coupled with a processor and storing computer program instructions to determine the distance from the construction vehicle to the surface. 
 
     
     
         3 . The sensing unit of  claim 1 , the sensing unit further comprising:
 a housing in which the plurality of laser rangefinders and the at least one video camera are mounted.   
     
     
         4 . The sensing unit of  claim 1 , wherein in operation each of the plurality of laser rangefinders and the at least one video camera are directed to the surface. 
     
     
         5 . The sensing unit of  claim 4 , wherein in operation each of the plurality of laser rangefinders is directed in a direction perpendicular to a direction of travel of the construction vehicle. 
     
     
         6 . The sensing unit of  claim 4 , wherein in operation each of the plurality of laser rangefinders is directed in a direction parallel to a direction of travel of the construction vehicle. 
     
     
         7 . The sensing unit of  claim 1 , wherein in operation the at least one video camera is directed downward to acquire a plurality of images of the surface to determine a two-dimensional velocity of the construction vehicle. 
     
     
         8 . The sensing unit of  claim 1 , wherein the at least one video camera is directed downward to acquire a plurality of images of the surface determine an offset of a directional trajectory of the construction vehicle. 
     
     
         9 . The sensing unit of  claim 1 , wherein each of the plurality of laser rangefinders is a time of flight laser rangefinder. 
     
     
         10 . The apparatus of  claim 1 , wherein each of the plurality of laser rangefinders is a phase difference laser rangefinder. 
     
     
         11 . The sensing unit of  claim 1 , wherein at least one of the plurality of laser rangefinders is the time of flight laser rangefinder and at least one other of the plurality of laser rangefinders is the phase difference laser rangefinder. 
     
     
         12 . The sensing unit of  claim 1 , wherein the processor is coupled to the sensing unit. 
     
     
         13 . The sensing unit of  claim 1 , wherein the processor is coupled to the construction vehicle and is remote from the construction vehicle. 
     
     
         14 . A method for determining a distance from a sensing unit of a construction vehicle to a surface comprising:
 receive a plurality of video images of the surface, the plurality of video images generated by a video camera;   measuring a distance from each of a plurality of laser rangefinders to the surface;   weighting the measured distance from each of the plurality of laser rangefinders to the surface using at least one weighting factor corresponding to each of the plurality of laser rangefinders; and   determining a weighted average distance from the plurality of laser rangefinders to the surface based on weighted measured distance from each of the plurality of laser rangefinders to the surface.   
     
     
         15 . The method of  claim 14 , further comprising:
 transmitting measured distance information to a processor; and   storing the measured distance information in a memory.   
     
     
         16 . The method of  claim 14 , further comprising:
 determining a two-dimensional velocity of the construction vehicle using the video camera.   
     
     
         17 . The method of  claim 14 , further comprising:
 determining an offset of a directional trajectory of the construction vehicle using the video camera.   
     
     
         18 . A storage device storing computer program instructions for controlling a sensing unit of a construction vehicle to measure a distance from the sensing unit to a surface, which, when executed on a processor, cause the processor to perform operations comprising:
 receiving a plurality of video images of the surface, the plurality of video images generated by a video camera;   measuring a distance from each of a plurality of laser rangefinders to the surface;   weighting measured distance from each of the plurality of laser rangefinders to the surface using at least one weighting factor corresponding to each of the plurality of laser rangefinders; and   determining a weighted average distance from the plurality of laser rangefinders to the surface based on weighted measured distance from each of the plurality of laser rangefinders to the surface.   
     
     
         19 . The storage device of  18 , the operations further comprising:
 transmitting a measured distance information to a processor; and   storing the measured distance information in a memory.   
     
     
         20 . The storage device of  18 , the operations further comprising:
 determining a two-dimensional velocity of the construction vehicle using the at least one video camera.   
     
     
         21 . The storage device of  claim 18 , the operations further comprising:
 determining an offset of a directional trajectory of the construction vehicle using the at least one video camera.   
     
     
         22 . An apparatus for determining a distance from a sensing unit of a construction vehicle to a surface comprising:
 a processor; and   a memory communicatively coupled with the processor and storing computer program instructions which when executed by the processor, cause the processor to perform operations comprising:   receiving a plurality of video images of the surface, the plurality of video images generated by a video camera;   measuring a distance from each of a plurality of laser rangefinders to the surface;
 weighting measured distance from each of the plurality of laser rangefinders to the surface using at least one weighting factor corresponding to each of the plurality of laser rangefinders; and 
   determining a weighted average distance from the plurality of laser rangefinders to the surface based on weighted measured distance from each of the plurality of laser rangefinders to the surface.   
     
     
         23 . The apparatus of  claim 22 , the operations further comprising:
 transmitting a measured distance information to a processor; and   storing the measured distance information in a memory.   
     
     
         24 . The apparatus of  claim 22 , the operations further comprising:
 determining a two-dimensional velocity of the construction vehicle using the at least one video camera.   
     
     
         25 . The apparatus of  claim 22 , the operations further comprising:
 determining an offset of a directional trajectory of the construction vehicle using the at least one video camera.