Vehicle Camera Calibration System

Abstract

Technique for performing camera calibration on a vehicle is disclosed. A method of performing camera calibration includes emitting, by a laser emitter located on a vehicle and pointed towards a road, a first laser pulse group towards a first location on a road and a second laser pulse group towards a second location on the road, where each laser pulse group includes one or more laser spots. For each laser pulse group: a first set of distances are calculated from a location of a laser receiver to the one or more laser spots, and a second set of distances are determined from an image obtained from a camera, where the second set of distances are from a location of the camera to the one or more laser spots. The method also includes determining two camera calibration parameters of the camera by solving two equations.

What is claimed is: 
     
         1 . A method comprising:
 emitting, by a laser emitter located on a vehicle, a laser pulse toward a first location on a road;   detecting, by a laser receiver located on the vehicle, a first distance between the laser receiver and the first location;   detecting, based at least in part upon an image captured by a camera pointed towards the first location, a second distance between the camera and the first location;   determining two camera calibration parameters based at least in part upon the first distance and the second distance; and   adjusting the two camera calibration parameters based at least on the laser pulse, such that the camera captures images of objects at the first location.   
     
     
         2 . The method of  claim 1 , wherein:
 the laser emitter is pointed toward the first location on the road; and   the laser emitter forms a first angle between a direction in which the laser emitter is pointed towards and an imaginary horizontal plane that is at least partly parallel to the road.   
     
     
         3 . The method of  claim 1 , wherein the laser emitter is pointed toward the first location. 
     
     
         4 . The method of  claim 1 , wherein:
 the laser emitter is located on a vehicle;   the laser receiver is located on the vehicle, and   the two camera calibration parameters are adjusted while the vehicle is moving.   
     
     
         5 . The method of  claim 1 , wherein the determining the two camera calibration parameters comprises solving two predetermined equations, wherein each of the two predetermined equations comprises the two camera calibration parameters, the first distance, and the second distance. 
     
     
         6 . The method of  claim 1 , further comprising determining, based at least in part upon a speed at which the vehicle is moving, a first angle formed in between a direction in which the laser emitter is pointed towards the road and an imaginary horizontal plane that is at least partly parallel to the road and that includes at least a portion of the laser emitter. 
     
     
         7 . The method of  claim 6 , further comprising adjusting the laser emitter according to at least the first angle to emit the laser pulse toward the first location. 
     
     
         8 . The method of  claim 1 , wherein:
 the two camera calibration parameters are a slope value and an intercept value;   the slope value is a result of the camera pointing with an angle with respect to an imaginary horizontal plane at least partially parallel to the road; and   the intercept value is a distance from the camera where a line intersects the imaginary horizontal plane when the camera is pointed towards with the angle.   
     
     
         9 . The method of  claim 1 , wherein:
 a distance between the laser emitter and the first location is a pre-determined distance; and   the pre-determined distance is proportional to a traveling speed of the vehicle.   
     
     
         10 . The method of  claim 1 , wherein determining the two camera calibration parameters comprises determining a slope value and an intercept value by:
 determining, by solving two predetermined linear equations, the slope value, and the intercept value with which the camera is calibrated, wherein:
 a first predetermined linear equation includes an unknown slope value, an unknown intercept value, and the first distance and the second distance; and 
 a second predetermined linear equation includes the unknown slope value, the unknown intercept value, and the first distance and the second distance. 
   
     
     
         11 . A non-transitory computer-readable medium storing instructions that, when executed by a processor, cause the processor to:
 emit, by a laser emitter located on a vehicle, a laser pulse toward a first location on a road;   detect, by a laser receiver located on the vehicle, a first distance between the laser receiver and the first location;   detect, based at least in part upon an image captured by a camera pointed towards the first location, a second distance between the camera and the first location;   determine two camera calibration parameters based at least in part upon the first distance and the second distance; and   adjust the two camera calibration parameters based at least on the laser pulse, such that the camera captures images of objects at the first location.   
     
     
         12 . The non-transitory computer-readable medium of  claim 11 , further comprising determining, while the vehicle is being driven, a location of an object in another image obtained by using the two camera calibration parameters. 
     
     
         13 . The non-transitory computer-readable medium of  claim 11 , wherein:
 a distance between the laser emitter and the first location is a pre-determined distance; and   the pre-determined distance is proportional to a traveling speed of the vehicle.   
     
     
         14 . The non-transitory computer-readable medium of  claim 13 , wherein the pre-determined distance is within a range of distances from a location of the camera at which the camera is configured to obtain images. 
     
     
         15 . The non-transitory computer-readable medium of  claim 13 , wherein the pre-determined distance is a distance from the location of the laser emitter to at least one laser spot. 
     
     
         16 . The non-transitory computer-readable medium of  claim 11 , wherein the laser pulse is emitted when the vehicle is stopped or parked on the road. 
     
     
         17 . The non-transitory computer-readable medium of  claim 11 , wherein the determining the two camera calibration parameters comprises solving two predetermined equations, wherein each of the two predetermined equations comprises the two camera calibration parameters, the first distance, and the second distance. 
     
     
         18 . The non-transitory computer-readable medium of  claim 11 , wherein the instructions further cause the processor to determine, based at least in part upon a speed at which the vehicle is moving, a first angle formed in between a direction in which the laser emitter is pointed towards the road and an imaginary horizontal plane that is at least partly parallel to the road and that includes at least a portion of the laser emitter. 
     
     
         19 . The non-transitory computer-readable medium of  claim 18 , wherein the instructions further cause the processor to adjust the laser emitter according to at least the first angle to emit the laser pulse toward the first location. 
     
     
         20 . The non-transitory computer-readable medium of  claim 11 , wherein:
 the two camera calibration parameters are a slope value and an intercept value;   the slope value is a result of the camera pointing with an angle with respect to an imaginary horizontal plane at least partially parallel to the road; and   the intercept value is a distance from the camera where a line intersects the imaginary horizontal plane when the camera is pointed towards with the angle.