Apparatus and method for measuring position of stereo camera

Abstract

An apparatus and method for measuring the position of a stereo camera. The apparatus for measuring a position of the camera according to an embodiment includes a feature point extraction unit for extracting feature points from images captured by a first camera and a second camera and generating a first feature point list based on the feature points, a feature point recognition unit for extracting feature points from images captured by the cameras after the cameras have moved, generating a second feature point list based on the feature points, and recognizing actual feature points based on the first feature point list and the second feature point list, and a position variation measurement unit for measuring variation in positions of the cameras based on variation in relative positions of the actual feature points.

What is claimed is: 
     
         1 . An apparatus for measuring a 3D position of an object, comprising:
 a laser line scanner obtaining frame-by-frame scan results for the object using a line laser and a single camera;   a stereo camera measuring position variation information of the stereo camera using images obtained from the stereo camera with respect to the object; and   a measurement unit measuring 3D position information of the object based on the position variation information of the stereo camera and the scan results for the object.   
     
     
         2 . The apparatus of  claim 1 , wherein the stereo camera is configured to:
 extract feature points from images captured by cameras included in the stereo camera and generate a first feature point list based on the feature points;   extract feature points from images captured by the cameras after the cameras have moved, generate a second feature point list based on the feature points, and recognize actual feature points based on the first feature point list and the second feature point list; and   measure the position variation information of the stereo camera based on variations in relative positions of the actual feature points.   
     
     
         3 . The apparatus of  claim 2 , wherein the measurement unit is configured to:
 convert the coordinates of all the frames of the scan results into a coordinate system of a reference frame based on the position variation information of the stereo camera and the positional relationship information between the stereo camera and the laser line scanner; and   obtain a set of converted coordinates of all the frames as the 3D position information of the object.   
     
     
         4 . The apparatus of  claim 3 , wherein the position variation information of the stereo camera includes a first rotation matrix and a first translation vector for indicating a positional relation between before and after movement of the cameras. 
     
     
         5 . The apparatus of  claim 4 , wherein the positional relationship information between the stereo camera and the laser line scanner includes a second rotation matrix and a second translation matrix for indicating a positional relation between a first camera included in the stereo camera and the laser line scanner. 
     
     
         6 . The apparatus of  claim 5 , wherein the set of converted coordinates is represented by the following equation:
     Xw ( t )= R ( t )[ RsX ( t )+ ts ]+ t ( t ),   wherein Xw(t) is the set of converted coordinates,   wherein R(t) is the first rotation matrix,   wherein Rs is the second rotation matrix,   wherein X(t) is a set of the coordinates,   wherein ts is the second translation matrix, and   wherein t(t) is the first translation matrix.   
     
     
         7 . A method for measuring a 3D position of an object, comprising:
 obtaining frame-by-frame scan results for the object, by a laser line scanner, using a line laser and a single camera;   measuring position variation information of a stereo camera using images obtained from the stereo camera with respect to the object; and   measuring 3D position information of the object based on the position variation information of the stereo camera and the scan results for the object.   
     
     
         8 . The method of  claim 7 , wherein the measuring position variation information comprises:
 extracting feature points from images captured by cameras included in the stereo camera and generating a first feature point list based on the feature points;   extracting feature points from images captured by the cameras after the cameras have moved, generating a second feature point list based on the feature points, and recognizing actual feature points based on the first feature point list and the second feature point list; and   measuring the position variation information of the stereo camera based on variations in relative positions of the actual feature points.   
     
     
         9 . The method of  claim 8 , wherein the measuring 3D position information comprises:
 converting the coordinates of all the frames of the scan results into a coordinate system of a reference frame based on the position variation information of the stereo camera and the positional relationship information between the stereo camera and the laser line scanner; and   obtaining a set of converted coordinates of all the frames as the 3D position information of the object.   
     
     
         10 . The method of  claim 9 , wherein the position variation information of the stereo camera includes a first rotation matrix and a first translation vector for indicating a positional relation between before and after movement of the cameras. 
     
     
         11 . The method of  claim 10 , wherein the positional relationship information between the stereo camera and the laser line scanner includes a second rotation matrix and a second translation matrix for indicating a positional relation between a first camera included in the stereo camera and the laser line scanner. 
     
     
         12 . The method of  claim 11 , wherein the set of converted coordinates is represented by the following equation:
     Xw ( t )= R ( t )[ RsX ( t )+ ts ]+ t ( t )   wherein Xw(t) is the set of converted coordinates,   wherein R(t) is the first rotation matrix,   wherein Rs is the second rotation matrix,   wherein X(t) is a set of the coordinates,   wherein ts is the second translation matrix, and   wherein t(t) is the first translation matrix.