Range finder and method

Abstract

Pattern projection apparatuses are placed on each other in a stack manner in a stripe pattern direction for projecting the same patterns. An image pickup apparatus (camera 1) is placed between the pattern projection apparatuses. The optical axes of the pattern projection apparatuses and the image pickup apparatus are aligned on the same plane parallel with the stripe pattern direction. On the plane, the principal points also become the same. An image of a stripe pattern is picked up directly by the image pickup apparatus without the intervention of a half mirror, etc., and is recoded. An image of the recoded stripe pattern is picked up by an image pickup apparatus (camera 2) and is decoded and the range of an object is measured by triangulation based on image correspondence points.

What is claimed is:  
     
         1 . A range finder comprising: 
 a projector for projecting a coded stripe pattern;    a first camera for picking up an image of the stripe pattern projected by the projector, the first camera placed so that a principal point of the first camera and a principal point of the projector are placed along a length direction of the stripe pattern; and    a second camera for picking up an image of the stripe pattern projected by the projector, the second camera placed so that a principal point of the second camera and the principal point of the first camera are placed away from each other in a direction being not parallel to the length direction of the stripe pattern,    wherein an area with change amount of the stripe pattern, which is picked up by the first camera, with respect to the stripe pattern projected by the projector being a predetermined value or more is determined;    wherein a new code is assigned to the area;    wherein the second camera picks up a recoded stripe pattern projected by the projector after the new code is assigned; and    wherein range information of a three-dimensional object onto which the stripe pattern is projected is generated based on the recoded stripe pattern picked up by the second camera.    
     
     
         2 . The range finder according to  claim 1 , 
 wherein the projector is at least one projector;    wherein the principal point of all the projector and the principal point of the first camera are placed along the length direction of the stripe pattern; and    wherein the coded stripe pattern projected from all the projector is matched with each other.    
     
     
         3 . The range finder according to  claim 2 , 
 wherein total number of the projectors is two; and    wherein the two projectors are placed so as to sandwich the first camera therebetween.    
     
     
         4 . The range finder according to  claim 1 , wherein texture information of a surface of the three-dimensional object onto which the stripe pattern is projected is generated from the image of the stripe pattern picked up by the first camera.  
     
     
         5 . A three-dimensional image pickup method comprising: 
 providing a projector for projecting a coded stripe pattern, a first camera and a second camera each for picking up the stripe pattern projected by the projector,    determining an area with change amount of the stripe pattern, which is picked up by the first camera, with respect to the stripe pattern projected by the projector being a predetermined value or more;    assigning a new code to the area;    picking up a recoded stripe pattern projected by the projector after the new code is assigned by the second camera; and    generating range information of a three-dimensional object onto which the stripe pattern is projected based on the image of the recoded stripe pattern picked up by the second camera,    wherein a principal point of the first camera and a principal point of the projector are placed along a length direction of the stripe pattern; and    wherein the principal point of the first camera and a principal point of the second camera are placed away from each other in a direction not parallel to the length direction of the stripe pattern.    
     
     
         6 . A three-dimensional image pickup method comprising: 
 providing a first projector and a second projector each for projecting a coded stripe pattern, and a first camera and a second camera for picking up images of the stripe patterns projected by the first projector and the second projector;    placing a principal point of the first camera and principal points of the first projector and the second projector along a length direction of the stripe pattern;    placing the two projectors to sandwich the first camera therebetween;    placing the principal point of the first camera and a principal point of the second camera away from each other in a direction not parallel to the length direction of the stripe pattern;    driving the first projector and the second projector to project stripe patterns in different time periods;    determining an area with change amount of the stripe pattern, which is picked up by the first camera, with respect to the stripe pattern projected by the first projector being a predetermined value or more;    assigning a new code to the area;    picking up a recoded stripe pattern projected by the first projector after the new code is assigned by the second camera;    generating first range information of a three-dimensional object onto which the stripe pattern is projected based on the recoded stripe pattern picked up by the second camera;    determining an area with change amount of the stripe pattern, which is picked up by the first camera, with respect to the stripe pattern projected by the second projector being a predetermined value or more;    assigning a new code to the area;    picking up an image of are coded stripe pattern projected by the second projector after the new code is assigned by the second camera;    generating second range information of the three-dimensional object onto which the stripe pattern is projected based on the image of the recoded stripe pattern picked up by the second camera; and    combining the first range information and the second range information to form total range information.