Apparatus and method for determining the coordinates of a three-dimensional object

Claim 1

Apparatus for determining the coordinates of a measurement point on a three-dimensional object comprising, in combination: first and second photoelectric conversion means disposed at a selected height from the object and spaced apart a predetermined distance in the direction of an x-axis and moveable together incrementally in the direction of a y-axis for respectively generating first and second data signals respectively representing first and second images of said object each divided into a plurality of measurement points and together constituting a stereoscopic image; first and second memory means respectively connected to said first and second photoelectric conversion means for respectively storing said first and second data signals representing said first image and said second image, respectively; measurement point setting means for storing data signals representing x and y coordinates of measurement points in said first image; correlation processing means connected to said first and second memory means and to said measurement point setting means for processing output signals from said first and second memory means and data signals from said measurement point setting means representing a selected measurement point in said first image and producing a measurement point in the second image substantially corresponding to the selected measurement point in said first image; mark generating means connected to said first and second memory means for adding to the data signal representing said first image a mark data signal concerning said selected measurement point and for adding to the data signal representing said second image a corresponding mark data signal concerning the measurement point supplied from said correlation processing means; image display means including a display screen and video signal control circuit means for raster scanning said display screen at a predetermined vertical synchronization frequency; signal processing means including means for applying the data signal representing said first image and containing said mark data signal to said image display means alternately with the data signal representing said second image and containing said corresponding mark data signal each at one-half the vertical synchronization frequency for producing on said display screen an image of said object including images of said mark data signal and said corresponding data signal, and means through which the display screen image of said object is viewed alternately with the left and right eye each at one-half said vertical synchronization frequency for presenting a three-dimensional image of said object and enabling visual examination to determine whether the image of the measurement point in said second image is correctly positioned in the viewed image; and calculating means connected to said correlation processing means and to said measurement point setting means for calculating values of the x, y, and height (z) coordinates of said selected measurement point when the image of the measurement point in said second image is determined to be correctly positioned in the viewed image.