Method for executing three-dimensional measurement utilizing correctively computing the absolute positions of CCD cameras when image data vary

#The present invention relates to a method of executing a three-dimensional measurement for measuring dimension of a measureable object such as an automotive body or a press mold or the like. More particularly, the invention relates to a method of measuring a three-dimensional dimension of a workpiece mounted on an objective position by providing a plurality of CCD cameras in position close to a measurable object.

#When directly measuring dimension of a measurable workpiece A having cubic configuration like an automotive body in an assembly factory in place of a laboratory equipped with a variety of measuring instruments, normally, such a conventional method described below is executed.

#As shown in FIG. 3, initially, a measuring jig B is secured to a predetermined measuring position in order to stably hold an objective workpiece A. Next, the objective workpiece A is positioned on the measuring jig B. At the same time, a pair of theodolites 1 and 2 are set to predetermined positions in front of a measurable surface of the positioned workpiece A.

#FIG. 1 is a perspective view showing an example of arrangement of a variety of measuring instruments while executing the method of measuring three-dimensional dimension of a measurable workpiece according to the method embodied by the invention;

#FIG. 2 is an operational flowcart designating procedure to implement the method of measuring three-dimensional dimension of a measurable workpiece according to an embodiment of the invention;

#FIG. 3 is a perspective view showing an example of arrangement of a variety of measuring instruments used for executing a conventional method of measuring three-dimensional dimension of a measurable workpiece; and

#FIG. 1 is a perspective view showing an example of arrangement of a variety of measuring instruments used for measuring three-dimensional dimension of a measurable workpiece according to the method embodied by the invention. The reference character A shown in FIG. 1 designates a measurable workpiece. The reference character B designates a measuring jig which stably positions and holds the measurable workpiece A. The reference character C designates four reference-point members which are disposed in the periphery of the measurable workpiece A. The reference character F designates a reference bar having a known distance between a pair of points D and E. These component members are respectively identical to those which are normally used for any conventional three-dimensional measuring system.

#In order to facilitate a plurality of CCD cameras to execute three-dimensional measurement to be described later on, a plurality of light emitting diodes are built in the center of each reference-point member C and the center point between a pair of points D and E of the reference bar F. Light points of those light emitting diodes are respectively designated as the measurable points.

#The reference numeral 10 shown in FIG. 1 designates a first CCD camera which is mounted on a tripod 11. The reference numeral 12 designates a second CCD camera which is mounted on a tripod 13. These first and second CCD cameras 10 and 12 are properly set to predetermined positions in front of a measurable workpiece A in a specific range in order that a measurable object A, those reference-point members C disposed in the periphery of the workpiece A, and the reference bar F, can properly be accommodated in each frame of those first and second CCD cameras 10 and 12.