An apparatus for machining a workpiece comprises means for clamping the workpiece, means for rotatingly driving the clamped workpiece, a tool for machining the workpiece, the tool having a part for engaging the workpiece, a tool holder, means for moving the tool holder with respect to the clamping means and a control unit with a memory for one or more control programs. The control unit is arranged to control the moving means according to a control program by means of measuring means providing the x,y-positions of the tool holder in such a manner that the tool follows a desired path along the clamping means for machining the workpiece. The apparatus comprises a measuring device located at a predetermined reference position with respect to the moving means. The control unit is arranged to control the moving means in such a manner that said tool part is moved along to the measuring device, wherein the measuring device delivers a measuring signal to the control unit, wherein the control unit determines the shape of said tool part and the position thereof with respect to the tool holder directly from the x,y-positions provided by the x,y-measuring means and stores these x,y-positions in the memory for use in the (each) control program for the corresponding tool.

An apparatus for working a workpiece comprises drive means for rotating a carrier about an axis of rotation and a tool for working the workpiece. The apparatus furthermore comprises means for moving said tool in an x-direction and a y-direction with respect to the drive means, and a control unit comprising a memory for one or more control programs. The control unit is arranged for controlling the moving means in accordance with a control program, in such a manner that the tool will follow one or more desired paths for working the workpiece. The control unit is furthermore arranged for measuring an apparatus parameter which influences the control program, such as the angle between the axis of rotation and one of the moving means and/or the tool contour and the position of said contour with respect to the axis of rotation. Said apparatus parameter(s) is (are) stored at the (each) control program in the memory. If a difference is detected between the stored apparatus parameter(s) and the measured one(s), the (each) control program is adapted so that the tool will still follow the desired path(s).

A system for measuring dimensions of cuboid objects may be used to measure dimensions of boxes travelling on a conveyor. The system has a pair of digital cameras which obtain images of one or more lines projected by a projector on upper surfaces of the objects. The height of the upper surfaces can be determined by triangulation. Lengths and widths of the upper surfaces are measured by locating endpoints of the projected lines and fitting rectangles to the located endpoints. The system does not require rigid mounting of the projector relative to the cameras. A third camera may be used to determine speed and direction of the conveyor motion.

The preferred embodiment of the invention includes hardware and software for scanning objects and extracting their geometry and color information so as to generate their 3D (three dimensional) representations in a computer. The preferred embodiment uses a computer, a video camera, a light source, and an indicator located within the field of view of the camera in a fixed position. Preferably, the light source projects a crisp line of light on the scanned object. The software of the preferred embodiment processes the frames produced by the camera. It preferably locates the illuminated line and the indicator, and uses this information to determine 3D coordinates of the illuminated points. The 3D coordinates of the points are used to construct 3D representations of objects. The preferred embodiment also obtains color information of the scanned object and maps it to the 3D representation.