Concepts leading to an accurate, automated system for making 3D measurements of robot position are described. The system is predicated on building complete kinematic models of the measurement apparatus and determining the model parameters from data obtained in a calibration procedure. The two primary calibration procedures required are the determination of the geometric parameters of the individual theodolites and the determination of the triangulation baseline, the six-degree-of-freedom relationship between two theodolites. The former are described. Simulations and an experiment testing the theodolite calibration procedures are reported. The results suggest that the methods described, when used in conjunction with high quality commercially available theodolites (measurement errors>

A system is described based on triangulation for making accurate, three dimensional coordinate measurements over size ranges appropriate for robot calibration, maintenance and diagnosis. Complete kinematic models are defined for the triangulation system components and calibration methods are described to determine the values for each parameter in the model. A one dimensional, linear, interferometer system provides the coordinate data that is the basis for the calibration procedures. Details of the algorithms for triangulation, baseline determination and theodolite simulation are given. The accuracy of the baseline determination algorithm is demonstrated with simulations.

The application of pattern recognition techniques to manufacturing processes is a rapidly developing technology. Automatic verification of the quality of printed wiring boards (PWB's) using pattern recognition techniques is one potential application in this field. Qualitatively, this problem is finding small, irregular features in an environment of complicated, but larger and well-defined geometric features. In addition to the basic pattern recognition task, stringent performance requirements, both for throughput and accuracy, must be met if actual production usage is expected. The method employed in this study is based on characterizing 5 × 5 or 7 × 7 element binary patterns derived from the class of PWB's being inspected as good or defective. A database of 80 512 × 512 element images of PWB's was constructed and used to determine the number of unique patterns and their rates of occurrence. The major experimental result of this study is that less than 500 of the possible (15/16)224 5 × 5 patterns are needed to describe all the border containing patterns in the 80 images. It is also apparent that more patterns would be required if the training database was larger. The small number of patterns needed to represent virtually all of the normal border patterns suggests a two-stage inspection strategy. In the first stage, each border pattern from the PWB being inspected is compared to a previously prepared list.

Manufacturing activities involve sub stantial numbers of visual tasks for pro cess control, assembly and inspection. Many of these tasks are simple and are done repetitively for prolonged periods, thus are subject to various degradations due to visual fatigue. In addition, cost of these operations has been rapidly increasing. There is an obvious need for automation in the area of visual tasks related to manufacturing.

A computer program, the Line Drawing Editor (LDE), that allows convenient modification of computer representations of simple line drawings has been designed and implemented. The distinguishing feature of the LDE from the multitude of interactive graphics programs that accomplish the same function is the use of a computer controlled TV camera for input and program control rather than conventional interactive input devices such as light pens or data tablets. A graphical editing language allows the LDE user to indicate, by marking the drawing in appropriate fashion, the changes that are to be made. The drawing, which was generated on a hardcopy output device, with the added edit information is placed in front of the camera. In successive phases the LDE computes a two dimensional homogeneous transformation relating the viewed drawing and its computer description, locates the lines added to the drawing, parses the added lines according to the edit language and finally uses this information to update the drawing description.

A new technique for the display of continuous tone images on a bilevel graphical output device is described. This technique belongs to the general class of algorithms that convey intensity information by the spatial arrangement of lit and unlit cells which are in a one-to-one correspondence with the picture elements (PEL's) in the original image. Besides the rendition of a gray scale in the processed image, the new algorithm also incorporates edge emphasis to increase the legibility of textual information and other areas of high detail. A simple theory of the algorithm, derived from an intensity distribution function, is given, along with the details of an implementation and results obtained using the new technique. The technique is interesting as it requires a nonzero noise component in the image signal being processed in order to generate a gray scale.

Abstract Two algorithms that solve the frequently occurring problem in computer graphics, windowing, are described. The primary distinction between the two algorithms is the need for multiplication and division in one of them. The algorithms are compared for running time and size on two commonly used minicomputer systems, the Digital Equipment Corporation PDP‐9/15 and PDP‐11. Not surprisingly the algorithm incorporating the extended arithmetic capability executes faster and the PDP‐11 versions are substantially smaller.

A graphics display system utilizing recently available 512 line plasma panels interfaced to a DEC PDP-11 computer will be described. As the panel electronics allow one cell to be turned on or off each 20 µs the required display processor functions are implemented in software with no loss of performance. This results in a display system with a rich instruction set as the entire PDP-11 instruction set becomes part of the graphics instruction set. Since the plasma panels combine both memory and selective erase, a unique capability has thus been achieved.