Recognition Equipment Incorp.

David P Himmel

Larry Wayne Bryan

George William Woster, Jr

A laser measuring system for industrial inspection having a laser producing a narrow beam of coherent light which is focused by telescope onto an article. The focused beam of light from the telescope is directed by a scanning means across the article at a known rate. The light reflected from the article is focused by an imaging lens offset from the scanning means onto an optical grating which is provided with alternate transparent and opaque bars. The collected light which passes through the transparent bars of the optical grating is sensed by a photomultiplier detector. A processor which sees the output of the photomultiplier detector determines the time interval between selected points of the output signal of the photomultiplier detector. As the scanning beam moves across the article it causes the laser spot observed by the photomultiplier to traverse the surface faster or slower depending on whether the scanning is proceeding up a portion of the surface of the article or down, respectively. Thus, the reflected light traverses the optical grating at a slower or faster rate and, therefore, the time interval measured by the processor between the selected points on the output of the detector increases as the scanning beam moves up the surface and decreases as the scanning moves down the surface. The processor provides an output directly related to the contour of the article which can be stored and compared with the contour of a master article or prototype.

Laser measuring system for inspection

An apparatus and method for reading randomly oriented characters having a laser producing a narrow beam of coherent light which is focused by a telescope onto indicia located on a written medium. The focus beam of light is directed by a scanner located intermediate the telescope and the indicia. The scanner directs the beam of light across an area in a known sequence. The light reflected from the written medium having the indicia thereon is received by a photomultiplier detector. The processor which receives the output of the photomultiplier detector determines the observed orientation of the indicia, and the angle between the observed orientation of the indicia and a desired orientation of the indicia. The processor then generates a signal which causes a beam rotating means located between the scanner and the indicia to be rotated to a position so that the indicia are now scanned in the known sequence having the desired orientation with respect to indicia. Characters which are to be read are located adjacent to the indicia. It is desired to scan the characters with the laser beam at the orientation to which the beam rotating means was rotated. The photomultipler detector receives the reflected light from the characters and the written medium as the characters are scanned in the known sequence at the desired orientation.

Apparatus and method for reading randomly oriented characters

A character feature detection system is provided for reliably reading non-touching hand printed and multi-font machine printed alphanumeric characters. An information field is scanned by a sensor array, and the sensor responses are digitized to form a binary character image. The image is thinned in one-cell layers as the image boundary and loops internal to the image are traced from boundary point to boundary point. A transition from one boundary point to another is defined by one of eight equally divergent vectors which are indicative of the local slope of a boundary between connected points. The sequence of vectors and their x-ray locations are recorded, and boundary slopes are indicated by a running average of four vectors representative of cell to cell transitions. Character features are detected from the sequence of boundary slopes to form a feature set including circumference counts, maximum and minimum image boundary limits, inflection points and loops. The image boundary is thinned to a one-cell stroke width, and character stops and nodes are located. Each stop arm is traced to identify valid stops, and the slope of each valid stop is determined to complete the feature set. The feature set is formatted and stored in a memory unit for character identification.

Slope feature detection system

A line image or a line signature is optically scanned to generate digital signals for storage in an image matrix. These digital signals represent black and white cells defining the line signature or line image and are initially processed by tracing the image boundary. During the tracing a 'thinning' or 'peeling off' operation is performed that evaluates black cells in the image matrix for conversion into white cell digital signals. This thinning or peeling off process, also identified as data compression, continues until the line signature or line image is composed of a single cell thickness. The final phase of the data compression operation includes another boundary tracing of the one cell thick image, and connecting a sequence of boundary points defining each black cell to form a string of vectors which represent the signature. The resulting vector catalog comprises a composition of data including a vector starting point and vector directions which are encoded and stored for future retrieval. When a stored line signature or line image is to be retrieved for display, the encoded vector data is recalled from storage to generate on a cathode ray tube the original vector data. This operation is known as data decompression and produces on the cathode ray tube a synthesis of the original line image or line signature. The compression and decompression operations, except thinning or peeling off, are also applicable to textured images or images having grayscale and thickness. Such textured images are first subdivided into binary images, each representing one bit of the grayscale, then the vector boundary encoding process is completed without thinning. The encoded vectors are stored for subsequent retrieval and display.

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Dallas, TX, United States of America

David P Himmel