US 4,379,308 AGranted

Apparatus for determining the parameters of figures on a surface

AssigneeCooper Industries, Inc.

InventorsWojciech Kosmowski, Richard Eddy, Martin O'Neill

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Abstract

The disclosed apparatus determines the parameters, such as size, shape, and position, of figures on a surface. It includes a camera means generating a video signal. A table assembly adjusts the position of the camera and surface on the table with respect to each other as specified by position signals. Control circuitry generates the position signals so as to bring at least a portion of a figure into the camera's field of view. The video signal generated when this portion of a figure is in view is used by processing circuitry to determine the figure's parameters. In one embodiment, the expected parameter values for a figure are retrieved from storage circuitry and compared against the parameter values as determined by the processing circuitry. If the parameter values are out of range, an error signal is generated. Error data may be recorded or transmitted to an external device for statistical analysis.

Claims11

Dependent claims

An inspection apparatus for determining parameters of a generally circular figure on a surface, comprising:

camera means for generating a video signal representative of the field of view before said camera means;
table means for supporting said camera means and said surface in an adjustable spaced position with respect to each other such that selected portions of said surface may be brought within said field of view, said table means accepting position signals to adjust said spaced position;
control means for generating position signals to bring at least a portion of said figure within said field of view and for supplying said position signals to said table means;
digitizer circuitry generating from said camera means video signal an associated digital signal which discriminates between portions of said video signal representing a portion of said figure within said field of view and other portions of said video signal;
sampling means for sampling said digital signal to determine associated values for a grid of picture elements, each said picture element corresponding to a fixed portion of said field of view and having a value indicating whether said corresponding fixed portion of said field of view includes a portion of said figure;
addressable storage means for storage and retrieval of said picture element values;
and
processing means, accessing said storage means, for determining the size and position of said figure from said picture element values associated with the video signal generated when said figure is entirely within said field of view of said camera means,
wherein said processing means includes means for accessing said storage means to locate first and second boundary picture elements in a grid column, each representing distinct boundary portions of said figure;
means for locating a midpoint picture element in the grid midway between said first and second boundary picture elements;
means for accessing a third boundary picture element in the same grid row as said midpoint picture element, representing another distinct portion of said figure;
and means for determining the size and center of said figure from the grid addresses of said three boundary picture elements.

9 more elements

An inspection apparatus for determining the size and position of generally circular holes in a printed circuit board, comprising:

first digital storage means for storage and retrieval of expected hole locations and sizes;
camera means for generating a video signal representative of the field of view before said camera means;
control means for accessing said first digital storage means to recall at least one of said expected hole locations, and for generating position signals indicating a portion of the printed circuit board corresponding to a recalled expected hole location;
table means, supporting said camera means and the printed circuit board in an adjustable spaced position with respect to each other, for accepting said position signals to adjust said spaced position of the printed circuit board to locate the expected hole location within the field of view of said camera means;
video digitizing means for converting said video signal into a corresponding grid of digital picture elements, each corresponding to a fixed portion of said field of view, and each having a value indicating whether the corresponding fixed portion of said field of view includes a portion of a located hole;
second digital storage means for storage and retrieval of said picture element values;
and
processing means, accessing said second digital storage means and coupled to said control means, for determining the size and position of a located hole from said position signals and from said picture element values associated with the video signal generated when said hole is entirely within the field of view of said camera means;
verification means, coupled to said first digital storage means and to said processing means, for comparing the determined size and position values of a located hole against the expected values, and for generating an error signal indicative of the results of said comparison.

6 more elements

Dependencies are inferred from the claim text.