公开(公告)号：US3563634A

公开(公告)日：1971-02-16

申请号：US3563634D

申请日：1967-12-14

Applicant: NAT RES DEV

Inventor： PARKS JOHN RONALD ,  RENGGER RALPH ERIC

IPC: G06K9/74 ,  G02B27/38

CPC classification number: G06K9/74

Abstract: OPTICAL ARRANGEMENTS FOR ISOLATING CHOSEN SPATIAL FREQUENCY COMPONENTS OF AN ANALOGUE FORM DENSITY OR INTENSITY OBJECT PATTERN, E.G. A PRINTED CHARACTER, IN WHICH A TRANSPARENCY OF THE OBJECT PATTERN IS DISPOSED IN A COLLIMATED LIGHT BEAM AND BY MEANS OF AN OPTICAL SYSTEM A DIFFRACTION PATTERN IS PRODUCED IN OR BEYOND THE FOURIER PLANE, SAID FOURIER PLANE CONTAINING A LIGHT STOP HAVING AN ANNULAR PASS APERTURE AND THE LIGHT PASSING SAID STOP BEING IMAGED IN A RESULTANT IMAGE PLANE.

公开(公告)号：US3553456A

公开(公告)日：1971-01-05

申请号：US3553456D

申请日：1968-05-31

Applicant: NAT RES DEV

Inventor： PARKS JOHN RONALD ,  RENGGER RALPH ERIC

IPC: G01B11/25 ,  G01N21/30 ,  G01B1/00

CPC classification number: G01B11/25

Abstract: A method and apparatus are disclosed in which a trace is optically projected on photocells incorporated in electrical circuitry providing a signal indicating the nearest photocell to a reference point on which the trace image is incident. The photocells can be positioned in line from the reference point and the image rotated around the point. The trace can be related to a standard profile, the distance of its image from the reference point representing divergences of workpiece profile from the standard. Provision can be made for providing a further signal indicating the direction of any such divergence. Provision can also be made for suppression of the signals except when they result from incidence on a photocell of light intensity greater than ambient intensity. In an alternative arrangement, the photocells comprise rings concentric on the reference point. The photocells may instead from a semicircular array, the image being doubled about the edge diameter thereof, or a pair of such arrays, the image being duplicated for projection on each array.