Position detecting device and method
First Claim
Patent Images
1. A device for detecting a mark having edges, said device comprising:
- image pickup means for picking up an image of the mark and producing an image signal corresponding thereto;
extracting means having an extracting level for extracting a component from the image signal, each extracted component having a predetermined relation to the extracting level; and
control means for controlling the extracting level in accordance with the width and the number of the signal components extracted, so as to obtain signals corresponding to the edges of the mark.
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Abstract
An improved method and device for detecting a position of a mark formed on an object, by providing plural peaks in an image density distribution, wherein the image of the object having the mark is picked up to provide an image signal which in turn is processed to provide an integrated image-density distribution of the image in a predetermined direction and wherein the position of the mark is detected on the basis of the plural peaks in the integrated image-density distribution.
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6 Claims
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1. A device for detecting a mark having edges, said device comprising:
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image pickup means for picking up an image of the mark and producing an image signal corresponding thereto; extracting means having an extracting level for extracting a component from the image signal, each extracted component having a predetermined relation to the extracting level; and control means for controlling the extracting level in accordance with the width and the number of the signal components extracted, so as to obtain signals corresponding to the edges of the mark. - View Dependent Claims (2, 3, 4)
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5. A method for detecting a mark having edges, the method comprising the steps of:
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picking up an image of the mark and producing an image signal corresponding thereto; extracting a component from the image signal, each extracted component having a predetermined relation with an extracting level; and controlling the extracting level in a first operation so that a signal component substantially of a predetermined width is obtained as a result of extraction with the controlled extracting level, and then controlling the extracting level in a second operation so that a predetermined number of signal components is obtained as a result of extraction with the controlled extracting level, such that signals corresponding to the edges of the mark are obtained by the extraction. - View Dependent Claims (6)
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Specification