Device for detecting displacement between patterns

Claim 3

A device as set forth in claim 1 in which said first and second means comprise memory means for storing the signals representing said successive fields.

Claim 4

A displacement detection device comprising: first means for detecting a pattern at selected time intervals in successive fields in a scanning direction; second means for storing signals representing the field of the pattern picked up by said first means; third means connected to said second means for storing the signals which were stored in said second means during the immediately previous time interval and which represent a field which is relatively displaced in position with respect to the field now in said second means; fourth means for obtaining the correlation value between the successive fields of the pattern stored in said second and third means during a given interval by comparing the signals stored in said second and third means,; fifth means for shifting the field stored in one of said second and third means relative to the other by a selected amount during said given interval; and sixth means for deriving as the position displacement between the successive fields of the pattern a value corresponding to the number of shifts required to obtain the maximum correlation value between the fields stored in said second and third means.

Claim 5

A displacement detection device comprising: first means for detecting a pattern at selected time intervals in successive fields in a scanning direction; second means for storing signals representing the field of the pattern picked up by said first means; third means connected to said second means for storing the signals which were stored in said second means during the immediately previous time interval and which represent a field which is relatively displaced in position with respect to the field now in said second means; fourth means for obtaining the correlation value between the successive fields of the pattern stored in said second and third means during a given interval by comparing the signals stored in said second and third means,; fifth means for shifting the field stored in one of said second and third means relative to the other by a selected amount during said given interval; and sixth means for deriving as the position displacement between the successive fields of the pattern a value corresponding to the number of shifts required to obtain the maximum correlation value between the fields stored in said second and third means.

Claim 6

A device as set forth in claim 3 further comprising seventh means for reading out the signals representing the field stored in said second means when the sum of the displacement derived by said sixth means reaches a predetermined value.

Claim 7

A device as set forth in claim 3 further comprising seventh means for detecting the top position of the field stored in said second means, and eighth means for reading out said field stored in said second means when said seventh means detects said top position.

Claim 8

A device as set forth in claim 3 further comprising seventh means for detecting the top and end positions of said field stored in said second means, and eighth means for reading out the pattern data between said top and end position detected by said seventh means.

Claim 9

A device as set forth in claim 3 wherein said first means is a two-dimensional pickup device.

Claim 10

A device as set forth in claim 3 further comprising seventh means for detecting whether the displacement detected by said sixth means is within a predetermined range, and eighth means for giving an alarm signal when said displacement is outside of said predetermined range.

Claim 11

A device as set forth in claim 3 in which said second and third means comprise first and second shift registers, respectively.

Claim 12

A device as set forth in claim 9 in which said second means further includes means for transferring the pattern picked up by said first means to said first shift register and means for recirculating the contents of said first shift register and said third means further includes means for transferring the contents of said first shift register to said second shift register and means for recirculating the contents of said second shift register.

Claim 13

A device as set forth in claim 10, in which said fourth means comprises means for detecting the coincidence between the outputs of said first and second shift registers and means for counting the number of the coincidences detected by said detecting means.