US5149980A — Substrate advance measurement system using cross-…

Claim 1

Independent Claim 231 words

A method for determining the distance of advance in a selected direction of a sheet of paper or other substrate, the method comprising the steps of: illuminating a selected surface of the substrate with light of at least a predetermined light strength signal at a predetermined angle; providing N light sensors, positioned in a linear array and uniformly spaced apart by a distance d along the linear array, that each receive and sense the signal strength of light issuing from the selected surface at a predetermined optical magnification factor MF and provide a first array of light strength signals s 1 (k) (k=1, 2, . . . , N), where N is a selected integer>2; allowing the substrate to move in the selected direction; allowing the array of sensors to each receive and sense a second array of light strength signals s 2 (k) (k=1, 2, . . . , N), for light issuing from the selected surface, after the substrate has moved; forming the cross-correlation function ##EQU9## of the first and second arrays of light strength signals, where L is a predetermined integer satisfying 1≦L<N and i is a selected integer satisfying 1≦i≦N, and determining the value of the interger K=K O that produces the largest value of the cross-correlation function value C(K); and determining that the substrate has moved an approximate distance D=(MF)(K O -i)d in the selected direction.

Claim 2

Independent Claim 231 words

A method for determining the distance of advance in a selected direction of a sheet of paper or other substrate, the method comprising the steps of: illuminating a selected surface of the substrate with light of at least a predetermined light strength signal at a predetermined angle; providing N light sensors, positioned in a linear array and uniformly spaced apart by a distance d along the linear array, that each receive and sense the signal strength of light issuing from the selected surface at a predetermined optical magnification factor MF and provide a first array of light strength signals s 1 (k) (k=1, 2, . . . , N), where N is a selected integer>2; allowing the substrate to move in the selected direction; allowing the array of sensors to each receive and sense a second array of light strength signals s 2 (k) (k=1, 2, . . . , N), for light issuing from the selected surface, after the substrate has moved; forming the cross-correlation function ##EQU9## of the first and second arrays of light strength signals, where L is a predetermined integer satisfying 1≦L<N and i is a selected integer satisfying 1≦i≦N, and determining the value of the interger K=K O that produces the largest value of the cross-correlation function value C(K); and determining that the substrate has moved an approximate distance D=(MF)(K O -i)d in the selected direction.

Claim 3

Dependent Claim 43 words

The method of claim 1, further comprising the step of treating motion of said substrate in said selected direction as absent unless said substrate has moved at least a distance μd in said selected direction, where μ is a selected positive threshold constant.

Claim 4

Dependent Claim 70 words

The method of claim 1, further comprising the steps of: forming a peak correlation value C p defined by ##EQU10## from said first array of light strengths; comparing the peak value C p with the maximum cross-correlation value C(K O ) found from said cross-correlation values C(K); and indicating that an error may be present if C(K O )/C p <f, where f is a predetermined positive number satisfying 0<f<1.

Claim 5

Dependent Claim 114 words

The method of claim 1, further comprising the steps of: determining the position x O , velocity v O and acceleration a O of a selected point Q on said substrate at a selected time t=t O ; predicting the position of said point Q at a selected time t=t O +Δt>t O by means of the relation x Q (t=t O +Δt)=x O +v O Δt+a O (Δt) 2 /2; and choosing the center Q' of the second array of light sensor positions corresponding to said second array of light strengths so that the center Q' approximately coincides with the position x Q (t=t O +Δt) at the selected time t=t O +Δt.

Claim 6

Dependent Claim 28 words

The method of claim 1, wherein said step of illuminating said substrate comprises illuminating said substrate with a light beam that is focused by a telecentric optical system.

Claim 7

Dependent Claim 27 words

The method of claim 1, wherein said step of illuminating said substrate with said light comprises causing said light to be reflected from said substrate selected surface.

Claim 8

Dependent Claim 25 words

The method of claim 1, wherein said step of illuminating said substrate with said light comprises causing said light to be transmitted through said substrate.

Claim 9

Independent Claim 272 words

A method for determining the distance of advance in a selected direction of a sheet of paper or other substrate, the method comprising the steps of: illuminating a selected surface of the substrate with light of at least a predetermined light strength signal at a predetermined angle; providing N light sensors, positioned in a linear array and uniformly spaced apart by a distance d along the linear array, that each receive and sense the signal strength of light issuing from the selected surface at a predetermined optical magnification factor MF and provide a first array of light strength signals s 1 (k) (k=1, 2, . . . , N), where N is a selected integer >2; allowing the substrate to move in the selected direction; allowing the array of sensors to each receive and sense a second array of light strength signals s 2 (k) (k=1, 2, . . . , N), for light issuing from the selected surface, after the substrate has moved; forming the cross-correlation function ##EQU11## of the first and second arrays of light strength signals, where L is a predetermined integer satisfying 1≦L<N and i is a selected integer satisfying 1≦i≦N; approximating the correlation function value C(x) (x=0,1,2, . . . , N-1) by a polynomial p(x) of selected degree M≧2 for M+1 consecutive values C(x) in a neighborhood of the largest value of C(x), and determining the value x=X 0 , drawn from the continuous line that is defined by 0≦x≦N, for which the polynomial p(x) attains a maximum value; and determining that the substrate has moved an approximate distance D=(MF)(X 0 -i)d in the selected direction.

Claim 10

Independent Claim 272 words

A method for determining the distance of advance in a selected direction of a sheet of paper or other substrate, the method comprising the steps of: illuminating a selected surface of the substrate with light of at least a predetermined light strength signal at a predetermined angle; providing N light sensors, positioned in a linear array and uniformly spaced apart by a distance d along the linear array, that each receive and sense the signal strength of light issuing from the selected surface at a predetermined optical magnification factor MF and provide a first array of light strength signals s 1 (k) (k=1, 2, . . . , N), where N is a selected integer >2; allowing the substrate to move in the selected direction; allowing the array of sensors to each receive and sense a second array of light strength signals s 2 (k) (k=1, 2, . . . , N), for light issuing from the selected surface, after the substrate has moved; forming the cross-correlation function ##EQU11## of the first and second arrays of light strength signals, where L is a predetermined integer satisfying 1≦L<N and i is a selected integer satisfying 1≦i≦N; approximating the correlation function value C(x) (x=0,1,2, . . . , N-1) by a polynomial p(x) of selected degree M≧2 for M+1 consecutive values C(x) in a neighborhood of the largest value of C(x), and determining the value x=X 0 , drawn from the continuous line that is defined by 0≦x≦N, for which the polynomial p(x) attains a maximum value; and determining that the substrate has moved an approximate distance D=(MF)(X 0 -i)d in the selected direction.

Claim 11

Dependent Claim 43 words

The method of claim 8, further comprising the step of treating motion of said substrate in said selected direction as absent unless said substrate has moved at least a distance μd in said selected direction, where μ is a selected positive threshold constant.

Claim 12

Dependent Claim 70 words

The method of claim 8, further comprising the steps of: forming a peak correlation value C p defined by ##EQU12## from said first array of light strengths; comparing the peak value C p with the maximum polynomial value p(X 0 ) found from said polynomial values p(x); and indicating that an error may be present if p(X 0 )/C p <f, where f is a predetermined positive number satisfying 0<f<1.

Claim 13

Dependent Claim 19 words

The method of claim 8, further comprising the step of choosing said number M to be equal to 2.

Claim 14

Dependent Claim 28 words

The method of claim 8, wherein said step of illuminating said substrate comprises illuminating said substrate with a light beam that is focused by a telecentric optical system.

Claim 15

Dependent Claim 27 words

The method of claim 8, wherein said step of illuminating said substrate with said light comprises causing said light to be reflected from said substrate selected surface.

Claim 16

Dependent Claim 25 words

The method of claim 8, wherein said step of illuminating said substrate with said light comprises causing said light to be transmitted through said substrate.

Claim 17

Independent Claim 239 words

A method for determining the distance of advance in a selected direction of a sheet of paper or other substrate, the method comprising the steps of: illuminating a selected surface of the substrate with light of at least a predetermined light strength signal at a predetermined angle; providing a linear array of N light sensors, uniformly spaced apart by a distance d along the linear array, that each receive and sense the signal strength of light issuing from the selected surface at a predetermined optical magnification factor MF and provide a first array of light strength signals s 1 (k) (i=1,2, . . . , N), where N is a selected integer >2; allowing the substrate to move in the selected direction; allowing the array of sensors to each receive and sense a second array of light strength signals s 2 (k) (k=1,2, . . . , N), for light issuing from the selected surface, after the substrate has moved; forming the cross-correlation function ##EQU13## of the first and second arrays of light strength signals, where L is a predetermined integer satisfying 1≦L<N, i is a selected integer satisfying 1≦i≦N, and the weights w k represent a Doubly Monotone weight function, and determining the value K 0 of the integer K that produces the largest value of the cross-correlation function value C(K); and determining that the substrate has moved an approximate distance D=(MF)(K 0 -i)d in the selected direction.

Claim 18

Independent Claim 239 words

A method for determining the distance of advance in a selected direction of a sheet of paper or other substrate, the method comprising the steps of: illuminating a selected surface of the substrate with light of at least a predetermined light strength signal at a predetermined angle; providing a linear array of N light sensors, uniformly spaced apart by a distance d along the linear array, that each receive and sense the signal strength of light issuing from the selected surface at a predetermined optical magnification factor MF and provide a first array of light strength signals s 1 (k) (i=1,2, . . . , N), where N is a selected integer >2; allowing the substrate to move in the selected direction; allowing the array of sensors to each receive and sense a second array of light strength signals s 2 (k) (k=1,2, . . . , N), for light issuing from the selected surface, after the substrate has moved; forming the cross-correlation function ##EQU13## of the first and second arrays of light strength signals, where L is a predetermined integer satisfying 1≦L<N, i is a selected integer satisfying 1≦i≦N, and the weights w k represent a Doubly Monotone weight function, and determining the value K 0 of the integer K that produces the largest value of the cross-correlation function value C(K); and determining that the substrate has moved an approximate distance D=(MF)(K 0 -i)d in the selected direction.

Claim 19

Dependent Claim 20 words

The method of claim 15, further comprising the step of choosing said weights w k to represent a rectangular function.

Claim 20

Dependent Claim 20 words

The method of claim 15, further comprising the step of choosing said weights w k to represent a trapezoidal function.

Claim 21

Dependent Claim 20 words

The method of claim 15, further comprising the step of choosing said weights w k to represent a triangular function.

Claim 22

Dependent Claim 26 words

The method of claim 15, wherein said step of illuminating said substrate with light comprises causing said light to be reflected from said substrate selected surface.

Claim 23

Dependent Claim 24 words

The method of claim 15, wherein said step of illuminating said substrate with light comprises causing said light to be transmitted through said substrate.

Claim 24

Dependent Claim 28 words

The method of claim 15, wherein said step of illuminating said substrate comprises illuminating said substrate with a light beam that is focused by a telecentric optical system.

Claim 25

Independent Claim 425 words

A method for determining the distance of advance in a selected direction in a two-dimensional plane of a sheet of paper or other substrate, the method comprising the steps of: illuminating a selected surface of the substrate with light of at least a predetermined light strength signal at a predetermined angle; providing a two-dimensional array of N 1 ×N 2 light sensors, uniformly spaced apart by distances d1 and d2 in two respective independent directions within the array, where each light sensor receives and senses the signal strength of light issuing from the selected surface at a predetermined optical magnification factor MF and provides a first array of light strength signals s 1 (k 1 ,k 2 ) (k 1 =1, 2, . . . , N 1 ; k 2 =1, 2, . . . , N 2 ), where N 1 and N 2 are selected integers >2; allowing the substrate to move in the selected direction; allowing the array of sensors to each receive and sense a second array of light strength signals s 2 (k 1 ,k 2 ) (k 1 =1, 2, . . . , N 1 ; k 2 =1, 2, . . . , N 2 ), for light issuing from from the selected surface, after the substrate has moved; forming the cross-correlation function C 2 (f1K 1 cos Ω+f1K 2 sin Ω+K 3 , f2K 1 sin Ω+f2K 2 cos Ω+K 4 ), where ##EQU14## of the first and second arrays of light strength signals, where L 1 and L 2 are predetermined integers satisfying 1≦L 1 <N 1 and 1≦L 2 <N 2 and i 1 and i 2 are selected integers satisfying 1≦i 1 ≦N 1 and 1≦i 2 ≦N 2 , and determining the values of the integers K 1 , K 2 , K 3 and K 4 , the values of the scale factors f1 and f2 (0<f1,f2≦1) and the value of the rotation angle Ω (0≦Ω<2π) that collectively product the larges value of the cross-correlation function value C 2 (f1K 1 cos Ω+f1K 2 sin Ω+K 3 , -f2K 1 sin Ω+f2K 2 cos Ω+K 4 ); and determining that the substrate has moved by a two-dimensional vector in the plane corresponding to the choice of the parameters K 1 , K 2 , K 3 , K 4 , f1, f2 and Ω that maximize the cross-correlation function value C 2 (f1K 1 cos Ω+f1K 2 sin Ω+K 3 , -f2K 1 sin Ω+f2K 2 cos Ω+K 4 ).

Claim 26

Independent Claim 425 words

A method for determining the distance of advance in a selected direction in a two-dimensional plane of a sheet of paper or other substrate, the method comprising the steps of: illuminating a selected surface of the substrate with light of at least a predetermined light strength signal at a predetermined angle; providing a two-dimensional array of N 1 ×N 2 light sensors, uniformly spaced apart by distances d1 and d2 in two respective independent directions within the array, where each light sensor receives and senses the signal strength of light issuing from the selected surface at a predetermined optical magnification factor MF and provides a first array of light strength signals s 1 (k 1 ,k 2 ) (k 1 =1, 2, . . . , N 1 ; k 2 =1, 2, . . . , N 2 ), where N 1 and N 2 are selected integers >2; allowing the substrate to move in the selected direction; allowing the array of sensors to each receive and sense a second array of light strength signals s 2 (k 1 ,k 2 ) (k 1 =1, 2, . . . , N 1 ; k 2 =1, 2, . . . , N 2 ), for light issuing from from the selected surface, after the substrate has moved; forming the cross-correlation function C 2 (f1K 1 cos Ω+f1K 2 sin Ω+K 3 , f2K 1 sin Ω+f2K 2 cos Ω+K 4 ), where ##EQU14## of the first and second arrays of light strength signals, where L 1 and L 2 are predetermined integers satisfying 1≦L 1 <N 1 and 1≦L 2 <N 2 and i 1 and i 2 are selected integers satisfying 1≦i 1 ≦N 1 and 1≦i 2 ≦N 2 , and determining the values of the integers K 1 , K 2 , K 3 and K 4 , the values of the scale factors f1 and f2 (0<f1,f2≦1) and the value of the rotation angle Ω (0≦Ω<2π) that collectively product the larges value of the cross-correlation function value C 2 (f1K 1 cos Ω+f1K 2 sin Ω+K 3 , -f2K 1 sin Ω+f2K 2 cos Ω+K 4 ); and determining that the substrate has moved by a two-dimensional vector in the plane corresponding to the choice of the parameters K 1 , K 2 , K 3 , K 4 , f1, f2 and Ω that maximize the cross-correlation function value C 2 (f1K 1 cos Ω+f1K 2 sin Ω+K 3 , -f2K 1 sin Ω+f2K 2 cos Ω+K 4 ).

Claim 27

Dependent Claim 26 words

The method of claim 22, wherein said step of illuminating said substrate with light comprises causing said light to be reflected from said substrate selected surface.

Claim 28

Dependent Claim 24 words

The method of claim 22, wherein said step of illuminating said substrate with light comprises causing said light to be transmitted through said substrate.

Claim 29

Dependent Claim 28 words

The method of claim 22, wherein said step of illuminating said substrate comprises illuminating said substrate with a light beam that is focused by a telecentric optical system.

Claim 30

Dependent Claim 263 words

Apparatus for determining the distance of advance in a selected direction of a sheet of paper or other substrate, the apparatus comprising: a light source and telecentric light focusing system for illuminating a selected surface of the substrate with light having a predetermined light strength and having a predetermined incidence angle relative to a selected light-receiving surface of the substrate; N light sensors, positioned in a linear array and uniformly spaced apart by a distance d along the linear array, that each receive and sense the signal strength of light reflected from the selected surface at a predetermined optical magnification factor MF and provide a first array of light strength signals s 1 (k) (k=1, 2, . . . , N) before the substrate has been moved, and the array of light sensors also receives and senses a second array of light strength signals s 2 (k) (k=1, . . . , N), for light issuing from the selected surface with the optical magnification factor MF, after the substrate has been moved, where N is a selected integer >2; and computation means for receiving the first and second arrays of light strength signals s 1 (k) and s 2 (k), for forming a cross correlation function ##EQU15## where L is a predetermined integer satisfying 1≦L<N and i is a selected integer satisfying 1≦i≦N, for determining the value of a positive integer K=K 0 that produces the largest value of the cross-correlation function C(K), and for determining and indicating that the substrate has moved an approximate distance D=(MF)(K 0 -i)d in the selected direction.

Claim 31

Dependent Claim 263 words

Apparatus for determining the distance of advance in a selected direction of a sheet of paper or other substrate, the apparatus comprising: a light source and telecentric light focusing system for illuminating a selected surface of the substrate with light having a predetermined light strength and having a predetermined incidence angle relative to a selected light-receiving surface of the substrate; N light sensors, positioned in a linear array and uniformly spaced apart by a distance d along the linear array, that each receive and sense the signal strength of light reflected from the selected surface at a predetermined optical magnification factor MF and provide a first array of light strength signals s 1 (k) (k=1, 2, . . . , N) before the substrate has been moved, and the array of light sensors also receives and senses a second array of light strength signals s 2 (k) (k=1, . . . , N), for light issuing from the selected surface with the optical magnification factor MF, after the substrate has been moved, where N is a selected integer >2; and computation means for receiving the first and second arrays of light strength signals s 1 (k) and s 2 (k), for forming a cross correlation function ##EQU15## where L is a predetermined integer satisfying 1≦L<N and i is a selected integer satisfying 1≦i≦N, for determining the value of a positive integer K=K 0 that produces the largest value of the cross-correlation function C(K), and for determining and indicating that the substrate has moved an approximate distance D=(MF)(K 0 -i)d in the selected direction.

Claim 32

Dependent Claim 25 words

The apparatus of claim 26, wherein said light used to illuminate said substrate is caused to be reflected from said selected surface of said substrate.

Claim 33

Dependent Claim 21 words

The apparatus of claim 26, wherein said light used to illuminate said substrate is caused to be transmitted through said substrate.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1995-09-22	1996-03-23	1996-09-22	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1999-09-22	2000-03-23	2000-09-22	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2003-09-22	2004-03-23	2004-09-22	$7700.00	Window Closed / Lapsed

Substrate advance measurement system using cross-correlation of light sensor array signals

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