Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Patent
1991-11-01
1992-09-22
Nelms, David C.
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
358105, G01N 2186
Patent
active
051499800
ABSTRACT:
Method and apparatus for determining the distance a sheet of paper, or other reflective or transmissive substrate material with a suitable, approximately planar surface, has moved in a given direction. The substrate is illuminated by reflection or transmission of light at non-normal incidence, and a linear array of N uniformly spaced light sensors is provide to receive and sense light issuing from the illuminated substrate. This produces a first or reference array of light signal strengths s.sub.1 (k) (k=1,2, . . . , N). The substrate is then moved in the given direction, and a second array of signal strengths s.sub.2 (k) (k=1, 2, . . . , N) is produced. A cross-correlation function C(K), formed from consecutive portions of the first and second light signal strength arrays, is then examined to determine the distance the substrate has moved in the given direction. A maximum in the cross-correlation function C(K) at K=K.sub.0 corresponds to displacement of the substrate in the given direction by a distance approximately equal to (MF)(K.sub.0 -i)d, where i is selected positive integer determined by the initial position of the substrate, the distance d is determined from the known spacing of the light sensors, and MF is the system optical magnification factor. The cross-correlation function can be computed with uniform or non-uniform weights in the sum. This one-dimensional approach is extended to determining the vector of two-dimensional movement of the substrate, including translation, rotation and scaling, in a two-dimensional plane.
REFERENCES:
patent: 3890462 (1975-06-01), Limb et al.
patent: 3919560 (1975-11-01), Nopper
patent: 3942022 (1976-03-01), Stumpf et al.
patent: 4270143 (1981-05-01), Morris
patent: 4373816 (1983-02-01), Laib
patent: 4683380 (1987-07-01), Shipkowski et al.
patent: 5033096 (1981-07-01), Morrison et al.
patent: 5062056 (1991-10-01), Lo et al.
patent: 5089712 (1992-02-01), Holland
Baldwin Richard R.
Ertel John
Holland William D.
Jamp Rueiming
Vincent Kent D.
Hewlett--Packard Company
Lee John R.
Nelms David C.
LandOfFree
Substrate advance measurement system using cross-correlation of does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Substrate advance measurement system using cross-correlation of , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Substrate advance measurement system using cross-correlation of will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1070883