US3747066A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical scanner and signal processing system
Assignee: OCR Systems Inc USA
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Filing: 1971-08-23
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Granted: 1973-07-17
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Expires: 1991-08-23
Abstract
Abstract The reflectance of each small area on a document being scanned by a photosensitive device in an array of photosensitive devices is compared with the reflectance of a larger surrounding region in order to generate a video signal for identifying the parts of a printed character or other pattern, which minimizes the effects of variations in document reflectance, variations in incident light intensity and noise.
Inventors
- 👤 R Vernot
- 👤 J Neill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 21:32
CPC Classifications
G; G06; G06V; G06V30/00; G06V30/10; G06V30/16; G06V30/162
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
237 words
An optical scanner and signal processing system comprising: scanning means comprising a first group of light-sensitive elements each adapted to sense the intensity of light impinging on it and to provide an output corresponding to the instantaneous value of said intensity and optical projecting means for projecting an image from a pattern-bearing medium onto said elements whereby the apertures of said elements reflected back onto the medium are aligned in a row to define a narrow elongated scanning area; background detecting means comprising a second group of lightsensitive elements different from and fewer in number than the elements in the first group, said optical projecting means also and simultaneously projecting an image from the pattern-bearing medium onto the second group of elements whereby the apertures of the elements in the second group reflected back onto the medium are aligned in a row to define an elongated background area which surrounds the scanning area, said background detecting means providing a plurality of outputs, each corresponding to the instantaneous brightness of an area on said medium surrounding the area viewed by an element of the scanning means; means for causing said images to traverse the apertUres of the scanning and background detecting means; and means for subtracting the output of each light-sensitive element of the scanning means from the background detecting means output corresponding thereto and producing a response when the difference between the outputs exceeds a predetermined limit.
Claim 2
Dependent Claim
237 words
An optical scanner and signal processing system comprising: scanning means comprising a first group of light-sensitive elements each adapted to sense the intensity of light impinging on it and to provide an output corresponding to the instantaneous value of said intensity and optical projecting means for projecting an image from a pattern-bearing medium onto said elements whereby the apertures of said elements reflected back onto the medium are aligned in a row to define a narrow elongated scanning area; background detecting means comprising a second group of lightsensitive elements different from and fewer in number than the elements in the first group, said optical projecting means also and simultaneously projecting an image from the pattern-bearing medium onto the second group of elements whereby the apertures of the elements in the second group reflected back onto the medium are aligned in a row to define an elongated background area which surrounds the scanning area, said background detecting means providing a plurality of outputs, each corresponding to the instantaneous brightness of an area on said medium surrounding the area viewed by an element of the scanning means; means for causing said images to traverse the apertUres of the scanning and background detecting means; and means for subtracting the output of each light-sensitive element of the scanning means from the background detecting means output corresponding thereto and producing a response when the difference between the outputs exceeds a predetermined limit.
Claim 3
Dependent Claim
46 words
An optical scanner and signal processing system according to claim 1 in which each light-sensitive element of the background detecting means provides a plurality of outputs and in which the subtracting means subtracts an output of the scanning means from each of said plurality of outputs.
Claim 4
Dependent Claim
45 words
An optical scanner and signal processing system according to claim 1 in which the background detecting means includes means for averaging the outputs of plurality of elements in the second group to provide an output from which an output of the scanning means is subtracted.
Claim 5
Dependent Claim
76 words
An optical scanner and signal processing system according to claim 1 in which the background detecting means includes first means for averaging the outputs of a plurality of elements in the second group to provide a first output from which an output of the scanning means is subtracted, and second means for averaging the outputs of the same plurality of elements to provide a second output from which another output of the scanning means is subtracted.
Claim 6
Dependent Claim
98 words
An optical scanner and signal processing system according to claim 1 in which the background detecting means comprises first averaging means receiving signals from a first plurality of elements of the second group and providing one of the plurality of outputs of the background detecting means and second averaging means receiving a plurality of signals from a second plurality of elements of the second group and providing another one of said plurality of outputs, the first plurality being different as a whole from the second plurality but having at least one element in common with the second plurality.
Claim 7
Dependent Claim
68 words
An optical scanner and signal processing system according to claim 1 in which said background detecting means includes means for averaging the outputs of a plurality of elements in the second group to provide an output from which an output of the scanning means is subtracted, and in which said averaging means includes means producing a weighted average with emphasis on certain elements of said plurality of elements.
Claim 8
Dependent Claim
73 words
An optical scanner and signal processing system according to claim 1 in which said background detecting means includes means for averaging the outputs of a plurality of elements of the second group to provide an output from which an output of the scanning means is subtracted, and in which said averaging means includes means producing a weighted average with emphasis on the element of the plurality of elements which receives the most light.
Claim 9
Dependent Claim
116 words
An optical scanner and signal processing system according to claim 1 in which said background detecting means includes means for averaging the outputs of a plurality of elements of the second group to provide an output from which an output of the scanning means is subtracted, and in which said averaging means includes means providing a first signal corresponding to an average of the outputs of the elements in said plurality, means providing a second signal corresponding to the output of the element in said plurality which receives the most light, and means averaging said first and second signals to provide an output from which an output of an element of the scanning means is subtracted.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-16 | 1977-01-15 | 1977-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-16 | 1981-01-15 | 1981-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-16 | 1985-01-15 | 1985-07-17 | $7700.00 | Window Closed / Lapsed |