US3741664A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for measuring the light transmission of a photographic film giving a digitized output
Assignee: Saab AB
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Filing: 1971-05-28
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Granted: 1973-06-26
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Expires: 1991-05-28
Abstract
Abstract Clock pulses are generated at a rate synchronized to scanning of a substance with a light beam. The light is energized in pulses having uniform duration in terms of clock pulses. Output of a photocell responding to incident light is integrated to produce a reference signal of linearly varying magnitude. Magnitude of output of a photocell receiving light passed through the substance is compared with the reference signal, and a difference signal is produced whenever the difference between compared signals has a predetermined sign. During a predetermined uniform portion of every light pulse, clock pulses are counted so long as the difference signal persists, giving a digitized measure of substance transparency/opacity.
Inventors
- 👤 J Torin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 06:35
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/27
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
251 words
A method of obtaining a digitized measurement of the relative opacity and transparency of different parts of a substance as the same is being scanned with a beam of light, which method is characterized by: A. producing clock pulses at a frequency which is synchronized to the rate at which the substance is being scanned; B. producing a train of successive energizing pulses that are synchronized to the clock pulses, every energizing pulse having a duration equal to the time required for producing a predetermined integral number of clock pulses and the pauses between successive energizing pulses likewise having uniform durations in terms of an integral number of clock pulses; C. in unison with production of the energizing pulses, energizing a light source used for scanning; D. producing a pulsing data signal, the pulses of which have a magnitude that corresponds to the intensity of light from said source that has passed through the substance being scanned; E. during the duration of each energizing pulse producing a reference magnitude signal having a magnitude that changes linearly at a predetermined rate; F. comparing the magnitude of each pulse of the data signal with its coexisting reference magnitude signal, and producing a difference signal whenever the difference between the compared magnitudes is of a predetermined sign; and G. during a predetermined portion of each energizing pulse, which portion is the same for every energizing pulse, counting clock pulses for as long as the difference signal coexists with said portion of the energizing pulse.
Claim 2
Independent Claim
251 words
A method of obtaining a digitized measurement of the relative opacity and transparency of different parts of a substance as the same is being scanned with a beam of light, which method is characterized by: A. producing clock pulses at a frequency which is synchronized to the rate at which the substance is being scanned; B. producing a train of successive energizing pulses that are synchronized to the clock pulses, every energizing pulse having a duration equal to the time required for producing a predetermined integral number of clock pulses and the pauses between successive energizing pulses likewise having uniform durations in terms of an integral number of clock pulses; C. in unison with production of the energizing pulses, energizing a light source used for scanning; D. producing a pulsing data signal, the pulses of which have a magnitude that corresponds to the intensity of light from said source that has passed through the substance being scanned; E. during the duration of each energizing pulse producing a reference magnitude signal having a magnitude that changes linearly at a predetermined rate; F. comparing the magnitude of each pulse of the data signal with its coexisting reference magnitude signal, and producing a difference signal whenever the difference between the compared magnitudes is of a predetermined sign; and G. during a predetermined portion of each energizing pulse, which portion is the same for every energizing pulse, counting clock pulses for as long as the difference signal coexists with said portion of the energizing pulse.
Claim 3
Independent Claim
130 words
A method of measuring the relative opacity and transparency of different parts of a substance as the same is being scanned with a beam of light, which method is characterized by: A. producing clock pulses at a frequency which is synchronized to the rate at which the substance is being scanned; B. producing a train of successive energizing pulses that are synchronized to the clock pulses, every energizing pulse having a duration equal to the time required for producing a predetermined integral number of clock pulses and the pauses between successive energizing pulses likewise having uniform durations in terms of an integral number of clock pulses; C. in unison with production of the energizing pulses, energizing a light source used for scanning; D. producing a pair of simultaneously pulsiNg signals,
Claim 4
Independent Claim
130 words
A method of measuring the relative opacity and transparency of different parts of a substance as the same is being scanned with a beam of light, which method is characterized by: A. producing clock pulses at a frequency which is synchronized to the rate at which the substance is being scanned; B. producing a train of successive energizing pulses that are synchronized to the clock pulses, every energizing pulse having a duration equal to the time required for producing a predetermined integral number of clock pulses and the pauses between successive energizing pulses likewise having uniform durations in terms of an integral number of clock pulses; C. in unison with production of the energizing pulses, energizing a light source used for scanning; D. producing a pair of simultaneously pulsiNg signals,
Claim 5
Dependent Claim
125 words
the other of which has a pulse magnitude that corresponds to the intensity of light at said light source; E. integrating said other pulsing signal to produce a comparison signal of constantly varying magnitude; F. continuously comparing the pulse magnitude of each pulse of said one pulsing signal with the then prevailing magnitude of said comparison signal, and producing a difference signal whenever the difference between the compared magnitudes is of a predetermined sign; and G. during a predetermined portion of each energizing pulse, which portion is the same for every energizing pulse, counting clock pulses for as long as the difference signal persists, to thus obtain a digitized measure of the relative opacity and transparency of the portion of the substance then being scanned.
Claim 6
Dependent Claim
125 words
the other of which has a pulse magnitude that corresponds to the intensity of light at said light source; E. integrating said other pulsing signal to produce a comparison signal of constantly varying magnitude; F. continuously comparing the pulse magnitude of each pulse of said one pulsing signal with the then prevailing magnitude of said comparison signal, and producing a difference signal whenever the difference between the compared magnitudes is of a predetermined sign; and G. during a predetermined portion of each energizing pulse, which portion is the same for every energizing pulse, counting clock pulses for as long as the difference signal persists, to thus obtain a digitized measure of the relative opacity and transparency of the portion of the substance then being scanned.
Claim 7
Dependent Claim
66 words
The method of claim 2, further characterized by: H. defining the portion of each energizing pulse during which clock pulses are to be counted by producing a train of phase-shifted pulse signals, each of which is in a predetermined phase relation to an energizing pulse; and I. counting clock pulses during each energizing pulse only while a phase-shifted pulse signal and a difference signal simultaneously coexist.
References Cited (Backward Citations)
US3006238A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-25 | 1976-12-25 | 1977-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-25 | 1980-12-25 | 1981-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-25 | 1984-12-25 | 1985-06-26 | $7700.00 | Window Closed / Lapsed |