US3678452A
Expired / Lapsed
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Recording elastic-wave phase holographic data
Assignee: BP America Production Co
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Filing: 1970-04-30
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Granted: 1972-07-18
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Expires: 1990-04-30
Abstract
Abstract In elastic-wave holography where transducers are used to convert the detected elastic waves into corresponding electrical signals, the phase pattern of many transducers spread over the hologram area is recorded by sampling all of the electrical signals during one cycle of the coherent elastic waves to get a relative time delay for the zero-axis crossings of each signal. Pulses at zeroaxis crossing times, produced by amplifying, clipping, and differentiating the signals, are then shaped or stretched to form short square waves of time duration M, or phase duration K electrical degrees, where K equals 360*/L, L being the integral number of phase intervals into which the coherent-wave cycle is subdivided. Each value of K also corresponds to one step of the gray scale used in recording the final hologram. To record the hologram directly or in a form suitable for later playback, all transducer outputs during one coherent-wave cycle are scanned L times, once for each successive K* interval, to detect the square-wave pulses. In each scan, the occurrence times of pulses correspond to those transducer positions in the hologram area having relative phases within the given K* interval. These are accordingly the positions for recording a particular gray-scale density on the final hologram. Succeeding scans detect the positions of different phase and different corresponding density on the hologram, until all phase intervals and hologram density points have been covered.
Inventors
- 👤 Daniel Silverman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 18:48
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/52; G01S7/56; G01S7/60; G01S15/00; G01S15/88; G01S15/89; G01S15/8906; G01S15/8965; G01S15/897; G03; G03H; G03H5/00
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
216 words
In a method of recording elastic-wave holographic data provided by a plurality of elastic-wave detector signal channels and a reference signal of frequency f, said recording to be of a parameter related to the relative phases between said reference signal and the signal in each of said detector channels, there being n channels and L independent equal-time spaced determinations in one cycle of said reference signal, the improvement comprising the steps of amplifying and clipping each of said detector signals and said reference signal to provide corresponding square-wave signals, differentiating each of said square-wave signals to provide brief voltage pulses at each zero-axis crossing of each of said signals, shaping each of said brief pulses of a given polarity into square-wave pulses of time duration M 1/fL, at a time of about M/ 2 following brief pulse of said reference signal, scanning each of said signal channels in sequence for the presence or absence of one of said square-wave pulses, recording on a record medium in the sequence of scanning said channels, an indication of the presence of square-wave pulses when they occur, and repeating said scanning and recording steps at each of a plurality of successive times M time units apart, until at least a total of L such scans have been completed and recorded.
Claim 2
Dependent Claim
216 words
In a method of recording elastic-wave holographic data provided by a plurality of elastic-wave detector signal channels and a reference signal of frequency f, said recording to be of a parameter related to the relative phases between said reference signal and the signal in each of said detector channels, there being n channels and L independent equal-time spaced determinations in one cycle of said reference signal, the improvement comprising the steps of amplifying and clipping each of said detector signals and said reference signal to provide corresponding square-wave signals, differentiating each of said square-wave signals to provide brief voltage pulses at each zero-axis crossing of each of said signals, shaping each of said brief pulses of a given polarity into square-wave pulses of time duration M 1/fL, at a time of about M/ 2 following brief pulse of said reference signal, scanning each of said signal channels in sequence for the presence or absence of one of said square-wave pulses, recording on a record medium in the sequence of scanning said channels, an indication of the presence of square-wave pulses when they occur, and repeating said scanning and recording steps at each of a plurality of successive times M time units apart, until at least a total of L such scans have been completed and recorded.
Claim 3
Dependent Claim
211 words
In elastic-wave phase holography wherein are recorded indications of the relative phases of coherent elastic waves of period T received by a plurality n of transducers which convert said elastic waves to electrical signals, said transducers being spread over a hologram area, the improvement comprising the steps of amplifying and clipping each of said n transducer signals to produce corresponding square-wave signals, differentiating said square-wave signals to produce brief positive and negative pulses at the zero-axis crossings of said square-wave signals, selecting said brief pulses of one polarity and shaping said selected pulses into square-wave pulses of duration M T/L where L is an integer equal to the number of phase-angle intervals into which said period T is subdivided for determining said relative phases, for at least L successive times spaced M seconds apart during at least one period T of said coherent waves, sampling the square-wave pulse outputs of said n transducers to detect the presence of said square-wave pulses, and following each sampling, and in a sequence related to the position of the corresponding transducer in said hologram area, recording an indication of the occurrence of each square-wave pulse in said sample, there being a range of relative phase angles and a corresponding hologram parameter associated with each sample.
Claim 4
Dependent Claim
211 words
In elastic-wave phase holography wherein are recorded indications of the relative phases of coherent elastic waves of period T received by a plurality n of transducers which convert said elastic waves to electrical signals, said transducers being spread over a hologram area, the improvement comprising the steps of amplifying and clipping each of said n transducer signals to produce corresponding square-wave signals, differentiating said square-wave signals to produce brief positive and negative pulses at the zero-axis crossings of said square-wave signals, selecting said brief pulses of one polarity and shaping said selected pulses into square-wave pulses of duration M T/L where L is an integer equal to the number of phase-angle intervals into which said period T is subdivided for determining said relative phases, for at least L successive times spaced M seconds apart during at least one period T of said coherent waves, sampling the square-wave pulse outputs of said n transducers to detect the presence of said square-wave pulses, and following each sampling, and in a sequence related to the position of the corresponding transducer in said hologram area, recording an indication of the occurrence of each square-wave pulse in said sample, there being a range of relative phase angles and a corresponding hologram parameter associated with each sample.
Claim 5
Dependent Claim
97 words
In elastic-wave phase holography, the improvement as in claim 2 in which said coherent elastic waves are generated in response to the output of a constant-frequency control oscillator and including the further steps of deriving a reference signal from the output of said oscillator, clipping said reference signal to produce a corresponding reference square-wave, diffErentiating said reference square wave to produce brief reference pulses coincident with the zero-axis crossings of said reference signal, and employing one of said brief reference pulses to initiate the first of said L successive samplings of said n transducer square-wave pulse outputs.
Claim 6
Dependent Claim
86 words
In elastic-wave phase holography, the improvement as in claim 2 in which said coherent elastic waves are generated in response to the output of a constant-frequency control oscillator of period T and including the further steps of deriving a reference signal from the output of said oscillator, multiplying said reference signal by the integral factor L to produce a constant-frequency sampling-control signal of period M T/L, and employing said sampling-control signal to initiate each of said L successive samplings of said n transducer square-wave pulse outputs.
Claim 7
Dependent Claim
35 words
In elastic-wave phase holography, the improvement as in claim 2 in which said step of recording comprises the step of reproducibly recording a quantity related to the occurrence of each square-wave pulse in said sample.
Claim 8
Dependent Claim
56 words
In elastic-wave phase holography, the improvement as in claim 5 including the additional steps of reading the reproducible recording of said quantity, and plotting on a record medium, in a position related to the position in said hologram area of the corresponding transducer, a quantity related to the occurrence of each square-wave pulse in said sample.
Claim 9
Dependent Claim
42 words
In elastic-wave phase holography, the improvement as in claim 6 in which said quantity plotted in each position on said medium is an area of gray-scale value related to the relative time of occurrence of the square-wave pulse in the coherent-wave cycle.
Claim 10
Dependent Claim
56 words
In elastic-wave phase holography, the improvement as in claim 5 in which said step of reproducibly recording comprises the steps of recording on a single track successive arrays of spots, each array comprising spots corresponding to the presence of square-wave pulses on sequentially sampled channels, and each successive array corresponding to one of said L samplings.
Claim 11
Dependent Claim
60 words
In elastic-wave phase holography, the improvement as in claim 5 in which said step of reproducibly recording comprises the steps of recording on each of multiple tracks, one corresponding to each of the transducer signal channels, at a time corresponding to one of the L successive samplings, a mark corresponding to the presence of a square-wave pulse in said channel.
Claim 12
Dependent Claim
210 words
In elastic-wave phase holography employing a holographic detecting array of n electrical transducers in an elastic-wave transmitting medium, each of said transducers acting to convert coherent elastic-wave energy of period T incident thereon into n corresponding electrical signals, the improved multiple-channel system for recording indications of the relative phases of said signals comprising n signal-channel means to amplify and clip each of said transducer electrical signals to produce corresponding square-wave signals, means to differentiate and rectify said square-wave signals to produce a brief pulse at each alternate zero-axis crossing of each of said square-wave signals of a given polarity, means to shape said brief pulses into square-wave pulses of duration M T/L seconds where L is an integer equal to the number of phase-angle intervals into which said period T is subdivided for determining said relative phases, means to sample, for at least L successive times spaced in time by M seconds, all of the outputs of said signal channels to detect the presence of said square-wave pulses, and means to record, as a function of detector position in said array and corresponding channel position in the order of sampling, an indication for each of said n channels as to which of said l samples contained the corresponding square-wave pulse.
Claim 13
Dependent Claim
210 words
In elastic-wave phase holography employing a holographic detecting array of n electrical transducers in an elastic-wave transmitting medium, each of said transducers acting to convert coherent elastic-wave energy of period T incident thereon into n corresponding electrical signals, the improved multiple-channel system for recording indications of the relative phases of said signals comprising n signal-channel means to amplify and clip each of said transducer electrical signals to produce corresponding square-wave signals, means to differentiate and rectify said square-wave signals to produce a brief pulse at each alternate zero-axis crossing of each of said square-wave signals of a given polarity, means to shape said brief pulses into square-wave pulses of duration M T/L seconds where L is an integer equal to the number of phase-angle intervals into which said period T is subdivided for determining said relative phases, means to sample, for at least L successive times spaced in time by M seconds, all of the outputs of said signal channels to detect the presence of said square-wave pulses, and means to record, as a function of detector position in said array and corresponding channel position in the order of sampling, an indication for each of said n channels as to which of said l samples contained the corresponding square-wave pulse.
Claim 14
Dependent Claim
57 words
An improved recording system for elastic-wave phase holography as in claim 10 including also means to display, as gray-valued spots in positions related to the positions of the corresponding transducers in said array, said indications of square-wave pulse occurrence, the said gray value being related to the sequential number of sample in said succession of L samples.
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) | 1975-07-18 | 1976-01-17 | 1976-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-18 | 1980-01-17 | 1980-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-18 | 1984-01-17 | 1984-07-18 | $7700.00 | Window Closed / Lapsed |