US3723958A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Acoustic imaging system
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1971-08-09
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Granted: 1973-03-27
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Expires: 1991-08-09
Abstract
Abstract An acoustic imaging system which is particularly useful at low sound levels. A light beam is made to pass twice through a region where the light can interact with the acoustic wave perturbed by the object. As a result a light image is created which is modulated at twice the acoustic frequency. Thus, a portion of the light has a frequency which is raised while another portion of the light has its frequency decreased by the acoustic frequency. Therefore, the modulated light may readily be segregated from the unmodulated light, for example, by a suitable bandpass filter. Because the scattered light does not disturb the image it is feasible to use a higher light intensity so that an optical image is obtainable even at low acoustic intensity. Furthermore, the resolution is improved because the system has a large aperture.
Inventors
- 👤 L Heflinger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 09:43
CPC Classifications
H; H04; H04N; H04N3/00; H04N3/02
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
165 words
A system for providing an image of an object illuminated with sound waves, said system comprising: a fluid within which the object to be imaged is disposed; an acoustic generator disposed for irradiating the object with a sound wave, thereby to create a perturbed sound wave; a light source disposed for interaction with the perturbed sound wave, said light source generating monochromatic light; a substantially spherical mirror for reflecting the light from said source and causing it to pass through the perturbed sound wave twice, whereby a portion of the light has its frequency shifted so that upon detection a frequency of twice the acoustic frequency is generated; means for scanning point by point in at least one dimension the light image obtained by reflection of the light wave; and means including a detector for receiving the light and segregating only the modulation component having a frequency of twice the acoustic frequency, said modulation component having an intensity indicative of the image of the object.
Claim 2
Independent Claim
165 words
A system for providing an image of an object illuminated with sound waves, said system comprising: a fluid within which the object to be imaged is disposed; an acoustic generator disposed for irradiating the object with a sound wave, thereby to create a perturbed sound wave; a light source disposed for interaction with the perturbed sound wave, said light source generating monochromatic light; a substantially spherical mirror for reflecting the light from said source and causing it to pass through the perturbed sound wave twice, whereby a portion of the light has its frequency shifted so that upon detection a frequency of twice the acoustic frequency is generated; means for scanning point by point in at least one dimension the light image obtained by reflection of the light wave; and means including a detector for receiving the light and segregating only the modulation component having a frequency of twice the acoustic frequency, said modulation component having an intensity indicative of the image of the object.
Claim 3
Dependent Claim
21 words
A system as dEfined in claim 1 wherein said spherical mirror has its center at the origin of said light source.
Claim 4
Independent Claim
196 words
A system for providing an image of an object illuminated with sound waves, said system comprising: a liquid within which the object to be imaged is disposed; an acoustic generator disposed in said liquid for irradiating the object with a sound wave, thereby to create a perturbed sound wave; a laser including lens means for providing an apparent point light source disposed for interaction with the perturbed sound wave, said laser generating monochromatic light; a spherical mirror for reflecting the light from said point light source and causing it to pass through the perturbed sound wave, whereby a portion of the light has a frequency shifted such that upon detection a frequency of twice the acoustic frequency is generated, said spherical mirror having its center at said point light source; mirror means for scanning point by point in at least one dimension the light image obtained by reflection of the light wave; a detector for receiving the light scanned by said mirror means to develop a signal; and means for segregating the signal portion having a frequency of twice the acoustic frequency and said signal portion having an intensity indicative of the image of the object.
Claim 5
Independent Claim
196 words
A system for providing an image of an object illuminated with sound waves, said system comprising: a liquid within which the object to be imaged is disposed; an acoustic generator disposed in said liquid for irradiating the object with a sound wave, thereby to create a perturbed sound wave; a laser including lens means for providing an apparent point light source disposed for interaction with the perturbed sound wave, said laser generating monochromatic light; a spherical mirror for reflecting the light from said point light source and causing it to pass through the perturbed sound wave, whereby a portion of the light has a frequency shifted such that upon detection a frequency of twice the acoustic frequency is generated, said spherical mirror having its center at said point light source; mirror means for scanning point by point in at least one dimension the light image obtained by reflection of the light wave; a detector for receiving the light scanned by said mirror means to develop a signal; and means for segregating the signal portion having a frequency of twice the acoustic frequency and said signal portion having an intensity indicative of the image of the object.
Claim 6
Dependent Claim
31 words
A system as defined in claim 3 wherein said means for segregating includes a band pass filter for passing only said signal having a frequency shifted by twice the acoustic frequency.
Claim 7
Dependent Claim
36 words
A system as defined in claim 3 wherein said means for segregating includes an oscilloscope for visually exhibiting said signal portion having a frequency of twice the acoustic frequency to exhibit an image of the object.
Claim 8
Dependent Claim
35 words
A system as defined in claim 5 wherein a scanner drive is provided for scanning said mirror means and for deflecting the electron beam of said oscilloscope thereby to exhibit an image of the object.
Claim 9
Dependent Claim
25 words
A system as defined in claim 3 wherein said laser includes an optical cavity, one end of said cavity being defined by said spherical mirror.
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) | 1976-03-26 | 1976-09-25 | 1977-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-26 | 1980-09-25 | 1981-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-26 | 1984-09-25 | 1985-03-27 | $7700.00 | Window Closed / Lapsed |