US3818427A - Process for recording acoustic, synthetic and microwave holograms - Google Patents

Process for recording acoustic, synthetic and microwave holograms Download PDF

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Publication number
US3818427A
US3818427A US00328742A US32874273A US3818427A US 3818427 A US3818427 A US 3818427A US 00328742 A US00328742 A US 00328742A US 32874273 A US32874273 A US 32874273A US 3818427 A US3818427 A US 3818427A
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row
recorded
rows
hologram
process according
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US00328742A
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English (en)
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D Pekau
R Diehl
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Siemens AG
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Siemens AG
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H3/00—Holographic processes or apparatus using ultrasonic, sonic or infrasonic waves for obtaining holograms; Processes or apparatus for obtaining an optical image from them

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  • PROCESS FOR RECORDING ACOUSTIC, SYNTHETIC AND MICROWAVE HOLOGRAMS Inventors: Dietlind Pekau, Krailling; Reiner Diehl, Heidelberg, both of Germany and Kunststoff, Germany ABSTRACT Foreign Application Priority Data 181/05 NP; 346/107 T, 108, 109, 110 R;
  • MIxER oscILLAToR STAGE v OSICILLOSCOPE 6 I L AMPLIFIER AMPLIFIER RECEIVER a l i i a I Lg I L I 8 SOUND TRANSMITTER 5 OBJECT 1 MIXER I/'7 oscILLAToR STAGE AMPLIFIER AMPLIFIER jg s 'fi l l 26 (4 9 5 11 II REcEIvER s L SOUND TRANSMITTER S 8 OBJECT 1 PROCESS FOR RECORDING ACOUSTIC, SYNTHETIC AND MICROWAVE HOLOGRAMS BACKGROUND OF THE INVENTION 1.
  • the present invention is directed to a process for recording acoustic, synthetic and microwave holograms in which a receiving transducer scans an object field emanating from an object to produce electrical output signals which are subsequently transformed into light signals and are recorded on a light sensitive medium to form the hologram.
  • the object must be displaced perpendicular to the hologram normal in order to obtain the necessary angle between the object and reference wave.
  • a reference wave which falls obliquely to the hologram plane, is simulated by changing the phase of the reference signal, which has the same frequency, at every scanned point.
  • the present invention is directed to a process for the recording of acoustic, synthetic or microwave holograms which during reconstruction of the hologram enable the complete separation of the reconstruction image from the non-diffracted light so that a considerable improved signal to noise ratio can be obtained.
  • the process records the hologram by scanning point by point and row by row the object wave field emanating from an object by a receiving transducer which produces an electrical output signal which is transformed into light signals that are recorded as holograms on a light sensitive medium in rows with the improvement comprising displacing every second row with respect to every first row in a direction parallel to the rows as the light signal is being recorded row by row on the light sensitive medium.
  • the degree of row displacement is less than the resolving power of the reconstructed image.
  • the electrical signals are transformed. into light signals by being presented on an oscilloscope screen and the step of displacing is accomplished by adding to the deflecting voltage of the oscilloscope a rectangular wave-form voltage whose frequency is equal to half of the frequency of the deflecting voltage of the oscilloscope.
  • the row displacement of every second row is accomplished by applying a time delay to the electrical output signals from the receiving transducer when scanning the second rows.
  • the receiving transducer scans the first rows in one direction and the second rows in an opposite direction and the electrical signals are transformed by an incandescent lamp or bulb into the light signals and the step of displacing utilizes the inertia of the incandescent bulb to produce the desired displacement between the rows.
  • FIG. 1 schematically shows an arrangement for executing the recording process according to the present invention
  • FIG. 2 illustrates a hologram with displaced rows produced by the process of the present invention
  • FIG. 3 diagrammatically shows an arrangement for a reconstruction of the holograms with displaced rows
  • FIG. 4 schematically shows an embodiment of the arrangement for executing the recording process according to the present invention.
  • FIG. 5 schematically shows another embodiment of the arrangement for executing the recording process according to the present invention.
  • the principles of the present invention are particularly useful in the method of recording an acoustic, synthetic or microwave hologram.
  • acoustic holograms For example, for recording of acoustic holograms, the amplitude and phase distribution of a sound field produced by a coherently irradiated object is scanned on a receiving plane (x y by a receiver transducer such as a sound receiver.
  • a coherent reference signals is attached to the output of the sound receiver and the interference signal which has thus been formed is visibly represented on electro-optical transducer and is then stored by being recorded on film.
  • the sound receiver can be a matrix of sound transducers which are electrically scanned or a single sound transducer which is mechanically moved over the receiving plane and thus scans the sound field in rows having predetermined spaced intervals.
  • FIG. 1 an example of a device for performing the process is illustrated.
  • An object which is to be recorded for example a metal plate 1, which has holes, is arranged in a tank 2 containing liquid.
  • an oscillator 3 produces a signal which is amplified by an amplifier 4 which drives a sound transmit ter 5 which is disposed in the tank 2 and can be a transducer which irradiates the object 1 with coherent sound waves.
  • the sound waves from the transducer 5 are diffracted by the object 1 to produce a sound field having an amplitude and phase distribution in a receiving plane 8' which is on the liquid surface of the tank 2.
  • the sound field in plane 8 is scanned by an ultrasonic receiver 8.
  • the ultrasonic receiver 8 is a receiving transducer which as illustrated is moved to scan the sound field in the receiving plane 8 point by point along rows.
  • the movement of the receiver 8 is controlled in two dimensions by a mechanical shifting device identified as X-Y.
  • the receiver 8 converts the ultrasonic signal into an electrical signal which is amplified by amplifier 9 and then conducted to a mixer stage 7.
  • a signal, which is obtained from the oscillator 3 is added to the electrical signal obtained from the ultrasonic receiver 8.
  • a resultant interference signal formed by the mixing of the coherent reference signal with the electrical signal from the receiver 8 is used to control the brightness of an incandescent bulb 10 which is moved synchronously with the ultrasonic receiver 8.
  • a camera 11 is focused on the bulb 10.
  • the camera 11 records the optical signals from the incandescent bulb 10 on a storage medium, such as a light sensitive medium 14, in rows 12 and 13 which have a spacing of Ax between rows as illustrated in FIG. 2.
  • the improvement of the process is the displacing of every alternative row so that every second row 13 is displaced a distance Ay with respect to every first row 12 in a direction parallel to the rows.
  • the output signal of the mixer stage 7 is conducted to an oscilloscope 6 which converts the electrical signal to an optical signal by displaying the signal on a screen.
  • the screen display is then recorded by the camera 11.
  • a constant rectangular wave-form voltage from means 25 is applied to the deflecting voltage of the oscilloscope while the signal of the every second row are being displayed.
  • the constant rectangular wave-form has a frequency which amounts to half the frequency of the deflecting voltage and cause the displacement Ay for every second row 13.
  • a second embodiment (FIG. of the process for producing the displacement is by delaying the output of the mixer stage 7 to the bulb by means 26 of an elec tric delay line when the stage 7 is producing the signals for the second row.
  • the time delay causes the desired spatially displacement Ay for the recording of each of the second rows 13 with regard to the first rows 12.
  • a third embodiment of the process for producing the displacement is a process in which the receiving transducer 8 scans the rows 12 in one direction and the rows 13 in the opposite direction.
  • the electrical signal from the mixer stage 7 is applied to the incandescent bulb 10 which has a time delay due to inertia. Since row 12 is scanned in one direction and row 13 in scanned in opposite directions, the inertia of the bulb 10 produces the desired displacement Ay.
  • the row displacement causes a scanning frequency of the amplitude and phase information of the object wave field to be effectively halved while maintaining a uniform band width and while the row displacement does not affect the constant to slowly varying component of the hologram transmission which produces a non-diffracted light during reconstruction.
  • the scanning frequency of the non-diffracted component amounts to double the recorded scanning frequency of the image information.
  • these components are spatially divided by this frequency difference so that the non-diffracted light can be filtered out without impairing the signal to noise ratio.
  • FIG. 3 A reconstruction of the hologram with the displaced rows is illustrated in FIG. 3.
  • the row displacements run parallel to the image plane of the figures.
  • the hologram 14 is illuminated with a convergent laser beam 15 which has a focal plane 16. Due to the illumination by the laser beam 15, the reconstructed image 17 of the object is produced shortly before the focal plane 16 and a conjugated image 18 together with higher order diffractions is formed behind the focal plane 16.
  • the focal plane 16 of the laser beam 15 as a result of the row displacement, the first orders of diffraction of the reconstructed image 17 and 18 are spatially separated from the non-diffracted light and the first order of diffraction of the constant component of the hologram transmission (the latter components lie outside of the image plane of FIG. 3).
  • a process of recording acoustic, synthetic and microwave holograms in which process an object wave field emanating from an object is scanned point by point and row by row by a receiving transducer which produces an electrical output signal which are transformed into light signals that are recorded as holograms on a light sensitive medium point by point in rows, the improvement comprising displacing every second row with respect to every first row in a direction parallel to the rows as the light signals are being recorded row by row on the light sensitive medium.
  • step of displacing every second row with respect to every first row is accomplished by applying time delay to the tion of scanning for every first row, and wherein the electrical signals are transformed into the light signals by being applied to an incandescent bulb with the displacing of the second rows with respect to the first rows utilizing the inertia of the incandescent bulb.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Holo Graphy (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
US00328742A 1972-02-16 1973-02-01 Process for recording acoustic, synthetic and microwave holograms Expired - Lifetime US3818427A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2207279A DE2207279A1 (de) 1972-02-16 1972-02-16 Verfahren zum aufzeichnen von akustischen, synthetischen oder mikrowellenhologrammen

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US3818427A true US3818427A (en) 1974-06-18

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US (1) US3818427A (es)
JP (1) JPS4890541A (es)
BE (1) BE795554A (es)
CA (1) CA979702A (es)
CH (1) CH552825A (es)
DE (1) DE2207279A1 (es)
FR (1) FR2172178B1 (es)
GB (1) GB1422801A (es)
IT (1) IT979050B (es)
LU (1) LU67031A1 (es)
NL (1) NL7301656A (es)
SE (1) SE379435B (es)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4805627A (en) * 1985-09-06 1989-02-21 Siemens Aktiengesellschaft Method and apparatus for identifying the distribution of the dielectric constants in an object
US5212571A (en) * 1991-11-22 1993-05-18 Advanced Imaging Systems Ultrasonic holographic imaging apparatus having zoom feature
US20040021911A1 (en) * 2002-07-31 2004-02-05 Corson John F. Array scanner noise reduction system

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI65677C (fi) * 1981-02-09 1984-06-11 Esko Alasaarela Holografisk b-avbildningsmetod

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3559465A (en) * 1967-05-24 1971-02-02 Perkin Elmer Corp Apparatus for constructing a hologram using acoustical radiation

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3559465A (en) * 1967-05-24 1971-02-02 Perkin Elmer Corp Apparatus for constructing a hologram using acoustical radiation

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4805627A (en) * 1985-09-06 1989-02-21 Siemens Aktiengesellschaft Method and apparatus for identifying the distribution of the dielectric constants in an object
US5212571A (en) * 1991-11-22 1993-05-18 Advanced Imaging Systems Ultrasonic holographic imaging apparatus having zoom feature
US20040021911A1 (en) * 2002-07-31 2004-02-05 Corson John F. Array scanner noise reduction system

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BE795554A (fr) 1973-06-18
DE2207279A1 (de) 1973-08-23
CH552825A (de) 1974-08-15
FR2172178A1 (es) 1973-09-28
GB1422801A (en) 1976-01-28
LU67031A1 (es) 1973-04-19
FR2172178B1 (es) 1976-11-05
JPS4890541A (es) 1973-11-26
NL7301656A (es) 1973-08-20
CA979702A (en) 1975-12-16
SE379435B (sv) 1975-10-06
IT979050B (it) 1974-09-30

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