APPARATUS FOR SCANNING AND REPRODUCING A THREE-DIMENSIONAL REPRESENTATION OF AN OBJECT

• US 3,636,250 A
• Filed: 02/26/1964
• Issued: 01/18/1972
• Est. Priority Date: 02/26/1964
• Status: Expired due to Term

• Current Assignee: Andrew V. Haeff
• Original Assignee: Andrew V. Haeff
• Inventors: Haeff, Andrew V.
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Orsino, Jr., Joseph A.
• Application Number:
  US04/347,603
• Time in Patent Office: 2,883 Days
• Field of Search: 343/7.9,10,14,6,12,17,5CM 35/10.4 178/6.5 250/199,217CR 158/58,59 161/19 90/13.5,13.8,13 331/94.5
• US Class Current: 358/480
• CPC Class Codes: B23D 57/0061 of devices for guiding or feeding saw wires
• CPC Class Codes: B23D 61/185 Saw wires; Saw cables; Twisted saw strips
• CPC Class Codes: G03F 1/68 Preparation processes not covered by groups G03F1/20 - G03F1/50

Abstract

The surface of the object to be reproduced is scanned in successive lines with a narrow beam of columated radiation, preferably light, the intensity of which is modulated at a fixed frequency. The radiation reflected from the object is received by a detector which generates a signal which is compared in phase with the modulating signal to generate a signal indicative of the relative distance between successive points as they are scanned on the object surface. This latter signal is then used to form successive solid cross sections of variable thickness in a developing medium to reproduce the relative distances measured to the object along each of the scan lines, so that the solid cross sections located adjacent one another in the order of the scanning pattern reproduce the surface of the object. In particular, the surface of the object is scanned by a laser beam which is amplitude modulated at a selected radiofrequency. The beam passes through an absorption cell containing a pressurized gas corresponding to that in the laser so that application of sufficient direct current excitation raises a nominal number of electrons to an energy state capable of absorbing photons of the laser energy. The beam passes through a portion of the cell surrounded by a cavity resonator tuned to one-half the desired modulation frequency which produces an oscillatory electric field that periodically varies the number of absorption electrons at the desired modulation frequency, thus modulating the intensity of the beam emerging from the cell. A full color replica of the object is provided by coloring the different cross-sectional profiles of the object as they are formed. By correctly phasing the color information with respect to the operation of cutting the successive cross section profiles in a tape medium, three paint atomizers, each containing a primary color, are used to direct the paint colors in the selected proportions to the edges of the tape medium. The atomizers consist of half wavelength mechanical resonators with piezoelectric driving crystals that transmit ultrasonic vibrations to quarter wave sections extending on either side of a central holding point. The amplitude of the electrical signal driving the crystal of each atomizer at a fixed ultrasonic frequency is modulated in accordance with the color information. Paint or other coloring fluid is drawn through small capillary holes extending from the center of the atomizer to its upper surface where it is broken up into small droplets and directed upward towardS the tape in quantities corresponding to the driving signal amplitude.

Claims

1. A device for providing a three-dimensional representation of an object surface comprising:

a source of electromagnetic radiation amplitude modulated by a radiofrequency signal;

means for scanning successive profiles of the object with a concentrated beam of the modulated radiation;

means for receiving echo return signals as the beam is scattered by the surface of the object during scanning;

means for comparing the phase of the radiofrequency modulating signal in the received signal with the phase of the radiofrequency modulation of said source and proviDing an output indicative of the phase difference;

a developing medium; and

means responsive to the output for scanning successive cross sections of said medium in the same sequence as the object scanned, said means being responsive to the output of the comparing means to produce a varying solid cross-sectional thickness along each cross section proportional to the variations of the indicated phase difference.

2. The device of claim 1 wherein said comparing means includes a first frequency converter circuit for receiving said radio frequency signal from said source and providing an intermediate frequency output signal having a phase indicative of the phase of the radiofrequency signal source, a second frequency converter circuit for producing a second intermediate frequency signal having a phase indicative of the phase of the radiofrequency modulating signal in the echo return signals, and a circuit responsive to the two intermediate frequencies output signals to produce an output signal having an amplitude proportional to the phase difference between the two intermediate frequency output signals.

3. A device for providing a representation of an object surface comprising:

laser means for providing a collimated beam of narrow band radiation of a frequency of the order of the frequency of visible light;

an absorption cell for modulating the intensity of the beam at a selected radiofrequency, said absorption cell containing a gas mixture under high pressure, said absorption cell being disposed to pass the laser beam through the gas mixture;

means for applying a fixed electric field excitation to the pressurized gas mixture in the absorption cell to ionize said gas mixture to raise a nominal number of the electrons in the gas mixture to an energy level capable of absorbing photons in the beam, means for subjecting the gas mixture within the absorption cell in the path of the laser beam to an oscillatory electric field at one-half the desired modulation frequency, said oscillatory electric field being applied transverse to the direction of said fixed electric field to increase and decrease the number of absorption electrons within the absorption cell in accordance with the instantaneous amplitude of the oscillatory electric field at the selected radiofrequency;

means for deflecting the beam to scan successive profiles of the object surface;

means responsive only to the frequency of the narrow band radiation for detecting the beam radiation scattered by the object surface during scanning; and

means for comparing the phase of the selected radio modulation frequency with the phase of the intensity variations in the beam scattered from the object surface to produce an output signal proportional to the phase difference.

4. A device for providing a three dimensional representation of the scanned surface of an object comprising:

means for scanning successive profiles on the surface of the object with a concentrated beam of radiation to provide a profile signal indicative of variations in relative distance to successive points on the object surface;

means for providing separate cross-sectional strips in a developing medium; and

means responsive to the amplitude of the profile signal for producing a solid thickness in said developing medium proportional to the amplitude of the profile signal corresponding to successive cross sections of the developing medium.

5. A photographic device for providing a representation of the dimensions of the surface of an object comprising:

a laser device for producing a collimated beam of radiation;

means for modulating the intensity of the beam at a radiofrequency having a nominal wavelength approximately 10 to a 100 times the largest depth dimension of the surface;

scanning means for deflecting the beam in a regular scanning pattern across the object surface;

means responsive to the energy in the beam scattered from the surface of the object during scanning for producing a detected signal indicative of the intensity oF the reflected energy;

means responsive to the detected signal from the detected signal producing means for generating an output signal indicative of the phase variation of the detected signal; and

means responsive to the output signal for forming a three-dimensional representation of the object surface having varying depth dimensions proportional to the amplitude variations of the output signal and transverse dimensions corresponding to the original scanning pattern.

6. A device for providing a three-dimensional representation of an object surface comprising:

a laser device for providing a collimated beam of narrow band radiation;

means for scanning the object surface in a regular scanning pattern with the beam;

means responsive to the narrow band radiation reflected from the object surface for producing an output signal indicative of the variations in the distance traveled by the energy in the reflected beam, said means including a highly selective radiation filtering device responsive only to the narrow band of the laser radiation; and

a developing means having a solid medium representative of successive portions of the scanning pattern, means responsive to the output signal for cutting the developing medium to represent successive profiles of the object surface, and means for arranging the cut portions of the developing medium in accordance with the original scanning pattern to produce a three-dimensional replica of the surface.

7. A photographic device for obtaining three-dimensional information comprising:

a laser source for providing a narrow collimated beam of narrow band radiation;

a radiofrequency signal source coupled to amplitude modulate the beam intensity of the laser source;

a beam deflection system for deflecting the beam to scan the surface of the object in a regular pattern;

a receiver circuit having a photoelectric cell responsive to the intensity of the narrow band radiation reflected from the object surface to produce a signal having a frequency equal to the modulating radiofrequency;

a phase comparison circuit coupled to receive the signal from the receiving circuit and the modulating radio frequency from the source to produce an output signal indicative of the phase variation between the two radiofrequency signals; and

means operated by the phase variation output signal for providing successive cross-sectional profiles arranged in accordance with the original scanning pattern to produce a three-dimensional replica of the depth dimensions of the surface.

8. The device of claim 7 further including means generating signals indicative of the scanning pattern;

means for recording the phase variation signal and the scanning pattern signals associated therewith; and

means for reproducing the phase variation output signal in synchronism with the scanning pattern signal, said reproducing means including means responsive to the scanning pattern variation signals for properly aligning the successive cross-sectional profiles provided by the phase variation signals.

9. A device for reproducing a replica representative of the dimension of the surface of an object comprising:

means for scanning the surface of the object in a pattern corresponding to successive profiles and generating a scanning signal;

means responsive to the scanning for producing a profile signal representative of the depth dimension along successive portions of the scanning pattern;

means for recording the profile signal along with the scanning signal representative of the scanning pattern;

means for reproducing the profile signal and the scanning signal;

an elongated solid developing medium;

means for advancing the developing medium longitudinally with respect to a fixed longitudinal position;

a cutting tool disposed at the fixed position and responsive to be positioned transversely by the profile signal for cutting the developing medium to represent successive profiles of the object surface; and

means responsive to the reproduced scanning signals for arranging adjacent profiles in a manner corresponding to the original scanning pattern, so that the surfaces of the cut developing medium form a replica of the object surface.

10. The device of claim 9 wherein said scanning means includes means for providing a light beam, a tilting mirror and a many sided rotating mirror, said tilting mirror and said many sided rotating mirror being arranged to deflect said light beam in a regular scanning pattern across the surface of the object.

11. The device of claim 9 wherein said scanning means includes means for providing a light beam, first and second signal-operated beam deflection units, each of said deflection units comprising two liquids having dissimilar indices of refraction and confined in separate substantially constant volumes, flexible means defining successive interfaces along a selected beam path between alternate prism-shaped volumes of the two liquids, and transducer means responsive to applied deflection signals for producing a pressure differential in the two liquid volumes across said flexible interface defining means to vary the angular position between adjacent interfaces to thereby change the prism angle of the prism-shaped volumes to deflect the light beam in accordance with the scanning signals generated, said first light beam deflection unit being arranged to deflect the light beam in a first direction normal to the selected beam path and said second light beam deflection unit being arranged to deflect the light beam in a second direction normal to the selected beam path and to the first direction so that the surface of the object is scanned in a regular pattern.

12. A device for reproducing a replica representative of the dimensions of the surface of an object comprising:

means for scanning the surface of the object in a regular scanning pattern and for generating a scanning signal indicative of that pattern;

means responsive to the scanning for producing a profile signal representative of the depth dimension along successive portions of the scanning pattern;

means for recording the profile signal along with the associated scanning signals;

means for reproducing the recorded profile signal and the associated scanning signal;

a fluid container having at least one translucent sidewall;

a dye-sensitized photopolymer solution responding to light radiation of a selected frequency band to produce a solid having a thickness representative of the energy distribution of that light radiation incident upon the translucent sidewall;

means providing a beam of light radiation of the selected frequency;

means coupled to receive the reproduced scanning signal for deflecting the light beam to scan the translucent sidewall in a pattern duplicating the regular scanning pattern for the object surface; and

means coupled to said beam source for modulating the intensity of the light radiation in the beam in response to the reproduced profile signal, to produce a photopolymer solid representative of the object surface scanned.

13. A device for producing a full color, three-dimensional replica of an object surface comprising:

a solid elongated tape;

means for moving the solid tape longitudinally past a fixed longitudinal position;

a cutting tool located at said fixed longitudinal position for cutting the tape, said cutting tool being positioned transversely in response to a profile signal to cut successive cross section profiles of the object surface;

coloring means having a transverse slit extending across the tape at a second fixed longitudinal position and including means for deriving a color signal representative of three primary colors as they appear on the surface of the object at the point corresponding to longitudinal section of the tape adjacent the transverse slit, three signal controlled liquid atomizers for directing a color spray through the transverse slit onto the cut surface of the tape, each of said atomizers containing a coloring fluid having one of said primary colors and having an output controlled by the corresponding color signal. Pg,70

14. A device for modulating the intensity of a beam of coherent radiation comprising:

a resonant cavity capable of resonating at one-half the desired modulating frequency;

a gas discharge tube having an enclosed chamber through which the beam may pass;

means for exciting the resonant cavity to generate electromagnetic oscillations for providing an oscillatory electric field at one-half the desired modulating frequency, said enclosed chamber being disposed within the resonant cavity transverse to the direction of the oscillatory electric field;

a gas mixture filling said enclosed chamber, said gas mixture providing ionizable gas molecules having energy levels for electrons capable of absorbing photons of energy from the coherent radiation of the beam in proportion to the intensity of an applied electric field;

means coupled to said gas discharge tube for providing a fixed ionizing electric field to said gas mixture directed along said tube normal to said oscillatory electric field for producing a nominal number of absorbing electrons so that the oscillatory electric field applied to the enclosed chamber by the electromagnetic oscillations within the resonant cavity produces a net electric field within said tube to cause the number of absorbing electrons to increase and decrease at the desired modulation frequency.

15. A device for modulating the intensity of the coherent radiation in a laser beam comprising:

an absorption cell being disposed to pass the laser beam through the gas mixture;

means for applying a fixed electric field excitation to the pressurized gas mixture in the absorption cell to raise a nominal number of the electrons in the gas mixture to an energy level capable of absorbing photons in the beam; and

means for subjecting the gas mixture within the absorption cell to an oscillatory electric field at half a desired modulation frequency, said oscillatory electric field being directed transverse to said fixed electric field to produce a net electric field effective to increase and decrease the number of absorption electrons within the absorption cell in accordance with the instantaneous amplitude of the oscillatory electric field at the modulation frequency.

16. A device for providing a full color, three-dimensional replica of an object surface comprising:

a solid elongated tape;

means for moving the tape longitudinally past a fixed longitudinal position while maintaining a fixed transverse position;

a cutting means located at said fixed longitudinal position for cutting a continuous profile in the tape as it is moved longitudinally, said cutting tool being positioned transversely in response to a profile signal indicative of the depth dimensions of successive cross-sectional profiles of the object surface;

coloring means having a transverse slit extending across the entire width of the tape at a second fixed longitudinal position;

means for deriving three primary color signals indicative of the coloring of the object surface, said means including a full color photograph of the object surface, a white light source for scanning successive points on the photograph corresponding to the successive points on the object surface represented by the tape adjacent the transverse slit, and three primary color-sensing means responsive to the intensity of each of the primary colors at the point being scanned on the photograph by the white light spot for producing three primary color signals, each having an amplitude representative of the intensity of the respective one of the primary colors; and

three liquid atomizers disposed within the coloring means, each atomizer containing a fluid for coloring the tape one of the primary colors and having a spray output which is directed towards the transverse slit and which is proportional to the amplitude of the respective color signal, so that the successive cross-sectional profiles cut in the tape are colored in accordance with the color signals derived by scanning the photograph; and

means for stacking and aligning The successive colored cross-sectional profiles cut in the tape to represent adjacent profiles of the object surface, so that the cut surfaces of the tape provide a full color, three dimensional replica of the object surface.

17. The device of claim 16 wherein each atomizer comprises:

a half wave ultrasonic resonator having upper and lower quarter wave sections on either side of the nodal plane, the upper quarter wave section having vertical capillary holes extending through the entire upper quarter wave section from the nodal plane;

means including a piezoelectric crystal disposed adjacent the nodal plane between the upper and lower quarter wave sections of the resonator to apply vertical ultrasonic vibrations at the resonant frequency to both the upper and lower quarter wave sections;

means for enclosing a liquid volume adjacent the lower end of the capillary holes in the upper quarter wave section to form a liquid reservoir, whereby the liquid in the reservoir moves upward through the capillary holes and is atomized and directed upward by the vibration at the upper surface of the upper quarter wave section.

18. The device of claim 17 wherein the upper surface of the upper quarter wave section of each atomizer has a concave cross section for focusing the atomized liquid towards a predetermined point above the upper surface.

19. The device of claim 17 wherein said means for applying vertical vibrations includes an oscillator circuit for producing an ultrasonic signal having a frequency substantially the same as the resonant frequency of the resonator, means for modulating the amplitude of the ultrasonic signal applied to each of the liquid atomizers in accordance with the respective color signals, and means coupling the modulated ultrasonic signals to the piezoelectric crystal of the respective atomizer to control the amplitude of the vibrations in the resonator and thus the amount of liquid atomized.

20. A device for providing a three dimensional representation of an object surface comprising:

laser means for providing a collimated beam of narrow band radiation;

means for deflecting the beam in accordance with applied vertical and horizontal deflection signals to scan successive profiles of the object surface;

means for modulating the intensity of the beam with a frequency modulated radiofrequency signal, the beam intensity modulating means including circuit means responsive to the applied deflection signals for producing a control signal proportional to the cosine function of the instantaneous total beam deflection angle, and means responsive to the control signal for producing a beam intensity modulating signal having a radiofrequency proportional to the amplitude of the control signal;

means responsive to the narrow band radiation for detecting the intensity modulation of the beam radiation scattered by the object surface during scanning; and

means for comparing the phase of the frequency modulated radiofrequency signal with the phase of the intensity variation in the beam radiation scattered by the object surface to produce an output signal proportional to the phase difference and indicative of the depth dimension of the object surface.

21. The device of claim 20 wherein said comparing means includes a first frequency converter circuit for receiving said radiofrequency signal from the beam intensity modulating means and providing an intermediate frequency output signal having a phase indicative of the phase of the radiofrequency signal, a second frequency converter circuit for producing a second intermediate frequency output signal having a phase indicative of the phase of the intensity variations in the scattered radiation, and a circuit responsive to the two intermediate frequency output signals to produce an output signal having an amplitude proportional to the phase difference difference between the two intermediate frequency output signals.

22. The device of claim 20 wherein the means for deflecting the beam in accordance with appliEd vertical and horizontal deflection signals comprises:

first and second light beam deflection units, each of said deflection units including two liquids having dissimilar indices of refraction confined in separate substantially constant volumes;

flexible means defining successive interfaces along a selected beam path between alternating prism shaped volumes of the two liquids; and

transducer means responsive to an applied deflection signal for producing a pressure differential in the two liquid volumes across said flexible interface defining means to vary the angular relationship between adjacent interfaces, the first light beam deflection unit being responsive to applied horizontal deflection signals and said second light beam deflection unit being responsive to vertical deflection signals to scan successive cross sections of the object'"'"''"'"'s surface.