METHOD FOR MAKING REDUCED BANDWIDTH HOLOGRAMS

• US 3,633,989 A
• Filed: 10/21/1969
• Issued: 01/11/1972
• Est. Priority Date: 10/21/1969
• Status: Expired due to Term

• Current Assignee: Stephen A. Benton
• Original Assignee: Stephen A. Benton
• Inventors: Benton, Stephen A.
• Primary Examiner(s): Schonberg, David
• Assistant Examiner(s): Sherman, Robert L.
• Application Number:
  US04/868,099
• Time in Patent Office: 812 Days
• Field of Search: 350/3.5
• US Class Current: 348/40
• CPC Class Codes: G03H 1/34 Systems for reducing the space-spatial bandwidth product
• CPC Class Codes: Y10S 359/90 Methods

Abstract

A method for making a low bandwidth stereoscopic hologram of a subject. Vertical parallax is eliminated to reduce information content. The remainder is transformed to a larger area thereby reducing the information spatial density of the resulting hologram. A narrow horizontal aperture is the means for limiting vertical parallax. The resulting hologram is suitable for television transmission. To view a stereoscopic image of the original subject a real image of the aperture is formed from the resulting hologram. An observer looks through the aperture image as if it were a window to view the stereoscopic subject image.

Claims

1. A method for making a hologram of a subject comprising the steps of:

illuminating said subject with light from a selected source to create a wave front reflecting therefrom having a given information content related to said subject;

limiting the information content of a wave front derived from said reflecting wave front;

forming an information-limited real image of said subject from said information-limited derived wave front;

combining said information-limited real image with a reference wave front of light having a select phase relationship with said information-limited wave front to form an interference pattern;

positioning an image-receiving surface proximate said information-limited real image; and

receiving said interference pattern on said image-receiving surface.

2. The method for making a hologram of a subject according to claim 1 wherein said step of illuminating said subject is carried out with a source of coherent light.

3. The method of making a hologram of a subject according to claim 2 wherein said information-limiting step comprises:

transferring a select portion of said derived wave front through an aperture having an aspect ratio representing a substantially large dimension in a direction parallel to a given plane of reference and a substantially limited dimension along an axis orthogonal to said plane.

4. A method for making a holographic image, of a subject, having information content and information spatial density limited to a predetermined amount comprising the steps of:

illuminating said subject with light from a select source to create a reflected wave front having a given information content and a waveform functionally related to said subject;

limiting the information content of a light wave front derived from said reflected wave front;

forming from said information-limited wave front an information limited stereOscopic real image of said subject having reduced information spatial density;

interferring said light forming said stereoscopic real image having limited information content and reduced information spatial density with a reference light beam having a select waveform and phase relationship with said information-limited wave front to form a holographic image;

positioning an image-receiving surface proximate said information-limited real image; and

receiving said holographic image on said image-receiving surface.

5. The method for making a holographic image of said subject according to claim 4 wherein:

limitation of information content is carried out by blocking all but a select portion of said derived wave front, and said stereoscopic real image is formed from said select portion.

6. The method for making a holographic image according to claim 4 wherein said information-limiting step includes the step of:

occluding all but a select portion of said derived wave front by passing said select portion through an aperture having a select aspect ratio.

7. The method for making a holographic image according to claim 6 further including the step of:

forming said aperture so as to transmit a greater amount of horizontal parallactic information than vertical parallactic information.

8. The method for making a holographic image according to claim 4 wherein said information-limiting step comprises:

transferring a select portion of said derived wave front through an aperture having an aspect ratio representing a substantially large dimension in a direction parallel to a given plane of reference and a substantially limited dimension along an axis orthogonal to said plane.

9. The method for making a holographic image according to claim 4 wherein said step of illuminating said subject is carried out with a source of coherent light.

10. A method for making a holographic image of a subject having a predeterminately limited information content and information spatial density, comprising the steps of:

illuminating said subject with coherent light to create a reflected wave front having a given information content and a waveform functionally related to said subject;

receiving said reflected wave front on an image-receiving surface;

interferring a first coherent reference light having selected waveform and direction with said reflected wave front at said image-receiving surface to form a first holographic image;

illuminating said first holographic image with coherent light having the time reverse waveform of said first reference light;

limiting the information content of a light wave front diffracted by said holographic image from said time reverse waveform;

reconstructing a three-dimensional information limited stereoscopic real image of said subject;

receiving said information-limited real image on a second image-receiving surface proximate said information-limited real image; and

interferring a second coherent reference light having selected waveform and direction with said information-limited real image at said second image receiving surface to form said information-limited holographic image.

11. The method for making an information-limited holographic image according to claim 10 including the step of recording said first holographic image on said first image-receiving surface.

12. The method for making an information-limited holographic image according to claim 11 wherein said information-limiting step comprises:

occluding all but a select portion of said first holographic image by placing adjacent thereto an aperture having a select aspect ratio representing a substantially large horizontal dimension and a substantially limited vertical dimension.

13. The method for making an information-limited holographic image according to claim 11 wherein said information-limiting step comprises:

limiting the area of said first image-receiving surface to a select aspect ratio representing a substantially Large dimension in a direction parallel to a given plane of reference and a substantially limited dimension along an axis orthogonal to said plane.

14. The method for making an information-limited hologram according to claim 10 including the step of recording said information-limited holographic image.

15. A method for forming a stereoscopic image of a subject comprising the steps of:

illuminating said subject with light from a selected source to create a wave front reflecting therefrom having a given information content related to said subject;

limiting the information content of a wave front derived from said reflecting wave front by transferring a select portion of said derived wave front through an aperture having an aspect ratio representing a substantially large horizontal dimension and a substantially limited vertical dimension;

forming an information-limited real image of said subject from said information-limited derived wave front, combining said information-limited real image with a reference wave front of light having a select phase relationship with said information-limited wave front to form an interference pattern;

positioning an image-receiving surface proximate said information limited real image;

receiving said interference pattern on said image-receiving surface; and

illuminating said image-receiving surface, having said interference pattern, with the time reverse waveform of said reference wave front to form a real image of said aperture thereby providing a point of observation for said stereoscopic image of said subject.

16. The method for forming a stereoscopic image according to claim 15 wherein the step of illuminating said image-receiving surface includes using a vertical line source of light.

17. A system for transmitting information from which stereoscopic images of a subject can be formed, comprising:

means for illuminating said subject with light from a selected source to create a reflected wave front having a given information content and a waveform functionally related to said subject;

means for limiting the information content of light wave front derived from said reflected wave front, said means including a narrow horizontal aperture;

means, including lens means positioned proximate said aperture, for forming from said information-limited wave front a stereoscopic real image of said subject having limited information content and spatial density;

means for interferring said light forming said stereoscopic real image having limited information content and spatial density with a reference light beam having a select waveform and phase relationship with said information-limited wave front to form a holographic image;

means for introducing said holographic image to an image-receiving surface proximate said stereoscopic real image;

means for scanning said image-receiving surface to form video signals representative of said holographic image; and

means for transmitting said video signals.