Direct electronic fourier transforms of optical images

• US 4,040,091 A
• Filed: 08/01/1974
• Issued: 08/02/1977
• Est. Priority Date: 12/29/1972
• Status: Expired due to Term

• Current Assignee: Research Corporation
• Original Assignee: Research Corporation
• Inventors: Kornreich, Philipp G., Kowel, Stephen T.
• Primary Examiner(s): Martin, John C.
• Application Number:
  US05/493,990
• Time in Patent Office: 1,097 Days
• Field of Search: 178/7.1, 178/7.3, 178/7.6, 178/DIG. 18, 178/DIG. 27, 315/55, 315/169 TV, 250/211 J, 250/211 R, 250/208, 250/213 R, 310/8.1, 310/8, 310/8.3, 310/9.7
• US Class Current: 348/198
• CPC Class Codes: G02F 1/11 based on acousto-optical elements, e.g. using variable diffraction by sound or like mechanical waves acousto-optical deflection G02F1/33
• CPC Class Codes: G06V 10/12 Details of acquisition arrangements; Constructional details thereof
• CPC Class Codes: G06V 10/20 Image preprocessing
• CPC Class Codes: G06V 10/42 Global feature extraction by analysis of the whole pattern, e.g. using frequency domain transformations or autocorrelation
• CPC Class Codes: G08B 13/18 Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength
• CPC Class Codes: G08B 13/1961 Movement detection not involving frame subtraction, e.g. motion detection on the basis of luminance changes in the image
• CPC Class Codes: G08B 13/19634 Electrical details of the system, e.g. component blocks for carrying out specific functions
• CPC Class Codes: H04N 3/10 by means not exclusively optical-mechanical H04N3/36 takes precedence

Abstract

Method and apparatus for directly converting between optical images and the spatial Fourier transforms of optical images by interacting sound waves and light. Controlled sound waves couple with optical images, and electrical signals may be derived from this coupling which are functions of the spatial Fourier transforms of the entire optical images. In a reverse process, optical images are obtained directly by coupling controlled sound waves with electrical signals which are a function of the spatial Fourier transforms of the optical images and with light.

Claims

1. A device for generating an electrical signal representation of an optical image comprising:

a medium having an electrical property which varies as a function of an optical image incident on the medium and as a function of time and space varying strain disturbances in the medium;

means for causing the incidence of an optical image on the medium;

means for causing in the medium a plurality of different time and space varying strain disturbances whose spatial wavelengths are selected substantially independently of any natural vibrating modes of the medium; and

means for measuring said electrical property of the medium at a plurality of said different strain disturbances in the medium to derive a plurality of electrical signals, each signal representing an aspect of the entire optical image rather than of a point of the image.

2. A device as in claim 1 wherein each of said plurality of different strain disturbances is substantially periodic in space and time.

3. A device as in claim 2 wherein each of a plurality of said electrical signals is a function of the light intensity distribution along at least one dimension of the entire image incident on a defined portion of the medium and of the periodicity of the strain disturbances in the medium at which the signal is derived.

4. A device as in claim 1 wherein each of said plurality of different strain disturbances is a vibration of the medium at a different frequency of vibration.

5. A device as in claim 4 wherein each of said electrical signals is a selected component of a Fourier transform representation of the light intensity distribution along at least one dimension of the entire optical image incident on a defined portion of the medium for the frequency of vibration of the medium at which the electrical signal is derived.

6. A device for obtaining a Fourier transform representation of an optical image comprising:

a medium having an electrical property which varies as a function of an optical image incident on the medium and as a function of the frequency of vibration of the medium;

means for causing the incidence of an optical image on the medium;

means for vibrating the medium at a plurality of different frequencies which are selected substantially independently of any natural vibrating modes of the medium; and

means for measuring the electrical property at a plurality of said different frequencies to derive thereby a plurality of electrical signals, said electrical signals being components of a Fourier transform representation of said optical image incident on the medium.

7. A device as in claim 6 wherein each of said electrical signals is a selected component of a Fourier Transform representation of the light intensity distribution along at least one dimension of the entire optical image incident on a defined portion of the medium for the frequency of vibration of the medium at which the electrical signal is derived.

8. A device as in claim 6 wherein each of said electrical signals is a selected component of a Fourier Transform representation of the light intensity distribution along a single dimension of the entire optical image incident on a defined portion of the medium for the frequency of vibration of the medium at which the electrical signal is derived.

9. Method of obtaining an electrical signal representation of an optical image comprising:

causing the incidence of an optical image on a medium having an electrical property which varies as a function of the optical image incident on it and as a function of time and space varying strain disturbance in the medium;

causing a plurality of different time and space varying strain disturbances in the medium, wherein the spatial wavelengths of said strain disturbances are selected substantially independently of any natural vibrating modes of the medium; and

measuring said electrical property of the medium at a plurality of said different strain disturbances in the medium to derive a plurality of electrical signals, each signal representing the entire optical image rather than a single small area of the image.

10. Method as in claim 9 wherein the strain disturbances in the medium are periodic in time and space.

11. Method as in claim 10 wherein each of a plurality of said electrical signals is a function of the light intensity distribution along at least one dimension of the entire image incident on a defined portion of the medium and of the periodicity of the strain disturbances in the medium at which the signal is derived.

12. Method as in claim 9 wherein each of said plurality of different strain disturbances is a vibration of the medium at a different frequency of vibration.

13. Method as in claim 12 wherein each of said electrical signals is a component of a Fourier Transform representation of the light intensity distribution along at least one dimension of the entire optical image incident on a defined portion of the medium for the frequency of vibration of the medium at which the electrical signal is derived.

14. Method as in claim 9 wherein the electrical signals are components of a Fourier Transform representation of the light intensity distribution along a signal selected dimension of the optical image.

15. Method as in claim 9 wherein the electrical property of the medium is the potential difference across a selected portion of the medium.

16. Method of obtaining a Fourier transform representation of an optical image comprising:

causing the incidence of an optical image on a medium having an electrical property which varies as a function of said optical image and as a function of the frequency of vibration of the medium;

vibrating the medium at a plurality of different frequencies which are selected substantially independently of any natural vibrating modes of the medium; and

measuring said electrical property of the medium at a plurality of said different frequencies of vibration to derive a plurality of electrical signals, said electrical signals being components of a Fourier transform representation of the optical image incident on the medium.

17. Method as in claim 16 wherein said electrical property of the medium is the potential difference across a selected portion of the medium.

18. Method as in claim 16 wherein said electrical signals are selected components of a Fourier Transform representation of the light intensity distribution along at least one selected dimension of the optical image.

19. Method as in claim 16 wherein said electrical signals are components of a Fourier Transform representation of the light intensity distribution along a single selected dimension of the optical image.

20. A system for generating electrical signal representations of selected portions of an optical image, comprising a plurality of devices each comprising:

a medium having an electrical property which varies as a function of an optical image incident on the medium and as a function of time and space varying strain disturbances in the medium;

means for causing the incidence of one of said selected portions of the optical image on the medium, a different portion of the medium being incident on each of said plurality of media;

means for causing a plurality of different time and space varying strain disturbances in the medium; and

means for measuring said electrical property of the medium at a plurality of said different strain disturbances in the medium to derive a plurality of electrical signals representing said optical image.

21. A system as in claim 20 wherein said portions of an optical image are different color content representations of the same optical image.

22. A device for obtaining a Fourier transform representation of an image comprising:

a medium having a property which varies as a Fourier transform function of an image formed at the medium and of strain waves interacting with the medium; and

means for measuring said property during the interaction of said image and selected strain waves at the medium, the resulting measurements being a Fourier transform representation of the entire image including at least phase terms of Fourier transform components.

23. A method of obtaining a Fourier transform representation of an image comprising the steps of:

providing a medium having a property varying as a Fourier transform function of the interaction of an image and of strain waves with the medium; and

measuring said property during the interaction of an image and strain waves with the medium, the resulting measurements being a Fourier transform representation of the entire image including at least phase terms.

24. A device comprising:

a medium having an electrical parameter which varies as a function of the intensity distribution of images formed on the medium and as a function of strain waves present in the medium;

means for forming a selected image on the medium;

means for causing selected strain waves to be present in the medium; and

means for measuring the magnitude of the parameter and the phase of the parameter relative to selected strain waves present in the medium while the image is formed on the medium to thereby derive electrical signals representing the image.

25. A device as in claim 24 wherein the measuring means include means for providing pairs of said electrical signals, each pair representing the magnitude and the phase of the parameter at a signal selected strain wave in the medium which has a selected spatial wavelength.

26. A device comprising:

a medium, means for forming an image on the medium, means for causing in the medium selected strain waves having spatial wavelengths which are selected substantially independently of any natural vibrating modes of the medium, and means for measuring a property of the medium at each of a plurality of said strain waves to derive thereby a plurality of signals each corresponding to a selected spatial wavelength and each representing an aspect of the entire image rather than of an incremental area of the image.

27. A device as in claim 26 wherein the property is an electrical property of the medium and the measuring means comprise means for measuring the magnitude of the property and the phase of the property relative to selected strain waves to thereby derive electrical signals each of which has a pair of components, each pair corresponding to a single selected spatial wavelength and comprising a magnitude component and a phase component.

28. A device comprising:

a medium, means for forming a selected image on the medium, means for causing in the medium selected strain waves whose spatial frequencies are selected substantially independently of any natural vibrating modes of the medium, and means for measuring a property of the medium to derive signals corresponding to Fourier transform components of the image corresponding to the spatial frequencies of selected ones of the strain waves present in the medium.

29. A method comprising the steps of:

providing a medium, forming an image on the medium, causing to be present in the medium strain waves whose spatial wavelengths are selected substantially independently of any natural vibrating modes of the medium, and measuring a selected property of the medium to derive signals representing the image and corresponding to the spatial wavelengths of selected strain waves present in the medium, each signal representing an aspect of the entire image rather than of a small area of the image.

30. A method as in claim 29 wherein the measuring step includes the substep of measuring the magnitude of the property and the phase of the property relative to selected strain waves present in the medium.

31. A method comprising the steps of:

forming an image on a medium which undergoes strain disturbances due to strain waves of selected spatial wavelengths present in the medium and measuring the magnitude and phase of a property of the medium at each of a selected plurality of spatial wavelengths of strain disturbances present in the medium to derive signals representing the image.

32. A method of deriving an electrical signal representation of an image comprising the steps of:

forming a representation of the image on a medium having a measurable electrical property, propagating strain wave disturbances in the medium and measuring at least a phase characteristic of said property relevant to said strain wave disturbances while the image is formed on the medium and while said strain wave disturbances are present in the medium.