Feature recognition system

• US 3,984,802 A
• Filed: 06/27/1966
• Issued: 10/05/1976
• Est. Priority Date: 06/27/1966
• Status: Expired due to Term

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Reimel, Paul F., Lippel, Lewis G. Jr.
• Primary Examiner(s): Wilbur, Maynard R.
• Assistant Examiner(s): Buczinski, S. C.
• Application Number:
  US04/561,685
• Time in Patent Office: 3,753 Days
• Field of Search: 331/94.5 R, 340/5 R, 340/5 H, 340/146.3 Q, 340/148, 179/1 SB, 179/1 SP, 343/5 SA, 324/77 K
• US Class Current: 367/3
• CPC Class Codes: G01H 3/08 Analysing frequencies present in complex vibrations, e.g. comparing harmonics present acoustic presence detection G01V1/001
• CPC Class Codes: G01N 29/0663 by acoustic holography acoustical holography per se G03H3/00
• CPC Class Codes: G01V 1/001 Acoustic presence detection

Abstract

9. A feature recognition system for identifying an unknown signal source, mprising:

First means for receiving a signal from the unknown signal source and producing a hologram thereof;

Second means for receiving the hologram and for correlating it with a signal reference of known sources; and

Third means associated with said second means for identifying the unknown source.

Claims

1. A feature recognition system for identifying the source of a radiated energy signal comprising, in combination:

receiver means adapted to receive the radiated signal and for producing an electrical output control signal modulated according to the radiated signal;

first laser means electrically connected to said receiver means to receive the control signal and for producing a first collimated coherent light beam at its output having a frequency which varies according to the control signal;

second laser means for producing a second collimated coherent light beam at its output having a constant frequency;

first optical means positioned to receive said first and second beams for superimposing one of said light beams on the other producing thereby a third collimated coherent light beam at its output with interferometric lines;

second optical means positioned to receive and condense said third beam and adapted to receive photosensitive film for exposing the film to said third beam at the focal point;

processor means positioned to receive the exposed film from said second optical means and develop the film forming thereby a hologram; and

third optical means positioned to receive said second beam and adapted to receive said hologram for cross-correlating the features of a reference with said hologram, the reference having the recognizable unique features of a known radiated energy source imaged on a transparent material.

2. The combination of claim 1 further comprising:

fourth optical means interposed between said first and second optical means for receiving said third beam means displaying a portion thereof.

3. The combination of claim 2 wherein said fourth optical means further comprises:

reflecting means receiving said third beam and changing the direction of a portion thereof;

lens means positioned to receive and condense said beam portion; and

screen means positioned in the focal plane of said lens to receive and display said condensed beam portion.

4. The combination of claim 2 further comprising:

fifth optical means interposed between said first and third optical means for receiving said second beam and adapted to receive the exposed film for displaying over a predetermined duration the feature recorded on the film by said second optical means.

5. The combination of claim 4 wherein said fifth optical means further comprises:

reflectiing means receiving said second beam and changing the direction of a portion thereof;

first lens means positioned to receive and modify the cross-sectional area of said beam portion for illuminating a predetermined portion of the film;

second lens means positioned to receive and condense said beam portion passing through the film; and

screen means positioned in the focal plane of said second lens to receive and display said condensed beam portion.

6. The combination of claim 1 wherein said second optical means further comprises:

film transport means for intermittently transporting the film sequentially through said second optical means, said processor means, and said third and fifth optical means;

shutter means drivingly connected to said film transport means positioned to receive and intermittently pass said third beam to the unexposed film;

lens means interpositioned between said shutter means and the film condensing said third beam to a focal point on the film and magnifying said condensed beam in a direction transverse of film travel; and

iris means interpositioned between said lens means and the film for occluding all but a narrow radial cross sectional area of said condensed beam.

7. Apparatus as set forth in claim 1 wherein said third optical means comprises:

first lens means receiving and modifying the cross-sectional area of said second beam for illuminating the reference;

second lens means interpositioned between the reference and the film to receive and condense said second beam passing through the reference at a focal point on the film;

third lens means having a focal point at the film for projecting the second beam which passes through the film; and

screen means positioned at the focal plane of said second lens means for positionally displaying said projected second beam.

8. The combination of claim 7 further includes an audible indicating means comprising:

reflecting means positioned at the other focal point of said projected second beam for changing the direction of a portion of said second beam;

lens means positioned with one focal point at said reflecting means;

light responsive means positioned at the other focal point of said condenser lens means for producing an electrical signal in response to said second beam received at said other focal point; and

alarm means connected to said light sensitive means for providing an audible signal.

9. A feature recognition system for identifying an unknown signal source, comprising:

first means for receiving a signal from the unknown signal source and producing a hologram thereof;

second means for receiving the hologram and for correlating it with a signal reference of known sources; and

third means associated with said second means for identifying the unknown source.

10. An acoustical signature recognition system for identifying an underwater sound source comprising, in combination:

receiver means adapted to receive an RF signal from a sonobuoy and for producing an electrical output control signal modulated according to the acoustical signal detected by the sonobuoy;

first laser means electrically connected to said receiver means to receive the control signal and for producing a first collimated coherent light beam at its output having a frequency which varies according to the control signal;

second laser means for producing a second collimated coherent light beam at its output having a constant frequency;

first optical means positioned to receive said first and second beams fro superimposing one of said beams on the other producing thereby a third collimated coherent light beam at its output with interferometric lines indicative of the frequency spectrum of the sonobuoy-detected acoustical signal;

second optical means positioned to receive and condense a third beam and adapted to receive photosensitive film for exposing the film to said third beam at the focal point;

processor means positioned to receive the exposed film from said second optical means and develop the film forming thereby a hologram of the frequency spectrum of the sonobuoy-detected signal; and

third optical means positioned to receive said second beam and adapted to receive said hologram for cross-correlating the acoustical signatures of a reference with said hologram, the reference having a plurality of recognizable unique acoustical signatures of known underwater sound sources imaged on a transparent material.