Three dimensional camera and range finder

• US 5,081,530 A
• Filed: 10/05/1990
• Issued: 01/14/1992
• Est. Priority Date: 06/26/1987
• Status: Expired due to Term

• Current Assignee: Antonio Medina
• Original Assignee: Antonio Medina
• Inventors: Medina, Antonio
• Primary Examiner(s): Kostak, Victor R.
• Application Number:
  US07/593,243
• Time in Patent Office: 466 Days
• Field of Search: 358/88, 358/89, 358/91, 358/90, 358/92, 358/95, 358/3, 356/1-6, 364/522
• US Class Current: 348/46
• CPC Class Codes: G01S 17/894 3D imaging with simultaneous measurement of time-of-flight at a 2D array of receiver pixels, e.g. time-of-flight cameras or flash lidar
• CPC Class Codes: G01S 7/48 of systems according to group G01S17/00
• CPC Class Codes: H04N 13/189 Recording image signals; Reproducing recorded image signals
• CPC Class Codes: H04N 13/207 using a single 2D image sensor
• CPC Class Codes: H04N 13/239 using two 2D image sensors having a relative position equal to or related to the interocular distance H04N13/243 takes precedence
• CPC Class Codes: H04N 13/254 in combination with electromagnetic radiation sources for illuminating objects
• CPC Class Codes: H04N 13/296 Synchronisation thereof; Control thereof
• CPC Class Codes: H04N 13/341 using temporal multiplexing
• CPC Class Codes: H04N 13/398 Synchronisation thereof; Control thereof
• CPC Class Codes: H04N 2013/0081 Depth or disparity estimation from stereoscopic image signals

Abstract

A three dimensional camera system in which a precisely timed beam of energy is emitted from a single source with the beam illuminating the scene. The reflected energy from the beam is detected with a camera whose sensitivity is precisely timed and synchronized with the emitted beam. The reflected energy is separated and segregated according to the time of arrival at the camera. One or more cycles of energy are emitted, the camera segregates reflected energy during each cycle by separately storing the energy detected before and after a given time. The ratio of two consecutive separately detected energies conveys depth or third dimension. Signals can be displayed to a viewer to create a stereoscopic image or used by a machine for automatic response to a three dimensional environment.

Claims

1. A three-dimensional camera system comprising:

means for emitting a beam of energy;

image detector means for detecting said energy when reflected from objects;

means to segregate said detected energy according to the time of arrival at said detector means, resulting in a least two segregated energies;

means for extracting information related to distance of object from said segregated energies.

2. A three-dimensional camera system as set forth in claim 1 wherein said means for emitting a beam of energy includes a flashlamp.

3. A three dimensional camera system as set forth in claim 1 wherein said means for emitting a beam of energy includes a laser.

4. A three-dimensional camera system as set forth in claim 1 wherein said means for emitting a beam of energy includes a microwave emitting antenna.

5. A three dimensional camera system as set forth in claim 1 wherein said means for emitting a beam of energy includes a sonic or ultrasonic source.

6. A three dimensional camera system as set forth in claim 1 wherein said means for emitting a beam of energy includes a sinusoidal modulator.

7. A three dimensional camera system as set forth in claim 1 wherein said means for emitting a beam of energy includes a pulsed modulator producing at least one pulse of energy.

8. A three dimensional camera system as set forth in claim 1 wherein said means for emitting a beam of energy includes the sun and its natural variations in intensity.

9. A three dimensional camera system as set forth in claim 1 wherein detector means for detecting said reflected energy includes a video camera.

10. A three dimensional camera system as set forth in claim 1 wherein detector means for detecting said reflected energy includes a photographic camera.

11. A three-dimensional camera system as set forth in claim 1 wherein detector means for detecting said reflected energy includes a solid state device type camera.

12. A three-dimensional camera system as set forth in claim 1 wherein means for segregating said detected energy includes a shutter that operates in synchronization with said means for emitting a beam of energy.

13. A three-dimensional camera system as set forth in claim 1 wherein means for segregating said detected energy includes a solid state sensor electronically shuttered during the arrival of said energy by application of a voltage to an integral electrode.

14. A three-dimensional camera system as set forth in claim 1 wherein means for segregating said detected energy includes an interline transfer charge couple device, whose transferring of pixel charge to opaque transport registers is effected during the arrival of said detected energy, said transfer of charge being stopped before the end of arrival of energy, resulting in part of pixel charge segregated from register charge.

15. A three dimensional camera system as set forth in claim 1 wherein means for segregating said detected energy includes a gated microchannel plate intensifier that is gated during the arrival of said energy.

16. A three dimensional camera system as set forth in claim 1 wherein means for segregating said detected energy includes a liquid crystal shutter that is operated during the arrival of said energy.

17. A three dimensional camera system as set forth in claim 12 wherein said shutter opens and closes in a rectangular wave mode with a delay for every other exposure substantially equal to the duration of the opened time and to the duration of the light pulse.

18. A three dimensional camera system as set forth in claim 12 wherein said shutter opens and closes in an arbitrary wave mode with a delay for every other exposure equal to the duration of the opened time and longer than the duration of the light pulse.

19. A three dimensional camera system as set forth in claim 12 wherein said shutter opens and closes in an arbitrary wave mode with a delay for every other exposure equal to half the duration of the triangular wave.

20. A three dimensional camera system as set forth in claim 12 wherein said shutter opens and closes with a delay from the onset of said energy pulses equal to twice the distance from the camera to the scene divided by the velocity of light.

21. A three dimensional camera system as set forth in claim 12 wherein said shutter opens and closes continuously and in alternation during the duration of an exposure or frame.

22. A three dimensional camera system as set forth in claim 1 wherein said camera has a shutter which opens and closes in opposite phase every other frame.

23. A three dimensional camera system as set forth in claim 1 wherein said means for extracting said information related to distance includes means for calculating the ratio of said segregated energies.

24. A three dimensional camera system as set forth in claim 1 wherein means for extracting said information related to distance includes means for calculating the ratio of the difference and the sum of said segregated energies.

25. A three dimensional camera system as set forth in claim 1 wherein said beam of energy of periodical intensity is a train of pulses modulated in frequency;

means for extracting phase information that includes shutter that operates in synchronization with the frequency of said pulses and that opens for a period of time corresponding to the phase deviation of the pulses modulated in frequency.

26. In a three dimensional camera system as set forth in claim 1 wherein said means for extracting information related to distance includes:

a pair of memory buffers for storing successively detected beams of energy, means for adding and means for subtracting values stored in said memory buffers,

additional buffers for separately storing the sums and differences derived from said adding and subtracting means, and means for dividing said additional buffers, one into the other to derive a normalized difference related to the distance of the object from the camera system and the beam emitting means.

27. A three-dimensional camera system means for creating a three-dimensional image including

means for emitting a beam of energy of periodical intensity, detector means for detecting said energy when reflected from objects,

and a phase detector means for detecting the phase difference between the beam when emitted and the beam when received.

28. In a three-dimensional camera system as set forth in claim 27, said phase detector means including a shutter and means for opening said shutter with the frequency as said means for emitting a beam but having a phase shift in alternate cycles.

29. In a three-dimensional camera system as set forth in claim 28 wherein said emitted beam is sinusoidal.

30. In a three-dimensional camera system as set forth in claim 28 wherein said emitted beam is pulsed.

31. In a three-dimensional camera system as set forth in claim 28 wherein said phase shift is equal to the duration of the emitted energy.

32. In a three-dimensional camera system as set forth in either of claims 29 or 30.

a pair of memory buffers for storing successively detected beams of energy, means for adding and means for subtracting values stored in said memory buffers,

additional buffers for separately storing the sums and differences derived from said adding and subtracting means, and means for dividing said additional buffers, one into the other to derive a normalized difference related to the distance of the object from the camera system and the beam emitting means.