Detector for three-dimensional optical imaging

• US 4,791,490 A
• Filed: 07/02/1987
• Issued: 12/13/1988
• Est. Priority Date: 07/02/1987
• Status: Expired due to Term

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Knight, Frederick K., Kalata, Kenneth
• Primary Examiner(s): Ng, Jin F.
• Assistant Examiner(s): Brinich, Stephen
• Application Number:
  US07/069,388
• Time in Patent Office: 530 Days
• Field of Search: 358/217-219, 358/901, 358/89, 358/209, 250/213 VT
• US Class Current: 348/215.1
• CPC Class Codes: H04N 13/10 Processing, recording or transmission of stereoscopic or multi-view image signals
• CPC Class Codes: H04N 13/189 Recording image signals; Reproducing recorded image signals
• CPC Class Codes: H04N 13/20 Image signal generators
• CPC Class Codes: H04N 13/207 using a single 2D image sensor
• CPC Class Codes: H04N 13/236 using varifocal lenses or mirrors
• CPC Class Codes: H04N 13/254 in combination with electromagnetic radiation sources for illuminating objects
• CPC Class Codes: H04N 2013/0081 Depth or disparity estimation from stereoscopic image signals

Abstract

The detector includes a focusing lens for focusing pulsed laser light reflected from an object onto a fiber optic array. The fiber optic array is configured to receive a two-dimensional image from the focusing lens and to convert the two-dimensional image into a line image. A streak camera responsive to light from the fiber optic array provides time resolution for the light from each of the fibers in the array. A two-dimensional detector records the light output from the streak camera and electronics store data and process information to construct three-dimensional images.

Claims

1. Detector for three-dimensional optical imaging comprising:

a focusing lens;

a fiber optic array configured to receive a two-dimensional image from the lens and to convert the two-dimensional image into a line image;

a streak camera responsive to light from the fiber optic array adapted to provide time resolution for light from each fiber of the fiber optic array;

a two-dimensional detector to record the light output from the streak camera; and

electronic apparatus to store and process information from the two-dimensional detector.

2. The detector of claim 1 wherein the streak camera includes a micro-channel plate for amplification.

3. The detector of claim 1 further including optics adapted to couple the output of the fiber optic array to the streak camera.

4. The detector of claim 3 wherein the optics include a coupling lens whose aperture matches the aperture of the fiber optic array.

5. The detector of claim 1 wherein the focusing lens is a set of lenses.

6. The detector of claim 1 wherein the focusing lens has a focal length in the range of 0.4-4 cm.

7. The detector of claim 1 wherein the fiber optic array has a square configuration at an end for receiving the two-dimensional image and a linear configuration at the other end for coupling light into the streak camera.

8. The detector of claim 7 wherein the square configuration comprises a 25×

25 array.

9. The detector of claim 1 wherein the streak camera includes circuitry for generating a ramp voltage to provide the time resolution.

10. The detector of claim 1 wherein the streak camera has a resolution of approximately 10 line pairs per millimeter.

11. The detector of claim 2 wherein the micro-channel plate has a 40 mm diameter.

12. The detector of claim 1 wherein the two-dimensional detector is a silicon intensified target (SIT) vidicon.

13. The detector of claim 1 wherein the two-dimensional detector is a charge coupled device (CCD).

14. The detector of claim 1 wherein the elctronic apparatus includes a general purpose digital computer.

15. The detector of claim 1 having a resolution of 25×

25 angular elements and 400 time elements.

16. The detector of claim 1 having a framing rate of 4 hertz.

17. The detector of claim 1 wherein the streak camera has a relative time resolution of 50 picoseconds.

18. The detector of claim 1 having an angular resolution of approximately 4% of the field of view of the focusing lens.

19. The detector of claim 1 further including a laser for illuminating an object with pulses in the range of 30-100 picoseconds.

20. The detector of claim 1 adapted to detect light received over a period of 25 to 400 nanoseconds.

21. The detector of claim 19 wherein the laser generates light in the range of 0.8 μ

m to 0.25 μ

m.

22. The detector of claim 1 having a depth resolution of approximately 0.5 cm.

25. The detector of claim 1 further including a microchannel plate to amplify light from the streak camera.

26. The detector of claim 25 further including fiber optic coupler to couple light from the microchannel plate to the two-dimensional detector.

27. The detector of claim 7 wherein the square configuration comprises a 16×

16 array.

23. Method for three-dimensional optical imaging comprising

focusing light reflected from an object onto a fiber optic array which converts a two-dimensional image into a line image;

determining time resolution for light from each fiber of the fiber optic array; and

processing the time resolution information to produce three-dimensional images of objects.

24. Three-dimensional optical imaging system comprising

a laser adapted to generate light pulses to illuminate an object;

a focusing lens to focus light reflected from the object;

a fiber optic array configured to receive a two-dimensional image from the lens and to convert the two-dimensional image into a line image;

a streak camera responsive to light from the fiber optic array adapted to provide time resolution for light from each fiber of the fiber optic array;

a two-dimensional detector to record the light output from the streak camera; and

electronic apparatus to store and process information from the two-dimensional detector.