Optical detection system

• US 10,295,658 B2
• Filed: 10/01/2015
• Issued: 05/21/2019
• Est. Priority Date: 10/02/2014
• Status: Active Grant

• Current Assignee: Johns Hopkins University
• Original Assignee: Johns Hopkins University
• Inventors: Torruellas, William E., Fry, Robert L., Bankman, Isaac N., Brown, David M., Tadmor, Gil, Clark, Jr., Thomas Raphael
• Primary Examiner(s): Abraham, Samantha K
• Application Number:
  US14/872,175
• Publication Number:
  US 20180081032A1
• Time in Patent Office: 1,328 Days
• CPC Class Codes: G01S 17/08 for measuring distance only indirect measurement G01S17/46; active triangulation systems G01S17/48
• CPC Class Codes: G01S 17/10 using transmission of interrupted, pulse-modulated waves determination of distance by phase measurements G01S17/32
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 7/4808 Evaluating distance, position or velocity data
• CPC Class Codes: G01S 7/4815 using multiple transmitters
• CPC Class Codes: G01S 7/484 Transmitters

Abstract

An active optical detection system includes an optical transmitter configured to transmit light in a signal pattern and an optical receiver configured to receive light and determine a correlation between the received light and the signal pattern. The correlation of the received light and the signal pattern is indicative of range to an object.

Claims

1. An active optical detection system comprising:

a signal generator configured to generate a plurality of signal patterns, each signal pattern comprising a unique transmit bit pattern;

an optical transmitter comprising a plurality of light sources, each light source being aligned to a different transmission angle, wherein the optical transmitter is configured to transmit light from each light source in accordance with one of the signal patterns of the plurality of signal patterns;

an optical receiver configured to receive light as a receive bit pattern; and

processing circuitry configured to;

determine a correlation between the receive bit pattern and one of the unique transmit bit patterns of the plurality of signal patterns, wherein the correlation between the receive bit pattern and the one of the unique transmit bit patterns determines a correlation spike that is indicative of a range to an object; and

determine a direction to the object based on the correlation and the transmission angle associated with the signal pattern for the one of the unique transmit bit patterns.

2. The active optical detection system of claim 1, wherein the optical receiver comprises a photo detector configured to detect light associated with the receive bit pattern.

3. The active optical detection system of claim 2, wherein the processing circuitry is further configured determine a direction of the object based on a segment of the photo detector which received the light associated with the receive bit pattern or the photo detector being one of a plurality of photo detectors which received the light associated with the receive bit pattern, wherein the segment of the photo detector or the photo detector being one of a plurality of photo detectors which received the received the light associated with the receive bit pattern is indicative of a reception angle.

4. The active optical detection system of claim 1, wherein the processing circuitry is further configured to determine a plurality of correlations between the receive bit pattern and the one of the unique transmit bit patterns of the plurality of signal patterns and determine a velocity of the object based on at least two correlations.

5. The active optical detection system of claim 1, wherein the processing circuitry further comprises detection logic configured to compare the correlation of the receive bit pattern and the one of the unique transmit bit patterns of the plurality of signal patterns to a predetermined correlation threshold, wherein the processing circuitry determination of the range of the object is based on the correlation satisfying the correlation threshold.

6. The active optical detection system of claim 1, wherein each signal pattern comprises a pseudo-random bit pattern.

7. The active optical detection system of claim 1, wherein the plurality of light sources comprises a plurality of lasers.

8. The active optical detection system of claim 7, wherein each laser of the plurality of lasers transmits light at a different wavelength.

9. The active optical detection source of claim 1, wherein the plurality of light sources comprises at least one light emitting diode.

10. The active optical detection system of claim 1, wherein the optical transmitter further comprises an optical amplifier to amplify transmitted by the plurality of light sources.

11. The active optical detection system of claim 10,

wherein the optical transmitter further comprises:

a multiplexor operably coupled to the optical amplifier to transmit modulated light signals to the optical amplifier as a single light signal; and

a demultiplexor operably coupled to the optical amplifier to separate amplified modulated light signals for transmission.

12. The active optical detection system of claim 1, wherein the optical receiver further comprises an optical filter to inhibit receipt of light of wavelengths different than wavelengths output by the plurality of light sources.

13. The active optical detection system of claim 1, wherein the optical transmitter is configured to transmit light from each light source at a different wavelength.

14. A method comprising:

generating a plurality of signal patterns, each signal pattern comprising a unique transmit bit pattern;

transmitting light via a plurality of light sources, each light source being aligned to a different transmission angle and each light source transmitting one of the plurality of signal patterns;

receiving the light at an active optical detection system as a receive bit pattern;

determining a correlation between the receive bit pattern and one of the unique transmit bit patterns of the plurality of signal patterns;

determining, by the active optical detection system, a range to an object based on a correlation spike determined from the correlation between the receive bit pattern and the one of the unique transmit bit patterns; and

determine a direction to the object based on the correlation and the transmission angle associated with the signal pattern for the one of the unique transmit bit patterns.

15. The method of claim 14 further comprising

determining the direction of the object based on a reception angle.

16. The method of claim 15 further comprising comparing the correlation between the receive bit pattern and the one of the unique transmit bit patterns of the plurality of signal patterns to a predetermined correlation threshold, wherein the determination of the range or the direction of the object is based on the correlations satisfying the correlation threshold.

17. The method of claim 14, further comprising:

determining a plurality of correlations between the receive bit pattern and the one of the unique transmit bit patterns of the plurality of signal patterns; and

determining a velocity of the object based on at least two correlations.