REMOTE MEASUREMENT OF SHALLOW DEPTHS IN SEMI-TRANSPARENT MEDIA

• US 20170184399A1
• Filed: 03/16/2017
• Published: 06/29/2017
• Est. Priority Date: 06/30/2011
• Status: Active Grant

• Current Assignee: Astralite Inc., The Board of Regents of the University of Colorado (University of Colorado System)
• Original Assignee: The Board of Regents of the University of Colorado (University of Colorado System)
• Inventors: Thayer, Jeffrey P., Crowley, Geoffrey, Gisler, Andrew W., Mitchell, Steven, Hayman, Matthew
• Granted Patent: US 11,313,678 B2
• Time in Patent Office: Days
• CPC Class Codes: G01C 13/008 measuring depth of open water
• 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 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/499 using polarisation effects
• CPC Class Codes: Y02A 90/30 Assessment of water resources

Abstract

Through discrimination of the scattered signal polarization state, a lidar system measures a distance through semi-transparent media by the reception of single or multiple scattered signals from a scattering medium. Combined and overlapped single or multiple scattered light signals from the medium can be separated by exploiting varying polarization characteristics. This removes the traditional laser and detector pulse width limitations that determine the system'"'"'s operational bandwidth, translating relative depth measurements into the conditions of two surface timing measurements and achieving sub-pulse width resolution.

Claims

1. A method of determining characteristics of at least two surfaces, comprising:

transmitting a pulse of polarized energy to the surfaces;

receiving reflected energy from the surfaces received over a period of time after a transmission of the energy;

sensing information indicative of one or more properties of two or more portions of received reflected energy, wherein the properties of each of the portions of the received reflected energy comprises one or more of;

(a) an orientation of the portion,

(b) an angular spread of the portion,

(c) a degree of polarization of the portion,

(d) an azimuthal polarization pattern of the portion,

(e) a high order scattering profile of the portion, and

(f) a range of a respective property being one of the properties (a) to (e); and

determining, using computational equipment, one or more elapsed time among the two or more portions of the received reflected energy, based on one or more differences among the properties of the portions, wherein

the elapsed time is less than a duration of the pulse of polarized energy.

2. The method of claim 1, further comprising determining the relative distances based on the elapsed time.

3. The method of claim 1, further comprising determining one or more of the properties based on the data.

4. The method of claim 1, wherein the properties of each of the portions of the received reflected energy comprises (a) the orientation of the portion.

5. The method of claim 1, wherein the properties of each of the portions of the received reflected energy comprises (b) the angular spread of the portion.

6. The method of claim 1, wherein the properties of each of the portions of the received reflected energy comprises (c) the degree of polarization of the portion.

7. The method of claim 1, wherein the properties of each of the portions of the received reflected energy comprises (d) the azimuthal polarization pattern of the portion.

8. The method of claim 1, wherein the properties of each of the portions of the received reflected energy comprises (e) the high order scattering profile of the portion.

9. The method of claim 1, wherein the properties of each of the portions of the received reflected energy comprises (f) the range of (d) the azimuthal polarization pattern of the portion.

10. The method of claim 1, wherein the surfaces comprises two surfaces, wherein the portions comprises two portions, and wherein the elapsed time comprises one elapsed time.

11. The method of claim 1, wherein the pulse of polarized energy is transmitted by a transmitter comprising a laser being one of a polarized laser, a pulsed laser, and a continuous wave (CW) laser.

12. The method of claim 1, wherein the received reflected energy collection is received by one or more sensors configured to receive a portion of the received reflected energy.

19. The navigation system of claim 1, wherein the navigation system is arranged in an automobile and configured for autonomous driving or to aid with driving.

20. The navigation system of claim 19, wherein the computational equipment is arranged in the automobile.

13. A method of imaging skin of a patient, comprising:

transmitting a pulse of polarized light to the skin of the patient;

receiving a collection of light, wherein the collection includes light from reflected from at least two portions of the skin of the patient over a period of time after a transmission of the pulse, wherein the first portion has a first depth and a second portion has a second depth that is greater than the first depth;

sensing information indicative of one or more properties of two or more portions of received light in the collection, wherein the properties of each of the portions of the received light comprise one or more of;

(a) an orientation of the portion,

(b) an angular spread of the portion,

(c) a degree of polarization of the portion,

(d) an azimuthal polarization pattern of the portion,

(e) a high order scattering profile of the portion, and

(f) a range of a respective property being one of the properties (a) to (e); and

determining, using computational equipment, characteristics of the skin based on one or more differences among the properties of the portions, wherein the elapsed time is less than a duration of the pulse.

14. The method of claim 13, wherein the determined characteristics of the skin include characteristics indicative of normal skin pathology.

15. The method of claim 13, wherein the determined characteristics of the skin include characteristics indicative of abnormal skin pathology.

16. The method of claim 13, wherein the transmitting a pulse of polarized light comprises transmitting with a laser selected from the group consisting of a polarized laser, a pulsed laser, and a continuous wave (CW) laser.

17. The method of claim 13, wherein the received reflected energy collection is received by one or more sensors configured to receive a portion of the received reflected energy.

18. A navigation system, comprising:

a light transmitter configured to transmit a pulse of polarized light to at least two surfaces within a transmission path of the pulse;

a light receiver configured to receive a collection of light, wherein the collection includes light from the surfaces received over a period of time after a transmission of the pulse by the light transmitter;

a sensor system configured for sensing information indicative of one or more properties of two portions of received light in the collection, wherein the properties of each of the portions of the received light comprise one or more of;

(a) an orientation of the portion,

(b) an angular spread of the portion,

(c) a degree of polarization of the portion,

(d) an azimuthal polarization pattern of the portion,

(e) a high order scattering profile of the portion, and

(f) a range of a respective property being one of the properties (a) to (e); and

computational equipment configured for determining an elapsed time between the two portions of the received light, based on a difference between the properties of the portions, and a relative distance based on the elapsed time, wherein the elapsed time is less than a duration of the pulse.