Methods and apparatus for imaging of occluded objects

Patent metadata

Field	Value
Publication number	US-9448060-B2
Application number	US-201615004933-A
Country	US
Kind code	B2
Filing date	Jan 23, 2016
Priority date	May 24, 2013
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

An active imaging system, which includes a light source and light sensor, generates structured illumination. The light sensor captures transient light response data regarding reflections of light emitted by the light source. The transient light response data is wavelength-resolved. One or more processors process the transient light response data and data regarding the structured illumination to calculate a reflectance spectra map of an occluded surface. The processors also compute a 3D geometry of the occluded surface.

First claim

What is claimed is:

1. A method comprising, in combination:
(a) an active imaging system generating structured illumination, which active imaging system includes a light sensor and a light source;
(b) the light sensor capturing transient light response data regarding reflections of light that is emitted by the light source and reflected from an occluded surface; and
(c) one or more processors processing the transient light response data and data regarding the structured illumination to calculate a reflectance spectra map of the occluded surface;
wherein the one or more processors also calculate three-dimensional spatial coordinates of each respective point in a set of points on the occluded surface.

2. A method comprising, in combination:
(a) an active imaging system generating structured illumination, which active imaging system includes a light sensor and a light source;
(b) the light sensor capturing transient light response data regarding reflections of light that is emitted by the light source and reflected from an occluded surface; and
(c) one or more processors processing the transient light response data and data regarding the structured illumination to calculate a reflectance spectra map of the occluded surface;
wherein the one or more processors classify the occluded object based at least in part on the reflectance spectra map.

3. A method comprising, in combination:
(a) an active imaging system generating structured illumination, which active imaging system includes a light sensor and a light source;
(b) the light sensor capturing transient light response data regarding reflections of light that is emitted by the light source and reflected from an occluded surface; and
(c) one or more processors processing the transient light response data and data regarding the structured illumination to calculate a reflectance spectra map of the occluded surface;
wherein the one or more processors identify a specific type of fluorescent material in the occluded surface, based at least on sensor data indicative of a specific absorption spectrum and specific emission spectrum of the occluded material.

4. A method comprising, in combination:
(a) an active imaging system generating structured illumination, which active imaging system includes a light sensor and a light source;
(b) the light sensor capturing transient light response data regarding reflections of light that is emitted by the light source and reflected from an occluded surface; and
(c) one or more processors processing the transient light response data and data regarding the structured illumination to calculate a reflectance spectra map of the occluded surface;
wherein the active imaging system computes or detects a synthetic temporal detection pattern.

5. A method comprising, in combination:
(a) an active imaging system generating structured illumination, which active imaging system includes a light sensor and a light source;
(b) the light sensor capturing transient light response data regarding reflections of light that is emitted by the light source and reflected from an occluded surface; and
(c) one or more processors processing the transient light response data and data regarding the structured illumination to calculate a reflectance spectra map of the occluded surface;
wherein the active imaging system computes or detects a synthetic wavelength band detection pattern.

6. A method comprising, in combination:
(a) an active imaging system generating structured illumination, which active imaging system includes a light sensor and a light source;
(b) the light sensor capturing transient light response data regarding reflections of light that is emitted by the light source and reflected from an occluded surface; and
(c) one or more processors processing the transient light response data and data regarding the structured illumination to calculate a reflectance spectra map of the occluded surface;
wherein the active imaging system computes or detects a synthetic spatial detection pattern.

7. A method comprising, in combination:
(a) an active imaging system generating structured illumination, which active imaging system includes an avalanche photodetector and a light source;
(b) the avalanche photodetector capturing transient light response data regarding reflections of light that is emitted by the light source and reflected from an occluded surface; and
(c) one or more processors processing the transient light response data and data regarding the structured illumination to calculate a reflectance spectra map of the occluded surface.

8. The method of claim 7 , wherein the light source is wavelength-resolved and wavelength-tunable.

9. The method of claim 7 , wherein the light source emits a series of pulses of light, such that:
(a) the light source emits a first wavelength during a first set of the pulses of light and not during other pulses in the series;
(b) the light source emits a second wavelength during a second set of the pulses of light and not during other pulses in the series;
(c) the light source emits a third wavelength during a third set of the pulses of light and not during other pulses in the series; and
(d) the first, second and third sets of pulses of light do not overlap each other.

10. The method of claim 7 , wherein the avalanche photodetector is wavelength-resolved and wavelength-tunable.

11. The method of claim 7 , wherein:
(a) the avalanche photodetector is wavelength-resolved and wavelength-tunable; and
(b) the light source is wavelength-resolved and wavelength-tunable.

12. Apparatus comprising:
(a) an active imaging system for generating structured illumination, which active imaging system includes a light sensor and a light source;
(b) the light sensor for capturing transient light response data regarding reflections of light that is emitted by the light source and reflected from an occluded surface; and
(c) one or more processors for processing the transient light response data and data regarding the structured illumination to calculate a reflectance spectra map of the occluded surface.

13. The apparatus of claim 12 , wherein the light sensor comprises an avalanche photodiode.

14. The apparatus of claim 12 , wherein the light sensor is wavelength-resolved and wavelength-tunable.

15. The apparatus of claim 12 , wherein the light source is wavelength-resolved and wavelength-tunable.

16. The apparatus of claim 12 , wherein:
(a) the light sensor is wavelength-resolved and wavelength-tunable; and
(b) the light source is wavelength-resolved and wavelength-tunable.

17. The apparatus of claim 12 , wherein the light source emits a series of pulses of light, such that:
(a) the light source emits a first wavelength during a first set of the pulses of light and not during other pulses in the series;
(b) the light source emits a second wavelength during a second set of the pulses of light and not during other pulses in the series;
(c) the light source emits a third wavelength during a third set of the pulses of light and not during other pulses in the series; and
(d) the first, second and third sets of pulses of light do not overlap each other.

Assignees

• Massachusetts Inst Technology

Inventors

• Velten Andreas
• Raskar Ramesh

Classifications

• G01N2021/6417

  Spectrofluorimetric devices · CPC title

• G01N21/255

  Details, e.g. use of specially adapted sources, lighting or optical systems · CPC title

• G01J3/027

  Control of working procedures of a spectrometer; Failure detection; Bandwidth calculation · CPC title

• G01J3/021

  using plane or convex mirrors, parallel phase plates, or particular reflectors · CPC title

• G01N21/27

  using photo-electric detection (G01N21/31 takes precedence){; circuits for computing concentration (logarithmic circuits G06G7/24; photometric circuits in general G01J)} · CPC title