Structured light projection for motion detection in augmented reality

Patent metadata

Field	Value
Publication number	US-9245307-B2
Application number	US-201113381329-A
Country	US
Kind code	B2
Filing date	Jun 1, 2011
Priority date	Jun 1, 2011
Publication date	Jan 26, 2016
Grant date	Jan 26, 2016

Abstract

Technologies are generally described for projecting structured light patterns onto an Augmented Reality (AR) scene in order to track AR camera motion in AR systems. In some examples, structured light patterns may be projected onto the AR scene from a light source in the same plane as the AR camera in order to preserve a consistent reference point for detecting the structured light pattern. The AR camera may detect the structured light patterns and determine the location of the AR camera based on a distance analysis of the detected structured light patterns. Based on the changing locations of the AR camera, the system may track the movement of the AR camera as its location relative to the AR scene changes.

First claim

What is claimed is:

1. A method to track camera movement in Augmented Reality (AR) systems using structured light projections, the method comprising:
projecting at least one structured light pattern in pulses from a structured light source onto a portion of an AR scene, wherein the pulses are synchronized with an opening and a closing of a shutter of an AR image capture unit, and a duration of each pulse is shorter than an open shutter duration of the AR image capture unit in order to reduce a blur associated with a motion of the AR image capture unit, and wherein the at least one structured light pattern is projected by the structured light source when the structured light source is positioned in a same horizontal and a same vertical plane as the AR image capture unit to facilitate preservation of a consistent origination point of the at least one structured light pattern;
detecting a reflected structured light pattern from one or more portions of the AR scene utilizing an image sensor in proximity of the AR image capture unit;
comparing the detected structured light pattern to a previously detected structured light pattern;
determining a change in an AR image capture unit location based on a comparison;
correlating the change in the AR image capture unit location with one or more captured images of the AR scene; and
tracking an AR image capture unit movement relative to the AR scene based on determination of changes in the detected structured light pattern.

2. The method according to claim 1 , further comprising:
performing a distance analysis on the at least one structured light pattern to determine the distance between the AR image capture unit and the one or more portions of the AR scene; and
determining the AR image capture unit location based on the distance analysis of the detected structured light pattern.

3. The method according to claim 1 , further comprising
continuously tracking the AR image capture unit movement relative to the AR scene based on continuous determination of the changes in the detected structured light pattern.

4. The method according to claim 1 , further comprising
projecting two or more structured light patterns on two or more portions of the AR scene for obtaining multiple samples of the AR scene.

5. The method according to claim 1 , wherein the structured light source is a laser emitting light source and the AR image capture unit is an AR camera.

6. The method according to claim 1 , wherein the structured light pattern is an array of dots, and a size of each dot and a distance between the dots are determined based on an expected distance between the AR image capture unit and the one or more portions of the AR scene.

7. The method according to claim 1 , wherein the structured light source, the image sensor, and the AR image capture unit are integrated as a portable AR camera.

8. The method according to claim 1 , wherein the structured light pattern is projected in the same horizontal and vertical planes as the AR image capture unit.

9. The method according to claim 1 , further comprising:
collimating the structured light through a collimating lens; and
applying a diffractive optical pattern after the collimating lens for producing the structured light pattern.

10. The method according to claim 1 , wherein the structured light source is encased in a transistor outline can (TO can) package including, a vertical cavity surface emitting laser (VCSEL).

11. The method according to claim 1 , further comprising
configuring the structured light source to produce a laser light having a wavelength greater than about 800 nanometers and less than about 1000 nanometers.

12. An apparatus to track camera movement in Augmented Reality (AR) systems using structured light projections, the apparatus comprising:
a memory adapted to store instructions, image data, and graph data; and
a first processing unit adapted to execute a dynamic modeling module in conjunction with the instructions, wherein the dynamic modeling module is adapted to:
project at least one structured light pattern in pulses from a structured light source onto a portion of an AR scene, wherein the pulses are synchronized with an opening and a closing of a shutter of an AR camera, and a duration of each pulse is shorter than an open shutter duration of the AR camera in order to reduce a blur associated with a motion of the AR camera, and wherein the at least one structured light pattern is projected by the structured light source when the structured light source is positioned in a same horizontal and a same vertical plane as the AR camera to facilitate preservation of a consistent origination point of the at least one structured light pattern, and the at least one structured light pattern is configured to change in lateral dimensions as a function of distance from the AR camera;
detect a reflected structured light pattern from one or more portions of the AR scene utilizing an image sensor in proximity of the AR camera;
compare the detected structured light pattern to a previously detected structured light pattern;
determine a change in an AR camera location based on a comparison;
correlate the change in the AR camera location with one or more captured images of the AR scene; and
track an AR image capture unit movement relative to the AR scene based on determination of changes in the detected structured light pattern.

13. The apparatus according to claim 12 , wherein the first processing unit is configured to change shape and size features of the at least one structured light pattern in lateral dimensions as a function of a distance between the one or more portions of the AR scene and the AR camera.

14. The apparatus according to claim 12 , wherein a laser emitting light source for projecting structured light is encased in one of: a transistor outline can (TO can) package, a vertical cavity surface emitting laser (VCSEL), or a vertical external cavity surface emitting laser (VECSEL).

15. A non-transitory computer-readable storage medium having instructions stored thereon to track camera movement in Augmented Reality (AR) systems using structured light projections, the instructions comprising:
projecting at least one structured light pattern in pulses from a structured light source onto a portion of an AR scene, wherein the pulses are synchronized with an opening and a closing of a shutter of an AR image capture unit and a duration of each pulse is shorter than an open shutter duration of the AR image capture unit in order to reduce a blur associated with a motion of the AR image capture unit, and wherein the at least one structured light, pattern is projected by the structured light source when the structured light source is positioned in a same horizontal and a same vertical plane as the AR image capture unit to facilitate preservation of a consistent origination point of the at least one structured light pattern;
detecting a reflected structured light pattern from one or more portions of the AR scene utilizing an image sensor in proximity of the AR image capture unit;
performing a distance analysis on the at least one structured light pattern to determine the distance between the AR image capture unit and the one or more portions of the AR scene;
determining a change in an AR image capture unit location based on the distance analysis of the detected structured light pattern;
correlating the change in the AR image cap unit location with one or more captured images of the AR scene; and
tracking an AR image capture unit movement relative to the AR scene based on determination of changes in the detected structur

Assignees

• Margalit Mordehai
• Empire Technology Dev Llc

Inventors

• Margalit Mordehai

Classifications

• G06T1/0007 Primary

  Image acquisition · CPC title

• G16Z99/00

  Subject matter not provided for in other main groups of this subclass · CPC title

• G01C3/00

  Measuring distances in line of sight; Optical rangefinders (tapes, chains or wheels for measuring length G01B3/00; active triangulation systems, i.e. using the transmission and reflection of electromagnetic waves other than radio waves, G01S17/48) · CPC title

• G01B11/25 Primary

  by projecting a pattern, e.g. {one or more lines,} moiré fringes on the object (G01B11/255 takes precedence {; image analysis for depth or shape recovery G06T7/50}) · CPC title