DETERMINING POSITIONAL INFORMATION OF AN OBJECT IN SPACE

• US 20140285818A1
• Filed: 03/14/2014
• Published: 09/25/2014
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Lmi Liquidating Co., LLC
• Original Assignee: Leap Motion Incorporated (Ultraleap Limited)
• Inventors: HOLZ, David
• Granted Patent: US 9,702,977 B2
• Time in Patent Office: Days
• US Class Current: 356/614
• CPC Class Codes: G01S 17/003 Bistatic lidar systems; Multistatic lidar systems
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 17/36 with phase comparison between the received signal and the contemporaneously transmitted signal
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/48 Active triangulation systems, i.e. using the transmission and reflection of electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4815 using multiple transmitters
• CPC Class Codes: G01S 7/483 Details of pulse systems

Abstract

The technology disclosed relates to determining positional information of an object in a field of view. In particular, it relates to calculating a distance of the object from a reference such as a sensor including scanning the field of view by selectively illuminating directionally oriented light sources and measuring one or more differences in property of returning light emitted from the light sources and reflected from the object. The property can be intensity or phase difference of the light. It also relates to finding an object in a region of space. In particular, it relates to scanning the region of space with directionally controllable illumination, determining a difference in a property of the illumination received for two or more points in the scanning, and determining positional information of the object based in part upon the points in the scanning corresponding to the difference in the property.

Claims

1. A method of determining positional information of a target object in a field of view, the method including:

scanning a field of view by selectively illuminating respective ones of a plurality of directionally oriented light sources that have overlapping fields of illumination;

measuring one or more differences in intensity of returning light emitted from the respective light sources and reflected from the target object using a sensor; and

determining positional information of the target object based at least in part upon one or more measured differences in intensity of the returning light.

2. The method of claim 1, wherein selectively illuminating the respective light sources includes varying brightness of pairs of overlapping light sources by dimming a first, initially on light source while brightening a second, initially off light source.

3. The method of claim 2, further including varying the brightness of the two overlapping sources by applying a quadratic formula.

4. The method of claim 2, further including varying the brightness of the two overlapping light sources according to a Gaussian distribution.

5. The method of claim 1, further including selectively illuminating the respective light sources one at a time.

6. The method of claim 1, further including the sensor scanning the field of view using a scanning mirror and a photo detector that rasterizes the field of view.

7. The method of claim 1, further including distinguishing among the respective light sources based on different frequencies of the respective light sources.

8. The method of claim 1, further including determining one or more angles for the light reflected from the target object, with respect to the sensor by mapping pixels of a camera array that captured the reflected light to the one or more angles.

9. The method of claim 1, wherein the sensor is positioned apart from the plurality of light sources and not between two of the light sources, further including determining an angle between the plurality of light sources and the target object.

10. The method of claim 9, further including determining a distance of the target object from the light sources or the sensor using

an angle between at least one of the light sources and the target object and

a second angle between the sensor and the target object.

11. The method of claim 2, further including illuminating two or more of the light sources respectively at different intensities of illumination.

12. The method of claim 2, further including performing a coarse scan of the field of view to assemble a low-resolution estimate of the target object position by illuminating a subset of light sources from the plurality of light sources.

13. The method of claim 12, further including:

following the coarse scan by performing a fine grained scan of a subsection the field of view based on the low-resolution estimate of the target object position; and

identifying distinguishing features of the target object based on a high-resolution data set collected during the fine grained scan.

14. The method of claim 1, further including performing a plurality of scans of the field of view and varying light properties of light emitted from the respective light sources among the scans.

15. The method of claim 1, wherein the plurality of directional light sources is arranged on one or more non-planar arcuate surfaces that include at least one of:

an arc;

or

an N-sided polygon.

16. The method of claim 1, wherein the plurality of directional light sources is arranged along a parabolic or hyperbolic curve.

17. The method of claim 16, wherein determining phase differences includes performing a Fourier transform on a series of intensity measurements of the light reflected from the target object.

18. A method of determining positional information of a target object in a field of view, the method including:

scanning a field of view by selectively illuminating respective ones of a plurality of directionally oriented light sources that have overlapping fields of illumination;

measuring one or more differences in property of returning light emitted from the respective light sources and reflected from the target object using a sensor; and

determining positional information of the target object based at least in part upon one or more measured differences in property of the returning light.

19. The method of claim 18, wherein the property is intensity of light.

20. A system of determining positional information of a target object in a field of view, the system including:

a processor and a computer readable storage medium storing computer instructions configured to cause the processor to;

scan a field of view by selectively illuminating respective ones of a plurality of directionally oriented light sources that have overlapping fields of illumination;

measure one or more differences in intensity of returning light emitted from the respective light sources and reflected from the target object using a sensor; and

determine positional information of the target object based at least in part upon one or more measured differences in intensity of the returning light.

21. A method of finding an object in a region of space, the method including:

scanning the region of space with directionally controllable illumination from selected ones of a set of illumination sources;

detecting illumination in the region of space including illumination reflected by the object;

determining a difference in a property of the illumination received for two or more points in the scanning; and

determining positional information of the object based at least in part upon the points in the scanning corresponding to the difference in the property.

22. The method of claim 21, further including:

conducting a second scanning of the region of space to obtain second positional information of the object; and

determining a change in the object based upon a comparison of a result from a first scanning and a result from the second scanning.

23. The method of claim 21, further including:

conducting a second scanning limited to a portion of the region of space corresponding to the positional information of the object obtained from a first scanning; and

determining additional positional information of the object based upon a result from the second scanning.

24. The method of claim 23, wherein the second scanning includes:

conducting the second scanning using a greater number of sources than used during a first scanning; and

wherein the determining comprises;

determining positional information of the object for additional accuracy based upon a result from the second scanning.