Systems and methods for detecting a tilt angle from a depth image

• US 8,340,432 B2
• Filed: 06/16/2009
• Issued: 12/25/2012
• Est. Priority Date: 05/01/2009
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Mathe, Zsolt, Marais, Charles Claudius
• Primary Examiner(s): MARIAM, DANIEL G
• Application Number:
  US12/485,804
• Publication Number:
  US 20100278431A1
• Time in Patent Office: 1,288 Days
• Field of Search: 382/103, 382/154, 382/190, 382/289, 382/209, 348/42, 348/48, 348/50, 348/169
• US Class Current: 382/190
• CPC Class Codes: G06T 7/73 using feature-based methods
• CPC Class Codes: G06V 10/20 Image preprocessing
• CPC Class Codes: G06V 10/40 Extraction of image or video features
• CPC Class Codes: G06V 20/64 Three-dimensional objects
• CPC Class Codes: G06V 40/103 Static body considered as a whole, e.g. static pedestrian or occupant recognition
• CPC Class Codes: H04N 23/611 where the recognised objects include parts of the human body

Abstract

A depth image of a scene may be received, observed, or captured by a device. A human target in the depth image may then be scanned for one or more body parts such as shoulders, hips, knees, or the like. A tilt angle may then be calculated based on the body parts. For example, a first portion of pixels associated with an upper body part such as the shoulders and a second portion of pixels associated with a lower body part such as a midpoint between the hips and knees may be selected. The tilt angle may then be calculated using the first and second portions of pixels.

Claims

1. A method, comprising:

receiving depth data, by a computer, the depth data having been captured from a camera component;

scanning, by the computer, a human target in the depth data;

identifying, by the computer, a first portion of pixels of the human target at the location of an upper body part of the human target;

identifying, by the computer, a second portion of pixels of the human target at the location of a lower body part of the human target; and

calculating, by the computer, a tilt angle of the human target relative to the camera component based on the first and second portions of pixels.

2. The method of claim 1, wherein the upper body part comprises the shoulders of the human target, and the lower body part comprises the hips of the human target or the knees of the human target.

3. The method of claim 1, wherein each of the pixels in the first portion and second portion of pixels has a depth value associated therewith.

4. The method of claim 3, wherein calculating the tilt angle based on the scanned human target further comprises:

calculating a first value associated with a vertical distance between the first and second portions.

5. The method of claim 4, wherein calculating the tilt angle based on the scanned human target further comprises:

calculating a first average depth value using the depth value for at least one pixel in the first portion;

calculating a second average depth value using the depth value for at least one pixel in the second portion; and

subtracting the second average depth value from the first average depth value to calculate a second value.

6. The method of claim 5, wherein calculating the tilt angle based on the scanned human target further comprises:

calculating an arctangent of the second value divided by the first value to determine the tilt angle.

7. A computer-readable storage device having stored thereon computer executable instructions for detecting a tilt, that, when executed on a computer, cause the computer to perform operations comprising:

receiving depth data, the depth data having been captured from a camera component;

scanning a human target in the depth data to determine a location of at least an upper body part and a lower body part;

identifying a first portion of pixels of the human target at the location of an upper body part of the human target;

identifying a second portion of pixels of the human target at the location of a lower body part of the human target; and

calculating a tilt angle of the human target relative to the camera component based on the first and second portions of pixels.

8. The computer-readable storage medium of claim 7, wherein the upper body part comprises shoulders of the human target and the lower body part comprises a midpoint between the hips and the knees of the human target.

9. The computer-readable storage device of claim 7, wherein at least one of the pixels in each of the first portion and second portion of pixels has a depth value associated therewith.

10. The computer-readable storage device of claim 9, wherein calculating the tilt angle using the upper body part and the lower body part comprises:

calculating a first value associated with a vertical distance between the first and second portions.

11. The computer-readable storage device of claim 10, wherein calculating the tilt angle using the upper body part and the lower body part comprises:

calculating a first average depth value using the depth value for each pixel in the first portion;

calculating a second average depth value using the depth value for each pixel in the second portion; and

subtracting the second average depth value from the first average depth value to calculate a second value.

12. The computer-readable storage device of 11, wherein calculating a tilt angle using the location of the upper body part and the lower body part comprises:

calculating an arctangent of the second value divided by the first value to determine the tilt angle.

13. A system for detecting a tilt, the system comprising:

a capture device, wherein the capture device comprises a camera component that receives depth data of a scene, wherein the depth data comprises a human target associated with a user; and

a computing device in operative communication with the capture device, wherein the computing device comprises a processor that receives the depth data from the capture device, determines a location of an upper body part and a lower body part of human target in the depth data, selects a first portion of pixels of the human target associated with the upper body part and a second portion of pixels of the human target associated with the lower body part, and calculates a tilt angle between the human target and the capture device using the first portion of pixels and the second portion of pixels.

14. The system of claim 13, wherein each of the pixels in the first portion and second portion of pixels has a depth value associated therewith.

15. The system of claim 14, wherein processor further calculates a tilt angle using the first portion of pixels and the second portion of pixels by calculating a first value associated with the vertical distance between the first and second portions.

16. The system of claim 15, wherein processor further calculates a tilt angle using the first portion of pixels and the second portion of pixels by:

calculating a first average depth value using the depth value for each pixel in the first portion;

calculating a second average depth value using the depth value for each pixel in the second portion;

subtracting the second average depth value from the first average depth value to calculate a second value.

17. The system of 16, wherein processor further calculates a tilt angle using the first portion of pixels and the second portion of pixels by:

calculating an arctangent of the second value divided by the first value to determine the tilt angle.