Smart transparency for virtual objects

• US 10,451,875 B2
• Filed: 05/27/2015
• Issued: 10/22/2019
• Est. Priority Date: 07/25/2014
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: Sutherland, Jeff, Sugden, Ben, Salter, Tom
• Primary Examiner(s): Chwasz, Jade R
• Application Number:
  US14/722,942
• Publication Number:
  US 20160025982A1
• Time in Patent Office: 1,609 Days
• Field of Search: 359 13, 359 15, 359 9, 359 10, 359 11, 359 32, 359 35
• CPC Class Codes: G02B 2027/0141 characterised by the informative content of the display
• CPC Class Codes: G02B 2027/0174 holographic
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0093 with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G06F 3/011 Arrangements for interaction with the human body, e.g. for user immersion in virtual reality blind teaching G09B21/00
• CPC Class Codes: G06F 3/04815 Interaction with a metaphor-based environment or interaction object displayed as three-dimensional, e.g. changing the user viewpoint with respect to the environment or object

Abstract

A head mounted display (HMD) device is configured with a sensor package that enables head tracking to determine the device user'"'"'s proximity to virtual objects in a mixed reality or virtual reality environment. A fade volume including concentrically-arranged volumetric shells is placed around the user including a near shell that is closest to the user, and a far shell that is farthest from the user. When a virtual object is beyond the far shell, the HMD device renders the object with full opacity (i.e., with no transparency). As the user moves towards a virtual object and it intersects the far shell, its opacity begins to fade out with increasing transparency to reveal the background behind it. The transparency of the virtual object increases as the object gets closer to the near shell and the object becomes fully transparent when the near shell reaches it so that the background becomes fully visible.

Claims

1. A method performed by a head mounted display (HMD) device employed by a user occupying a physical environment, the HMD device having one or more processors and supporting rendering of a virtual reality environment that includes virtual objects, comprising:

placing, using the one or more processors coupled to the HMD device, a fade volume that surrounds the user, the fade volume having a near shell that is proximate to the user and a far shell that is distal to the user, in which the near shell is positioned a radial distance from the user such that the near shell is distinct from the user;

determining, using the one or more processors and one or more sensors coupled to the HMD device, a location of a virtual object with respect to the near and far shells by tracking the user'"'"'s location within the virtual reality environment; and

rendering, using the one or more processors, the virtual object with transparency when it is located between the near and far shells, the transparency increasing as the virtual object becomes closer to the near shell,

wherein the HMD device is configured to continuously render the virtual reality environment so that no part of the physical environment or the user is displayed on the HMD device.

2. The method of claim 1 further including rendering the virtual object with full opacity when the virtual object is located beyond the far shell of the fade volume.

3. The method of claim 1 further including rendering the virtual object with full transparency when the virtual object intersects the near shell of the fade volume.

4. The method of claim 1 further including performing the rendering of the virtual object using alpha compositing and interpolating an alpha value based on a transparency curve that is established over a spatial distance between the near and far shells of the fade volume or performing the rendering of the virtual object using ordered dithering.

5. The method of claim 4 in which the transparency curve is a linear curve and the alpha value is interpolated on a linear basis.

6. The method of claim 4 further including performing the alpha compositing for the virtual object on a per-pixel basis.

7. The method of claim 1 further including performing head tracking to determine a proximity of the fade volume to the virtual object.

8. The method of claim 7 in which the head tracking utilizes a sensor package in the HMD device for generating depth data.

9. The method of claim 8 further including generating the depth data using one or more depth-from-stereo imaging analyses or using a depth sensor.

10. The method of claim 8 further including using the sensor package to determine a current height of the user'"'"'s head above the ground of the physical environment.

11. The method of claim 10 further including sizing the fade volume according to the height of the user'"'"'s head.

12. The method of claim 1 further including configuring a radius of the far shell to be between one and one-half and two and one-half times a radius of the near shell.

13. The method of claim 12 further including configuring the radius of the near shell to be approximately one-half meter and the radius of the far shell to be approximately one meter.

14. The method of claim 1 further including performing the transparent rendering of the virtual object to show a background of the virtual reality environment, the background including one or more of virtual ground, or other virtual objects.

15. The method of claim 1 further including configuring the near and far shells using one of cylinder, sphere, capsule, or non-radial volume.

16. The method of claim 1 further including configuring the near and far shells as concentrically aligned cylinders having different radii or as spheres having different radii that share a common center.