Safety feature for projection subsystem using laser technology

Patent metadata

Field	Value
Publication number	US-9500939-B2
Application number	US-201314413548-A
Country	US
Kind code	B2
Filing date	Jul 17, 2013
Priority date	Aug 6, 2012
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

A projection subsystem includes a projector for projecting an image on a projection surface and a safety feature for tuning the projector when presence of a human is detected in front of the projection surface. This safety feature includes: —an apparatus for computing a depth view corresponding to at least a portion of the projection surface, —a camera for acquiring a captured image, —a computing circuit for detecting an object between the projector and the projection surface from this depth view and determining that the object is a human from the captured image, and a control circuit for tuning the projector accordingly.

First claim

The invention claimed is:

1. A method for safely projecting an image comprising steps of:
Projecting an image on a projection surface by actuating a projector;
Computing a depth view corresponding to at least a portion of said projection surface;
Acquiring a captured image by a camera;
Detecting from said depth view and said captured image a presence of a human between said projector and the projecting surface, wherein detecting comprises:
delimiting at least one area within said depth view;
applying a body feature recognition algorithm on an area of said captured image corresponding to said delimited area; and
determining that the human is present and located between said projector and the projecting surface when a body feature of the human is recognized; and

Tuning said projector in response to the detection.

2. The method of claim 1 , wherein said depth view is computed from a pair of images provided by a pair of stereoscopic cameras.

3. The method of claim 1 , wherein the step of delimiting comprises determining a base depth within said depth view corresponding to said projection surface and grouping points within the depth view having a depth substantially different from said base depth as part of the delimited area.

4. The method of claim 1 , wherein the step of tuning comprises switching the projector off.

5. The method of claim 1 , wherein the body feature is a human face and wherein the step of detecting comprises detecting that said human face is facing said projector.

6. A projection subsystem comprising:
a projector for projecting an image on a projection surface; and
a safety feature for tuning said projector when a human is detected between the projection surface and said projector,
wherein said safety feature comprises:
an apparatus for computing a depth view corresponding to at least a portion of said projection surface,
a camera system for acquiring a captured image, and
a computing circuit for delimiting at least one area of said depth view corresponding to a portion of the depth view located closer to the projection subsystem than said projection surface, applying a body feature recognition algorithm on an area of the captured image corresponding to said delimited area, determining that the area of the captured image includes a human positioned between the projection surface and said projector and tuning said projector in response to said determination.

7. The projection subsystem according to claim 6 , wherein said apparatus comprises a pair of stereoscopic cameras providing a pair of stereoscopic images from which said depth view is computed.

8. The projection subsystem according to claim 6 , wherein delimiting at least one area comprises determining a base depth corresponding to said projection surface and grouping points within said depth view having a depth substantially different from said base depth as part of the delimited area.

9. The projection subsystem according to claim 6 , wherein tuning comprises switching said projector off.

10. The projection subsystem according to claim 7 , wherein said camera system is one among said pair of stereoscopic cameras.

11. The projection subsystem according to claim 6 , wherein said body feature is a human face detected facing said projector.

12. A computer program product comprising a non-transitory computer readable medium, having thereon a computer program comprising program instructions, the computer program being loadable into a data-processing unit and adapted to cause execution of a method for safely projecting an image when the computer program is run by the data-processing unit, wherein the method comprises:
obtaining an image to project;
projecting said image on a projection surface by actuating a projector;
computing a depth view corresponding to at least a portion of said projection surface;
acquiring a captured image by a camera;
detecting from said depth view and said captured image a presence of a human between said projector and the projecting surface, wherein detecting comprises:
delimiting an area within said depth view;
applying a body feature recognition algorithm on an area of the captured image corresponding to said delimited area; and
determining that a human is between said projector and the projecting surface when a body feature is recognized; and

tuning said projector in response to the detection.

13. The computer program product of claim 12 , wherein the step of delimiting comprises determining a base depth within said depth view corresponding to said projection surface and groups of points within the depth view having a depth substantially different from said base depth as part of the delimited area.

14. The computer program product of claim 12 , wherein the step of tuning comprises switching the projector off.

15. The computer program product of claim 12 , wherein the body feature is a human face and wherein the step of detecting comprises detecting that said human face is facing said projector.

Assignees

• St Microelectronics Int Nv

Inventors

• Roffet Frederique
• Cuisenier Laurent

Classifications

• H04N9/3161 Primary

  using laser light sources (using laser beams scanning the display screen H04N9/3129) · CPC title

• G03B21/2033

  LED or laser light sources · CPC title

• G03B21/2053 Primary

  Intensity control of illuminating light (controlled by video signal processing H04N5/74 or H04N9/31) · CPC title

• H04N9/3194

  including sensor feedback · CPC title

• G03B21/2086

  Security or safety means in lamp houses · CPC title