Granted Patent B2

US 8,290,208 · App. 12/352,030 · Granted Oct 16, 2012

Abstract

Claims (55)

1. A method for providing improved eye safety while operating an image projection system, comprising:

a. operating an image projection system that generates a modulated light beam which forms images on a display surface;

b. monitoring an area in front of the display surface, and at least inclusive of the display surface, with an image capture device;

c. analyzing images acquired by an image capture device to locate subjects that can obstruct a portion of the modulated light beam prior to the display surface, the image analysis including feature extraction analysis of the images of the subjects to identify candidate head regions therein, and the image analysis further including motion analysis to track motion of the subjects;

d. determining a head blanking region and one or more associated head monitoring regions for a candidate head region associated with a subject, the head monitoring regions being determined using the motion analysis and corresponding to image areas where a head blanking region is likely to be in a subsequent time as the subject moves;

e. blanking image projection to at least the head blanking region by substantially reducing the light levels of the modulated light beam provided to the head blanking region;

f. prioritizing ongoing image analysis to the associated head monitoring regions to determine new head positions as the subject moves such that more computing capacity is devoted to analyzing image data in the head monitoring regions than to analyzing image data in other image areas; and

g. modifying head region image blanking to track and overlap the new head positions.

2. The method according to claim 1 , wherein the image analysis utilizes at least one of body shape analysis, image difference analysis, shadow image analysis, subject-in-box analysis, or motion analysis, or combinations thereof, as search techniques for locating subjects in the monitored area.

3. The method according to claim 1 , wherein the feature extraction analysis utilizes one or more methods for locating candidate head regions, including body shape analysis, head shape analysis, skin area analysis, facial feature analysis, or eye-shine analysis, either individually or in combination.

4. The method according to claim 1 , wherein an initial image blanking region is provided using an expanded image blanking region determined by expanding the determined head blanking region, the initial image blanking region being substantially larger than the determined head blanking region, and wherein the initial image blanking region is used to blank image projection for an initial time period.

5. The method according to claim 4 , wherein the process of determining the expanded initial image blanking region includes silhouette blanking or expanded torso area blanking.

6. The method according to claim 1 , wherein the head monitoring region has an associated size, position and movement, the size, position and movement of the head monitoring region being determined responsive to size, motion and activities determined for the corresponding subject.

7. The method according to claim 1 , wherein the size of the head blanking region depends on the subject's motion.

8. The method according to a claim 1 , wherein the subject is a person or an animal.

9. The method according to claim 1 , wherein the monitored area is monitored using an image capture device or with a sensing device other than an image capture device prior to a modulated image display light beam being provided to the display surface.

10. The method according to claim 1 , wherein an image capture device is an infrared (IR) imaging camera.

11. The method according to claim 1 , wherein the monitored area is further monitored with sensing devices other than image capture devices, those sensing devices including sensors that can distinguish between animate subjects and inanimate objects that are within the monitored area.

12. The method according to claim 11 , wherein the sensing devices include at least one of a monostatic microwave sensor or a non-contact bio-electric field sensor.

13. The method according to claim 11 , wherein image blanking is removed for objects that are identified as inanimate.

14. A method for providing improved eye safety while operating an image projection system, comprising:

a. operating an image projection system that generates a modulated light beam which forms images on a display surface;

b. monitoring an area in front of the display surface, and at least inclusive of the display surface, with at least one image capture device;

c. analyzing images acquired by an image capture device to locate subjects that can obstruct a portion of the modulated light beam prior to the display surface;

d. analyzing the images of the located subjects to locate subject bodies or head features, thereby identifying candidate head regions on the subjects;

e. determining a head blanking region and one or more associated head monitoring regions for a candidate head region associated with a subject, the head monitoring regions being determined using the motion analysis and corresponding to image areas where a head blanking region is likely to be in a subsequent time as the subject moves;

f. blanking image projection to the head blanking regions by substantially reducing the light levels of the modulated light beam provided to the head blanking regions;

g. prioritizing ongoing image analysis to the associated head monitoring regions to determine new head positions as the subject moves such that more computing capacity is devoted to analyzing image data in the head monitoring regions than to analyzing image data in other image areas; and

h. validating identification of candidate head regions and associated head blanking regions based on further image analysis, and continuing image blanking for positively identified head regions, and ending image blanking for invalidated head regions.

15. The method according to claim 14 , wherein the image analysis utilizes body shape analysis, image difference analysis, shadow image analysis, subject-in-box analysis, motion analysis, or combinations thereof, as search techniques for locating subjects in the monitored area.

16. The method according to claim 14 wherein the method utilizes body shape analysis, head shape analysis, skin area analysis, facial feature analysis, or eye-shine analysis, either individually or in combination, to locate head features.

17. A method for providing improved eye safety while operating an image projection system, comprising:

a. operating an image projection system that generates a modulated light beam which forms images on a display surface;

b. monitoring an area in front of the display surface, and at least inclusive of the display surface, with at least one sensing device;

c. analyzing data collected by a sensing device to locate objects that can obstruct a portion of the modulated light beam prior to the display surface;

d. further analyzing data related to the objects to determine whether the objects are animate or inanimate;

e. blanking image projection to at least portions of an identified animate object, while allowing image projection to identified inanimate objects;

wherein the sensing device is a visible imaging camera used for calibration of the image projection system and the image analysis in step c further comprises analyzing the deviations in the mean value of light reflecting off the display surface and looking for extended regions where the deviations are significantly larger than other regions indicative of an obstructing object in the light beam.

18. The method according to claim 17 , wherein the sensing devices comprises at least one of the following; an image capture device, a monostatic microwave sensor, or a non-contact bio-electric field sensor, or combinations thereof.

19. The method according to claim 17 , wherein sensing of an identified animate object is done using an image capture device, and subsequent image analysis of the acquired images provides identification of candidate head regions on the identified animate object.

20. The method according to claim 19 , wherein a head blanking region and associated head monitoring regions are determined for a candidate head region associated with the object.

21. The method according to claim 19 , wherein image projection to the head blanking region is blanked by substantially reducing the light levels of the modulated light beam provided to the head blanking region.

22. The method according to claim 19 , wherein ongoing image analysis is prioritized to identified head monitoring regions to determine new head positions as the object moves in the monitored area.

23. A laser projection system providing improved eye safety, comprising:

a. a laser light source which provides a light beam;

b. a light modulation means which imparts image data to provide a modulated light beam;

c. a projection lens which forms an image on a display surface with the modulated light beam;

d. at least one camera directed for image capture of a monitored area including the display surface;

e. obstruction analysis means to assess the monitored area to locate objects that can intercept a portion of the modulated light beam prior to the display surface;

f. feature extraction analysis means to assess images of obstructing objects to determine head characteristic features and to identify candidate head regions thereon; and

g. motion analysis means to assess the motion of the obstructing objects;

wherein the candidate head regions are analyzed relative to motion and head characteristic features to determine both head blanking regions and head monitoring regions, the head monitoring regions being determined using the motion analysis and corresponding to image areas where a head blanking region is likely to be in a subsequent time as the subject moves, such that portions of the modulated light beam that are directed to at least the head blanking regions are blanked by the projection system, while the projection system uses the defined head monitoring regions to track and modify head region image blanking relative to object movement such that more computing power is devoted to analyzing image data in the head monitoring regions than to analyzing image data in other image areas.

24. The method according to claim 1 , further including using further image analysis to validate or invalidate one or more of the identified candidate head regions and associated head blanking regions.

25. The method according to claim 24 , further including the continuation of image blanking for validated head regions, and the ending of image blanking for at least one invalidated head region.

26. The method according to claim 14 , further including monitoring the monitored area using one or more sensing devices that can distinguish between animate and inanimate objects, wherein the one or more sensing devices include a monostatic micro-wave sensor or a non-contact bio-electric field sensor.

Assignments (19)