Object detection

• US 20050128306A1
• Filed: 12/10/2004
• Published: 06/16/2005
• Est. Priority Date: 12/11/2003
• Status: Abandoned Application

• Current Assignee: Sony United Kingdom Limited (Sony Group Corp.)
• Original Assignee: Sony United Kingdom Limited (Sony Group Corp.)
• Inventors: Haynes, Simon Dominic, Porter, Robert Mark Stefan, Rambaruth, Ratna
• Application Number:
  US11/009,770
• Publication Number:
  US 20050128306A1
• Time in Patent Office: Days
• US Class Current: 348/207.990
• CPC Class Codes: G06T 2207/30201 Face
• CPC Class Codes: G06T 7/254 involving subtraction of images
• CPC Class Codes: G06T 7/277 involving stochastic approaches, e.g. using Kalman filters
• CPC Class Codes: G06V 10/22 by selection of a specific region containing or referencing a pattern; Locating or processing of specific regions to guide the detection or recognition
• CPC Class Codes: G06V 40/161 Detection; Localisation; Normalisation
• CPC Class Codes: H04N 23/611 where the recognised objects include parts of the human body

Abstract

Object detection apparatus in which regions of a test image from an ordered series of images are compared with data indicative of the presence of an object, comprises a change detector operable to detect regions of the test image which are substantially unchanged with respect to a previous image in the series; and an object detector operable not to perform object detection on regions of the test image identified by the change detector as being substantially unchanged.

Claims

1. Object detection apparatus in which regions of a test image from an ordered series of images are compared with data indicative of the presence of an object;

the apparatus comprising;

a change detector operable to detect regions of the test image which are substantially unchanged with respect to a previous image in the series; and

an object detector operable not to perform object detection on regions of the test image identified by the change detector as being substantially unchanged.

2. Apparatus according to claim 1, in which the series of images is a video signal.

3. Apparatus according to claim 1, in which the change detector is operable to detect regions of the test image which are substantially unchanged with respect to the preceding image in the series.

4. Apparatus according to claim 1, in which the change detector is operable to detect whether elements of the image have changed in accordance with at least one predetermined test sequence of image elements.

5. Apparatus according to claim 4, in which the change detector is operable to detect whether elements of the image have changed in accordance with at two or more different predetermined test sequences of image elements.

6. Apparatus according to claim 5, in which the sequences are raster scans of the image elements having different starting positions and/or directions.

7. Apparatus according to claim 5, in which at least one of the sequences is applied after another of the sequences, the later-applied sequence omitting image elements in the earlier-applied sequence which were detected not to have changed.

8. Apparatus according to claim 4, in which the change detector is operable to terminate detection in respect of a test sequence when a change is first detected at an image element in that sequence.

9. Apparatus according to claim 1, in which the change detector is arranged to detect a change at an image position if there is more than a threshold difference between corresponding image elements at that image position in the test image and the previous image.

10. Apparatus according to claim 9, in which the image elements are pixels.

11. Apparatus according to claim 9, in which the image elements are image blocks.

12. Apparatus according to claim 1, comprising a pre-processor operable to identify low-difference regions within the test image where there exists less than a threshold intra-image difference across groups of pixels within those regions;

the object detector being operable not to perform object detection on regions of the test image identified by the pre-processor as low-difference regions or detected by the change detector as being substantially unchanged.

13. Apparatus according to claim 1, in which the object detector is operable:

to derive a set of attributes from respective blocks of a region;

to compare the derived attributes with attributes indicative of the presence of an object;

to derive a probability of the presence of an object by a similarity between the derived attributes and the attributes indicative of the presence of an object; and

to compare the probability with a threshold probability.

14. Apparatus according to claim 13, in which the attributes comprise the projections of image areas onto one or more image eigenvectors.

15. Apparatus according to claim 1, in which the ordered sequence of images has associated motion indicators representing inter-image motion, the change detector being operable to detect image portions specified by the motion indicators as having inter-image motion.

16. Apparatus according to claim 1, in which the face detector is arranged to output object detection results obtained in respect of a previous image for those regions of the test image identified by the change detector as being substantially unchanged.

17. Apparatus according to claim 1, in which the objects are faces.

18. Video conferencing apparatus comprising apparatus according to claim 1.

19. Surveillance apparatus comprising apparatus according to claim 1.

20. A camera arrangement comprising apparatus according to claim 1.

21. A method of object detection, in which an image region of a test image from an ordered series of images are compared with data indicative of the presence of an object;

the method comprising the steps of;

detecting regions of the test image which are substantially unchanged with respect to a previous image in the series; and

performing object detection on the test image apart from regions of the test image identified by the change detector as being substantially unchanged.

22. Computer software having program code for carrying out a method according to claim 21.

23. A providing medium for providing program code according to claim 22.

24. A medium according to claim 23, the medium being a storage medium.

25. A medium according to claim 23, the medium being a transmission medium.