Method for segmenting an image and an image transmission system and image transmission unit therefore

• US 20070003138A1
• Filed: 02/27/2004
• Published: 01/04/2007
• Est. Priority Date: 03/03/2003
• Status: Abandoned Application

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Brady, John, Hobson, Paola, Kadir, Timar
• Application Number:
  US10/547,438
• Publication Number:
  US 20070003138A1
• Time in Patent Office: Days
• US Class Current: 382/173
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/20161 Level set
• CPC Class Codes: G06T 7/12 Edge-based segmentation
• CPC Class Codes: G06T 7/149 involving deformable models, e.g. active contour models
• CPC Class Codes: G06T 7/194 involving foreground-background segmentation

Abstract

A method (500) for segmenting an image comprises the step of identifying (502) one or more regions in the image. The method further comprises the steps of applying a single embedded surface for a Level Sets representation of said image; and performing region control logic (504) to enable said Level Sets, representation to manipulate one or more region boundaries in order to segment said image. This provides a method by which unsupervised image segmentation can be performed on an arbitrary number of classes/objects in the image.

Claims

1. A method (500) for segmenting an image, the method comprising the step of:

identifying (502) one or more regions in said image;

the method characterised by the steps of;

applying a single embedded surface for a Level Sets representation of said image; and

performing region control logic (504) to enable said Level Sets representation to manipulate one or more region boundaries in order to segment said image.

2. The method for segmenting an image according to claim 1, wherein the step of performing region control logic comprises the steps of:

applying a region competition cost function to said image to determine how to manipulate said one or more boundaries.

3. The method for segmenting an image according to claim 2, where said cost function comprises a curvature dependent term as a boundary cost.

4. The method for segmenting an image according to claim 2, the method further characterised by the step of:

calculating a global cost in said region competition cost function and performing region control logic to minimise a value of said calculated global cost.

5. The method for segmenting an image according to claim 1, wherein the step of performing region control logic comprises the step of performing merge or compete operations of a zero level set by means of a contour speed function.

6. The method for segmenting an image according to claim 1, wherein the step of applying a single embedded surface represents any number of disconnected regions, the method further characterised by the step of:

applying a pixel-labelling algorithm to identify disconnected regions separately.

7. The method for segmenting an image according to claim 6, wherein the step of applying a pixel-labelling algorithm is used at each iteration of a boundary curve evolution, to identify disconnected regions and/or to extract the Foreground/Background region labels.

8. The method for segmenting an image according to claim 6, the method further characterised by the step of:

assigning neighbouring pixels of a region with the same label such that a region is able to grow or shrink over the Boundary pixels.

9. The method for segmenting an image according to claim 1, wherein the step of performing region control logic comprises the step of:

performing a merge operation on Boundary pixels of said one or more regions of said image, or

performing a compete operation on Boundary pixels of said one or more regions of said image, such that said one or more regions are able to grow or shrink.

10. The method for segmenting an image according to claim 9, the method further characterised by the step of:

setting one or more speeds on said embedded surface to control said merging or competing operations.

11. The method for segmenting an image according to claim 9, wherein the step of merging is restricted such that only unique pairs of regions are merged at any single iteration of performing region control logic.

12. The method for segmenting an image according to claim 9, the method further characterised by the step of:

applying one or more merge flags to said one or more regions;

wherein a status of said one or more merge flags of each region in a pair of regions under consideration are assessed before proceeding to said step of performing a merge operation.

13. The method for segmenting an image according to claim 1, wherein the step of identifying comprises identifying two or more of:

a Foreground region of said image, a Background region of said image and/or a boundary of said image, in a Level Sets framework.

14. The method for segmenting an image according to claim 13, wherein said Foreground region is defined as a region where the embedding surface (ψ

) has a value greater than zero and also includes negative or zero boundary terms adjacent to said region.

16. The method for segmenting an image according to claim 13, wherein the step of applying a pixel-labelling algorithm comprises applying a positive label to a Foreground region and a negative label to a Background region,

the method further characterised by the step of:

conducting a local search, for example in an eight-pixel neighbourhood, around a Boundary pixel under consideration in order to detect whether a region adjacent to a Boundary pixel is a Foreground region or a Background region.

17. The method for segmenting an image according to claim 16, wherein a Foreground region is deemed present where any pixel in said local search is detected as having a positive label that differs from that of the Boundary pixel under consideration.

18. The method for segmenting an image according to claim 16, wherein a Background region is deemed present where any pixel in said local search is detected as having a negative label that differs from that of the Boundary pixel under consideration.

19. The method for segmenting an image according to claim 16, wherein any Boundary pixel identified as being adjacent to a further Boundary pixel from a same region is configured to grow prior to performing region competition control logic.

20. The method for segmenting an image according to claim 16, the method further characterised by the step of:

enabling Foreground-to-Foreground region competition by causing one region to shrink.

21. The method for segmenting an image according to claim 1, wherein said Level Set representation is implemented using a finite difference approximation to take into account a direction of surface movement.

22. Currently Amended) The method for segmenting an image according to claim 1, wherein said step of identifying one or more regions in said image identifies attributes of said image.

23. The method for segmenting an image according to claim 22, wherein said step of identifying comprises identifying one or more of the following attributes of said image:

image pixel intensities, texture features, colour, edge distribution.

24. The method for segmenting an image according to claim 1, the method further characterised by the step of:

applying a cost function to said labelled pixels to determine whether to perform a merging or competing operation of said pixels.

15. (canceled)

25. (canceled)

26. (canceled)

27. (canceled)