Foreground/background separation in digital images

• US 8,358,841 B2
• Filed: 09/10/2010
• Issued: 01/22/2013
• Est. Priority Date: 05/03/2006
• Status: Active Grant

• Current Assignee: FotoNation Limited (Adeia Inc.)
• Original Assignee: DigitalOptics Corporation Europe Limited (Adeia Inc.)
• Inventors: Steinberg, Eran, Corcoran, Peter, Prilutsky, Yury, Bigioi, Petronel, Pososin, Alexei, Ciuc, Mihai, Zamfir, Adrian, Capata, Adrian
• Primary Examiner(s): STREGE, JOHN B
• Application Number:
  US12/879,953
• Publication Number:
  US 20100329549A1
• Time in Patent Office: 865 Days
• Field of Search: 382/173, 382/168
• US Class Current: 382/173
• CPC Class Codes: G06T 7/11 Region-based segmentation
• CPC Class Codes: G06T 7/136 involving thresholding
• CPC Class Codes: G06T 7/194 involving foreground-background segmentation
• CPC Class Codes: G06V 10/28 Quantising the image, e.g. histogram thresholding for discrimination between background and foreground patterns
• CPC Class Codes: G06V 10/56 relating to colour
• CPC Class Codes: G06V 40/162 using pixel segmentation or colour matching

Abstract

A method for providing improved foreground/background separation in a digital image of a scene is disclosed. The method comprises providing a first map comprising one or more regions provisionally defined as one of foreground or background within the digital image; and providing a subject profile corresponding to a region of interest of the digital image. The provisionally defined regions are compared with the subject profile to determine if any of the regions intersect with the profile region. The definition of one or more of the regions in the map is changed based on the comparison.

Claims

1. A method for defining one or more regions each as foreground or background in a digital image of a scene, comprising:

providing a first map comprising one or more regions provisionally defined as one of foreground or background within a digital image;

analyzing one or more of said one or more regions to determine a distribution of luminance within pixels of said one or more of said one or more regions;

responsive to said luminance distribution for a first region of said one or more of said one or more regions having more than one distinct luminance peak, dividing said first region into more than one sub-region based on proximity of a pixel luminance to said luminance peaks; and

changing in said first map a designation of said sub-regions based on said division.

2. A method as claimed in claim 1, further comprising:

providing a subject profile corresponding to a region of interest of said digital image;

comparing at least some of said one or more provisionally defined regions with said subject profile to determine if any of said regions or sub-regions of said first map intersect with said profile region;

changing in said first map a designation of one or more of said regions or sub-regions based on said comparison.

3. A method as claimed in claim 1, wherein providing said first map comprises:

analyzing at least some of said one or more regions of the digital image in a color space to determine a color distribution within said at least some of said one or more regions, said color distribution having a plurality of distinct color peaks; and

segmenting said at least some of said one or more regions based on proximity of pixel color to said color peaks.

4. A method as claimed in claim 3, wherein said analyzed regions are regions provisionally defined as foreground within said first map.

5. A method as claimed in claim 3 wherein said digital image is provided in LAB space and wherein said color space comprises [a,b] values for pixels and wherein said luminance comprises L values for pixels.

6. An apparatus configured to define one or more regions each as foreground or background in a digital image of a scene, comprising

a processor and

one or more processor-readable media for programming the processor to control the apparatus to perform a method comprising:

acquiring said digital image;

providing a first map comprising one or more regions provisionally defined as one of foreground or background within said digital image;

analyzing one or more of said one or more regions to determine a distribution of luminance within pixels of said one or more of said one or more regions;

responsive to said luminance distribution for a first region of said one or more of said one or more regions having more than one distinct luminance peak, dividing said first region into more than one sub-region based on proximity of a pixel luminance to said luminance peaks; and

changing in said first map a designation of at least one of said sub-regions based on said dividing.

7. An apparatus as claimed in claim 6, wherein the method further comprises:

providing a subject profile corresponding to a region of interest of said digital image;

comparing at least some of said one or more provisionally defined regions with said subject profile to determine if any of said regions or sub-regions of said first map intersect with said profile region;

changing in said first map a designation of one or more of said regions or sub-regions based on said comparison.

8. An apparatus as claimed in claim 6, wherein providing said first map comprises:

analyzing at least some of said one or more regions of the digital image in a color space to determine a color distribution within said at least some of said one or more regions, said color distribution having a plurality of distinct color peaks; and

segmenting said regions based on proximity of pixel color to said color peaks.

9. An apparatus as claimed in claim 8, wherein said analyzed regions are regions provisionally defined as foreground within said first map.

10. An apparatus as claimed in claim 8 wherein said digital image is provided in LAB space and wherein said color space comprises [a,b] values for pixels and wherein said luminance comprises L values for pixels.

11. One or more non-transitory computer-readable storage media having code embedded therein for programming a processor to perform a method of defining one or more regions each as foreground or background in a digital image of a scene, wherein the method comprises:

providing a first map comprising one or more regions provisionally defined as one of foreground or background within the digital image;

analyzing one or more of said one or more regions to determine a distribution of luminance within pixels of said one or more of said one or more regions;

responsive to said luminance distribution for a first region of said one or more of said one or more regions having more than one distinct luminance peak, dividing said first region into more than one sub-region based on proximity of a pixel luminance to said luminance peaks; and

changing in said first map a designation of said sub-regions based on said division.

12. The one or more computer-readable storage media as claimed in claim 11, wherein the method further comprises:

providing a subject profile corresponding to a region of interest of said digital image;

comparing at least some of said one or more provisionally defined regions with said subject profile to determine if any of said regions or sub-regions of said first map intersect with said profile region;

changing in said first map a designation of one or more of said regions or sub-regions based on said comparison.

13. The one or more computer-readable storage media as claimed in claim 11, wherein providing said first map comprises:

analyzing at least some of said one or more regions of the digital image in a color space to determine a color distribution within said at least some of said one or more regions, said color distribution having a plurality of distinct color peaks; and

segmenting said regions based on proximity of pixel color to said color peaks.

14. The one or more computer-readable storage media as claimed in claim 13, wherein said analyzed regions are regions provisionally defined as foreground within said first map.

15. The one or more computer-readable storage media as claimed in claim 13, wherein said digital image is provided in LAB space and wherein said color space comprises [a,b] values for pixels and wherein said luminance comprises L values for pixels.