Device and method for creating a saliency map of an image

• US 20070116361A1
• Filed: 12/14/2004
• Published: 05/24/2007
• Est. Priority Date: 12/18/2003
• Status: Active Grant

• Current Assignee: Interdigital Vc Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: Thomson Licensing (Vantiva SA)
• Inventors: Francois, Edouard, Thoreau, Dominique, Le Meur, Olivier, Le Callet, Patrick, Barba, Dominique
• Granted Patent: US 7,853,076 B2
• Time in Patent Office: Days
• US Class Current: 382/181
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 5/73 Deblurring; Sharpening
• CPC Class Codes: G06T 7/262 using transform domain methods, e.g. Fourier domain methods
• CPC Class Codes: G06V 10/451 with interaction between the filter responses, e.g. cortical complex cells
• CPC Class Codes: G06V 10/462 Salient features, e.g. scale invariant feature transforms [SIFT]
• CPC Class Codes: G06V 10/56 relating to colour

Abstract

The invention concerns a device and a method for creating a saliency map of an image. It comprises the steps of: Projection of said image according to the luminance component and if said image is a color image, according to the luminance component and according to the chrominance components, Perceptual sub-bands decomposition of said components according to the visibility threshold of a human eye, Extraction of the salient elements of the sub-bands related to the luminance component, Contour enhancement of said salient elements in each sub-band related to the luminance component, Calculation of a saliency map from the contour enhancement, for each sub-band related to the luminance component. Creation of the saliency map as a function of the saliency maps obtained for each sub-band.

Claims

1. Method for creating a saliency map of an image wherein it comprises the steps of:

Projection of said image according to the luminance component and if said image is a color image, according to the luminance component and according to the chrominance components,

Perceptual sub-bands decomposition of said components according to the visibility threshold of a human eye,

Extraction of the salient elements of the sub-bands related to the luminance component,

Contour enhancement of said salient elements in each sub-band related to the luminance component,

Calculation of a saliency map from the contour enhancement, for each sub-band related to the luminance component.

Creation of the saliency map as a function of the saliency maps obtained for each sub-band.

2. Method according to claim 1 wherein it comprises, further to the perceptual sub-bands decomposition,

a step of achromatic contrast sensitivity function for the luminance component and if said image is a color image,

a step of chromatic sensitivity function for the chromatic components.

3. Method according to claim 2 wherein it comprises a step of visual masking, further to the step of contrast sensitivity function, for each sub-band of the luminance component and of the chromatic components.

4. Method according to claim 3 wherein, when said image is a color image, it comprises a step of chromatic reinforcement of the luminance sub-bands.

5. Method according to claim 1, wherein the perceptual sub-bands decomposition is obtained by carving-up the frequency domain both in spatial radial frequency and orientation.

6. Method according to claim 5 wherein the perceptual decomposition of the luminance component leads to 17 psycho visual sub-bands distributed on four crowns.

7. Method according to claim 5 wherein the perceptual decomposition of the chromatic components leads to 5 psycho visual sub-bands distributed on two crowns for each chromatic component.

8. Method according to claim 4, wherein the chromatic reinforcement of the luminance component is done on the sub-bands of the second crown and based on the sub-bands of the first crown of the chromatic components.

9. Device for creating a saliency map of an image wherein it comprises means for:

Projecting said image according to the luminance component and if said image is a color image, according to the luminance component and according to the chrominance components,

Transposing into the frequential domains said luminance and chrominance signals,

Decomposing into perceptual sub-bands said components of the frequential domain according to the visibility threshold of a human eye,

Extracting the salient elements of the sub-bands related to the luminance component,

Contour enhancing said salient elements in each sub-band related to the luminance component,

Calculating a saliency map from the contour enhancement, for each sub-band related to the luminance component.

Creating the saliency map as a function of the saliency maps obtained for each sub-band.