Method for processing a digital image, in particular for processing contour regions, and corresponding device

1. A method of processing a digital image comprising at least one contour zone, the method comprising:

performing a contour zone sharpness processing comprising

converting cues related to a level of pixels of the at least one contour zone into initial main cues lying between zero and a main value dependent on an amplitude of the at least one contour zone,

performing a sharpness sub-processing on the initial main cues to obtain final main cues, and

converting the final main cues into final cues.

2. A method according to claim 1 , wherein the sharpness sub-processing comprises, for each pixel in the at least one contour zone, determining an intermediate cue and subtracting the intermediate cue from a maximum initial main cue to obtain the final main cue.

3. A method according to claim 1 , wherein the digital image comprises a color image comprising a red component, a green component, and a blue component, each of the red, green, and blue components having a respective contour zone; wherein the amplitude of the at least one contour zone is determined based upon the respective contour zone of each of the red, green, and the blue components; and wherein the contour zone sharpness processing is performed on each of the red, green, and blue components.

4. A method according to claim 1 , further comprising displaying the digital image on a display screen based upon the final cues.

5. A method according to claim 3 , wherein the amplitude of the at least one contour zone is also determined based upon a direction of variation of the contour zones of each of the red, green, and blue components.

6. A method according claim 5 wherein, determining of the amplitude of the at least one contour zone comprises:

multiplying the contour zone of each of the red, green, and blue components by the respective direction of variation;

adding the multiplied contour zone of each of the red, green, and blue components to thereby obtain a modified contour zone;

calculating the amplitude of the at least one contour zone by subtracting values of the cues related to the level of pixels of the at least one contour zone from values of cues of the modified contour zone.

7. A device for processing a digital image comprising at least one contour zone, comprising:

contour zone sharpness processing circuitry to perform a contour zone sharpness processing and comprising

first conversion circuitry to convert cues related to a level of pixels of the at least one contour zone into initial main cues lying between zero and a main value dependent on an amplitude of the at least one contour zone,

sharpness sub-processing circuitry to perform a sharpness processing on the initial main cues to obtain final main cues, and

second conversion circuitry to convert the final main cues into final cues.

8. A device according to claim 7 , wherein the sharpness sub-processing circuitry comprises:

determining circuitry to determine, for each pixel in the at least one contour zone, an intermediate cue; and

subtraction circuitry to subtract the intermediate cue from a maximum initial main cue to obtain the final main cue.

9. A device according to claim 8 , wherein the digital image comprises a color image comprising a red component, a green component, and a blue component, each of the red, green, and blue components having a respective contour zone; wherein the first conversion circuitry comprises amplitude determination circuitry to determine an amplitude of the at least one contour zone based upon the contour zone of each of the red, green, and the blue components; and wherein the contour zone sharpness processing is performed on each of the red, green, and blue components.

10. A device according to claim 9 , wherein the amplitude determination circuitry also determines the amplitude of the at least one contour zone based upon a direction of variation of the contour zones of each of the red, green, and blue components.

11. A device according to claim 10 , wherein the sharpness sub-processing comprises, for each pixel in the at least one contour zone, determining an intermediate cue and subtracting the intermediate cue from a maximum initial main cue to obtain the final main cue.

12. A device according to claim 11 , wherein the amplitude of the at least one contour zone is also determined based upon a direction of variation of the contour zones of each of the red, green, and blue components.

13. A device according to claim 10 , wherein the digital image comprises a color image comprising a red component, a green component, and a blue component, each of the red, green, and blue components having a respective contour zone; wherein the amplitude of the at least one contour zone is determined based upon the contour zone of each of the red, green, and the blue components; and wherein the contour zone sharpness processing is performed on each of the red, green, and blue components.

14. A device according to claim 13 wherein, determining of the amplitude of the at least one contour zone comprises:

multiplying the contour zone of each of the red, green, and blue components by the respective direction of variation;

adding the multiplied contour zone of each of the red, green, and blue components to thereby obtain a modified contour zone;

calculating the amplitude of the at least one contour zone by subtracting values of the cues related to the level of pixels of the at least one contour zone from values of cues of the modified contour zone.

15. A device for processing a digital image comprising at least one contour zone, the device comprising:

circuitry to perform a contour zone sharpness processing by at least

converting cues related to a level of pixels of the at least one contour zone into initial main cues lying between zero and a main value dependent on an amplitude of the at least one contour zone,

performing a sharpness sub-processing on the initial main cues to obtain final main cues, and

converting the final main cues into final cues.