Method for processing display data, corresponding device and program

1. A method comprising:

processing display data by an electronic data processing device, said display data representing at least one piece of information to be displayed on a screen, wherein the processing comprises:

obtaining at least one reference image representing said at least one piece of information to be displayed;

generating at least one altered image from said reference image and from at least one alteration parameter, implementing at least one procedure of adding noise to said reference image, comprising generation of a pre-determined number of altered images by using an altered image generator which, for each pixel of the reference image, carries out a processing distinction according to a color of said pixel, said processing distinction comprising:

assigning a same given random color for the corresponding pixels of the altered images when the color of the pixel of the reference image is equal to a pre-determined color; and

the assigning a different random color for the corresponding pixels of the altered images when the color of the pixel of the reference image is different from the pre-determined color.

2. The method according to claim 1 , wherein the number of altered images is greater than or equal to three.

3. The method according to claim 1 , wherein the number of altered images is greater than or equal to a frequency of display of the image of the screen on which said altered images must be displayed.

4. The method according to claim 1 , wherein the generating at least one altered image implements a procedure of extracting portions of said reference image delivering at least one altered image.

5. The method according to claim 1 , wherein said function of adding noise to said reference image delivering at least one altered image comprises, for a plurality of pixels of the reference image, the application of the following expression:

D t ( x,y )= A thr ( F ( T ( x,y )))

wherein:

A represents a value of assigning;

D t (x, y) represents the pixel having co-ordinates (x, y) of the altered image D t ;

Thr is a thresholding function;

F is a contrast function; and

T (x, y) r represents the pixel having co-ordinates (x, y) of the reference image denoted T.

6. The method according to claim 5 , wherein said contrast function is:

F

⁡

(

x

)

=

α

⁢

⁢

x

+

β

255

⁢

α

+

β

+

γ

wherein:

α is a parameter of control of density of the altered image;

β is a contrast control parameter; and

γ is a noise-level control parameter.

7. The method according to claim 1 , further comprising at least one iteration of a step of displaying said at least one altered image on the screen.

8. The method according to claim 1 , wherein said at least one reference image represents a random keypad to be displayed.

9. A device comprising:

a processor; and

a non-transitory computer-readable medium comprising instructions stored thereon, which when executed by the processor configure the processor to perform a method of processing of display data, said display data representing at least one piece of information to be displayed on a screen, wherein the processing comprises:

obtaining at least one reference image representing said at least one piece of information to be displayed;

generating at least one altered image from said reference image and from at least one alteration parameter, implementing at least one procedure of adding noise to said reference image, comprising generation of a pre-determined number of altered images by using an altered image generator which, for each pixel of the reference image, carries out a processing distinction according to a color of said pixel, said processing distinction comprising:

assigning a same given random color for the corresponding pixels of the altered images when the color of the pixel of the reference image is equal to a pre-determined color; and

assigning a different random color for the corresponding pixels of the altered images when the color of the pixel of the reference image is different from the pre-determined color.

10. A non-transitory computer-readable medium comprising a computer program product comprising program code instructions which, when executed by a processor configure the processor to perform acts comprising:

processing display data, said display data representing at least one piece of information to be displayed on a screen, wherein the processing comprises:

obtaining at least one reference image representing said at least one piece of information to be displayed;

generating at least one altered image from said reference image and from at least one alteration parameter, implementing at least one procedure of adding noise to said reference image, comprising generation of a pre-determined number of altered images by using an altered image generator which, for each pixel of the reference image, carries out a processing distinction according to a color of said pixel, said processing distinction comprising:

assigning a same given random color for the corresponding pixels of the altered images when the color of the pixel of the reference image is equal to a pre-determined color; and

assigning a different random color for the corresponding pixels of the altered images when the color of the pixel of the reference image is different from the pre-determined color.