METHOD FOR DISPLAYING AN ELEMENTARY IMAGE OF A COMPOSITE IMAGE AND AN ASSOCIATED VIEWING DEVICE

1 . A method for displaying an elementary image from a composite image grouping several elementary images ( 32 , 34 , 36 ), on a viewing device ( 10 ) with a memory ( 20 ) capable of allocating a global memory area ( 74 ) for the processing of images, the composite image ( 30 ) having an initial compression format and a given initial size ( 86 ), the method comprising:

a step ( 48 ) for saving the composite image ( 30 ) in the global memory area ( 74 ) allocated for the processing of images of the viewing device ( 10 ), and

a step for decoding and displaying ( 72 ) on the viewing device ( 10 ), elementary images ( 32 , 34 , 36 ) derived from the composite image ( 30 ),

characterized in that it further includes a transcoding step intended for recompressing the composite image ( 30 ) according to a compression algorithm into a different final compression format and final size ( 90 ) from the initial compression format and from the initial size ( 86 ), the transcoding step including:

a step ( 57 ) for partitioning the composite image ( 30 ) into a number of portions ( 88 ), and successively for each portion ( 88 ) of the composite image ( 30 ):

a step ( 58 ) for decoding the sole portion ( 88 ) of the composite image ( 30 ) in a decoding memory area ( 80 ), within the global memory area ( 74 ) allocated to the processing of images of the viewing device ( 10 ), and

a step ( 60 ) for recompressing the decoded portion of the composite image ( 30 ) into a final compression format within a memory area ( 82 ) allocated to the processing of the composite image ( 30 ) in the final compression format, and

in that the decoding and display step ( 72 ) is carried out from the recompressed composite image ( 30 ).

2 . The display method according to claim 1 , characterized in that the transcoding step further successively includes for each portion ( 88 ) of the composite image ( 30 ) a step ( 62 ) for freeing the decoding memory area ( 80 ), within the global memory area ( 74 ) allocated to the processing of images of the viewing device ( 10 ).

3 . The display method according to any of the preceding claims, characterized in that the step ( 57 ) for partitioning the composite image ( 30 ) is capable of defining each portion ( 88 ) of the composite image ( 30 ) in a number of lines ( 40 ) of pixels.

4 . The display method according to any of the preceding claims, characterized in that the recompression step ( 60 ) includes a step for adding an index table, intended to determine the position of the elementary images ( 32 , 34 , 36 ) of the composite image ( 30 ) in the final compression format in the global memory area ( 74 ) allocated to the processing of images.

5 . The display method according to any of the preceding claims, characterized in that it further includes a step ( 56 ) for comparison between the size ( 86 ) of the composite image ( 30 ) in the initial compression format and a predefined initial size ( 78 ), intended for initiating the transcoding step.

6 . The display method according to any of the preceding claims, characterized in that it further includes a step ( 64 ) for comparison between the final size ( 90 ) of the whole of the recompressed portions of the composite image ( 30 ) and a predefined final size ( 84 ) intended for stopping the transcoding step.

7 . The display method according to any of the preceding claims, characterized in that the initial compression format of the composite image ( 30 ) is an element from the group consisting in: GIF and PNG.

8 . The display method according to any of the preceding claims, characterized in that the viewing device ( 10 ) is a mobile telephone.

9 . The viewing device ( 10 ) with a memory ( 20 ), capable of displaying an elementary image of a composite image grouping several elementary images ( 32 , 34 , 36 ), the composite image ( 30 ) having an initial compression format and a given initial size ( 86 ), the device ( 10 ) capable of allocating a global memory area ( 74 ) for the processing of images, comprising:

means ( 20 ) for saving the composite image ( 30 ), in the global memory area ( 74 ) allocated for the processing of images of the viewing device ( 10 ), and

decoding and display means, intended for displaying on the viewing device ( 10 ), elementary images ( 32 , 34 , 36 ) derived from the composite image ( 30 ),

characterized in that it further includes transcoding means, intended for recompressing the composite image ( 30 ), according to a compression algorithm, into a final compression format and final size ( 90 ) which are different from the initial compression format and from the initial size ( 86 ), the transcoding means including:

means for partitioning the composite image ( 30 ) into a number of portions ( 88 ) and successively for each portion ( 88 ) of the composite image ( 30 ):

means for decoding the sole portion ( 88 ) of the composite image ( 30 ) in the decoding memory area ( 80 ), within the global memory area ( 74 ) allocated to the processing of images of the viewing device ( 10 ), and

means for recompressing the decoded portion of the composite image ( 30 ) into a final compression format within a memory area ( 82 ) allocated to the processing of the composite image ( 30 ) in the final compression format,

and in that the decoding and display means are applied to the recompressed composite image ( 30 ).