Method and apparatus for maximizing the visual quality of image presented in electric form

DETAILED DESCRIPTION OF THE INVENTION Referring to the block diagram in FIG.
1, the procedure of the invention works as follows.
An image e.
g.
in an RGB format is received in block 4 and converted into an Ls.
alpha.
format.
This conversion is described later on by referring to FIG.
3.
After this, an adjustment of the greyness balance is effected in block 5.
In block 5, highest and lowest values for parameter L are determined and compared with predefined values.
If necessary, based on the comparison, the whole Ls.
alpha.
colour space of the image is shifted so that the highest and lowest values fall on the desired point in the colour space.
After the adjustment of the greyness balance, the colour reproduction of the image is accentuated.
The stages of the accentuation process are represented by blocks 6 and 7.
In block 6, colour reproduction is accentuated globally concerning the whole image, and in block 7 local colour areas are accentuated.
The local colour areas are determined by finding certain predefined hues and colours close to them and adjusting the areas encountered to suitable values.
After both greyness balance and colour reproduction have been corrected, an Ls.
alpha.
=>RGB conversion is performed in block 8 to obtain new R.
sub.
1, G.
sub.
1 and B.
sub.
1 values.
The apparatus represented by FIG.
2 comprises in its simplest form a visual processor 1, which classifies the image and performs the necessary operations to determine how the image is to be corrected.
Moreover, the apparatus comprises a signal processor 2, which is used to perform the RGB=>Ls.
alpha.
conversion and is electrically connected to the visual processor 1.
Controlled by the visual processor, the signal processor makes the required changes in the image.
The apparatus shown in FIG.
2 also comprises a printer or a display 3 used to print or display the corrected image.
Referring now to FIG.
3, the RGB=>Ls.
alpha.
conversion performed in the first stage of the procedure of the invention is described.
The colour space represented by FIG