HS>Yes, I agree that DCT is lossy, but it is effective in true
HS>colour/high colour modes.
DG>Could you please give me a give overview of DCT. Don't worry about
DG>details. Just the basics, I'm not interested in implementing it, just
DG>want to know an overview of how it works. Thanks.
Discrete Cosine Transform turns an array of intensity data into an array of 
frequency data that tell how fast the intensities vary. JPEG applies the DCT 
8x8 rectangles of pixel data. For images with multiple components (ie, YCbCr 
images) the DCT is appled separately to 8x8 blocks of data for each 
mponent.
You apply the value of the algorithm to the already re-mapped colour matrix.
algorithm :-
F(u,v) = 1/4*C(u)*C(v) * (matrix[x,cos] * matrix[y,sin] *
F(x,y) * cos(2x+1)*(u*pi) / 16 * cos(2y + 1)*(v*pi))
where C(z) = ( 1 / sqrt(2) if z == 0 else
                   sqrt(1) if z != 0 )
DG>Danial.
DG>___
DG> X SLMR 2.1a X
... Error 3032 - Recursion error. See error 3032.
--- Ezycom V1.48g0 01fd016b
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