Patent ID: 6104838
Filing Date: 2000-08-15
Classification: H04N

Abstract:
A method for performing 1/16 size decoding of an encoded digital image comprising the steps of:applying a combined horizontal 2-point inverse weighting function and inverse discrete cosine transform to a lower quarter of an input block of coefficients IN0, IN1 to produce a second block;applying a combined vertical 2-point inverse weighting function and inverse discrete cosine transform to a lower quarter of the second block; andapplying a horizontal 2-point inverse weighting function and inverse discrete cosine transform and applying a vertical 2-point inverse weighting function and inverse discrete cosine transform are performed according to the following equation: ##EQU1## where P(x,y) represents the pixel value at location (x,y); C'(h)=1 when h=0 or .sqroot.2 when h=1; Q""(h,v)=2Q(h,v) when h=0, v=0, or Q(h,v) when h.noteq.0 or v.noteq.0, Q(h,v) represents the weighted DCT coefficient at each location (h,v); w(0)=1; w(1)=CS4/(4*CS7*CS2); and CSm=cos(m.pi./16).