Patent ID: 6201898
Filing Date: 2001-03-13
Classification: H04N

Abstract:
An image coding apparatus that codes an input pixel value whose dynamic range is d-bit, to obtain a quantization value of n-bit and transmits it:predictive value generating means for generating a predictive value of the input pixel value from pixels in the vicinity of the input pixel;linear quantization unit generating means for generating a linear quantization unit having linear quantization representative points for quantization whose accuracy is d-bit and quantization width is 2.sup.d-n, the number of which points being obtained by subtracting a pre-set addition upper limit number from 2.sup.n ;non-linear quantization unit generating means for generating a non-linear quantization unit that adds, to the quantization representative values of said linear quantization unit, quantization representative points of not more than said addition upper limit number are added in the vicinity of said predictive value, the quantization width in the vicinity of said predictive value of said non-linear quantization unit being smaller than that of said linear quantization unit; andquantization means for quantizing the input pixel value by said non-linear quantization unit to obtain a quantization value.