Patent ID: 6453053
Filing Date: 2002-09-17
Classification: G06T,H04N

Abstract:
An electronic watermark insertion apparatus, comprising:conversion means for performing discrete cosine transform for an original image to convert the original image into data f(i) of frequency components, i being 1, 2, . . . , n; electronic watermark insertion means for multiplying a partial average of the data f(i) and electronic watermark data w(i) determined in advance for the individual factors (i), i being 1, 2, . . . , n, and adding the data f(i) to the results obtained by multiplying the results of the multiplication by a constant to determine an electronic watermark containing data F(i), i being 1, 2, . . . , n; quantization means for quantizing the data F(i) with a quantization step sizes Q(i), i being 1, 2, . . . , n; and coding means for compression coding the data after the quantization; the partial average of the data f(i) being given by (V(iâˆ’1)+V(i)+V(i+1))/3 where V(iâˆ’1)=|integral part of (f(iâˆ’1)/Q(iâˆ’1)Ã—Q(iâˆ’1)|, V(i)=|integral part of (f(i)/Q(i)Ã—Q(i)|, and V(i+1)=|integral part of (f(i+1)/Q(i+1)Ã—Q(i+1)|.