Patent ID: 7646883
Filing Date: 2010-01-12
Classification: G06T

Abstract:
1. A digital watermark detection method comprising: extracting a specific frequency component signal from an input image signal; subjecting the input image signal to orthogonal transformation to generate a first transformed image signal; subjecting the specific frequency component signal to orthogonal transformation to generate a second transformed image signal; combining the first transformed image signal and the second transformed image signal to generate a combined image signal; subjecting the combined image signal to orthogonal transformation to generate a third transformed image signal; estimating watermark information embedded within the input image signal by searching for a peak appearing in the third transformed image signal; and subjecting a target signal to be compressed to amplitude compression based on a compression characteristic which varies according to at least one of an amplitude of the target signal and a frequency of the target signal to obtain a compression signal, the target signal being formed of at least one of the first transformed image signal, the second transformed image signal and the combined image signal.