CREATION AND REGENERATION OF ELECTRONIC WATERMARK IMAGE WITH TWO WATERMARK INFORMATION IMAGES EMBEDDED THEREIN

摘要

PROBLEM TO BE SOLVED: To provide a method capable of embedding two watermark information images in the entire original image and individually regenerating two pieces of watermark information.SOLUTION: (A) Random sequence having values which consist of +1 and -1 is multiplied to a watermark information image 1 and a watermark information image 2. (B) Fourier transformation is performed to a product obtained by the multiplication to obtain a real part and an imaginary part of a Fourier transformation coefficient. (C) The real part of the Fourier transformation coefficient and the imaginary part of the Fourier transformation coefficient are added, and a hologram image 1 is obtained from the sum. (D) An appropriate positive micro constant is multiplied to the hologram image 1, its product is added to an original image 1 being a foundation, and the sum is an electronic watermark image. When regenerating the image, the original image 1 is subtracted from the electronic watermark image, and its difference is a hologram image 2. (E) Fourier inverse transformation is performed to the hologram image 2 to acquire a Fourier inverse transformation coefficient. (F) The watermark information image 1 is obtained from an absolute value of the real part of the Fourier inverse transformation coefficient. (G) The watermark information image 2 is obtained from an absolute value of the imaginary part of the Fourier inverse transformation coefficient.