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Watermark method and watermark device based on host digital hologram

A digital hologram and watermarking technology, applied in image data processing, image data processing, instruments, etc., can solve problems such as no related solutions, and achieve the effect of improving security, good transparency, and good robustness

Inactive Publication Date: 2015-07-22
FUJIAN NORMAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, when the hologram is the host file, compared with the general digital image, the hologram is an interference pattern that records all the information of the original light wave and is modulated by the reference light wave. From the perspective of the spatial frequency domain, the general digital hologram includes the diffracted light spectrum information of the zero-order image, the original image and the conjugate image. The impact of the hologram itself should also take into account the impact of the watermark signal on the host hologram during optical or digital reproduction. There is currently no relevant solution for embedding a three-dimensional object watermark based on a digital hologram.

Method used

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  • Watermark method and watermark device based on host digital hologram
  • Watermark method and watermark device based on host digital hologram
  • Watermark method and watermark device based on host digital hologram

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Embodiment 1

[0094] The off-axis digital hologram is the most commonly used holographic recording method when the angle between the object light and the reference light meets certain conditions, and there is no mutual interference in the diffracted light. The light intensity of the hologram surface is the result of the interference between the object light U(x,y) and the reference light R(x,y), which can be expressed as:

[0095] h c (x,y)=[U(x,y)+R(x,y)]·[U(x,y)+R(x,y)] *

[0096] Let the plane reference light wave R(x,y)=A r exp[j2π(αx+βy)], for h c (x, y) is used for Fourier transform, and F{} is used to represent the Fourier transform symbol. The frequency spectrum of the off-axis digital hologram can be expressed as:

[0097] F{h c (x,y)}=G 0 (f x , f y )+G + (f x , f y )+G - (f x , f y )

[0098] in G + (f x , f y )=F{R(x,y)U * (x,y)},G - (f x , f y )=F{R * (x,y)U(x,y)};

[0099] where G 0 (f x , f y ), G + (f x , f y ), G - (f x , f y ) represent t...

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Abstract

The invention relates to the field of multimedia digital signal processing, in particular to a watermark method and a watermark device based on a host digital hologram. By the watermark method, virtual three-dimensional object Fresnel holographic watermark signals which are encrypted via random phases are preprocessed and then are subjected to carrier modulation and interference coding on the basis of spectral characteristic analysis of the host digital hologram, the watermark signals do not pass through frequency spectrum center positions of zero-order images, original images and conjugate images of the digital hologram in a spatial frequency domain, and the watermark signals can be embedded in the original host digital hologram by a spatial domain superposing method. Because the watermark signals are encrypted by the random phases, the safety of the host digital hologram is improved. The hologram at a watermark embedding position is directly cut out through the spatial domain so as to recover the watermark signals, information of the original host hologram is not required, and blind extraction is implemented.

Description

technical field [0001] The invention relates to the field of multimedia digital signal processing, in particular to a watermarking method and device based on a host digital hologram. Background technique [0002] Digital watermarking is a digital media copyright protection technology that has appeared in recent years. The so-called digital watermarking technology is to embed some iconic information into multimedia content through a certain algorithm, but it will not affect the value and use of the original content and will not be perceived or noticed by people. Watermark information can be the author's serial number, company logo and text with special meaning, etc. It can identify the author, owner, publisher and user, and carry copyright protection information and certification information, the purpose is to identify illegally copied and stolen digital products, and protect the legal copying and dissemination of digital products. [0003] Digital holography uses photodete...

Claims

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Application Information

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IPC IPC(8): G06T1/00
Inventor 陈家祯郑子华叶锋连桂仁许力
Owner FUJIAN NORMAL UNIV
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