Watermark Placement in Watermarking of Time Varying Media Signals

a technology of time-varying media and watermarking, applied in the field of digital watermarking, can solve the problems of reducing detection performance, reducing visual quality, propagating temporally and spatially watermark errors, etc., and achieves the effects of preventing accumulation of visual distortion, reducing detection performance, and improving compression efficiency

Inactive Publication Date: 2010-12-23
DIGIMARC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This approach enhances watermark embedding and detection performance by minimizing bit-rate increase and preventing deconstructive interference, maintaining visual quality and detection strength even in bit-rate constrained applications.

Problems solved by technology

One challenge, however, is that some compression methods use a technique called “motion compensation” that may interfere with the watermark signal or create artifacts in the host signal in which the watermark is embedded.
Unless compensated properly, watermark error propagates both temporally and spatially as a result of motion compensation.
Propagation of watermark signal to the consecutive frames has two potential disadvantages: it degrades the visual quality, and may interfere (most probably deconstructive interference) with the consecutive watermark signals reducing detection performance.

Method used

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  • Watermark Placement in Watermarking of Time Varying Media Signals
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  • Watermark Placement in Watermarking of Time Varying Media Signals

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example implementation

[0026]We would like to determine a global spatial shift value that will coincide with the motion of the most number of blocks of the frame. The compressed domain implementation has a unique advantage at this point. Motion vectors for each block (macro-block) of the frame may be obtained by simply decoding the motion vector VLC's, without employing a costly motion estimation algorithm. Under this observation, pseudo-code of the method is given below. This method is also illustrated in FIG. 2:[0027]1. Decode motion VLC's to obtain motion vectors (MV.x and MV.y) for each block (step 200).[0028]2. Compute the 2-D histogram of motion vectors (step 202)[0029]a. For all blocks[0030]i. Hist[MV.x][MV.y]+=1;[0031]3. Find the maxima of the histogram, i.e. the bin with highest count.[0032]4. Define the coordinates of the maxima as the dominant motion (DMV.x, DMV.y) (204).[0033]5. Shift the watermark Wk+1 by DMV (206).[0034]a. Wk+1(x,y)=Wk+1(x+DMV.x, y+DMV.y)[0035]6. Execute the rest of the algo...

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Abstract

A method of placing a watermark in a video stream estimates motion between frames in the video stream, and computes a representative motion for a frame. Before embedding the watermark in that frame, the method spatially adjusts a digital watermark by the representative motion. This method is particularly suited for embedding a watermark in a video stream compressed using motion estimation. In this case, the method uses the motion vectors in the video stream to compute a dominant motion for a frame, and then shifts the watermark by this dominant motion before embedding it in the frame.

Description

RELATED APPLICATION DATA[0001]This application is a continuation of U.S. application Ser. No. 10 / 300,921, filed Nov. 19, 2002, which claims benefit of U.S. Provisional Application 60 / 404,038 filed Aug. 15, 2002, which is hereby incorporated by reference.TECHNICAL FIELD[0002]The invention relates to digital watermarking.BACKGROUND AND SUMMARY[0003]Digital watermarking is a process for modifying physical or electronic media to embed a hidden machine-readable code into the media. The media may be modified such that the embedded code is imperceptible or nearly imperceptible to the user, yet may be detected through an automated detection process. Most commonly, digital watermarking is applied to media signals such as images, audio signals, and video signals. However, it may also be applied to other types of media objects, including documents (e.g., through line, word or character shifting), software, multi-dimensional graphics models, and surface textures of objects.[0004]Digital waterma...

Claims

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Application Information

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Patent Type & AuthorityApplications(United States)
IPC IPC(8): G06K9/00G06T1/00H04L9/00H04N7/26H04N7/36H04N7/50
CPCG06T1/0085G06T2201/0053H04N19/537H04N19/61H04N19/467H04N19/51
InventorCELIK, MEHMET U.
OwnerDIGIMARC CORP