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A synchronization marker was embedded into an HD image (1920 ¡¿ 1080) to evaluate its performance against cropping. The image of HD size was divided into 640 ¡¿ 256 regions, and 318 bits (39 ASCII characters) were embedded into each region. The embedded area was identified by detecting the marker position. This figure shows the extraction of watermark information from the marker embedded image. Figure(a) shows the original image (1920 ¡¿ 1080), figure(b) is the image divided into 640 ¡¿ 256 and embedded, figure(c) is 950 ¡¿ 512 by cropping, and (d) is the image obtained from the image in figure(c).
In figure(e), the embedded area was extracted from the position of the marker, and in figure(f), the watermark information was extracted, and the correct answer rate was 97.0%.
The detection of the marker position causes a detection error of several pixels, however, the Fourier transform is, resistant to synchronization fluctuations of several pixels, hence, the extraction error is low.
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IEEE/ICACT20220093 Slide.21
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