Strategic Young Researcher Overseas Visits Programfor Accelerating Brain Circulation 2011
“Development of Young Researchers
Based on International Joint Research
on Green Energy Systems”
Progress Report

1. Name: Kotaro Sonoda
2. Title: Assistant Professor

3. Host Institution: Adam Mickiewicz University (Poland)

4. Host Researcher: Professor Alexander Sek

5. Duration: 27- March -2012 – 27- March- 2013

6. Research Topic:
Applied diagnosis based on audible sound enrichment that realize
the measurement and control for high efficient energy systems
7. Overview of the Results of the Collaborative Research:
In recent years, a mechanism that controls the system intelligently by using
information of the various data shared on the system network has been practiced.
New power grid systems (smart grid), and electric vehicles are good
representatives of targeting of energy saving and high efficiency. At the sametime, we also need to consider the cooperation with equipment that is notconnected to the information network. In other words, it is required to have avariety of the means of conveying information of the equipment condition to thenetwork.

In this study, we aim to convey additional information to the receiver byembedding watermark into the sound wave that is emitted from the system. The
embedded information is extracted by decoding the received sound wave. Here,it is important to keep the sound wave robust against deterioration during its
propagation in air. Furthermore, it is preferable that the quality of the produced
watermarked sound is not significantly deteriorated from the original one.
Prof. Sek has studied the detection limits of human discrimination against
modulated sound. During my stay at AMU, I developed new digitalwatermarking method based on the sound modulation and carried out somelistening experiments with Professor Sek`s support and suggestions.
We proposed a new digital watermarking method that is embedded by requantizing the distribution of the time varying sound magnitudes in accordancewith watermark message bit. In this method, observing the time-varying
magnitudes of the several components on the short-term Fourier spectrum, therelation of selected four bins of the histogram on the magnitudes have beenchanged. Here, the targeted frequency components are not selected from anequally spaced  	  scale, rather they are selected from the scale of nERBs(Equivalent Rectangular Bandwidth). The nERBs are logarithmic scaleaccording to the frequency resolution of human hearing.

Figure 1: Proposed watermarking method
The robustness test against typical signal manipulations or attacks showedvery good performance of the proposed method. Subjective listening tests havealso been carried out to assess the quality of the watermarked signal, i.e.
audibility of distortions resulting from watermark. The results show that theproposed watermarking technique resists the MP3 compression attacks in thecase of embedding payload below 2 kHz. However, the proposed procedureperforms slightly poorer against the attacks of noise addition, band pass filteringand echo addition. Results of hearing tests showed that the proposed method
doesn’t produce audible deteriorations. Finally, multi-band embedding wasinvestigated. Results showed that the multi-band embedding can embed up to 20
bits without decrease in robustness against MP3.
For the future work, the countermeasure to increase robustness against noiseand echo addition, band pass filtering, pitch modification are strongly desired.

8. Deployment Plans for Future Collaborative Research:

We, Prof. Sek and I, have been researching the improvement of the above
proposed watermarking method, and plan to publish them.
A watermarking method for the musical signal has been proposed and tested
during my stat. As the next step, we will try to embed the watermark into thesound wave which is emitted from the mechanical systems.

9. List of Collaborative Research Progress:
Conference Presentation(s)● [1] Kotaro Sonoda ``Content based audio watermarking in DWT domain,'' Openseminar on Acoustics (OSA2012), 2012
● [2] Kotaro Sonoda, Alexander Sek, ``Digital watermarking method based on
STFT histogram,'' International Conference on 	  Intelligent Information Hiding
and Multimedia Signal Processing 	  (IIHMSP2013), 2013