Harumi Murata

Multichannel audio watermarking method by multiple embedding

The objective of this work is to increase the capacity of watermark information in the audio watermarking method based on amplitude modification. We increase the capacity of watermark information by embedding multiple watermarks in the different levels of audio data independently. Moreover, we aim to improve the sound quality by modifying the scaling curve of the conventional method.

An Audio Watermarking Method Using Tones of Diatonic Chord

For audio signals, the sound quality of the stego signal should not deteriorate as much as host signal. With current methods, high sound quality means that the difference between the host and stego signals is small. We proposed a method with which high sound quality means that the sound quality of the stego signal is maintained as music even if another sound, except for host signal, is perceived. Accordingly, we focused on the counterpoint of music theory. A watermark signal is added in consonance to the tones of the host signal based on counterpoint. For this study, we used a diatonic chord as consonance. We also used a sound with an instrumental timbre as the watermark signal. The sound quality of the stego signal does not produce an unpleasant feeling to the listener even if the watermark signal is perceived.

Multi-Layer Audio Watermarking Based on Amplitude Modification

In the conventional method proposed by W.N.Lie et al., it is difficult to satisfy both the capacity of watermark information and the robustness to MP3 compression. The objective of this work is to increase the capacity of watermark information in the audio watermarking based on low-frequency amplitude modification. We increase the capacity of watermark information by embedding multiple watermarks in individual layers. In the proposed method, it has plural data channels, so it is possible to embed watermark information by selecting the proper data channel according to the capacity of data or extraction accuracy.

An audio watermarking method using sampled sound for polyphonic music

The objective of this work is to devise a new way to embed a watermark into digital audio signal. In conventional methods, it is required that the watermark is embedded without noise perception. However, it is difficult to embed the watermark without noise perception. Hence, we propose an embedding method so as to permit a perception of an embedded watermark signal. For watermarked audio signal, high sound quality is needed even if noises are perceived. Therefore, we estimate notes into music data and decide their timbre by musical instrument identification. Furthermore, for improving the sound quality, we embed one bit of watermark into one tone using the corresponding sampled sound for each tone.

An audio watermarking method by using automatic music transcription information

The objective of this work is to embed watermark information into digital audio data as the deterioration of sound quality is not perceivable to human ears. Hence, we consider that watermark information is embedded in the consonance to melody line or bass line. Generally, unison, octave, perfect fifth and perfect fourth are called consonance and human ears can hardly feel annoyed for consonance. Hence, we focus on perfect fifth and perfect fourth in the consonance. For decision of embedding positions, we need to estimate tone pitches, and we use spectrogram analysis as a technique of automatic music transcription. We embed watermark information with perfect fifth or perfect fourth of consonance from the pitch which is estimated by spectrogram analysis, and we aim at good sound quality of watermarked audio signal without sense of discomfort. Therefore, we propose an audio watermarking method by using automatic music transcription information.

A watermarking method for audio signals played with single musical instrument based on music transcription information

The objective of this work is to embed watermark information into digital audio data as the deterioration of sound quality is not perceivable to human ears. And hence, we consider that watermark information is embedded in the consonance to melody line or bass line. Generally, unison, octave, perfect fifth and perfect fourth are called consonance and human ears can hardly feel annoyed for consonance. And hence, we focus on perfect fifth and perfect fourth in the consonance. For decision of embedding positions, we need to estimate tone pitches, and we use spectrogram analysis as a technique of automatic music transcription. We embed watermark information with perfect fifth or perfect fourth of consonance from the pitch which is estimated by spectrogram analysis, and we aim the sound quality of watermarked audio signal without sense of discomfort. And hence, we propose an audio watermarking method by using automatic music transcription information.

Improvement of scale factor for time‐domain audio watermarking based on low‐frequency amplitude modification.

The objective of this work is to improve the sound quality for the audio watermark method based on amplitude modification. We improve the sound quality by modifying the scaling curve smoothly. The audio watermarking method based on amplitude modification has been proposed by Lie as a prevention technique against copyright infringement. The watermark information is embedded into audio signals in the time domain. One‐bit watermark information is embedded by modifying the differences of average‐of‐absolute‐amplitude from three sections in a group of samples. At the section boundary points, the scaling factors are forced to 1.0 to ensure continuity. The factors are then progressively increased or decreased to the stable value near the center of section. However, when the adjacent sections were both increased or both decreased, signal discontinuities happen in this boundary point and cause the “click” sounds that are perceivable to human ears. In this paper, we aim to make the audio waveform continuous and smo...