17-09-2012, 03:07 PM
VOICE MORPHING
VOICE MORPHING.doc (Size: 38 KB / Downloads: 20)
ABSTRACT
This paper addresses the capability needed in telecommunication system to support mobile access to real-time sights and sounds of a complex environment defined as a virtual reality service (VRS) episode. The constant development of terminal and networking equipment are paving way for the provision of a VRS and the creation of VRS episodes. This paper describes a mobile VRS environment in general and the core architecture and describes the various entities employed to perform a VRS episode setup task. The proposed VRS architecture is in full harmony with the preceding generation of all-IP multimedia networks currently under study in the third generation partnership project
INTRODUCTION
Voice morphing is a technology developed at the Los Alamos National Laboratory in New Mexico, USA by George Papcun and publicly demonstrated in 1999. Voice morphing enables speech patterns to be cloned and an accurate copy of a person's voice be made which can then say anything the operator wishes it to say, appearing in the voice of someone else. Voice morphing has tremendous possibilities in military psychological warfare and subversion, particularly in conjunction with the use of recorded telephone conversations as evidence in courts of law. An agency can use voice morphing to provide a fake confession or incriminating evidence appearing to be spoken by a suspect which in reality is fake. Voice morphing is a powerful battlefield weapon which can be used to provide fake orders to the enemy's troops, appearing to come from their own commanders. In 1990, the US department of defence considered using voice morphing to produce a propaganda recording of Iraqi president Saddam Hussein, which could then be distributed throughout the Arab world and Iraq to discredit the Iraqi leader.
Definition
Voice morphing means the transition of one speech signal into another. Like image morphing, speech morphing aims to preserve the shared characteristics of the starting and final signals, while generating a smooth transition between them. Speech morphing is analogous to image morphing. In image morphing the in-between images all show one face smoothly changing its shape and texture until it turns into the target face. It is this feature that a speech morph should possess. One speech signal should smoothly change into another, keeping the shared characteristics of the starting and ending signals but smoothly changing the other properties.
INTROSPECTION OF THE MORPHING PROCESS
Speech morphing can be achieved by transforming the signal's representation from the acoustic waveform obtained by sampling of the analog signal, with which many people are familiar with, to another representation. To prepare the signal for the transformation, it is split into a number of 'frames' - sections of the waveform. The transformation is then applied to each frame of the signal. This provides another way of viewing the signal information. The new representation (said to be in the frequency domain) describes the average energy present at each frequency band. Further analysis enables two pieces of information to be obtained: pitch information and the overall envelope of the sound. A key element in the morphing is the manipulation of the pitch information. If two signals with different pitches were simply cross-faded it is highly likely that two separate sounds will be heard. This occurs because the signal will have two distinct pitches causing the auditory system to perceive two different objects. A successful morph must exhibit a smoothly changing pitch throughout.The pitch information of each sound is compared to provide the best match between the two signals' pitches. To do this match, the signals are stretched and compressed so that important sections of each signal match in time. The interpolation of the two sounds can then be performed which creates the intermediate sounds in the morph. The final stage is then to convert the frames back into a normal waveform.
VOICE MORPHING.doc (Size: 38 KB / Downloads: 20)
ABSTRACT
This paper addresses the capability needed in telecommunication system to support mobile access to real-time sights and sounds of a complex environment defined as a virtual reality service (VRS) episode. The constant development of terminal and networking equipment are paving way for the provision of a VRS and the creation of VRS episodes. This paper describes a mobile VRS environment in general and the core architecture and describes the various entities employed to perform a VRS episode setup task. The proposed VRS architecture is in full harmony with the preceding generation of all-IP multimedia networks currently under study in the third generation partnership project
INTRODUCTION
Voice morphing is a technology developed at the Los Alamos National Laboratory in New Mexico, USA by George Papcun and publicly demonstrated in 1999. Voice morphing enables speech patterns to be cloned and an accurate copy of a person's voice be made which can then say anything the operator wishes it to say, appearing in the voice of someone else. Voice morphing has tremendous possibilities in military psychological warfare and subversion, particularly in conjunction with the use of recorded telephone conversations as evidence in courts of law. An agency can use voice morphing to provide a fake confession or incriminating evidence appearing to be spoken by a suspect which in reality is fake. Voice morphing is a powerful battlefield weapon which can be used to provide fake orders to the enemy's troops, appearing to come from their own commanders. In 1990, the US department of defence considered using voice morphing to produce a propaganda recording of Iraqi president Saddam Hussein, which could then be distributed throughout the Arab world and Iraq to discredit the Iraqi leader.
Definition
Voice morphing means the transition of one speech signal into another. Like image morphing, speech morphing aims to preserve the shared characteristics of the starting and final signals, while generating a smooth transition between them. Speech morphing is analogous to image morphing. In image morphing the in-between images all show one face smoothly changing its shape and texture until it turns into the target face. It is this feature that a speech morph should possess. One speech signal should smoothly change into another, keeping the shared characteristics of the starting and ending signals but smoothly changing the other properties.
INTROSPECTION OF THE MORPHING PROCESS
Speech morphing can be achieved by transforming the signal's representation from the acoustic waveform obtained by sampling of the analog signal, with which many people are familiar with, to another representation. To prepare the signal for the transformation, it is split into a number of 'frames' - sections of the waveform. The transformation is then applied to each frame of the signal. This provides another way of viewing the signal information. The new representation (said to be in the frequency domain) describes the average energy present at each frequency band. Further analysis enables two pieces of information to be obtained: pitch information and the overall envelope of the sound. A key element in the morphing is the manipulation of the pitch information. If two signals with different pitches were simply cross-faded it is highly likely that two separate sounds will be heard. This occurs because the signal will have two distinct pitches causing the auditory system to perceive two different objects. A successful morph must exhibit a smoothly changing pitch throughout.The pitch information of each sound is compared to provide the best match between the two signals' pitches. To do this match, the signals are stretched and compressed so that important sections of each signal match in time. The interpolation of the two sounds can then be performed which creates the intermediate sounds in the morph. The final stage is then to convert the frames back into a normal waveform.