Independent thesis Advanced level (degree of Master (Two Years))Student thesisAlternative title
Futuristisk Teleconfernecing (Swedish)
Majorly the intension behind the engineering besides expecting cool and futuristic is to get appropriate eye contact and emotions back into the teleconferencing domain that two dimensional setups simply cannot provide. Under this system, the distant participant can make clear visual communication with particular people in her or his own frame of perspective. Teleconferencing is a communication technology that allows users at two or more different localizations to interact by making a face-to-face assembling environment. TC systems carry both audio, video and data streams throughout the session it has been gaining popularity in all government sectors. From the most recent demonstration of such a fantast manner of teleconferencing from university of southern California, “Attaining visual communication in a One-to-Many 3D Video Teleconferencing System”, receive a 3D teleconferencing developing a 3D teleconferencing is not only concerning the video but also experiencing a 3D audio by users. A 3D audio system can be described as a reliable audio captured by positioning of speakers. In this thesis we effort to develop a 3D audio system where two microphones and two speakers are used. This structure designed based on the behavior of the human ear while capturing sounds. I studied different usable methods for such structure and then I designed a new system which will be robust and friendly user. The idea of this new system from the scientist Zuccarelli’s theory(1983) which he said that human ear not only capture the sounds it emits sounds as well, and he designed holophonic for the recording sounds from human ear in scientific manner but he did not reveal. I took the concept from him then I captured all the positions of sounds in spherical form. I found that the sound is coming from which direction depending on the pattern of the sound signal; to capture the sounds and to find the directions I used interference and diffraction of the head. An ideal microphone arrangement therefore should be able to guide maximum directivity towards speech no matter which direction it initiates. Directional microphone technology has been used in hearing instruments since the late 1960s, and has been shown to effectively improve speech understanding in background noise. In a futurist implementation of directional microphones system can be interested for industrial and medical applications as well.
In this thesis I have taken the reference of 3D video teleconference by Southern California to design 3D audio teleconference. For teleconference only video is not clear, both 3D audio and video give very good communication, expressions, emotions virtually like the remote people are residing just beside us. I have implemented one structure using two microphones and two speakers, I have implemented this structure in real time using Matlab and done experiments practically. I fixed two directional microphones at distance of 17 cm apart. With one speaker I sent signal at a frequency of 2.5 KHz and the positions are varies in spherical form and observed all positions frequency spectrums and signal patterns by using phase delays. Then I have taken two speakers one is just nearer to the microphone to capture the sound coming from microphone that is fixed at 1.25 KHZ. The other speaker is at 2.5 KHz and varies in spherical form, observed all the positions magnitudes, spectrums and patterns. Instead of placing one microphone just nearer to the microphone I just kept one obstacle between microphone and speaker with fixed frequency and the other speaker is again varies spherically and observed all the positions spectrums and patterns. This is called head diffraction. Finally I found all the variations in all directions in signal strength, pattern and in spectrums. I got very great differences in two positions in front and back. I implemented 3d space for Audio Teleconference. From the above results I have concluded as follows. Here I have compared my results before interference and after interference. Before interference I have used one speaker (2.5 KHz) and two microphones and tested signal level in front and back positions. The signal strength in the front position is stronger than the than the back position. In this stage I could not achieve same signal strengths in front and back positions. To achieve this I have chosen interference with two speakers .One speaker is placed at a fixed position near to the microphones with constant emitting frequency (1.25 KHz) and other speaker is moving in all directions. In this method again I compared my signal in front and back positions. Here the signal strength is almost same in both positions. Finally I have tried to implement same method with head diffraction. In this method again the signal strength is fluctuated in front and back positions. Finally the implemented method is best method for audio teleconferencing room. Using this method we can communicate from any direction of the teleconference room. No need to sit exactly nearer to the microphone. The audio signal strength is almost similar from all the directions of the teleconference room. If there are any obstacles in the teleconference room this method will not be successful.
Place, publisher, year, edition, pages
2012. , 34 p.
Audio Signal processing, Microphones, Interference, Diffraction, Human hearing Mechanism
Telecommunications Computer Science Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:bth-4323Local ID: oai:bth.se:arkivexBCD602DB9E0B6B78C1257C89002F4531OAI: oai:DiVA.org:bth-4323DiVA: diva2:831656