CEC343 Ocean Acoustics Syllabus:
CEC343 Ocean Acoustics Syllabus – Anna University Regulation 2021
COURSE OBJECTIVES:
● To enable the student to understand the importance of ocean acoustics for marine applications.
● To understand the physics of sound propagation and the factors affecting sound signal in the ocean
● To study the types and characteristics of acoustic transducers and arrays
● To understand the sources of ambient noise present in the sea and impacts of sound on marine diversity
● To expose the student in the basics of underwater acoustic signal processing and image processing
UNIT I FUNDAMENTALS OF UNDERWATER ACOUSTICS
Ocean Acoustic environment; Measuring sound levels and relevant units; Sound propagation in the ocean – sound velocity profiles in the deep water and shallow water; Sound attenuation in the sea – absorption, scattering, transmission loss, reverberation, Snell’s law, target strength; SONAR systems- active, passive SONAR equations and system parameters.
UNIT II UNDERWATER ACOUSTIC TRANSDUCERS AND DEVICES
Principles of transduction and SONAR transducer design; Electromechanical Analog circuits, coupling coefficient, efficiency, Directivity characteristics of receivers, frequency response characteristics of transducers, Transducer measurement techniques; Physical geometry of arrays – linear, planar, cylindrical, spherical, beam patterns, array gain.
UNIT III AMBIENT NOISE IN THE OCEAN
Sources of noise, Natural and Physical sounds – Seismic, Wind, Wave, Rain and Turbulence; Biological sounds – Dolphin, Whales, Fishes; Man made Noises- Shipping Machinery noises, Pile driving, Wind Mlls; Variability of Ambient noises; Frequency Bands, Noise levels of all above; Impacts of Sound on Marine Animals.
UNIT IV PROCESSING OF UNDERWATER ACOUSTIC SIGNALS AND IMAGES
Representations of the signals – Fourier representations, Spatial filtering; Matched filters and Autocorrelations, Temporal resolution; Signal to Noise Ratio, Estimation of Auto Covariance, Cross Covariance; Power spectra of different Underwater Signals, Classification of signals; Concept and Types of beamforming techniques; Image segmentation, Filtering, Equalization and Restoration
UNIT V UNDERWATER ACOUSTIC INSTRUMENTS AND ITS APPLICATION
Principles of Sonar systems, Echosounder – single beam, multi beam; Side scan sonars – Imaging, Underwater acoustic camera; Sub bottom profilers –Sediment classification; Acoustic modem – Tsunami systems; Acoustic Positioning system- Transponders, USBL, SSBL systems, HiPAP; Underwater telephone; Underwater noise recorders; Underwater Beacons.
30 PERIODS
PRACTICAL EXERCISES: 30 PERIODS
1. Applying sonar equations in the design of ocean instruments
2. Auto correlation and Cross Correlation of underwater signals
3. Simulation of transmission loss in the ocean
4. Frequency Analysis of underwater ambient noise data
5. Comparison of sound velocity gradients for different ocean depths
6. Applying digital filters to underwater signal
7. Beamforming of vertical linear array data
8. Characterization of hydrophones for receiving and transmitting responses
9. Acoustic characterization of ship machinery noises
10. Acoustic characterization of whale / any marine animal sound
11. Underwater image enhancement – filtering
12. Underwater image enhancement – color enhancement
COURSE OUTCOMES:
On successful completion of this course, the student will be able to
CO1: Understand the basics of underwater sound and its propagation in ocean
CO2: To simulate / design any underwater SONAR systems for ocean application
CO3: To identify different kinds of noises present in the ocean and its impacts on the marine biodiversity
CO4: Ability to get exposure in analyzing and applying suitable techniques for underwater acoustic signals and images
CO5: To recognize different types of SONAR systems used practically
TOTAL:60 PERIODS
TEXTBOOKS
1. Robert J Urick,―Principles of underwater sound, Third Edition, Peninsula Publishing,2013
2. Herman Medwin and Clarence S. Clay, ―Fundamental of acoustical oceanography, First Edition, Academic Press,1998.
REFERENCES
1. L.M. Brekhovskikh and Yu. P. Lysanov,―Fundamentals of ocean acoustics, Third Edition, Springer,2003
2. John G Proakis and Manolakis, ―Digital Signal Processing Principles Algorithms and Applications, Fourth Edition, Pearson, 2006.
3. Rafael C. Gonzalez, Richard E. Woods, Steven Eddins, ―Digital Image Processing using MATLAB, Third Edition, Gatesmark Publishing,2020.