Engineering Commons^™

Noise Reduction With Microphone Arrays For Speaker Identification, Zachary Gideon Cohen

Master's Theses

The presence of acoustic noise in audio recordings is an ongoing issue that plagues many applications. This ambient background noise is difficult to reduce due to its unpredictable nature. Many single channel noise reduction techniques exist but are limited in that they may distort the desired speech signal due to overlapping spectral content of the speech and noise. It is therefore of interest to investigate the use of multichannel noise reduction algorithms to further attenuate noise while attempting to preserve the speech signal of interest.

Specifically, this thesis looks to investigate the use of microphone arrays in conjunction with multichannel …

Early Forest Fire Detection Using Texture, Blob Threshold, And Motion Analysis Of Principal Components, Georges Fouad Moussa

Master's Theses

Forest fires constantly threaten ecological systems, infrastructure and human lives. The purpose behind this study is minimizing the devastating damage caused by forest fires. Since it is impossible to completely avoid their occurrences, it is essential to accomplish a fast and appropriate intervention to minimize their destructive consequences. The most traditional method for detecting forest fires is human based surveillance through lookout towers. However, this study presents a more modern technique. It utilizes land-based real-time multispectral video processing to identify and determine the possibility of fire occurring within the camera’s field of view. The temporal, spectral, and spatial signatures of …

An Overview Of Binary Arithmetic Architectures & Their Implementation In Dsp Systems, Joseph Waddell

Electrical Engineering

This project gives looks at different binary adder and multiplier architectures and how they are implemented in a DSP system as a digital filter. Testing is performed in the Digilent Nexys2 FPA board and filters are implemented using various realizations including normal direct form I and cascade direct forms I and II. Signal filtering is performed in real time at various frequencies and results are provided on an oscilloscope and with a stereo speaker.

802.15.4 Low Intermediate Frequency Radio Receiver, Sanjay Avasarala

Electrical Engineering

This project involves the design, building, and testing of a low intermediate frequency 802.15.4 receiver that uses an FPGA to perform final demodulation to baseband.

"Auto-Tuned" Stereo, Daniel Montes

Electrical Engineering

The purpose of this project is to determine the capability of introducing delay and gain to audio signals to synthesize a “tuned” experience. The project uses audio operational amplifiers, field effect transistors, a class D amplifier, microphones, speakers, a 32-bit microcontroller for design and testing. When implementing the MOSFET into the all pass filter, the phase delay occurs by varying the transistor resulted in minimal change in phase. MOSFETs are used as variable resistors to vary the phase change and gain. By modifying the gain the synthesized distance from each speaker can be adjusted. Varying the phase change provides the …

Digital Graphic Equalizer Implemented Using An Fpga, Anthony Giardina

Electrical Engineering

A graphic equalizer is a device that adjusts the tonal quality of an audio signal. When sound is converted from a digital format to analog sound waves, there are amplification and transducing steps in-between the two formats. Common devices to perform these tasks are speakers, amplifiers, DACs, etc. Many of these devices exhibit a non-uniform frequency response over the range of human hearing. Thus, it is possible that certain frequency ranges of the audio signal will be amplified and others will be attenuated. To counteract this, an audio equalizer can be used to boost and attenuate certain frequency ranges within …

Hardware And Software Study Of Active Noise Cancellation, Riggi Aquino, Jacob Lincoln

Electrical Engineering

Noise cancellation involves removing an unwanted noise while keeping the source sound. The source sound may consist of speech, music played from a device such as an iPod or a computer, or no sound at all. The objective of this project is to study the process of noise cancellation both as hardware and as software. The hardware will consist of building a noise cancelling circuit that uses headphones as an output, a microphone to pick up the noise to be cancelled and, if desired, a source sound. The software portion of the experiment will use MATLAB to simulate the hardware …

Spectral Shape Division Multiplexing (Ssdm): Apparatus, Transmitter, Receiver And Detection, Fausto Daniel Holguín-Sánchez

Master's Theses

Wireless communication companies require to use the frequency spectrum to operate. Both frequency licenses and infrastructure to reuse frequencies are costly resources subject to increasing demand. This work introduces a novel multiplexing method that saves spectrum called Spectral Shape Division Multiplexing (SSDM). Under certain configurations, SSDM displays higher flexibility and throughput than other spectrally efficient methods.

SSDM defines the structure of a wireless multi-carrier by software. It is similar to Orthogonal Frequency Division Multiplexing (OFDM) in that both use overlapped sub-carriers to make efficient use of allocated spectrum. However, SSDM has several advantages. Where OFDM organizes sub-carriers orthogonally, SSDM allows …

Study Of Statistical And Computational Intelligence Methods Of Detecting Temporal Signature Of Forest Fire Heat Plume From Single-Band Ground-Based Infrared Video, Daniel G. Kohler

Master's Theses

This thesis will analyze video from land-based, cooled mid-wave infrared cameras to identify temporal features indicative of a heat plume from a forest fire. Desirable features and methods will show an ability to distinguish between heat plume movement and other movements, such as foliage, vehicles, humans, and birds in flight. Features will be constructed primarily using combinations of statistics and principal component analysis (PCA) with intent to detect key characteristics of fire and heat plume: persistence and growth. Several classification systems will combine and filter the features in an attempt to classify pixels as either heat or non-heat. The classification …

Digital Guitar Effects Unit And Amplifier, Kevin Salvador

Electrical Engineering

This report outlines the design and implementation of a digital guitar effects unit and amplifier. The main portion of this project consisted of the digital equalizer and effects. Several commercial equalizers were researched in order to decide the typical frequency bands and average amount of bands total. Eventually 8 bands were selected. A range of approximately 20Hz-3kHz was chosen based on test data of guitar signals. Popular effects that were incorporated in this project include Distortion, Echo, Reverb, Chorus and Flanger. The digital processor chosen was a Texas Instruments c6713 floating point processor. Designs for the various filters were done …

Real-Time Musical Analysis Of Polyphonic Guitar Audio, John E. Hartquist

Master's Theses

In this thesis, we analyze the audio signal of a guitar to extract musical data in real-time. Specifically, the pitch and octave of notes and chords are displayed over time. Previous work has shown that non-negative matrix factorization is an effective method for classifying the pitches of simultaneous notes. We explore the effect of window size, hop length, and other parameters to maximize the resolution and accuracy of the output.

Other groups have required prerecorded note samples to build a library of note templates to search for. We automate this step and compute the library at run-time, tuning it specifically …

Multi-Circle Detections For An Automatic Medical Diagnosis System, Dingran Lu

Master's Theses

Real-time multi-circle detection has been a challenging problem in the field of biomedical image processing, due to the variable sizes and non-ideal shapes of cells in microscopic images. In this study, two new multi-circle detection algorithms are developed to facilitate an automatic bladder cancer diagnosis system: one is a modified circular Hough Transform algorithm integrated with edge gradient information; and the other one is a stochastic search approach based on real valued artificial immune systems. Computer simulation results show both algorithms outperform traditional methods such as the Hough Transform and the geometric feature based method, in terms of both precision …

Robot X, Alan Truong, Alex Haag

Computer Engineering

The following report outlines the design decisions behind Robot X for the 2012 Cal Poly Roborodentia competition held annually during Open House. This investigation includes detailed overview of Robot X's sensory system, driving system, conveyor belt system, and can compartment system. In addition, basic hardware and software design are explored.