Resume

• Statistical machine learning.
• Image processing and analysis / Computer vision.
• Signal processing.

Microarray data analysis

Microarrays enable simultaneous monitoring of thousands of genes in a tissue. Methods for analyzing such data including normalization, gene selection and phenotypic state prediction have to account for both technical and biological noise in the data. I am working on evaluating the effectiveness of existing methods and developing novel methods to address these issues. New methods to incorporate Gene Ontology (GO) tags for state prediction are being explored with the help of probabilistic generative models for multimodal data. Phenotypic state prediction performance is being used to evaluate these methods.

Competitive Expectation Maximization

Expectation Maximization is a commonly used machine learning tool in missing data problems with an application in probabilistic mixture modeling. However, it is inherently a local maximum likelihood algorithm and sensitive to initialization. Also in probabilistic mixture modeling, an important research problem is the automatic determination of the number of clusters. Addressing these issues, I have worked on implementing a variant of Competitive Expectation Maximization (CEM) algorithm. While determining the number of mixture components automatically, CEM is known to achieve global maximum likelihood with a high probability. Implementation was done in C.

Semantic evaluation of features using word prediction performance

Large databases of digital images that come with words associated with the images help to learn relationships among visual features of image regions and words. This can be used to predict words for new images automatically (auto-annotation). It has applications in content-based image indexing and retrieval and also generic object recognition. I am working on identifying and evaluating visual features and segmentation algorithms using word prediction performance index. In addition, this work involves programming in C and C++ and also writing shell scripts to set up and manage experiments on large databases.

Modifications to Normalized Cuts segmentation algorithm

As part of my Masters thesis, I worked on modifying the Normalized Cuts segmentation algorithm to improve its grouping performance on natural images. Further, comparison of the original and modified versions of Normalized Cuts algorithm was done using word prediction tool.

Human face detection and tracking in color image sequences

Human Face Recognition technology requires isolation of face(s) of individuals from an image sequence/video. As part of my undergraduate thesis, I worked in a group of two to develop an algorithm to detect/track and segment human face(s) from color images/video. This was performed using statistical skin color modeling and connected component operators. This module provided necessary input to a surveillance system employing face recognition technology. The algorithm was implemented in MATLAB.

• "A fast connected components labeling algorithm for real-time pupil detection," Prasad Gabbur, Hong Hua, and Kobus Barnard, accepted for publication, Machine Vision and Applications, 2009.
• "Preserving the aesthetics during non-fixed aspect ratio scaling of the digital border," Hui Chao, Prasad Gabbur, and Anthony Wiley, ACM Symposium on Document Engineering, pp. 144-146, 2007.
• "Cross modal disambiguation," Kobus Barnard, Keiji Yanai, Matthew Johnson, and Prasad Gabbur, in Toward Category-Level Object Recognition, Jean Ponce, Martial Hebert, Cordelia Schmidt, eds., Springer-Verlag LNCS Vol. 4170, 2006.
• "Evaluation Strategies for Image Understanding and Retrieval," Keiji Yanai, Nikhil V. Shirahatti, Prasad Gabbur and Kobus Barnard, Proc. of ACM Multimedia Workshop on Multimedia Information Retrieval (MIR), Singapore, November, 2005 (Invited paper).
• "Color and Color Constancy in a Translation Model for Object Recognition," Kobus Barnard, Prasad Gabbur, IS&T/SID 11th Color Imaging Conference, pp. 364-369, 2003.
• "The effects of segmentation and feature choice in a translation model of object recognition," Kobus Barnard, Pinar Duygulu, Raghavendra Guru, Prasad Gabbur, David Forsyth, IEEE Conf. on Computer Vision and Pattern Recognition (CVPR), Vol. 2, pp. 675-682, 2003.
• "Development of an Autonomous Aerial Reconnaissance System," Jessica Dooley, Ekaterina Taralova, Prasad Gabbur, Timothy Spriggs, International Aerial Robotics Competition, Fort Benning, GA, 2003 (Competition best paper).
• "Human Face Detection and Tracking using Skin Color Modeling and Connected Component Operators," Prem Kuchi, Prasad Gabbur, P. Subbanna Bhat, Sumam David S., IETE Jl. of Research, Vol. 38, No. 3&4, pp. 289-293, May-Aug 2002.

• Automatic Image Rescaling Preserving Design Intention, Imaging Systems Lab, Hewlett Packard Laboratories, Summer 2006, Palo Alto, CA.
• Word-Prediction as a Tool to Evaluate Low-Level Vision Processes, IBM Research Human Computer Interaction Seminars, IBM Almaden Research Center, Spring 2004, San Jose, CA.
• Color and Color Constancy in a Translation Model for Object Recognition, IS&T/SID 11th Color Imaging Conference, Summer 2003, Scottsdale, AZ.
  
  Some talks given on campus:
  
  
• A gentle introduction to Gaussian distribution, Computer Vision Undergraduate Seminar, Computer Vision Lab, Spring 2009, Tucson, AZ.
• Particle Filters (Part 1), Computer Vision Lab, Fall 2007, Tucson, AZ.
• Particle Filters (Part 2), Computer Vision Lab, Fall 2007, Tucson, AZ.
• Analyzing error of fit functions for ellipses, 3D Visualization and Imaging Systems Lab, Spring 2007, Tucson, AZ.
• Parametric Inference, Statistics Seminar, Computer Vision Lab, Fall 2006, Tucson, AZ.

Research Associate, with Kobus Barnard, Computer Science Dept., University of Arizona, Spring, Summer & Fall 2003, Spring 2005, Spring, Summer & Fall 2007, Spring, Summer & Fall 2008, Spring 2009

• Working on microarray data analysis.
• Worked on Competitive Expectation Maximization.
• Worked on image segmentation and visual features for auto-annotation using joint image-word modeling.

Research Assistant, with Hong Hua, Optical Sciences Center, University of Arizona, Fall 2005, Spring & Fall 2006

Working on vision-based eye-gaze tracking for fovea contingent displays.

Research Associate Intern, Hewlett Packard Labs, Palo Alto, CA., Summer 2006

Worked with Hui Chao on automatic content extraction and layout change in multilayer PSD images. Developed a real-time algorithm to do connected component labeling to aid in the process of automatic content extraction.

Software Engineer, IntelliVision Corporation, San Jose, CA., Summer & Fall 2004

• Worked on a motion detection algorithm in video for surveillance and security applications. Evaluated performances of different color spaces (RGB, HSL, CIE L*a*b* and YCbCr) in suppressing the effects of small illumination changes and weak shadows on motion detection.
  
• Developed DSP algorithms for a people counting system based on a planar scan infra-red sensor. This system has been successfully installed to continuously monitor a secure area in one of the airports in the US.

Intern, Eyematic Interfaces Inc., Los Angeles, CA., Summer 2002

Worked on using synthetic images for face representations under varying illumination conditions. Rendered a database of synthetic face images under different illuminations using 3D Studio Max software. These images were used in training their face finder neural network to improve its performance when operating under poor lighting conditions. Also developed quantitative measures to compare performances of face detection systems and used these measures to show an improvement in performance of the above system.

Teaching Assistant, University of Arizona, Spring & Fall 2002

Course - C Programming for Engineering Applications (ECE275). Supervised programming labs, conducted lectures and maintained class website.

Grader, University of Arizona, Fall 2001

Course - Digital Signal Processing (ECE 429/529). Graded assignments and tracked student grades.

Young Engineering Research Fellow, Indian Institute of Science, Bangalore, India, Fall 2000

Research with Prof. K. R. Ramakrishnan on developing a computational method for human face detection and tracking in color image sequences.

Intern, Centre for Development of Telematics (C-Dot), India, Spring 2000

Implemented a database project, in C++, on automating a mobile service billing system. Designed an object-oriented model for maintaining their subscriber database and used it in automating the billing process. Worked in a team of 3 to accomplish the goals of the project.

Error control coding

Compared performances of uncoded and convolutionally coded communication systems using QPSK modulation over Additive White Gaussian Noise (AWGN) channels. The decoding scheme was implemented using Viterbi algorithm.

Modeling of speech signals

• Performed speech signal analysis/synthesis using Linear Predictive Coding (LPC).
• Determined AR-coefficients of a speech process using Yule-Walker equations.
• Modeled a deterministic signal as the impulse response of an all-pole filter using Prony's method.

Adaptive filter design

Performed noise cancellation in speech signals using RLS adaptive filter and Wiener filter.

Computer graphics

• Implemented line and polygon drawing algorithms.
• Implemented 3D viewing pipeline.
• Implemented recursive ray-tracing.

Image analysis/Computer vision algorithms

• Implemented image morphology algorithms for dilation, erosion, opening, closing and connected component labeling.
• Implemented edge detection algorithms using Robert, Sobel, Prewitt, Frie-Chen and LOG operators with hysteresis thresholding and non-maximum suppression.
• Implemented Hough transform for straight-line detection.
• Performed image segmentation using Kittler'’s algorithm.

4-bit Microprocessor Design

Worked in a team of three to design a 4-bit microprocessor with an associated instruction set. The design used an efficient microprogramming architecture. Basic gate-level implementation and simulation was done in VHDL.

Offline signature verification system

Authentication/verification of hand-written signatures can be automated using digital signal processing algorithms on scanned images of signatures. As an attempt towards this, I developed software in MATLAB for automatic verification of hand-written signatures using simple geometric features.

• Random Processes for Engineering Applications.
• Stochastic Processes.
• Linear Algebra.
• Numerical Analysis.
• Computer Vision.
• Computer Graphics.
• Regression and Multivariate Analysis.
• Digital Image Processing.
• Digital Communication Systems.
• Information Theory.
• Algebraic Coding Theory.
• Linear Systems Theory.
• Computer Aided Logic Design.
• Advanced Digital Signal Processing.
• Advanced Concepts in Software Systems - Multimedia Data Mining and Retrieval.
• Fundamentals of Statistical Machine Learning.

• Graduate College Fellowship, University of Arizona, Fall 2001.
• Young Engineering Research Fellow of the Indian Institute of Science, Bangalore, India.
• 3rd rank to the University in my undergraduate degree (2nd in a class of 75).

• Languages: C, C++, HTML, Perl.
• Packages: MATLAB, PSPICE, Code Composer Studio (TI), 3D Studio Max (discreet).
• Hardware Description Language: VHDL.
• Assembly level programming: INTEL 8085, 8086, MC68000, TI TMS320C54x.
• Word Processing: LaTeX, MS Office.
• Operating Systems: GNU/LINUX, MS Windows.