2. Conference Papers
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Item Quality and complexity comparison of H.264 intra mode with JPEG2000 and JPEG(2004) Aravind, A.L.; Rao, B.P.; Kudva, S.S.; Babu, S.; Sumam, David S.; Rao, A.V.The recently proposed H.264 video coding standard offers significant coding gains over previously defined standards. An enhanced intra-frame prediction algorithm has been proposed in H.264 for efficient compression of I-frames. This paper investigates the scope of the intraframe coder of H.264 for image coding. We compare the quality of this coder and the complexity of its decoder with the commonly used image codecs (JPEG and JPEG2000). Our results demonstrate that H.264 has a strong potential as an alternative to JPEG and JPEG2000. �2004 IEEE.Item Performance analysis of compensation current extraction techniques for 3?, 3-wire shunt active power filter under unbalanced supply(2009) Gondat, J.M.; Anantha, Adithya, V.; Sumam, David S.Actve power filters are effective in mitgating line current harmonics and compensating for the reactive power in the line. Many papers comparing the performance of active power filter extraction algorithms are found in the literature, but there is explicit mention about the suitability of any particular extraction algorithm under all conditions. Hence this paper is an attempt to compare the performance of direct methods of compensating current extraction algorithms for three-phase active power filters under different conditions of mains supply using Matlab/Simulink�. Both transient and steady state conditions are considered. The compensating techniques under analysis are: synchronous detection method, sychronous reference frame method, id-iq method, instantaneous active reactive power theory (p-q theory) modied p-q theory, adaptive noise cancellation, notch filtering and Fourier based sinusoidal subtraction algorithms. Under balanced conditions all the compensatng techniques give proper result, but under balanced conditions only few of the compensating techniques work satisfactorily. In fact the equal resistance synchronous detection method and Fourier based sinusoidal subtraction algorithms perform better under extreme conditions. With proper implementation, sinusoidal subtraction algorithm performs better under both transient and steady state conditions. � 2009 IEEE.Item Improved algorithms for implementation of MPEG2 AAC decoder on FPGA(2005) Shenoy, R.R.; Naik, S.S.; Sumam, David S.This paper discusses methods to implement the IMDCT filter bank, Noiseless decoder, Inverse quantiser and Scale factor application modules of MPEG-2 Advanced Audio Coding decoder more efficiently when implemented on FPGAs. The efficiency of the algorithms has been validated through implementation on Xilinx Virtex II FPGAs.Item Implementation of JPEG2000 still image codec on blackfin (ADSP - BF535) processor(2004) Kiran, K.S.; Shivaprakash, H.; Subrahmanya, M.V.; Raj, S.; Sumam, David S.With increasing use of Multimedia in everyday life, there is a need not only for better image compression techniques which can be used in a wide range of applications but also for efficient implementation of these compression algorithms on power-efficient platforms. To cater to such needs several compression methodologies have been proposed and standardized. We have implemented, JPEG2000, an emerging standard for still image compression on the Analog Devices Blackfin Digital Signal Processor (DSP). Implementation of still-image compression on programmable DSPs offer several advantages like ease of changing the codec standard, improved value addition by customizing the codec to the target application, scalability in image sizes etc. This paper presents the implementation details of the JPEG2000 still image codec on ADSP-BF535 processor based Analog Devices EZ-kit Lite board, and the quality of the results obtained demonstrate the potential of the low-power Micro-Signal Architecture of Blackfin processor as a good choice for embedded multimedia applications.Item Implementation of JPEG2000 still image codec on blackfin (ADSP - BF535) processor(2004) Kiran, K.S.; Shivaprakash, H.; Subrahmanya, M.V.; Raj, S.; Sumam, David S.With increasing use of Multimedia in everyday life, there is a need not only for better image compression techniques which can be used in a wide range of applications but also for efficient implementation of these compression algorithms on power-efficient platforms. To cater to such needs several compression methodologies have been proposed and standardized. We have implemented, JPEG2000, an emerging standard for still image compression on the Analog Devices Blackfin Digital Signal Processor (DSP) Implementation of still-image compression on programmable DSPs offer several advantages like ease of changing the codec standard, improved value addition by customizing the codec to the target application, scalability in image sizes etc. This paper presents the implementation details of the JPEG2000 still image codec on ADSP-BF535 processor based Analog Devices EZ-kit Lite board, and the quality of the results obtained demonstrate the potential of the low-power Micro -Signal Architecture of Blackfin processor as a good choice for embedded multimedia applications.Item Comprehensive address generator for digital signal processing(2009) Kini, M.R.; Sumam, David S.Computational efficiency of Signal Processing Algorithm implemented in hardware depends on efficiency of datapath, memory speed, and generation of addresses for data access. In case of signal processing applications, pattern of data access is complex in comparison with other applications. If implemented in a general purpose processor, address generation for signal processing applications will require execution of a series of instructions and use of datapath elements like adders, shifters etc. In general, considerable processor resources and time are utilized. It is desirable to execute one loop of a kernel per clock. This demands generation of typically three addresses per clock: two addresses for data sample/coefficient and one for storage of processed data. A set of dedicated, efficient Address Generator Units (AGU) will definitely enhance the performance. This paper focuses on design and implementation of Address Generators for complex addressing modes required by Multimedia Signal Processing algorithms. Among other addressing modes, a novel algorithm is developed for accessing data in a Bit-Reversed order for Fast Fourier Transforms (FFT), and Zig-zag order for Discrete Cosine Transforms (DCT). When mapped to hardware, this scales linearly in gate complexity with increase in the size and uses less components. �2009 IEEE.Item Automatic speech recognition using audio visual cues(2004) Yashwanth, H.; Mahendrakar, H.; Sumam, David S.Automatic speech recognition (ASR) systems have been able to gain much popularity since many multimedia applications require robust speech recognition algorithms. The use of audio and visual information in the speaker-independent continuous speech recognition process makes the performance of the system better compared to the ones with only the audio information. There has been a marked increase in the recognition rates by the use of visual data to aid the audio data available. This is due to the fact that video information is less susceptible to ambient noise than audio information. In this paper a robust Audio-Video Speech Recognition (AVSR) system that allows us to incorporate the Coupled Hidden Markov Model (CHMM) model for fusion of audio and video modalities is presented. The application records the input data and recognizes the isolated words in the input file over a wide range of Signal to Noise Ratio (SNR.) The experimental results show a remarkable increase of about 10% in the recognition rate in the AVSR compared to the audio only ASR and 20% compared to the video only ASR for an SNR of 5dB. �2004 IEEE.Item Adaptive local cosine transform for seismic image compression(2006) Aparna, P.; Sumam, David S.A typical seismic analysis involves collection of data by an array of seismometers, transmission over a narrow-band channel, and storage of data for analysis. Transmission and archiving of large volumes of data involves great cost. Hence there is a need to devise suitable methods for compressing the seismic data without compromising on the quality of the reconstructed signal. This paper presents our work on the seismic data compression based on adaptive local cosine transform and its associated multi-resolution and best-basis methodology and compares the results with wavelet based implementation. � 2006 IEEE.Item A system level solution for power quality problems(2005) Padiyar, U.H.; Shetti, S.S.M.; Sumam, David S.The power quality deterioration is still an unsolved problem due to the increased power electronic load getting into the system. Every, consumer friendly equipment is power electronic controlled in one-way or other. The current drawn by all of these equipments are generally non-sinusoidal in nature, and are distorting the voltage wave as well. Many solutions proposed so far, though found useful in some cases have never become a system solution for the power quality deterioration problem. This paper proposes a unique innovative solution to these problems by a correction at the generation level by changing the shape of source wave keeping in view the nature of new loads. This paper presents PSPICE� simulated results to justify the need for source wave shape change, which will act as a system level solution to the limit peak currents drawn by the new generation power electronic loads. � 2006 IEEE.Item A system level solution to improve VRM efficiency(2009) Padiyar, U., H.; Sumam, David S.; Shetti, S.S.M.An investigation of the synchronous buck regulator working as a Voltage regulator module (VRM) for Processor power supply applications, under light load condition is presented. VRM, a very special case of power supply belongs to switched mode power supply family. Important design specifications include low output voltage with extremely small tolerance band, high load current of large slew rates, small foot print, low cost etc. Higher operating efficiencies are desired to enable extended battery mode operation in mobile platforms in addition to reducing heat dissipation. This paper identifies the source of energy inefficiency and suggests a variable frequency approach as a cost effective system level solution, to enhance the efficiency of the converter supplying widely varying load with special emphasis to light load operation.