With the several developments in visualization, sensing, perception innovation, and transmission ... more With the several developments in visualization, sensing, perception innovation, and transmission systems, 3D information has considered as main part of real-world applications such as multimedia, medical, architecture, manufacturing, computer vision, security, and more. Acquiring the scene depth information is one of the fundamental demands for some of these applications. Although the extracting of 3D information has been studied for more than three decades in different fields including robotics, computer graphics, and computer vision, it remains a challenge and fundamental issue. Systems with high accuracy, more quality of information and high frame rate of data processing have been a unique research opportunity for numerous researchers in order to control the huge volume data and provide convenient solutions. Therefore, several 3D systems of various types, which have satisfied multiple objectives have been proposed and developed to meet the previous requirements. However, in the l...
Journal of Telecommunication, Electronic and Computer Engineering, 2018
This paper presents a new method of stereo matching algorithms known as a Multistage Hybrid Media... more This paper presents a new method of stereo matching algorithms known as a Multistage Hybrid Median Filter (MHMF). The main challenging problem within computer vision field is stereo matching, considering the many drawbacks and issues resulting from stereo matching, which makes it a difficult and unresolved approach. Large studies and methods have been introduced and attempted to deal with stereo matching problems from a different perspective. However, most of these existing methods still suffer from low accuracy and algorithms complexity. Thus, to provide valuable and efficient solutions to stereovision community and to support researchers in the same line of research, we created a highly efficient and robust algorithms based on Hybrid Median Filter (MHF). In this paper, the (MHMF) is introduced as a newly implemented method of stereo matching algorithms. This method consists of three main stages, in which each stage involves multiple processes. In stage 1, the Basic Block Matching ...
2019 13th European Conference on Antennas and Propagation (EuCAP), 2019
An enhanced sensor based on symmetrical split ring resonator (SSRR) functioning at microwave freq... more An enhanced sensor based on symmetrical split ring resonator (SSRR) functioning at microwave frequencies has been proposed for detecting and characterizing the cracked surface of the metal materials. The enhanced SSRR sensor is modelled using a High Frequency Structure Simulator (HFSS) and the reflection S11 is performed for testing the aluminum metal with crack and without crack at the frequency range of 100 MHz to 3GHz. Variation of crack width and depth has been investigated and the most obvious finding emerged from this study is that the ability of detecting a minimum of sub-millimetre crack width and depth which is a round 10 μm width or depth where the minimum shift of reflected frequency is recorded at 6.2 MHz and 3 MHz for crack width and depth respectively. The enhanced SSRR provides high capability of detecting small crack defection by utilizing the interaction between coupled gap resonators and it is useful for various applications such as aircraft fuselages, nuclear powe...
Journal of Telecommunication, Electronic and Computer Engineering, 2017
One of the most important key steps of stereo vision algorithms is the disparity map implementati... more One of the most important key steps of stereo vision algorithms is the disparity map implementation, where it generally utilized to decorrelate data and recover 3D scene framework of stereo image pairs. However, less accuracy of attaining the disparity map is one of the challenging problems on stereo vision approach. Thus, various methods of stereo matching algorithms have been developed and widely investigated for implementing the disparity map of stereo image pairs including the Dynamic Programming (DP) and the Basic Block Matching (BBM) methods. This paper mainly presents an evaluation between the Dynamic Programming (DP) and the Basic Block Matching (BBM) methods of stereo matching algorithms in term of disparity map accuracy, noise enhancement, and smoothness. Where the Basic Block Matching (BBM) is using the Sum of Absolute Difference (SAD) method in this research as a basic algorithm to determine the correspondence points between the target and reference images. In contrast, ...
2011 IEEE International RF & Microwave Conference, 2011
In this work we present a transmitter module design of 2×2 MIMO-OFDM (multiple input multiple out... more In this work we present a transmitter module design of 2×2 MIMO-OFDM (multiple input multiple output - orthogonal frequency division multiplexing) system for wireless backhaul application. The system provides better than 10−7 of BER (bit error rate) at 8Mbps full duplex single link rate for the intended wireless distance. The transmitter operates in dual conversion architecture to translate a 10MHz
2000 TENCON Proceedings. Intelligent Systems and Technologies for the New Millennium (Cat. No.00CH37119)
Abstract In this paper, we introduce a video compression system based on three dimensional subban... more Abstract In this paper, we introduce a video compression system based on three dimensional subband coding for very low bit-rate videoconferencing and tele-monitoring application. The video codec first performs a three-dimensional subband decomposition of a group of video frames, and then encodes the subbands with different quantization methods. DPCM coding with a deterministic dithering is used for the lowest tempo-spatial subband. For high frequency subbands a combination of multiscale edge detection methods and ...
2000 TENCON Proceedings. Intelligent Systems and Technologies for the New Millennium (Cat. No.00CH37119), 2000
Abstract A joint optimization method for design of filter banks and related dithered quantizers b... more Abstract A joint optimization method for design of filter banks and related dithered quantizers by using time-domain formulation of filter banks is provided. Mathematical analysis and experiments show that in lattice vector quantization of the image subbands by appropriate choice of dither, it would be possible to replace signal-dependent artifacts with signal-independent white noise. This process improves the perceptual quality of reconstructed image, especially at low bit-rates and makes it more practical for a noise-removal ...
Proceedings of IEEE Region 10 International Conference on Electrical and Electronic Technology. TENCON 2001 (Cat. No.01CH37239)
Abstract We present our results on the development of a robust video coder. The system consists o... more Abstract We present our results on the development of a robust video coder. The system consists of 3-dimensional subband filtering, optimized scalar quantization of the lowest temporal-spatial frequency subband and modified pyramid vector quantization for high frequency subbands. To improve the visual quality of the system at low bit-rates, dithering is used for the pyramid vector quantizers and its effectiveness is proved by a pair-comparison subjective test. To increase robustness to noise, productive enumeration is used for the ...
Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)
Abstract We explain our results on development of a robust video coder, The coder consists of 3D ... more Abstract We explain our results on development of a robust video coder, The coder consists of 3D subband filtering in the first stage, an optimized scalar quantization (SQ) of lowest tempo-spatial frequency subband, and a pyramid vector quantization (PVQ) for high frequency subbands. To increase robustness to noise productive enumeration is used for PVQ. Also with phase scrambling the distribution of the lowest temporal-spatial band is changed to Gaussian which results in a better SQ coding gain for this band. The output ...
Journal of Computer Networks and Communications, 2014
We propose a new architecture of dynamic time-wavelength division multiplexing-passive optical ne... more We propose a new architecture of dynamic time-wavelength division multiplexing-passive optical network (TWDM-PON) system that employs integrated all-optical packet routing (AOPR) module using4λ×10 Gbps downstream signal to support 20 km fiber transmission. This module has been designed to support high speed L2 aggregation and routing in the physical layer PON system by using multicasting cross-gain modulation (XGM) to route packet from any PON port to multiple PON links. Meanwhile, the fixed wavelength optical line terminal (OLT) transmitter with wavelength tuning free features has been designed to integrate with the semiconductor optical amplifier (SOA) and passive arrayed waveguide grating (AWG). By implementing hybrid multicasting and multiplexing, the system has been able to support a PON system with full flexibility function for managing highly efficient dynamic bandwidth allocation to support the4λ×10 Gb/s TWDM-PON system used to connect 4 different PON links using fixed wavel...
Requirements for future bandwidth demand from access network keep changing, in order to support m... more Requirements for future bandwidth demand from access network keep changing, in order to support more streaming video on multicasting and broadcasting packet, a novel architecture of dynamic Multi- wavelength Time Wavelength Division Multiplexing Passive Optical Network (TWDM PON) system using multicasting Cross Gain Multiplexing (XGM) and all optical packet routing (AOPR) module in optical line terminal (OLT) is presented. The multicasting XGM technique was implemented by using Semiconductor Optical Amplifier (SOA). The study proved that the single PON port/card was able to generate multicast and broadcast packet up to more than 512 users using 8 PON link over existing PON infrastructure. The architecture is designed to support flexible dynamic wavelength allocation based on bandwidth demand from each customer from 10Gbps single channel to multiple channels of 10Gbps using multiple PON port. This paper is concluded with an analysis and discussion on the simulation of physical performance of gain saturation effect in pre amplification device using SOA components, the number of multicasting wavelength affecting the BER, the Q factor and quality of the signal in the downstream proposed system.
2000 TENCON Proceedings. Intelligent Systems and Technologies for the New Millennium (Cat. No.00CH37119)
Image/video compression is one of the major components used in video-telephony, videoconferencing... more Image/video compression is one of the major components used in video-telephony, videoconferencing and multimedia-related applications. Compression allows efficient utilization of channel bandwidth and/or storage size. One of the commonly used methods for image and video compression is JPEG (an image compression standard). In our present work, a real time (the first made in Malaysia) JPEG hardware decoder has been successfully
2000 TENCON Proceedings. Intelligent Systems and Technologies for the New Millennium (Cat. No.00CH37119), 2000
This paper describes the implementation of the baseline JPEG decoder on the TI 32 bit floating po... more This paper describes the implementation of the baseline JPEG decoder on the TI 32 bit floating point DSP processor TMS320C3 1 (Texas Instruments). The decoder can be used to decode compressed gray scale image and video signal. But with slight modifications to the ...
2012 18th Asia-Pacific Conference on Communications (APCC), 2012
ABSTRACT A novel architecture of WDM/TDM PON system using all optical packet routing (AOPR) in op... more ABSTRACT A novel architecture of WDM/TDM PON system using all optical packet routing (AOPR) in optical line termination (OLT) is proposed in this paper. This architecture is design using cross gain modulation (XGM) none return to zero (NRZ) WDM to return to zero (RZ) optical time division multiplexing (OTDM) technique using Semiconductor Optical Amplifier (SOA) component. This study proved that without implementing 10Gbps OLT card in the system, four 2.5Gbps WDM downstream signals could be multiplexed to carry 10Gbps OTDM signal by utilizing the existing E/GPON network infrastructure. In addition, this architecture also proved that it could be deployed as an open platform of hybrid solution of WDM/TDM PON for 10Gbps and ready for 40Gbps and 100Gbps platform in the future. This paper is concluded with an analysis and discussion on the gain saturation effect in SOA components affecting the BER, Q factor and quality of the signal in the proposed system.
2000 TENCON Proceedings. Intelligent Systems and Technologies for the New Millennium (Cat. No.00CH37119)
... 2D-IDCT have been successfully incorporated in the hardware JPEG codec prototype also develop... more ... 2D-IDCT have been successfully incorporated in the hardware JPEG codec prototype also developed in the University Technology of Malaysia. ... DCT Block Size 8x8 points Data FormatOperating Speed 11.06Mhz Total Logic Cells Required 2465 Total Flip-flops Required 1912 ...
This paper introduces a video compression system for very low bit–rate video–conferencing and tel... more This paper introduces a video compression system for very low bit–rate video–conferencing and tele–monitoring applications. The video codec first performs a three–dimensional subband decomposition on a group of video frames, and then encode the subbands with different quantization methods. By using a cubic spline wavelet, the spatial filter bank acts as a multiscale edge detector. This property is used for efficient selection and coding of high frequency subbands with geometric vector quantization. For lowest tempo–spatial subband, a DPCM coding with an entropy coder was used. Results at several low bit rates (16,32, 64, 128 Kbps) are reported and compared with H.263, the standard for low bit rate video coding.
This paper describes the development of a low complexity and fixed–rate video compression scheme ... more This paper describes the development of a low complexity and fixed–rate video compression scheme based on three–dimensional subband coding of video signals. The video codec first performs three–dimensional subband decomposition on a group of video frames, and then encode high frequency subbands with pyramid vector quantization and lowest tempo–spatial band with a DPCM coding in time and space. To improve the visual quality of reconstructed video, different types of subtractive and non–subtractive dithering of pyramid vector quantizers were experimented and its effectiveness was proved by a standard pair comparison subjective test. Coder complexity was reduced by using longer filters in the first level of spatial decomposition for better selectivity and coding gain and shorter filter in the second level of decomposition for lower complexity. Results at different low bit–rate (64, 128 and 384 Kbps) for several standard video sequences are reported and compared with ITU standard H.263.
2012 IEEE 3rd International Conference on Photonics, 2012
ABSTRACT The evolution of access network technology utilizing Passive Optical Network (PON) has p... more ABSTRACT The evolution of access network technology utilizing Passive Optical Network (PON) has provided a means for high speed broadband to be effectively implemented in Malaysia through FTTH technology. As the bandwidth demand and number of subscribers is increasing, WDM-PON is considered the best candidate for future deployment. On the same note, this paper presents the development of tunable 16 channels WDM-PON system, focusing on the colourless ONU's uplink signal transmission. This system is utilizing a software controlled tunable transceiver in both OLT and ONU, thus would enable colourless mode of operation. A 16 channels wavelength plan has also been defined for the upstream and downstream communication. Besides that, an athermal AWG is introduced in the network for wavelengths multi/de-multiplexing operation. An experimental setup has been made to simulate an optical modulated upstream signal from the colourless ONU to the OLT. The resulting upstream signals will be analyzed and characterized based on the availability, distance, optical received power as well as its quality on BER and the eye diagram. The results show that the ability of the developed tunable WDM-PON system to operate at 2.5Gbps for the upstream transmission and should be able to support the future plan of WDM-PON deployment in Malaysia.
With the several developments in visualization, sensing, perception innovation, and transmission ... more With the several developments in visualization, sensing, perception innovation, and transmission systems, 3D information has considered as main part of real-world applications such as multimedia, medical, architecture, manufacturing, computer vision, security, and more. Acquiring the scene depth information is one of the fundamental demands for some of these applications. Although the extracting of 3D information has been studied for more than three decades in different fields including robotics, computer graphics, and computer vision, it remains a challenge and fundamental issue. Systems with high accuracy, more quality of information and high frame rate of data processing have been a unique research opportunity for numerous researchers in order to control the huge volume data and provide convenient solutions. Therefore, several 3D systems of various types, which have satisfied multiple objectives have been proposed and developed to meet the previous requirements. However, in the l...
Journal of Telecommunication, Electronic and Computer Engineering, 2018
This paper presents a new method of stereo matching algorithms known as a Multistage Hybrid Media... more This paper presents a new method of stereo matching algorithms known as a Multistage Hybrid Median Filter (MHMF). The main challenging problem within computer vision field is stereo matching, considering the many drawbacks and issues resulting from stereo matching, which makes it a difficult and unresolved approach. Large studies and methods have been introduced and attempted to deal with stereo matching problems from a different perspective. However, most of these existing methods still suffer from low accuracy and algorithms complexity. Thus, to provide valuable and efficient solutions to stereovision community and to support researchers in the same line of research, we created a highly efficient and robust algorithms based on Hybrid Median Filter (MHF). In this paper, the (MHMF) is introduced as a newly implemented method of stereo matching algorithms. This method consists of three main stages, in which each stage involves multiple processes. In stage 1, the Basic Block Matching ...
2019 13th European Conference on Antennas and Propagation (EuCAP), 2019
An enhanced sensor based on symmetrical split ring resonator (SSRR) functioning at microwave freq... more An enhanced sensor based on symmetrical split ring resonator (SSRR) functioning at microwave frequencies has been proposed for detecting and characterizing the cracked surface of the metal materials. The enhanced SSRR sensor is modelled using a High Frequency Structure Simulator (HFSS) and the reflection S11 is performed for testing the aluminum metal with crack and without crack at the frequency range of 100 MHz to 3GHz. Variation of crack width and depth has been investigated and the most obvious finding emerged from this study is that the ability of detecting a minimum of sub-millimetre crack width and depth which is a round 10 μm width or depth where the minimum shift of reflected frequency is recorded at 6.2 MHz and 3 MHz for crack width and depth respectively. The enhanced SSRR provides high capability of detecting small crack defection by utilizing the interaction between coupled gap resonators and it is useful for various applications such as aircraft fuselages, nuclear powe...
Journal of Telecommunication, Electronic and Computer Engineering, 2017
One of the most important key steps of stereo vision algorithms is the disparity map implementati... more One of the most important key steps of stereo vision algorithms is the disparity map implementation, where it generally utilized to decorrelate data and recover 3D scene framework of stereo image pairs. However, less accuracy of attaining the disparity map is one of the challenging problems on stereo vision approach. Thus, various methods of stereo matching algorithms have been developed and widely investigated for implementing the disparity map of stereo image pairs including the Dynamic Programming (DP) and the Basic Block Matching (BBM) methods. This paper mainly presents an evaluation between the Dynamic Programming (DP) and the Basic Block Matching (BBM) methods of stereo matching algorithms in term of disparity map accuracy, noise enhancement, and smoothness. Where the Basic Block Matching (BBM) is using the Sum of Absolute Difference (SAD) method in this research as a basic algorithm to determine the correspondence points between the target and reference images. In contrast, ...
2011 IEEE International RF & Microwave Conference, 2011
In this work we present a transmitter module design of 2×2 MIMO-OFDM (multiple input multiple out... more In this work we present a transmitter module design of 2×2 MIMO-OFDM (multiple input multiple output - orthogonal frequency division multiplexing) system for wireless backhaul application. The system provides better than 10−7 of BER (bit error rate) at 8Mbps full duplex single link rate for the intended wireless distance. The transmitter operates in dual conversion architecture to translate a 10MHz
2000 TENCON Proceedings. Intelligent Systems and Technologies for the New Millennium (Cat. No.00CH37119)
Abstract In this paper, we introduce a video compression system based on three dimensional subban... more Abstract In this paper, we introduce a video compression system based on three dimensional subband coding for very low bit-rate videoconferencing and tele-monitoring application. The video codec first performs a three-dimensional subband decomposition of a group of video frames, and then encodes the subbands with different quantization methods. DPCM coding with a deterministic dithering is used for the lowest tempo-spatial subband. For high frequency subbands a combination of multiscale edge detection methods and ...
2000 TENCON Proceedings. Intelligent Systems and Technologies for the New Millennium (Cat. No.00CH37119), 2000
Abstract A joint optimization method for design of filter banks and related dithered quantizers b... more Abstract A joint optimization method for design of filter banks and related dithered quantizers by using time-domain formulation of filter banks is provided. Mathematical analysis and experiments show that in lattice vector quantization of the image subbands by appropriate choice of dither, it would be possible to replace signal-dependent artifacts with signal-independent white noise. This process improves the perceptual quality of reconstructed image, especially at low bit-rates and makes it more practical for a noise-removal ...
Proceedings of IEEE Region 10 International Conference on Electrical and Electronic Technology. TENCON 2001 (Cat. No.01CH37239)
Abstract We present our results on the development of a robust video coder. The system consists o... more Abstract We present our results on the development of a robust video coder. The system consists of 3-dimensional subband filtering, optimized scalar quantization of the lowest temporal-spatial frequency subband and modified pyramid vector quantization for high frequency subbands. To improve the visual quality of the system at low bit-rates, dithering is used for the pyramid vector quantizers and its effectiveness is proved by a pair-comparison subjective test. To increase robustness to noise, productive enumeration is used for the ...
Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)
Abstract We explain our results on development of a robust video coder, The coder consists of 3D ... more Abstract We explain our results on development of a robust video coder, The coder consists of 3D subband filtering in the first stage, an optimized scalar quantization (SQ) of lowest tempo-spatial frequency subband, and a pyramid vector quantization (PVQ) for high frequency subbands. To increase robustness to noise productive enumeration is used for PVQ. Also with phase scrambling the distribution of the lowest temporal-spatial band is changed to Gaussian which results in a better SQ coding gain for this band. The output ...
Journal of Computer Networks and Communications, 2014
We propose a new architecture of dynamic time-wavelength division multiplexing-passive optical ne... more We propose a new architecture of dynamic time-wavelength division multiplexing-passive optical network (TWDM-PON) system that employs integrated all-optical packet routing (AOPR) module using4λ×10 Gbps downstream signal to support 20 km fiber transmission. This module has been designed to support high speed L2 aggregation and routing in the physical layer PON system by using multicasting cross-gain modulation (XGM) to route packet from any PON port to multiple PON links. Meanwhile, the fixed wavelength optical line terminal (OLT) transmitter with wavelength tuning free features has been designed to integrate with the semiconductor optical amplifier (SOA) and passive arrayed waveguide grating (AWG). By implementing hybrid multicasting and multiplexing, the system has been able to support a PON system with full flexibility function for managing highly efficient dynamic bandwidth allocation to support the4λ×10 Gb/s TWDM-PON system used to connect 4 different PON links using fixed wavel...
Requirements for future bandwidth demand from access network keep changing, in order to support m... more Requirements for future bandwidth demand from access network keep changing, in order to support more streaming video on multicasting and broadcasting packet, a novel architecture of dynamic Multi- wavelength Time Wavelength Division Multiplexing Passive Optical Network (TWDM PON) system using multicasting Cross Gain Multiplexing (XGM) and all optical packet routing (AOPR) module in optical line terminal (OLT) is presented. The multicasting XGM technique was implemented by using Semiconductor Optical Amplifier (SOA). The study proved that the single PON port/card was able to generate multicast and broadcast packet up to more than 512 users using 8 PON link over existing PON infrastructure. The architecture is designed to support flexible dynamic wavelength allocation based on bandwidth demand from each customer from 10Gbps single channel to multiple channels of 10Gbps using multiple PON port. This paper is concluded with an analysis and discussion on the simulation of physical performance of gain saturation effect in pre amplification device using SOA components, the number of multicasting wavelength affecting the BER, the Q factor and quality of the signal in the downstream proposed system.
2000 TENCON Proceedings. Intelligent Systems and Technologies for the New Millennium (Cat. No.00CH37119)
Image/video compression is one of the major components used in video-telephony, videoconferencing... more Image/video compression is one of the major components used in video-telephony, videoconferencing and multimedia-related applications. Compression allows efficient utilization of channel bandwidth and/or storage size. One of the commonly used methods for image and video compression is JPEG (an image compression standard). In our present work, a real time (the first made in Malaysia) JPEG hardware decoder has been successfully
2000 TENCON Proceedings. Intelligent Systems and Technologies for the New Millennium (Cat. No.00CH37119), 2000
This paper describes the implementation of the baseline JPEG decoder on the TI 32 bit floating po... more This paper describes the implementation of the baseline JPEG decoder on the TI 32 bit floating point DSP processor TMS320C3 1 (Texas Instruments). The decoder can be used to decode compressed gray scale image and video signal. But with slight modifications to the ...
2012 18th Asia-Pacific Conference on Communications (APCC), 2012
ABSTRACT A novel architecture of WDM/TDM PON system using all optical packet routing (AOPR) in op... more ABSTRACT A novel architecture of WDM/TDM PON system using all optical packet routing (AOPR) in optical line termination (OLT) is proposed in this paper. This architecture is design using cross gain modulation (XGM) none return to zero (NRZ) WDM to return to zero (RZ) optical time division multiplexing (OTDM) technique using Semiconductor Optical Amplifier (SOA) component. This study proved that without implementing 10Gbps OLT card in the system, four 2.5Gbps WDM downstream signals could be multiplexed to carry 10Gbps OTDM signal by utilizing the existing E/GPON network infrastructure. In addition, this architecture also proved that it could be deployed as an open platform of hybrid solution of WDM/TDM PON for 10Gbps and ready for 40Gbps and 100Gbps platform in the future. This paper is concluded with an analysis and discussion on the gain saturation effect in SOA components affecting the BER, Q factor and quality of the signal in the proposed system.
2000 TENCON Proceedings. Intelligent Systems and Technologies for the New Millennium (Cat. No.00CH37119)
... 2D-IDCT have been successfully incorporated in the hardware JPEG codec prototype also develop... more ... 2D-IDCT have been successfully incorporated in the hardware JPEG codec prototype also developed in the University Technology of Malaysia. ... DCT Block Size 8x8 points Data FormatOperating Speed 11.06Mhz Total Logic Cells Required 2465 Total Flip-flops Required 1912 ...
This paper introduces a video compression system for very low bit–rate video–conferencing and tel... more This paper introduces a video compression system for very low bit–rate video–conferencing and tele–monitoring applications. The video codec first performs a three–dimensional subband decomposition on a group of video frames, and then encode the subbands with different quantization methods. By using a cubic spline wavelet, the spatial filter bank acts as a multiscale edge detector. This property is used for efficient selection and coding of high frequency subbands with geometric vector quantization. For lowest tempo–spatial subband, a DPCM coding with an entropy coder was used. Results at several low bit rates (16,32, 64, 128 Kbps) are reported and compared with H.263, the standard for low bit rate video coding.
This paper describes the development of a low complexity and fixed–rate video compression scheme ... more This paper describes the development of a low complexity and fixed–rate video compression scheme based on three–dimensional subband coding of video signals. The video codec first performs three–dimensional subband decomposition on a group of video frames, and then encode high frequency subbands with pyramid vector quantization and lowest tempo–spatial band with a DPCM coding in time and space. To improve the visual quality of reconstructed video, different types of subtractive and non–subtractive dithering of pyramid vector quantizers were experimented and its effectiveness was proved by a standard pair comparison subjective test. Coder complexity was reduced by using longer filters in the first level of spatial decomposition for better selectivity and coding gain and shorter filter in the second level of decomposition for lower complexity. Results at different low bit–rate (64, 128 and 384 Kbps) for several standard video sequences are reported and compared with ITU standard H.263.
2012 IEEE 3rd International Conference on Photonics, 2012
ABSTRACT The evolution of access network technology utilizing Passive Optical Network (PON) has p... more ABSTRACT The evolution of access network technology utilizing Passive Optical Network (PON) has provided a means for high speed broadband to be effectively implemented in Malaysia through FTTH technology. As the bandwidth demand and number of subscribers is increasing, WDM-PON is considered the best candidate for future deployment. On the same note, this paper presents the development of tunable 16 channels WDM-PON system, focusing on the colourless ONU's uplink signal transmission. This system is utilizing a software controlled tunable transceiver in both OLT and ONU, thus would enable colourless mode of operation. A 16 channels wavelength plan has also been defined for the upstream and downstream communication. Besides that, an athermal AWG is introduced in the network for wavelengths multi/de-multiplexing operation. An experimental setup has been made to simulate an optical modulated upstream signal from the colourless ONU to the OLT. The resulting upstream signals will be analyzed and characterized based on the availability, distance, optical received power as well as its quality on BER and the eye diagram. The results show that the ability of the developed tunable WDM-PON system to operate at 2.5Gbps for the upstream transmission and should be able to support the future plan of WDM-PON deployment in Malaysia.
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