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Dũng Võ

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University of Glasgow

Jameel M Al-Khayri

King Faisal University

Dr.Mahmoud Lotfy

Minufiya University

Kafrelsheikh University

Gwen Robbins Schug

University of North Carolina at Greensboro

Jesper Hoffmeyer

University of Copenhagen

Michael J. Gonzalez

Universidad de Puerto Rico Rio

Richard Cloutier

Université du Québec à Rimouski

Viacheslav Kuleshov

Stockholm University

Kerala Agricultural University

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Papers by Dũng Võ

Visually lossless compression for color images with low line memory requirement using non-uniform quantizers

The paper proposes a novel method to compress color images with imperceptible quality loss. The a... more The paper proposes a novel method to compress color images with imperceptible quality loss. The algorithm explores the difference in error perceptibility of human visual system for various areas. It is done by implementing different non-uniform quantizers for flat, detail and random blocks of pixels. These blocks are classified based on principle component analysis (PCA) and prediction error. For hardware

A Novel Content Based Scene Retrieval using Multi-frame Features

A Novel Automatic Deforming for Smartphone Image Scanning using Gradient-based Corner Detection

Development of large arrays of microcalorimeters for precision gamma-ray spectroscopy

IEEE Nuclear Science Symposium Conference Record, 2005

... MICROCALORIMETERS Microcalorimeters (microbolometers) are sensing elements whose temperature ... more

Optimal spatial-temporal weight prediction for inter-frame coding of H.264/AVC video sequences

The 2010 International Conference on Advanced Technologies for Communications, 2010

The paper proposes a novel method for optimal weight prediction in coding inter-frame of H.264/AV... more The paper proposes a novel method for optimal weight prediction in coding inter-frame of H.264/AVC compressed video sequences. The weights are optimized so that the motion compensated frames is closest to the current frame. This minimizes the residual frame and thus helps reducing the number of bits required to code the residual frame. We first consider the general optimal spatial-temporal weight prediction and then specify the special solution in case of temporal weight prediction using two reference frames (bi-predictive coding). Simulations on a wide range of video sequences are performed to verify the effectiveness of the algorithm on both visual quality and rate-distortion relation.

Filter-Bank Based Super-Resolution for Rotated and Blurry Undersampled Images

2006 Fortieth Asilomar Conference on Signals, Systems and Computers, 2006

The ill-posed problem of image super-resolution (SR) is considered in the frequency domain using ... more The ill-posed problem of image super-resolution (SR) is considered in the frequency domain using a filter bank approach. A low resolution (LR) imaging system is modeled in this paper using different fractional translation, rotation and blurs for each LR image. Synthesis filters are then found which provide a minimal time averaged mean squared error (TAMSE) reconstruction under a wide sense stationary (WSS) signal assumption. Presented simulations for many kinds of images demonstrate the effectiveness of the algorithm.

Optimal motion compensated spatio-temporal filter for quality enhancement of H.264/AVC compressed video sequences

2009 16th IEEE International Conference on Image Processing (ICIP), 2009

The paper proposes a novel algorithm to enhance the quality of H.264/AVC compressed video sequenc... more The paper proposes a novel algorithm to enhance the quality of H.264/AVC compressed video sequences by using an in-loop spatio-temporal motion compensated filter (MCSTF). Extra information from surrounding coded frames are used together with the information of the current coded frame to reduce the coding artifacts. With the availability of the original frame, the MCSTF coefficients are optimized at the

Edge-based directional fuzzy filter for compression artifact reduction in JPEG images

2008 15th IEEE International Conference on Image Processing, 2008

We propose a novel method to reduce both blocking and ringing artifacts in compressed images and ... more We propose a novel method to reduce both blocking and ringing artifacts in compressed images and videos. Based on the directional characteristics of ringing artifacts along edges, we use a directional fuzzy filter which is adaptive to the direction of the ringing artifacts. The filter exploits the spatial order, the rank order and the spread information of the signal together with the position of the pixels to enhance the quality of the compressed image. Simulations results on compressed images and videos having simple and complex edges show the improvement of the proposed directional fuzzy filter over the conventional fuzzy filtering and approaches.

Directional motion-compensated spatio-temporal fuzzy filtering for quality enhancement of compressed video sequences

2008 15th IEEE International Conference on Image Processing, 2008

We propose a directional fuzzy lter to enhance the quality of compressed video sequences. A motio... more We propose a directional fuzzy lter to enhance the quality of compressed video sequences. A motion compensated spatiotemporal lter (MCSTF) is applied to intra-frame and inter-frame pixels to reduce both spatial and temporal artifacts. The MC-STF is adaptive to the pixel location, the intensity and position of surrounding pixels. To evaluate the ickering artifacts, a new metric is proposed to take into account the tracking characteristic of human eyes. Simulations on H.264 compressed videos show improvement in artifact reduction of the proposed directional fuzzy lter over other conventional spatial or temporal ltering approaches.

<title>Spatio-temporal fuzzy filtering for coding artifacts reduction</title>

Visual Communications and Image Processing 2008, 2008

A 3D fuzzy-filtering scheme is proposed for reduction of compression artifacts such as blocking a... more A 3D fuzzy-filtering scheme is proposed for reduction of compression artifacts such as blocking and ringing noises. The proposed scheme incorporates information from temporally-neighboring frames as well as from spatially-neighboring pixels by accounting for the spatio-temporal relationships in the definitions of spatial-rank orders and spread information for the fuzzy-filter. Extra information from a 3D set of pixels of the surrounding frames helps enhance the clustering characteristic of the fuzzy filter while preserving the frame edges. The proposed scheme also exploits the chroma components from neighboring frames to reconstruct the color of the current frame more faithfully. The experimental results show that both the subjective and the objective qualities of post-processed video are significantly improved.

Data pruning-based compression using high order edge-directed interpolation

2009 IEEE International Conference on Acoustics, Speech and Signal Processing, 2009

This paper proposes a data pruning-based compression scheme to improve the rate-distortion relati... more This paper proposes a data pruning-based compression scheme to improve the rate-distortion relation of compressed images and video sequences. The original frames are pruned to a smaller size before compression. After decoding, they are interpolated to their original size by an edge-directed interpolation. The data pruning is optimized to obtain the minimal distortion in the interpolation phase. Furthermore, a novel high order interpolation is proposed to adapt the interpolation to many edge directions. This high order ltering uses extra surrounding pixels and achieves more robust edge-directed image interpolation. Simulation results are shown for both image interpolation and coding applications.

Automatic video deshearing for skew sequences capturedby rolling shutter cameras

2011 18th IEEE International Conference on Image Processing, 2011

Abstract A novel automatic video deshearing is proposed to reduce the skew artifacts (jelly artif... more

Temporal exposure inconsistency correction for CMOS captured video sequences

2012 IEEE International Conference on Consumer Electronics (ICCE), 2012

The paper proposes a novel method to correct the temporal inconsistency in exposure of video sequ... more The paper proposes a novel method to correct the temporal inconsistency in exposure of video sequences captured from CMOS cameras. The temporal exposure consistency is improved by avoiding significant change in histogram over frames. This is done by histogram equalization where the target histogram is the temporal low-pass filtered result from the previous frames' histogram. Simulations on different video sequences verify the effectiveness of the algorithm.

Real time video stabilization with reduced temporal mismatch and low frame buffer

2012 IEEE International Conference on Consumer Electronics (ICCE), 2012

This paper proposes a real time video stabilization method which only requires a low number of bu... more This paper proposes a real time video stabilization method which only requires a low number of buffered frames. The effect of temporal mismatch between the original and deshaked frames to the black border artifacts is also considered. This mismatch effect is then removed by delaying the motion compensation with a suitable number of frames. To minimize the number of buffered

Localized filtering for artifact removal in compressed images

2011 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 2011

The paper proposes a novel method for coding artifact reduction in compressed images. For removin... more The paper proposes a novel method for coding artifact reduction in compressed images. For removing blocking artifacts, a localized DCT-based filter with condition on the similarity between surrounding blocks is considered. To reduce ringing, a localized fuzzy filter is utilized to avoid the blurry effect of linear filter and painting-like effect of conventional fuzzy filter. To enhance chroma components and reduce the color bleeding, the localized filter for luma component are implemented for the chroma components. Simulations on a wide range of compressed images are performed to verify the effectiveness of the algorithm.

An investigation in dehazing compressed images and video

OCEANS 2010 MTS/IEEE SEATTLE, 2010

... SADi,j(k, l) = ∑ 0≤m,n≤N−1 |y(Ni + m, N j + n) −y(Nk + m, N l + n)| . (44) We now can show ... more

Integrating Pressure Data From Formation Tester Tools and DSTs To Characterize Deepwater Fields, East Kalimantan, Indonesia

SPE Reservoir Evaluation & Engineering, 2001

... Typically, a zone selected for testing is based on the following criteria: (1) it must be cor... more

Performance Evaluation of Trilateral Wells: Field Examples

Spe Reservoir Engineering, 1995

Recent advances in horizontal drilling and completion technology have led to the successful compl... more Recent advances in horizontal drilling and completion technology have led to the successful completion of multilateral horizontal wells (wells with two or more laterals penetrating separate zones that produce through a single wellbore to the surface). Evaluating performance of these commingled horizontal wells poses unique problems that have led to development of a practical procedure for that purpose. This paper

Gulf of Mexico Horizontal Well Improves Attic-Oil Recovery in Active Waterdrive Reservoir

Spe Reservoir Engineering, 1997

High-pressure xenon ion chambers for gamma-ray spectroscopy in nuclear safeguards

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2003

There has been a long-standing need for a room-temperature gamma-ray detector system with high ef... more There has been a long-standing need for a room-temperature gamma-ray detector system with high efficiency and adequate resolution for nuclear safeguards applications. For nuclear safeguards, measurements must resolve the uranium complex at 186 keV and the plutonium complex at 414 keV. The need for adequate room-temperature resolution has been met by CdZnTe detectors, but these small detectors cannot produce the efficiency needed for broad application in nuclear safeguards. The high-pressure xenon (HPXe) detector offers resolution, efficiency, intrinsic radiation resistance and temperature stability, making this detector type a viable candidate for broad application in nuclear safeguards. We will examine the current status HPXe detector systems, contrast HPXe with other detector types for nuclear safeguards applications, and discuss our efforts to improve the HPXe detector operating characteristics. r

Visually lossless compression for color images with low line memory requirement using non-uniform quantizers

The paper proposes a novel method to compress color images with imperceptible quality loss. The a... more The paper proposes a novel method to compress color images with imperceptible quality loss. The algorithm explores the difference in error perceptibility of human visual system for various areas. It is done by implementing different non-uniform quantizers for flat, detail and random blocks of pixels. These blocks are classified based on principle component analysis (PCA) and prediction error. For hardware

A Novel Content Based Scene Retrieval using Multi-frame Features

A Novel Automatic Deforming for Smartphone Image Scanning using Gradient-based Corner Detection

Development of large arrays of microcalorimeters for precision gamma-ray spectroscopy

IEEE Nuclear Science Symposium Conference Record, 2005

... MICROCALORIMETERS Microcalorimeters (microbolometers) are sensing elements whose temperature ... more

Optimal spatial-temporal weight prediction for inter-frame coding of H.264/AVC video sequences

The 2010 International Conference on Advanced Technologies for Communications, 2010

The paper proposes a novel method for optimal weight prediction in coding inter-frame of H.264/AV... more The paper proposes a novel method for optimal weight prediction in coding inter-frame of H.264/AVC compressed video sequences. The weights are optimized so that the motion compensated frames is closest to the current frame. This minimizes the residual frame and thus helps reducing the number of bits required to code the residual frame. We first consider the general optimal spatial-temporal weight prediction and then specify the special solution in case of temporal weight prediction using two reference frames (bi-predictive coding). Simulations on a wide range of video sequences are performed to verify the effectiveness of the algorithm on both visual quality and rate-distortion relation.

Filter-Bank Based Super-Resolution for Rotated and Blurry Undersampled Images

2006 Fortieth Asilomar Conference on Signals, Systems and Computers, 2006

The ill-posed problem of image super-resolution (SR) is considered in the frequency domain using ... more The ill-posed problem of image super-resolution (SR) is considered in the frequency domain using a filter bank approach. A low resolution (LR) imaging system is modeled in this paper using different fractional translation, rotation and blurs for each LR image. Synthesis filters are then found which provide a minimal time averaged mean squared error (TAMSE) reconstruction under a wide sense stationary (WSS) signal assumption. Presented simulations for many kinds of images demonstrate the effectiveness of the algorithm.

Optimal motion compensated spatio-temporal filter for quality enhancement of H.264/AVC compressed video sequences

2009 16th IEEE International Conference on Image Processing (ICIP), 2009

The paper proposes a novel algorithm to enhance the quality of H.264/AVC compressed video sequenc... more The paper proposes a novel algorithm to enhance the quality of H.264/AVC compressed video sequences by using an in-loop spatio-temporal motion compensated filter (MCSTF). Extra information from surrounding coded frames are used together with the information of the current coded frame to reduce the coding artifacts. With the availability of the original frame, the MCSTF coefficients are optimized at the

Edge-based directional fuzzy filter for compression artifact reduction in JPEG images

2008 15th IEEE International Conference on Image Processing, 2008

We propose a novel method to reduce both blocking and ringing artifacts in compressed images and ... more We propose a novel method to reduce both blocking and ringing artifacts in compressed images and videos. Based on the directional characteristics of ringing artifacts along edges, we use a directional fuzzy filter which is adaptive to the direction of the ringing artifacts. The filter exploits the spatial order, the rank order and the spread information of the signal together with the position of the pixels to enhance the quality of the compressed image. Simulations results on compressed images and videos having simple and complex edges show the improvement of the proposed directional fuzzy filter over the conventional fuzzy filtering and approaches.

Directional motion-compensated spatio-temporal fuzzy filtering for quality enhancement of compressed video sequences

2008 15th IEEE International Conference on Image Processing, 2008

We propose a directional fuzzy lter to enhance the quality of compressed video sequences. A motio... more We propose a directional fuzzy lter to enhance the quality of compressed video sequences. A motion compensated spatiotemporal lter (MCSTF) is applied to intra-frame and inter-frame pixels to reduce both spatial and temporal artifacts. The MC-STF is adaptive to the pixel location, the intensity and position of surrounding pixels. To evaluate the ickering artifacts, a new metric is proposed to take into account the tracking characteristic of human eyes. Simulations on H.264 compressed videos show improvement in artifact reduction of the proposed directional fuzzy lter over other conventional spatial or temporal ltering approaches.

<title>Spatio-temporal fuzzy filtering for coding artifacts reduction</title>

Visual Communications and Image Processing 2008, 2008

A 3D fuzzy-filtering scheme is proposed for reduction of compression artifacts such as blocking a... more A 3D fuzzy-filtering scheme is proposed for reduction of compression artifacts such as blocking and ringing noises. The proposed scheme incorporates information from temporally-neighboring frames as well as from spatially-neighboring pixels by accounting for the spatio-temporal relationships in the definitions of spatial-rank orders and spread information for the fuzzy-filter. Extra information from a 3D set of pixels of the surrounding frames helps enhance the clustering characteristic of the fuzzy filter while preserving the frame edges. The proposed scheme also exploits the chroma components from neighboring frames to reconstruct the color of the current frame more faithfully. The experimental results show that both the subjective and the objective qualities of post-processed video are significantly improved.

Data pruning-based compression using high order edge-directed interpolation

2009 IEEE International Conference on Acoustics, Speech and Signal Processing, 2009

This paper proposes a data pruning-based compression scheme to improve the rate-distortion relati... more This paper proposes a data pruning-based compression scheme to improve the rate-distortion relation of compressed images and video sequences. The original frames are pruned to a smaller size before compression. After decoding, they are interpolated to their original size by an edge-directed interpolation. The data pruning is optimized to obtain the minimal distortion in the interpolation phase. Furthermore, a novel high order interpolation is proposed to adapt the interpolation to many edge directions. This high order ltering uses extra surrounding pixels and achieves more robust edge-directed image interpolation. Simulation results are shown for both image interpolation and coding applications.

Automatic video deshearing for skew sequences capturedby rolling shutter cameras

2011 18th IEEE International Conference on Image Processing, 2011

Abstract A novel automatic video deshearing is proposed to reduce the skew artifacts (jelly artif... more

Temporal exposure inconsistency correction for CMOS captured video sequences

2012 IEEE International Conference on Consumer Electronics (ICCE), 2012

The paper proposes a novel method to correct the temporal inconsistency in exposure of video sequ... more The paper proposes a novel method to correct the temporal inconsistency in exposure of video sequences captured from CMOS cameras. The temporal exposure consistency is improved by avoiding significant change in histogram over frames. This is done by histogram equalization where the target histogram is the temporal low-pass filtered result from the previous frames' histogram. Simulations on different video sequences verify the effectiveness of the algorithm.

Real time video stabilization with reduced temporal mismatch and low frame buffer

2012 IEEE International Conference on Consumer Electronics (ICCE), 2012

This paper proposes a real time video stabilization method which only requires a low number of bu... more This paper proposes a real time video stabilization method which only requires a low number of buffered frames. The effect of temporal mismatch between the original and deshaked frames to the black border artifacts is also considered. This mismatch effect is then removed by delaying the motion compensation with a suitable number of frames. To minimize the number of buffered

Localized filtering for artifact removal in compressed images

2011 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 2011

The paper proposes a novel method for coding artifact reduction in compressed images. For removin... more The paper proposes a novel method for coding artifact reduction in compressed images. For removing blocking artifacts, a localized DCT-based filter with condition on the similarity between surrounding blocks is considered. To reduce ringing, a localized fuzzy filter is utilized to avoid the blurry effect of linear filter and painting-like effect of conventional fuzzy filter. To enhance chroma components and reduce the color bleeding, the localized filter for luma component are implemented for the chroma components. Simulations on a wide range of compressed images are performed to verify the effectiveness of the algorithm.

An investigation in dehazing compressed images and video

OCEANS 2010 MTS/IEEE SEATTLE, 2010

... SADi,j(k, l) = ∑ 0≤m,n≤N−1 |y(Ni + m, N j + n) −y(Nk + m, N l + n)| . (44) We now can show ... more

Integrating Pressure Data From Formation Tester Tools and DSTs To Characterize Deepwater Fields, East Kalimantan, Indonesia

SPE Reservoir Evaluation & Engineering, 2001

... Typically, a zone selected for testing is based on the following criteria: (1) it must be cor... more

Performance Evaluation of Trilateral Wells: Field Examples

Spe Reservoir Engineering, 1995

Recent advances in horizontal drilling and completion technology have led to the successful compl... more Recent advances in horizontal drilling and completion technology have led to the successful completion of multilateral horizontal wells (wells with two or more laterals penetrating separate zones that produce through a single wellbore to the surface). Evaluating performance of these commingled horizontal wells poses unique problems that have led to development of a practical procedure for that purpose. This paper

Gulf of Mexico Horizontal Well Improves Attic-Oil Recovery in Active Waterdrive Reservoir

Spe Reservoir Engineering, 1997

High-pressure xenon ion chambers for gamma-ray spectroscopy in nuclear safeguards

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2003

There has been a long-standing need for a room-temperature gamma-ray detector system with high ef... more There has been a long-standing need for a room-temperature gamma-ray detector system with high efficiency and adequate resolution for nuclear safeguards applications. For nuclear safeguards, measurements must resolve the uranium complex at 186 keV and the plutonium complex at 414 keV. The need for adequate room-temperature resolution has been met by CdZnTe detectors, but these small detectors cannot produce the efficiency needed for broad application in nuclear safeguards. The high-pressure xenon (HPXe) detector offers resolution, efficiency, intrinsic radiation resistance and temperature stability, making this detector type a viable candidate for broad application in nuclear safeguards. We will examine the current status HPXe detector systems, contrast HPXe with other detector types for nuclear safeguards applications, and discuss our efforts to improve the HPXe detector operating characteristics. r