8 research outputs found
A family of stereoscopic image compression algorithms using wavelet transforms
With the standardization of JPEG-2000, wavelet-based image and video
compression technologies are gradually replacing the popular DCT-based methods. In
parallel to this, recent developments in autostereoscopic display technology is now
threatening to revolutionize the way in which consumers are used to enjoying the
traditional 2-D display based electronic media such as television, computer and
movies. However, due to the two-fold bandwidth/storage space requirement of
stereoscopic imaging, an essential requirement of a stereo imaging system is efficient
data compression.
In this thesis, seven wavelet-based stereo image compression algorithms are
proposed, to take advantage of the higher data compaction capability and better
flexibility of wavelets. [Continues.
A family of stereoscopic image compression algorithms using wavelet transforms
With the standardization of JPEG-2000, wavelet-based image and video
compression technologies are gradually replacing the popular DCT-based methods. In
parallel to this, recent developments in autostereoscopic display technology is now
threatening to revolutionize the way in which consumers are used to enjoying the
traditional 2D display based electronic media such as television, computer and
movies. However, due to the two-fold bandwidth/storage space requirement of
stereoscopic imaging, an essential requirement of a stereo imaging system is efficient
data compression.
In this thesis, seven wavelet-based stereo image compression algorithms are
proposed, to take advantage of the higher data compaction capability and better
flexibility of wavelets. In the proposed CODEC I, block-based disparity
estimation/compensation (DE/DC) is performed in pixel domain. However, this
results in an inefficiency when DWT is applied on the whole predictive error image
that results from the DE process. This is because of the existence of artificial block
boundaries between error blocks in the predictive error image. To overcome this
problem, in the remaining proposed CODECs, DE/DC is performed in the wavelet
domain. Due to the multiresolution nature of the wavelet domain, two methods of
disparity estimation and compensation have been proposed. The first method is
performing DEJDC in each subband of the lowest/coarsest resolution level and then
propagating the disparity vectors obtained to the corresponding subbands of
higher/finer resolution. Note that DE is not performed in every subband due to the
high overhead bits that could be required for the coding of disparity vectors of all
subbands. This method is being used in CODEC II. In the second method, DEJDC is
performed m the wavelet-block domain. This enables disparity estimation to be
performed m all subbands simultaneously without increasing the overhead bits
required for the coding disparity vectors. This method is used by CODEC III.
However, performing disparity estimation/compensation in all subbands would result
in a significant improvement of CODEC III. To further improve the performance of
CODEC ill, pioneering wavelet-block search technique is implemented in CODEC
IV. The pioneering wavelet-block search technique enables the right/predicted image
to be reconstructed at the decoder end without the need of transmitting the disparity
vectors. In proposed CODEC V, pioneering block search is performed in all subbands
of DWT decomposition which results in an improvement of its performance. Further,
the CODEC IV and V are able to perform at very low bit rates(< 0.15 bpp). In
CODEC VI and CODEC VII, Overlapped Block Disparity Compensation (OBDC) is
used with & without the need of coding disparity vector. Our experiment results
showed that no significant coding gains could be obtained for these CODECs over
CODEC IV & V.
All proposed CODECs m this thesis are wavelet-based stereo image coding
algorithms that maximise the flexibility and benefits offered by wavelet transform
technology when applied to stereo imaging. In addition the use of a baseline-JPEG
coding architecture would enable the easy adaptation of the proposed algorithms
within systems originally built for DCT-based coding. This is an important feature
that would be useful during an era where DCT-based technology is only slowly being
phased out to give way for DWT based compression technology.
In addition, this thesis proposed a stereo image coding algorithm that uses JPEG-2000
technology as the basic compression engine. The proposed CODEC, named RASTER
is a rate scalable stereo image CODEC that has a unique ability to preserve the image
quality at binocular depth boundaries, which is an important requirement in the design
of stereo image CODEC. The experimental results have shown that the proposed
CODEC is able to achieve PSNR gains of up to 3.7 dB as compared to directly
transmitting the right frame using JPEG-2000
Web-based Stereoscopic Collaboration for Medical Visualization
Medizinische Volumenvisualisierung ist ein wertvolles Werkzeug zur Betrachtung von Volumen- daten in der medizinischen Praxis und Lehre. Eine interaktive, stereoskopische und kollaborative Darstellung in Echtzeit ist notwendig, um die Daten vollständig und im Detail verstehen zu können. Solche Visualisierung von hochauflösenden Daten ist jedoch wegen hoher Hardware- Anforderungen fast nur an speziellen Visualisierungssystemen möglich. Remote-Visualisierung wird verwendet, um solche Visualisierung peripher nutzen zu können. Dies benötigt jedoch fast immer komplexe Software-Deployments, wodurch eine universelle ad-hoc Nutzbarkeit erschwert wird. Aus diesem Sachverhalt ergibt sich folgende Hypothese: Ein hoch performantes Remote- Visualisierungssystem, welches für Stereoskopie und einfache Benutzbarkeit spezialisiert ist, kann für interaktive, stereoskopische und kollaborative medizinische Volumenvisualisierung genutzt werden.
Die neueste Literatur über Remote-Visualisierung beschreibt Anwendungen, welche nur reine Webbrowser benötigen. Allerdings wird bei diesen kein besonderer Schwerpunkt auf die perfor- mante Nutzbarkeit von jedem Teilnehmer gesetzt, noch die notwendige Funktion bereitgestellt, um mehrere stereoskopische Präsentationssysteme zu bedienen. Durch die Bekanntheit von Web- browsern, deren einfach Nutzbarkeit und weite Verbreitung hat sich folgende spezifische Frage ergeben: Können wir ein System entwickeln, welches alle Aspekte unterstützt, aber nur einen reinen Webbrowser ohne zusätzliche Software als Client benötigt?
Ein Proof of Concept wurde durchgeführt um die Hypothese zu verifizieren. Dazu gehörte eine Prototyp-Entwicklung, deren praktische Anwendung, deren Performanzmessung und -vergleich.
Der resultierende Prototyp (CoWebViz) ist eines der ersten Webbrowser basierten Systeme, welches flüssige und interaktive Remote-Visualisierung in Realzeit und ohne zusätzliche Soft- ware ermöglicht. Tests und Vergleiche zeigen, dass der Ansatz eine bessere Performanz hat als andere ähnliche getestete Systeme. Die simultane Nutzung verschiedener stereoskopischer Präsen- tationssysteme mit so einem einfachen Remote-Visualisierungssystem ist zur Zeit einzigartig. Die Nutzung für die normalerweise sehr ressourcen-intensive stereoskopische und kollaborative Anatomieausbildung, gemeinsam mit interkontinentalen Teilnehmern, zeigt die Machbarkeit und den vereinfachenden Charakter des Ansatzes. Die Machbarkeit des Ansatzes wurde auch durch die erfolgreiche Nutzung für andere Anwendungsfälle gezeigt, wie z.B. im Grid-computing und in der Chirurgie
TechNews digests: Jan - Nov 2009
TechNews is a technology, news and analysis service aimed at anyone in the education sector keen to stay informed about technology developments, trends and issues. TechNews focuses on emerging technologies and other technology news. TechNews service : digests september 2004 till May 2010 Analysis pieces and News combined publish every 2 to 3 month
Digital hologram recording systems: some performance improvements
The work presented in this thesis was performed under the EU's Framework
7 (FP7) project, 'REAL3D'. The aim of this project is to develop methods
based on digital holography for real time capture and display of 3D objects.
This thesis forms a small subset of all the work done in this project. Much of
the research work was aimed towards fullling our part of the requirements
of the REAL3D project. The central theme of the research presented in
this thesis is that of improving the performance of the digital holographic
imaging system for its use in 3D display. This encompasses research into
speed up of reconstruction algorithms, understanding the in
uence of noise
and developing techniques to increase resolution and angular perspective
range in reconstructions.
The main original contributions of this research work presented in this thesis
are:
A computer-interfaced automatic digital holographic imaging
system employing `phase shifting' has been built. This system
is capable of recording high-quality digital holograms of a real world
3D object. The object can be rotated on a rotational stage and a full
360 range of perspectives can be recorded. Speckle reduction using
moving diusers can be performed to improve the image quality of the
reconstructed images. A LabView based user friendly interface has
been developed.
Novel methods based on space-time tradeo and xed point
arithmetic have been developed and implemented for speed-
ing up the reconstruction algorithm used in digital holography.
This has resulted in the publication of one peer-reviewed journal pub-
lication and one conference proceeding [1, 2].
The in
uence of additive noise, particularly quantization noise
in digital holography has been studied in detail. A model
has been developed to understand the in
uence of noise on the re-
constructed image quality. Based on this model, a method has been
developed to suppress quantization noise in a memory ecient man-
ner. This work led to the publication of two peer-reviewed journal
publications [3, 4].
A novel method of removing the twin image has been devel-
oped.
Methods to increase the perspectives in holography based on
synthetic aperture have been implemented.
Apart from these primary contributions, the author of this thesis has
also contributed in the form of assisting in experiments, creating gures
for various papers, writing computer programs and discussions during
group meetings. In total, 6 peer-reviewed journal papers (3 being
primary author) have been published and 6 conference proceedings (3
being primary author) have been published. Additionally, 2 talks have
been given at international conferences
Recommended from our members
Automated system design for the efficient processing of solar satellite images. Developing novel techniques and software platform for the robust feature detection and the creation of 3D anaglyphs and super-resolution images for solar satellite images.
The Sun is of fundamental importance to life on earth and is studied by scientists from many disciplines. It exhibits phenomena on a wide range of observable scales, timescales and wavelengths and due to technological developments there is a continuing increase in the rate at which solar data is becoming available for study which presents both opportunities and challenges. Two satellites recently launched to observe the sun are STEREO (Solar TErrestrial RElations Observatory), providing simultaneous views of the SUN from two different viewpoints and SDO (Solar Dynamics Observatory) which aims to study the solar atmosphere on small scales and times and in many wavelengths. The STEREO and SDO missions are providing huge volumes of data at rates of about 15 GB per day (initially it was 30 GB per day) and 1.5 terabytes per day respectively. Accessing these huge data volumes efficiently at both high spatial and high time resolutions is important to support scientific discovery but requires increasingly efficient tools to browse, locate and process specific data sets.
This thesis investigates the development of new technologies for processing information contained in multiple and overlapping images of the same scene to produce images of improved quality. This area in general is titled Super Resolution (SR), and offers a technique for reducing artefacts and increasing the spatial resolution. Another challenge is to generate 3D images such as Anaglyphs from uncalibrated pairs of SR images. An automated method to generate SR images is presented here. The SR technique consists of three stages: image registration, interpolation and filtration. Then a method to produce enhanced, near real-time, 3D solar images from uncalibrated pairs of images is introduced.
Image registration is an essential enabling step in SR and Anaglyph processing. An accurate point-to-point mapping between views is estimated, with multiple images registered using only information contained within the images themselves. The performances of the proposed methods are evaluated using benchmark evaluation techniques. A software application called the SOLARSTUDIO has been developed to integrate and run all the methods introduced in this thesis. SOLARSTUDIO offers a number of useful image processing tools associated with activities highly focused on solar images including: Active Region (AR) segmentation, anaglyph creation, solar limb extraction, solar events tracking and video creation
Network distributed 3D video quality monitoring system
This project description presents a research and development work whose primary goal
was the design and implementation of an Internet Protocol (IP) network distributed
video quality assessment tool. Even though the system was designed to monitor H.264
three-dimensional (3D) stereo video quality it is also applicable to di erent formats of 3D
video (such as texture plus depth) and can use di erent video quality assessment models
making it easily customizable and adaptable to varying conditions and transmission
scenarios.
The system uses packet level data collection done by a set of network probes located
at convenient network points, that carry out packet monitoring, inspection and analysis
to obtain information about 3D video packets passing through the probe's locations.
The information gathered is sent to a central server for further processing including 3D
video quality estimation based on packet level information.
Firstly an overview of current 3D video standards, their evolution and features is
presented, strongly focused on H.264/AVC and HEVC. Then follows a description of
video quality assessment metrics, describing in more detail the quality estimator used
in the work. Video transport methods over the Internet Protocol are also explained in
detail as thorough knowledge of video packetization schemes is important to understand
the information retrieval and parsing performed at the front stage of the system, the
probes.
After those introductory themes are addressed, a general system architecture is
shown, explaining all its components and how they interact with each other. The development
steps of each of the components are then thoroughly described.
In addition to the main project, a 3D video streamer was created to be used in the
implementation tests of the system. This streamer was purposely built for the present
work as currently available free-domain streamers do not support 3D video streaming.
The overall result is a system that can be deployed in any IP network and is
exible
enough to help in future video quality assessment research, since it can be used as
a testing platform to validate any proposed new quality metrics, serve as a network
monitoring tool for video transmission or help to understand the impact that some
network characteristics may have on video quality
The Art of Movies
Movie is considered to be an important art form; films entertain, educate, enlighten and inspire audiences.
Film is a term that encompasses motion pictures as individual projects, as well as — in metonymy — the field in general. The origin of the name comes from the fact that photographic film (also called filmstock) has historically been the primary medium for recording and displaying motion pictures. Many other terms exist — motion pictures (or just pictures or “picture”), the silver screen, photoplays, the cinema, picture shows, flicks — and commonly movies