2,189 research outputs found
A Real Time Image Processing Subsystem: GEZGIN
In this study, a real-time image processing subsystem, GEZGIN, which is currently being developed for BILSAT-1, a 100kg class micro-satellite, is presented. BILSAT-1 is being constructed in accordance with a technology transfer agreement between TÜBITAK-BILTEN (Turkey) and SSTL (UK) and planned to be placed into a 650 km sunsynchronous orbit in Summer 2003. GEZGIN is one of the two Turkish R&D payloads to be hosted on BILSAT-1. One of the missions of BILSAT-1 is constructing a Digital Elevation Model of Turkey using both multi-spectral and panchromatic imagers. Due to limited down-link bandwidth and on-board storage capacity, employment of a realtime image compression scheme is highly advantageous for the mission. GEZGIN has evolved as an implementation to achieve image compression tasks that would lead to an efficient utilization of both the down-link and on-board storage. The image processing on GEZGIN includes capturing of 4-band multi-spectral images of size 2048x2048 8- bit pixels, compressing them simultaneously with the new industry standard JPEG2000 algorithm and forwarding the compressed multi-spectral image to Solid State Data Recorders (SSDR) of BILSAT-1 for storage and down-link transmission. The mission definition together with orbital parameters impose a 6.5 seconds constraint on real-time image compression. GEZGIN meets this constraint by exploiting the parallelism among image processing units and assigning compute intensive tasks to dedicated hardware. The proposed hardware also allows for full reconfigurability of all processing units
Basics of RF electronics
RF electronics deals with the generation, acquisition and manipulation of
high-frequency signals. In particle accelerators signals of this kind are
abundant, especially in the RF and beam diagnostics systems. In modern machines
the complexity of the electronics assemblies dedicated to RF manipulation, beam
diagnostics, and feedbacks is continuously increasing, following the demands
for improvement of accelerator performance. However, these systems, and in
particular their front-ends and back-ends, still rely on well-established basic
hardware components and techniques, while down-converted and acquired signals
are digitally processed exploiting the rapidly growing computational capability
offered by the available technology. This lecture reviews the operational
principles of the basic building blocks used for the treatment of
high-frequency signals. Devices such as mixers, phase and amplitude detectors,
modulators, filters, switches, directional couplers, oscillators, amplifiers,
attenuators, and others are described in terms of equivalent circuits,
scattering matrices, transfer functions; typical performance of commercially
available models is presented. Owing to the breadth of the subject, this review
is necessarily synthetic and non-exhaustive. Readers interested in the
architecture of complete systems making use of the described components and
devoted to generation and manipulation of the signals driving RF power plants
and cavities may refer to the CAS lectures on Low-Level RF.Comment: 36 pages, contribution to the CAS - CERN Accelerator School:
Specialised Course on RF for Accelerators; 8 - 17 Jun 2010, Ebeltoft, Denmar
EChO Payload electronics architecture and SW design
EChO is a three-modules (VNIR, SWIR, MWIR), highly integrated spectrometer,
covering the wavelength range from 0.55 m, to 11.0 m. The baseline
design includes the goal wavelength extension to 0.4 m while an optional
LWIR module extends the range to the goal wavelength of 16.0 m.
An Instrument Control Unit (ICU) is foreseen as the main electronic subsystem
interfacing the spacecraft and collecting data from all the payload
spectrometers modules. ICU is in charge of two main tasks: the overall payload
control (Instrument Control Function) and the housekeepings and scientific data
digital processing (Data Processing Function), including the lossless
compression prior to store the science data to the Solid State Mass Memory of
the Spacecraft. These two main tasks are accomplished thanks to the Payload On
Board Software (P-OBSW) running on the ICU CPUs.Comment: Experimental Astronomy - EChO Special Issue 201
Web-Based Visualization of Very Large Scientific Astronomy Imagery
Visualizing and navigating through large astronomy images from a remote
location with current astronomy display tools can be a frustrating experience
in terms of speed and ergonomics, especially on mobile devices. In this paper,
we present a high performance, versatile and robust client-server system for
remote visualization and analysis of extremely large scientific images.
Applications of this work include survey image quality control, interactive
data query and exploration, citizen science, as well as public outreach. The
proposed software is entirely open source and is designed to be generic and
applicable to a variety of datasets. It provides access to floating point data
at terabyte scales, with the ability to precisely adjust image settings in
real-time. The proposed clients are light-weight, platform-independent web
applications built on standard HTML5 web technologies and compatible with both
touch and mouse-based devices. We put the system to the test and assess the
performance of the system and show that a single server can comfortably handle
more than a hundred simultaneous users accessing full precision 32 bit
astronomy data.Comment: Published in Astronomy & Computing. IIPImage server available from
http://iipimage.sourceforge.net . Visiomatic code and demos available from
http://www.visiomatic.org
Efficient Hardware Implementation Of Haar Wavelet Transform With Line-Based And Dual-Scan Image Memory Accesses
Image compression is of great importance in multimedia systems and applications because it drastically reduces bandwidth requirements for transmission and
memory requirements for storage. An image compression algorithm JPEG2000 isbased on Discrete Wavelet Transform. In the hardware implementation of DiscreteWavelet
Transform (DWT) and inverse DiscreteWavelet Transform (IDWT),the main problems are storage memory, internal processing buffer, and the limitation of the FPGA resources. Based on non-separable 2-D DWT, the method
used to access the image memory has a direct impact on the internal buffer size,the power consumption and, the transformation speed. The need for internal buffer reduces the image memory access time. The main objectives of this thesis are as follows; to implement a 2-D Haar wavelet transform for large gray-scale image, to reduce the number of image memory access by implementing the 2-
D Haar wavelet transform with a suitable combination between using external memory and internal memory, and targeting a low-power and high-speed architecture
based on multi-levels non-separable discrete Haar wavelet transform. In this work, the proposed two architectures reduce the number of image memory access. The line-based architecture reduces the internal buffer by 2 x 0.5 x N
where N presents the image size. This happens for the low-pass coefficients and for the high-pass coefficients. The dual-scan architecture does not use the internal
memory. Overall both architectures work well on the Altera FPGA board at frequency 100 MHz
VHDL design and simulation for embedded zerotree wavelet quantisation
This thesis discusses a highly effective still image compression algorithm – The Embedded Zerotree Wavelets coding technique, as it is called. This technique is simple but achieves a remarkable result. The image is wavelet-transformed, symbolically coded and successive quantised, therefore the compression and transmission/storage saving can be achieved by utilising the structure of zerotree. The algorithm was first proposed by Jerome M. Shapiro in 1993, however to minimise the memory usage and speeding up the EZW processor, a Depth First Search method is used to transverse across the image rather than Breadth First Search method as initially discussed in Shapiro\u27s paper (Shapiro, 1993). The project\u27s primary objective is to simulate the EZW algorithm from a basic building block of 8 by 8 matrix to a well-known reference image such Lenna of 256 by 256 matrix. Hence the algorithm performance can be measured, for instance its peak signal to noise ratio can be calculated. The software environment used for the simulation is a Very-High Speed Integrated Circuits - Hardware Description Language such Peak VHDL, PC based version. This will lead to the second phase of the project. The secondary objective is to test the algorithm at a hardware level, such FPGA for a rapid prototype implementation only if the project time permits
On the Relationship between Integer Lifting and Rounding Transform
In this paper we analyze the relationship between integer Lifting scheme and Rounding transform as means to compute the wavelet transform in signal processing area. We bring some new results which better describe relationship, reversibility and equivalence of integer lifting scheme and rounding transform concept
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