Abstract—The contourlet transform is a new two-dimensional
extension of the wavelet transform using multiscale and direc-
tional fi lter banks. The contourlet expansion is composed of
basis images oriented at various directions in multiple scales,
with fl exible aspect ratios. Given this rich set of basis images,
the contourlet transform effectively captures smooth contours
that are the dominant feature in natural images.
外國人開發的電磁時域有限差分方法工具包
Electromagnetic Finite-Difference Time-Domain (EmFDTD)
is a basic two-dimensional FDTD code developed at the
School of Electrical Engineering, Sharif University of
Technology.
This code has been written based on the standard
Yee s FDTD algorithm. Applications include propagation,
scattering, and diffraction of electromagnetic waves
in homogeneous and non-homogeneous isotropic media
for in-plane propagating waves. Negative permittivites
or permeabilities as well as dispersion is not included.
Zero, Periodic, and Perfectly Matched Layer boundary
conditions may be selectively applied to the solution
domain.
The program is best suited for study of propagation and
diffraction of electromagnetic waves in Photonic Crystal
structures.
EmFDTD is written in MATLAB language and has been
tested under MATLAB 5.0 and higher versions.
A cylindrical wave expansion method is developed to obtain the scattering field for an ideal
two-dimensional cylindrical invisibility cloak. A near-ideal model of the invisibility cloak is set up
to solve the boundary problem at the inner boundary of the cloak shell. We confirm that a cloak
with the ideal material parameters is a perfect invisibility cloak by systematically studying the
change of the scattering coefficients from the near-ideal case to the ideal one. However, due to the
slow convergence of the zeroth order scattering coefficients, a tiny perturbation on the cloak would
induce a noticeable field scattering and penetration.
This application note describes the implementation of a two-dimensional Rank Order filter. Thereference design includes the RTL VHDL implementation of an efficient sorting algorithm. Thedesign is parameterizable for input/output precision, color standards, filter kernel size,maximum horizontal resolution, and implementation options. The rank to be selected can bemodified dynamically, and the actual horizontal resolution is picked up automatically from theinput synchronization signals. The design has a fully synchronous interface through the ce, clk,and rst ports.
The tar file contains the following files:
ptfsf.c: heart of the perfect TFSF code
ptfsf.h: header file for same
ptfsf-demo.c: FDTD code which demonstrates use of perfect TFSF code. Essentially this program used to generate results shown in the paper
ptfsf-file-maker.c: code to generate an incident-field file using the "perfect" incident fields
ptfsf-demo-file.c: FDTD code which uses the perfect incident fields stored in a file
fdtdgen.h: defines macros used in much of my code
Makefile: simple make-file to compile programs
Also include are some simple script files to run the programs with reasonable values.
The code assumes a two-dimensional computational domain with TMz polarization (i.e., non-zero field Ez, Hx, and Hy). The program is currently written so that the incident field always strikes the lower-left corner of the total-field region first. (If you want a different corner, that should be a fairly simple tweak to the code, but for now you ll have to make that tweak yourself.)
這是06年4月剛剛完成的程序，從opencore.org下載而來。用vhdl語言描寫，以及matlab仿真，testbench，以及在xinlinx上的綜合。
The MDCT core is two dimensional discrete cosine transform implementation designed for use in compression systems like JPEG. Architecture is based on parallel distributed arithmetic with butterfly computation.
Abstract-The effect of the companding process on QAM signals
has been under investigation for the past several years. The
compander, included in the PCM telephone network to improve
voice performance, has an unusual affect on digital QAM data
signals which are transmitted over the same channel. The quantization
noise, generated by the companding process which is multiplicative
(and asymmetric), degrades the detectability performance
of the outermost points of the QAM constellation more
than that of the inner points.
The combined effect of the companding noise and the inherent
white gaussian noise of the system, leads us to a re-examination of
signal constellation design.
In this paper we investigate the detectability performance of a
number of candidates for signal constellations including, a typical
rectangular QAM constellation, the same constellation with the
addition of a smear-desmear operation, and two new improved
QAM constellation designs with two-dimensional warpi
We describe and demonstrate an algorithm that takes as input an
unorganized set of points fx1 xng IR3 on or near an unknown
manifold M, and produces as output a simplicial surface that
approximates M. Neither the topology, the presence of boundaries,
nor the geometry of M are assumed to be known in advance — all
are inferred automatically from the data. This problem naturally
arises in a variety of practical situations such as range scanning
an object from multiple view points, recovery of biological shapes
from two-dimensional slices, and interactive surface sketching.
The frequency domain plays an important role in image
processing to smooth, enhance, and detect edges of images. Although
image data typically does not include imaginary values, the fast Fourier
transform (FFT) has been used for obtaining spectra. In this paper,
the fast Hartley transform (FHT) is used to transform two-dimensional
image data. Because the Hartley transform is real valued, it does
not require complex operations. Both spectra and autocorrelations of
two-dimensional ultrasound images of normal and abnormal livers were
computed.
