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Examine the code for a Java class that can be used to perform forward and inverse 2D Fourier transforms on 3D surfaces in the space domain. Learn how the 2D Fourier transform behaves for a variety of different sample surfaces in the space domain.
Revised: Wed Oct 21 16:16:44 CDT 2015
This page is included in the following book:
Digital Signal Processing - DSP
Table of contents
Preface
This is the second module in a two-part series. The first part published
earlier was titled
Java1490-2D Fourier Transforms using Java, Part 1 . In this module, I will
teach you how to perform two-dimensional (2D) Fourier transforms using Java. Iwill
- Explain the conceptual and computational aspects of 2D Fourier
transforms
- Explain the relationship between the space domain and the
wavenumber domain
- Provide sufficient background information that you will be able to
appreciate the importance of the 2D Fourier transform
- Provide Java software to perform 2D Fourier transforms
- Provide Java software to test and exercise that capability
Two separate programs
I will present and explain two separate programs. One program consists of a
single class named
ImgMod30 . The purpose of this class is to
satisfy the computational requirements for forward and inverse 2D Fouriertransforms. This class also provides a method for rearranging the spectral data
into a more useful format for plotting. The second program named
ImgMod31 will be used to test the 2D Fourier transform class, and also
to illustrate the use of 2D Fourier transforms for some well known samplesurfaces.
A third class named
ImgMod29 will be used to display various
3D surfaces resulting from the application of the 2D Fourier transform. Iexplained this class in an earlier module titled
Plotting 3D Surfaces using Java .
Using the class named ImgMod30
The 2D Fourier transform class couldn't be easier to use. To perform a
forward transform execute a statement similar to the following:
ImgMod30.xform2D(spatialData,realSpect,
imagSpect,amplitudeSpect);
The first parameter in the above statement is a reference to an array object
containing the data to be transformed. The other three parameters refer to arrayobjects that will be populated with the results of the transform.
To perform an inverse transform execute a statement similar to the following:
Questions & Answers
how does the planets on our solar system orbit
how many Messier objects are there in space
Astronomy (from Ancient Greek ἀστρονομία (astronomía) 'science that studies the laws of the stars') is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution.
Rafael
what is big bang theory?
Rosemary
what type of activity astronomer do?
Rosemary
the big bang theory is a theory which states that all matter was compressed together in one place the matter got so unstable it exploded releasing All its contents in the form of hydrogen
Roaul
I want to be an astronomer. That's my dream
Astrit
Who named the the whole galaxy?
what is the dark matter
Richard
what are the factors upon which the atmosphere is stratified
bigbang is the beginning of the universe
Sokak
but thats just a theory
Sokak
nothing will happen, don't worry brother.
Vansh
these are Rocky substances between mars and jupiter
GANGAIN
Comets are cosmic snowballs of frozen gases , rock and dust that orbit the sun. They are mostly found between the orbits of Venus and Mercury.
Aarya
hey can anyone guide me abt international astronomy olympiad
sahil
how can we learn right and true ?
why the moon is always appear in an elliptical shape
Because when astroid hit the Earth then a piece of elliptical shape of the earth was separated which is now called moon.
Hemen
Did you mean eye sight or sea level
Minal
oh sorry it's sea level
lidiya
according to the theory of astronomers why the moon is always appear in an elliptical orbit?
Gatjuol
hi !!! I am new in astronomy....
I have so many questions in mind ....
all of scientists of the word they just give opinion only.
but they never think true or false ...
i respect all of them...
I believes whole universe depending
on true ...থিউরি
Govinda
we're all stars and galaxies a part of sun. how can science prove thx with respect old ancient times picture or books..or anything with respect to present time .but we r a part of that universe
w astronomy and cosmology!
Michele
another theory of universe except big ban
there many theory to born universe but what is the reality of big bang theory to born universe
Asmit
what is the exact value of π?
Nagalakshmi
there are many theories regarding this it's on you believe any theory that you think is true ex. eternal inflation theory, oscillation model theory, multiple universe theory the big bang theory etc.
Aarya
I think after Big Bang!
Michele
from where on earth could u observe all the stars during the during the course of an year
I think it couldn't possible on earth
Nagalakshmi
in this time i don't Know
Michele
is that so. the question was in the end of this chapter
Karuna
in theory, you could see them all from the equator (though over the course of a year, not at pne time). stars are measured in "declination", which is how far N or S of the equator (90* to -90*). Polaris is the North star, and is ALMOST 90* (+89*).
So it would just barely creep over the horizon.
Christopher
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Source:
OpenStax, Digital signal processing - dsp. OpenStax CNX. Jan 06, 2016 Download for free at https://legacy.cnx.org/content/col11642/1.38
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