<< Chapter < Page
  Digital signal processing - dsp     Page 7 / 21
Chapter >> Page >

End of the ImgMod30 class

Listing 4 also signals the end of the class definition for the class named ImgMod30.

The program named ImgMod31

The purpose of this program is to exercise and to test the 2D Fourier transform methods and the axis shifting method provided by the class namedImgMod30.

Command line parameters

The main method in this class reads two command line parameters and uses them to select:

  • A specific case involving a particular 3D input surface in the space domain.
  • A specific display format.

Forward and inverse Fourier transforms

The program performs a 2D Fourier transform on that surface followed by an inverse 2D Fourier transform. Six different plots are produced in this processshowing different aspects of the transform and the inverse transform.

Fourteen cases

There are 14 different cases built into the program with case numbers ranging from 0 to 13 inclusive. Each of the cases is designed such that the results ofthe analysis should be known in advance by a person familiar with 2D Fourier analysis and the wavenumber domain. Thus, these cases can be used to confirmthat the transform code was properly written.

The cases are also designed to illustrate the impact of various space domain characteristics on the wavenumber spectrum. This information will be usefullater when analyzing the results of performing 2D transforms on photographic images for example.

A stack of output images

Each time the program is run, it produces a stack of six output images in the top-left corner of the screen. A brief description of each of the outputimages is provided in the following list. The top-to-bottom order of the stack is:

  1. Space domain output of inverse Fourier transform. Compare with original input in 6 below.
  2. Amplitude spectrum in wavenumber domain with shifted origin. Compare with 5 below.
  3. Imaginary wavenumber spectrum with shifted origin.
  4. Real wavenumber spectrum with shifted origin.
  5. Amplitude spectrum in wavenumber domain without shifted origin. Compare with 2 above.
  6. Space domain input data. Compare with 1 above.

To view the images near the bottom of the stack, you must physically move those on top to get them out of the way.

Numeric output

In addition, the program produces some numeric output on the command line screen that may be useful in confirming the validity of the forward and inversetransform processes. Figure 2 shows an example of the numeric output.

Figure 2. Numeric output.
height = 41 width = 41height = 41 width = 412.0 1.9999999999999916 0.5000000000000002 0.499999999999998450.49999999999999956 0.4999999999999923 1.7071067811865475 1.70710678118655260.2071067811865478 0.20710678118654233 0.20710678118654713 0.207106781186554351.0 1.0000000000000064 -0.4999999999999997 -0.49999999999999484-0.5000000000000003 -0.4999999999999965

(Note that I manually inserted some and spaces line breaks in Figure 2 to cause the numeric values to line up in columns so as to be morereadable.)

The size of the surfaces

The first two lines of numeric output in Figure 2 show the size of the spatial surface for the forward transform. The second two lines show the size ofthe wavenumber surface for the inverse transform.

Questions & Answers

what is mutation
Janga Reply
what is a cell
Sifune Reply
how is urine form
Sifune
what is antagonism?
mahase Reply
classification of plants, gymnosperm features.
Linsy Reply
what is the features of gymnosperm
Linsy
how many types of solid did we have
Samuel Reply
what is an ionic bond
Samuel
What is Atoms
Daprince Reply
what is fallopian tube
Merolyn
what is bladder
Merolyn
what's bulbourethral gland
Eduek Reply
urine is formed in the nephron of the renal medulla in the kidney. It starts from filtration, then selective reabsorption and finally secretion
onuoha Reply
State the evolution relation and relevance between endoplasmic reticulum and cytoskeleton as it relates to cell.
Jeremiah
what is heart
Konadu Reply
how is urine formed in human
Konadu
how is urine formed in human
Rahma
what is the diference between a cavity and a canal
Pelagie Reply
what is the causative agent of malaria
Diamond
malaria is caused by an insect called mosquito.
Naomi
Malaria is cause by female anopheles mosquito
Isaac
Malaria is caused by plasmodium Female anopheles mosquitoe is d carrier
Olalekan
a canal is more needed in a root but a cavity is a bad effect
Commander
what are pathogens
Don Reply
In biology, a pathogen (Greek: πάθος pathos "suffering", "passion" and -γενής -genēs "producer of") in the oldest and broadest sense, is anything that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. The term pathogen came into use in the 1880s.[1][2
Zainab
A virus
Commander
Definition of respiration
Muhsin Reply
respiration is the process in which we breath in oxygen and breath out carbon dioxide
Achor
how are lungs work
Commander
where does digestion begins
Achiri Reply
in the mouth
EZEKIEL
what are the functions of follicle stimulating harmones?
Rashima Reply
stimulates the follicle to release the mature ovum into the oviduct
Davonte
what are the functions of Endocrine and pituitary gland
Chinaza
endocrine secrete hormone and regulate body process
Achor
while pituitary gland is an example of endocrine system and it's found in the Brain
Achor
what's biology?
Egbodo Reply
Biology is the study of living organisms, divided into many specialized field that cover their morphology, physiology,anatomy, behaviour,origin and distribution.
Lisah
biology is the study of life.
Alfreda
Biology is the study of how living organisms live and survive in a specific environment
Sifune
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Digital signal processing - dsp. OpenStax CNX. Jan 06, 2016 Download for free at https://legacy.cnx.org/content/col11642/1.38
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Digital signal processing - dsp' conversation and receive update notifications?

Ask