Diff for "EMAN2/Tutorials/ri2ap"

Differences between revisions 7 and 11 (spanning 4 versions)

Changing image format from real/imaginary to amplitude/phase format in EMAN2 is a straightforward procedure. To illustrate the process start with a test image and perform an inplace Fourier transform on it as follows:

   1 [someone@localhost] e2.py
   2 
   3 Welcome to EMAN2
   4 Prompt provided by IPython
   5 Enter '?' for ipython help
   6 
   7 In [3]:  e = EMData(32,32,32)
   8 
   9 In [4]:  e.process_inplace("testimage.axes")
  10 
  11 In [5]:  e.do_fft_inplace()

You now have an EMData object (e) in real/imaginary format. You can verify that the image is in this format by calling the function is_ri, for example try:

   1 In [6]:  e.is_ri()
   2 Out[6]:  True

To convert the image to amplitude/phase format simply do the following:

   1 In [7]:  e.ri2ap()
   2 
   3 In [8]:  e.is_ri()
   4 Out[8]:  False
   5 
   6 In [9]:  e.get(2,0,0)
   7 Out[9]:  62.0
   8 
   9 In [10]:  e.get(3,0,0)
  10 Out[10]:  3.1415927410125732

Note that it's relatively straightforward to access values from the EMData object (e) using the get function call, and that we have verified the EMData object is in amplitude/phase format using the function is_ri, as demonstrated above. Finally, you can convert back to to real/imaginary format by doing:

   1 In [11]:  e.ap2ri()
   2 
   3 In [12]:  e.is_ri()
   4 Out[12]:  True

-  ⇤ ← Revision 7 as of 2008-02-12 23:18:00 → 
  Size: 1210
  Editor: DavidWoolford
  Comment:
+   ← Revision 11 as of 2009-02-04 21:08:46 → ⇥
  Size: 1337
  Editor: DavidWoolford
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
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-{{{
[someone@localhost]$ e2.py
+{{{#!python
[someone@localhost] e2.py
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-You now have an EMData object (e) in real/imaginary format. To convert the image to amplitude/phase format simply do the following:
+You now have an EMData object (e) in real/imaginary format. You can verify that the image is in this format by calling the function '''is_ri''', for example try:
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-{{{
+{{{#!python
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+}}}

To convert the image to amplitude/phase format simply do the following:

{{{#!python
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+Line 44:
-Note that it's relatively straightforward to access values from the EMData object (e) using the '''get''' function call, and that you can always tell if an EMData object is in real/imag or amplitude/phase format by calling the function '''is_ri''', as demonstrated above. Finally, you can convert back to to real/imaginary format by doing:
+Note that it's relatively straightforward to access values from the EMData object (e) using the '''get''' function call, and that we have verified the EMData object is in amplitude/phase format using the function '''is_ri''', as demonstrated above. Finally, you can convert back to to real/imaginary format by doing:
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+Line 46:
-{{{
+{{{#!python