Diff for "EMAN2/Tutorials/ri2ap"

Differences between revisions 7 and 8

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:

[someone@localhost]$ e2.py

Welcome to EMAN2
Prompt provided by IPython
Enter '?' for ipython help

In [3]:  e = EMData(32,32,32)

In [4]:  e.process_inplace("testimage.axes")

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:

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

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

In [7]:  e.ri2ap()

In [8]:  e.is_ri()
Out[8]:  False

In [9]:  e.get(2,0,0)
Out[9]:  62.0

In [10]:  e.get(3,0,0)
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 that EMData 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:

In [11]:  e.ap2ri()

In [12]:  e.is_ri()
Out[12]:  True

-  ⇤ ← Revision 7 as of 2008-02-12 23:18:00 → 
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  Editor: DavidWoolford
  Comment:
+   ← Revision 8 as of 2008-02-12 23:21:09 → ⇥
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  Editor: DavidWoolford
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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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+}}}

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

{{{
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-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 that EMData 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: