Differences between revisions 8 and 13 (spanning 5 versions)

Contents

Adding and multiplying images

The following example shows various ways of adding, subtracting, multiplying and dividing images. The given example uses 2D images but the functionality generalizes for 3D images.

Adding and multiplying images

First I make different two example images that have the same dimensions

   1 [someone@localhost] e2.py
   2 
   3 Welcome to EMAN2
   4 Prompt provided by IPython
   5 Enter '?' for ipython help
   6 
   7 In [3]:  A = test_image(0)
   8 
   9 In [4]:  B = test_image(1)

or try a = test_image_3d(2), a = test_image(0) etc - see the test image gallery.

Add/multiply/subtract/divide images and store the result in a new image

   1 In [5]: C = A + B # add two images, the result is stored in C
   2 
   3 In [6]: display(C) # observe C
   4 
   5 In [7]: C = A * B # multiply the two images component wise, the result is stored in C
   6 
   7 In [7]: C = A / B # division
   8 
   9 In [8]: C = A - B # subtraction

Add/multiply B and A, store result in A

   1 In [9]: A.add(B) # Add the pixels of A to the pixels of B - result stored in A
   2 
   3 In [10]: A.mult(B) # Multiple the pixels in a by the pixels of B - result stored in A

Subtract B from A and store it in A

   1 In [11]: C = B*-1 # multiply B by negative one, store it C
   2 
   3 In [12]: A.add(C) # equivalent to subtracting B from A
   4 
   5 In [13]: A.add(B*-1) # equivalent to line above

EMAN2/Tutorials/AddAndMultiply (last edited 2009-03-06 17:36:06 by DavidWoolford)

-  ⇤ ← Revision 8 as of 2009-02-04 21:07:22 → 
  Size: 1271
  Editor: DavidWoolford
  Comment:
+   ← Revision 13 as of 2009-03-06 17:36:06 → ⇥
  Size: 1452
  Editor: DavidWoolford
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
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-The following example shows various ways of adding and multiplying images. The given example uses 3D images but the functionality generalizes for 2D images.
+<<TableOfContents>>
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-= Set up 2 identical images =
+The following example shows various ways of adding, subtracting, multiplying and dividing images. The given example uses 2D images but the functionality generalizes for 3D images.

= Adding and multiplying images =

First I make different two example images that have the same dimensions
-Line 11:
+Line 16:
-In [3]:  e = EMData()
+In [3]:  A = test_image(0)
-Line 13:
+Line 18:
-In [4]:  e.set_size(32,32,32)
+In [4]:  B = test_image(1)
}}}
-Line 15:
+Line 21:
-In [5]:  e.process_inplace('testimage.axes')
+''or try a = test_image_3d(2), a = test_image(0) etc - see the [[EMAN2/Galleries/Testimages|test image gallery]].''
-Line 17:
+Line 23:
-In [6]:  f = e.copy() # f is precise replica of e
}}}
''or try a = test_image_3d(2), a = test_image(0) etc - see the [[EMAN2/Galleries/Testimages|test image gallery]].'
-Line 21:
+Line 24:
-= Make e different to f =
+== Add/multiply/subtract/divide images and store the result in a new image ==
-Line 24:
+Line 27:
-In [7]:  t = Transform({"type":"eman","alt":45,"phi":20,"az":11})
+In [5]: C = A + B # add two images, the result is stored in C
-Line 26:
+Line 29:
-In [8]:  t.set_trans(1,-2,5)
+In [6]: display(C) # observe C
-Line 28:
+Line 31:
-In [9]:  t.set_mirror(True)
+In [7]: C = A * B # multiply the two images component wise, the result is stored in C
-Line 30:
+Line 33:
-In [10]:  e.transform(t)
+In [7]: C = A / B # division
-Line 32:
+Line 35:
-In [11]: e.mult(2.5) # multiply all pixel values by 2.5

In [12]: e.add(13) # Adds 13 to all pixels
+In [8]: C = A - B # subtraction
-Line 37:
+Line 38:
-= Add and multiply images =
+== Add/multiply B and A, store result in A ==
-Line 40:
+Line 41:
-In [13]: g = f + e # add two images, the result is stored in g
+In [9]: A.add(B) # Add the pixels of A to the pixels of B - result stored in A
-Line 42:
+Line 43:
-In [14]: display(g) # observe g
+In [10]: A.mult(B) # Multiple the pixels in a by the pixels of B - result stored in A
-Line 44:
+Line 45:
-In [15]: f.add(e) # Add the pixels of e into f directly
+}}}
-Line 46:
+Line 47:
-In [16]: f.mult(e) # Multiple the pixels in f by the pixels in e
+== Subtract B from A and store it in A ==
-Line 48:
+Line 49:
-In [17]: g = f * e # Multiple the pixels in f by the pixels in e and store the result in g
+{{{#!python
In [11]: C = B*-1 # multiply B by negative one, store it C

In [12]: A.add(C) # equivalent to subtracting B from A

In [13]: A.add(B*-1) # equivalent to line above