Rotating and/or Translating Images

What follows is a very simply demonstration of using the Transform object to transform EMData (image) objects. A very thorough explanation of using the Transform is presented in Using the EMAN2 Transform class and you are encouraged to at least be aware of that page's existence.

Using EMData.transform

The first example here is a 3D example.

   1 [someone@localhost]# e2.py
   2 
   3 Welcome to EMAN2
   4 Prompt provided by IPython
   5 Enter '?' for ipython help
   6 
   7 
   8 In [3]:  e = test_image_3d()
   9 
  10 In [4]:  t = Transform({"type":"eman","az":45,"alt":90})
  11 
  12 In [5]:  t.set_trans(1,-2,5)
  13 
  14 In [6]:  t.set_scale(1)
  15 
  16 In [7]:  e.transform(t)
  17 
  18 In [8]:  display(e)

This second example is a 2D example.

   1 In [9]:  e = test_image() # This is a 2D test image
   2 
   3 In [10]:  t = Transform({"type":"2d","alpha":45}) # Note 2D terminology
   4 
   5 In [11]:  t.set_trans(3,-2) # Note 2D translation
   6 
   7 In [12]:  t.set_mirror(True)
   8 
   9 In [13]:  e.transform(t)
  10 
  11 In [14]:  display(e)

Using the Processor Framework

You can use the processor framework to process an EMData object in and out of place. In the latter case it is more efficient to use the processing framework as opposed to make a copy followed by EMData.transform.

   1 In [15]:  t = Transform(....) # Construct a transform as above
   2 
   3 In [16]:  out_of_place = e.process("math.transform",{"transform":t}) # Out of place
   4 
   5 In [17]:  e.process_inplace("math.transform",{"transform":t}) # Inplace
   6 
   7 In [18]:  e.transform(t) # exactly the same as line above