# vtkImage::GetScalarPointer from Python (to numpy array)?
**URL:** https://discourse.vtk.org/t/vtkimage-getscalarpointer-from-python-to-numpy-array/324
**Category:** Support
**Created:** [February 25, 2019, 4:26pm UTC](https://discourse.vtk.org/t/vtkimage-getscalarpointer-from-python-to-numpy-array/324 "2019-02-25T16:26:47Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@estan](https://discourse.vtk.org/u/estan)
#### Post date: [February 25, 2019, 4:26pm UTC](https://discourse.vtk.org/t/vtkimage-getscalarpointer-from-python-to-numpy-array/324/1 "2019-02-25T16:26:48Z")
It returns a `str` on the format `_00007f55d65c1010_p_void`. Any way to get a Python array to the underlying image data in a zero copy way? I looked at `numpy_support.py` but couldn’t find anything like that.
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### Author:  [@estan](https://discourse.vtk.org/u/estan)
#### Post date: [February 25, 2019, 4:36pm UTC](https://discourse.vtk.org/t/vtkimage-getscalarpointer-from-python-to-numpy-array/324/2 "2019-02-25T16:36:03Z")
Replying to self, I think I found the answer in `Common/Core/Testing/Python/TestSwigPointer.py`.
One can create a VTK array and use `SetVoidArray(..)`.
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### Author:  [@estan](https://discourse.vtk.org/u/estan)
#### Post date: [February 26, 2019, 7:04am UTC](https://discourse.vtk.org/t/vtkimage-getscalarpointer-from-python-to-numpy-array/324/3 "2019-02-26T07:04:32Z")
Worked like a charm. Excerpt from my code:
```python
from vtk import vtkUnsignedCharArray
from vtk.util.numpy_support import vtk_to_numpy
...
array = vtkUnsignedCharArray()
array.SetNumberOfTuples(numBytes)
array.SetVoidArray(image.GetScalarPointer(), numBytes, 1)
frame = vtk_to_numpy(array)
```
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### Author:  [@banesullivan](https://discourse.vtk.org/u/banesullivan)
#### Post date: [February 27, 2019, 2:06am UTC](https://discourse.vtk.org/t/vtkimage-getscalarpointer-from-python-to-numpy-array/324/4 "2019-02-27T02:06:08Z")
FYI, [`vtki`](http://docs.vtki.org/en/latest/) has some very useful numpy-VTK array access helpers that might help you down the road!
say you have some image data (`vtkImageData` = `vtki.UniformGrid`) given in the example dataset:
```python
>>> import vtk
>>> from vtki import examples
>>> import numpy as np
>>> data = examples.load_uniform()
>>> isinstance(data, vtk.vtkImageData)
True
>>> isinstance(data.active_scalar, np.ndarray)
True
```
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### Author:  [@cory.quammen](https://discourse.vtk.org/u/cory.quammen)
#### Post date: [February 27, 2019, 4:55am UTC](https://discourse.vtk.org/t/vtkimage-getscalarpointer-from-python-to-numpy-array/324/5 "2019-02-27T04:55:16Z")
See Berk’s 5-part series of blog posts on VTK/NumPy integration, starting with [Improved VTK – numpy integration](https://blog.kitware.com/improved-vtk-numpy-integration/).
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### Author:  [@estan](https://discourse.vtk.org/u/estan)
#### Post date: [February 27, 2019, 7:51am UTC](https://discourse.vtk.org/t/vtkimage-getscalarpointer-from-python-to-numpy-array/324/6 "2019-02-27T07:51:28Z")
Thanks for the pointers to both of you.
In this case I could make due with just `vtk_to_numpy`. I needed to write the RGB bytes of the image to stdin of an ffmpeg process. Perhaps I could have done that without involving numpy at all (what I did was `process.stdin.write(nparray.tobytes())`)
(The image came from a vtkWindowToImage filter.)