[scikit-image] How to see full image after transformation not the cropped one

[Stefan van der Walt]

Hi Serge



Hhere you go (attached).



Notes:



- The transform is very sensitive *outside of any coordinates specified
  in the source coordinates*, so make sure it covers your whole image
- The process I follow here is as follows: estimate the transform,
  calculate where the corners of the image will go, then estimate a new
  transform that includes a shift that positions the result on a new,
  larger output image
- Estimate `affine` (forward) and warp on `affine.inverse` (because warp
  expects an inverse transformation to be provided)


I hope that helps!



Stéfan





On Thu, Apr 6, 2017, at 15:50, Stefan van der Walt wrote:

> On Thu, Apr 6, 2017, at 09:57, Stefan van der Walt wrote:

>> On Wed, Apr 5, 2017, at 19:02, Serge Shakhov wrote:

>>>  Just want to clarify. Am I right that your solution isn't
>>>  applicable to PiecewiseAffineTransform at all?
>>> Do you think it may be possible to find a workaround?

>> 

>> Sorry, I should have been clearer.  With "defined" I meant
>> implemented.
> 

> Upon closer inspection, it turns out that the PiecewiseAffineTransform
> *does* have an inverse implemented.  It was the "+" operator causing
> the problem.
> 

> Still, I have found cases now where I get invalid answers for valid-
> seeming sets of coordinates.  I'm investigating further, but I think I
> have a solution to your problem.
> 

> Stéfan

> 

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