estimate-transform

estimate_transform

skimage.transform.estimate_transform(ttype, src, dst, **kwargs) [source]

Estimate 2D geometric transformation parameters.

You can determine the over-, well- and under-determined parameters with the total least-squares method.

Number of source and destination coordinates must match.

Parameters:	ttype : {‘similarity’, ‘affine’, ‘piecewise-affine’, ‘projective’, ‘polynomial’} Type of transform. kwargs : array or int Function parameters (src, dst, n, angle): NAME / TTYPE FUNCTION PARAMETERS 'similarity' `src, `dst` 'affine' `src, `dst` 'piecewise-affine' `src, `dst` 'projective' `src, `dst` 'polynomial' `src, `dst`, `order` (polynomial order, default order is 2) Also see examples below.
Returns:	tform : GeometricTransform Transform object containing the transformation parameters and providing access to forward and inverse transformation functions.

Examples

>>> import numpy as np
>>> from skimage import transform as tf

>>> # estimate transformation parameters
>>> src = np.array([0, 0, 10, 10]).reshape((2, 2))
>>> dst = np.array([12, 14, 1, -20]).reshape((2, 2))

>>> tform = tf.estimate_transform('similarity', src, dst)

>>> np.allclose(tform.inverse(tform(src)), src)
True

>>> # warp image using the estimated transformation
>>> from skimage import data
>>> image = data.camera()

>>> warp(image, inverse_map=tform.inverse) 

>>> # create transformation with explicit parameters
>>> tform2 = tf.SimilarityTransform(scale=1.1, rotation=1,
...     translation=(10, 20))

>>> # unite transformations, applied in order from left to right
>>> tform3 = tform + tform2
>>> np.allclose(tform3(src), tform2(tform(src)))
True