Utilities used by wiimatch

This module provides utility functions for use by wiimatch module.

Author:Mihai Cara (contact: help@stsci.edu)

jwst.wiimatch.utils.create_coordinate_arrays(image_shape, center=None, image2world=None, center_cs='image')

Create a list of coordinate arrays/grids for each dimension in the image shape. This function is similar to numpy.indices except it returns the list of arrays in reversed order. In addition, it can center image coordinates to a provided center and also convert image coordinates to world coordinates using provided image2world function.

image_shape : sequence of int

The shape of the image/grid.

center : iterable, None, optional

An iterable of length equal to the number of dimensions in image_shape that indicates the center of the coordinate system in image coordinates when center_cs is 'image' otherwise center is assumed to be in world coordinates (when center_cs is 'world'). When center is None then center is set to the middle of the “image” as center[i]=image_shape[i]//2. If image2world is not None and center_cs is 'image', then supplied center will be converted to world coordinates.

image2world : function, None, optional

Image-to-world coordinates transformation function. This function must be of the form f(x,y,z,...) and accept a number of arguments numpy.ndarray arguments equal to the dimensionality of images.

center_cs : {‘image’, ‘world’}, optional

Indicates whether center is in image coordinates or in world coordinates. This parameter is ignored when center is set to None: it is assumed to be False. center_cs cannot be 'world' when image2world is None unless center is None.

coord_arrays : list

A list of numpy.ndarray coordinate arrays each of image_shape shape.

eff_center : tuple

A tuple of coordinates of the effective center as used in generating coordinate arrays.

coord_system : {‘image’, ‘world’}

Coordinate system of the coordinate arrays and returned center value.

>>> import wiimatch
>>> wiimatch.utils.create_coordinate_arrays((3,5,4))
((array([[[-1.,  0.,  1.,  2.],
          [-1.,  0.,  1.,  2.],
          [-1.,  0.,  1.,  2.],
          [-1.,  0.,  1.,  2.],
          [-1.,  0.,  1.,  2.]],
         [[-1.,  0.,  1.,  2.],
          [-1.,  0.,  1.,  2.],
          [-1.,  0.,  1.,  2.],
          [-1.,  0.,  1.,  2.],
          [-1.,  0.,  1.,  2.]],
         [[-1.,  0.,  1.,  2.],
          [-1.,  0.,  1.,  2.],
          [-1.,  0.,  1.,  2.],
          [-1.,  0.,  1.,  2.],
          [-1.,  0.,  1.,  2.]]]),
    array([[[-2., -2., -2., -2.],
          [-1., -1., -1., -1.],
          [ 0.,  0.,  0.,  0.],
          [ 1.,  1.,  1.,  1.],
          [ 2.,  2.,  2.,  2.]],
         [[-2., -2., -2., -2.],
          [-1., -1., -1., -1.],
          [ 0.,  0.,  0.,  0.],
          [ 1.,  1.,  1.,  1.],
          [ 2.,  2.,  2.,  2.]],
         [[-2., -2., -2., -2.],
          [-1., -1., -1., -1.],
          [ 0.,  0.,  0.,  0.],
          [ 1.,  1.,  1.,  1.],
          [ 2.,  2.,  2.,  2.]]]),
    array([[[-2., -2., -2., -2.],
          [-2., -2., -2., -2.],
          [-2., -2., -2., -2.],
          [-2., -2., -2., -2.],
          [-2., -2., -2., -2.]],
         [[-1., -1., -1., -1.],
          [-1., -1., -1., -1.],
          [-1., -1., -1., -1.],
          [-1., -1., -1., -1.],
          [-1., -1., -1., -1.]],
         [[ 0.,  0.,  0.,  0.],
          [ 0.,  0.,  0.,  0.],
          [ 0.,  0.,  0.,  0.],
          [ 0.,  0.,  0.,  0.],
          [ 0.,  0.,  0.,  0.]]])), (1.0, 2.0, 2.0), u'image')