prtools.crop#

crop(x, shape, shift=None, mode='absolute', indexing='ij')[source]#

Extract a contiguous subarray from a larger array.

The subarray is extracted about the center of the source array unless a shift is specified.

Parameters:

x (array_like) – Source array
shape (array_like of ints) – Shape of subarray array in (nrows, ncols).
shift (array_like of ints, optional) – Subarray center shift. Default is None (subarray is extracted about the center of the source array).
mode ({'absolute', 'center'}, optional) – Specifies how the subarray center located. If ‘absolute’ (default) the subarray is extracted about the location given by shift. If ‘center’, the subarray is extracted about the center of the source array shifted by shift.
indexing ({'ij', 'xy'}, optional) – Matrix (‘ij’, default) or cartesian (‘xy’) indexing of shift.

Returns:

out – Subarray extracted from the source array.

Return type:

ndarray

See also

pad()

Examples

>>> circ = prtools.circle(shape=(128,128), radius=64)
>>> circ_crop = prtools.crop(circ, shape=(110,110))
>>> fig, ax = plt.subplots(nrows=1, ncols=2, figsize=(5,2))
>>> ax[0].imshow(circ, cmap='gray')
>>> ax[0].set_title('Original array')
>>> ax[1].imshow(circ_crop, cmap='gray')
>>> ax[1].set_title('Subarray')

>>> circ = prtools.circle(shape=(128,128), radius=64)
>>> circ_crop = prtools.crop(circ, shape=(64,64), shift=(32,32))
>>> fig, ax = plt.subplots(nrows=1, ncols=2, figsize=(5,2))
>>> ax[0].imshow(circ, cmap='gray')
>>> ax[0].set_title('Original array')
>>> ax[1].imshow(circ_crop, cmap='gray')
>>> ax[1].set_title('Subarray')

>>> circ = prtools.circle(shape=(128,128), radius=64)
>>> circ_crop = prtools.crop(circ, shape=(64,64), shift=(-32,-32),
...                                  mode='center')
>>> fig, ax = plt.subplots(nrows=1, ncols=2, figsize=(5,2))
>>> ax[0].imshow(circ, cmap='gray')
>>> ax[0].set_title('Original array')
>>> ax[1].imshow(circ_crop, cmap='gray')
>>> ax[1].set_title('Subarray')