Module « scipy.ndimage »

Fonction zoom - module scipy.ndimage

Signature de la fonction zoom

def zoom(input, zoom, output=None, order=3, mode='constant', cval=0.0, prefilter=True, *, grid_mode=False) 

Description

zoom.__doc__

    Zoom an array.

    The array is zoomed using spline interpolation of the requested order.

    Parameters
    ----------
    input : array_like
        The input array.
    zoom : float or sequence
        The zoom factor along the axes. If a float, `zoom` is the same for each
        axis. If a sequence, `zoom` should contain one value for each axis.
    output : array or dtype, optional
        The array in which to place the output, or the dtype of the
        returned array. By default an array of the same dtype as input
        will be created.
    order : int, optional
        The order of the spline interpolation, default is 3.
        The order has to be in the range 0-5.
    mode : {'reflect', 'grid-mirror', 'constant', 'grid-constant', 'nearest',            'mirror', 'grid-wrap', 'wrap'}, optional
        The `mode` parameter determines how the input array is extended
        beyond its boundaries. Default is 'constant'. Behavior for each valid
        value is as follows (see additional plots and details on
        :ref:`boundary modes <ndimage-interpolation-modes>`):
    
        'reflect' (`d c b a | a b c d | d c b a`)
            The input is extended by reflecting about the edge of the last
            pixel. This mode is also sometimes referred to as half-sample
            symmetric.
    
        'grid-mirror'
            This is a synonym for 'reflect'.
    
        'constant' (`k k k k | a b c d | k k k k`)
            The input is extended by filling all values beyond the edge with
            the same constant value, defined by the `cval` parameter. No
            interpolation is performed beyond the edges of the input.
    
        'grid-constant' (`k k k k | a b c d | k k k k`)
            The input is extended by filling all values beyond the edge with
            the same constant value, defined by the `cval` parameter. Interpolation
            occurs for samples outside the input's extent  as well.
    
        'nearest' (`a a a a | a b c d | d d d d`)
            The input is extended by replicating the last pixel.
    
        'mirror' (`d c b | a b c d | c b a`)
            The input is extended by reflecting about the center of the last
            pixel. This mode is also sometimes referred to as whole-sample
            symmetric.
    
        'grid-wrap' (`a b c d | a b c d | a b c d`)
            The input is extended by wrapping around to the opposite edge.
    
        'wrap' (`d b c d | a b c d | b c a b`)
            The input is extended by wrapping around to the opposite edge, but in a
            way such that the last point and initial point exactly overlap. In this
            case it is not well defined which sample will be chosen at the point of
            overlap.
    cval : scalar, optional
        Value to fill past edges of input if `mode` is 'constant'. Default
        is 0.0.
    prefilter : bool, optional
        Determines if the input array is prefiltered with `spline_filter`
        before interpolation. The default is True, which will create a
        temporary `float64` array of filtered values if `order > 1`. If
        setting this to False, the output will be slightly blurred if
        `order > 1`, unless the input is prefiltered, i.e. it is the result
        of calling `spline_filter` on the original input.
    grid_mode : bool, optional
        If False, the distance from the pixel centers is zoomed. Otherwise, the
        distance including the full pixel extent is used. For example, a 1d
        signal of length 5 is considered to have length 4 when `grid_mode` is
        False, but length 5 when `grid_mode` is True. See the following
        visual illustration:

        .. code-block:: text

                | pixel 1 | pixel 2 | pixel 3 | pixel 4 | pixel 5 |
                     |<-------------------------------------->|
                                        vs.
                |<----------------------------------------------->|

        The starting point of the arrow in the diagram above corresponds to
        coordinate location 0 in each mode.

    Returns
    -------
    zoom : ndarray
        The zoomed input.

    Notes
    -----
    For complex-valued `input`, this function zooms the real and imaginary
    components independently.

    .. versionadded:: 1.6.0
        Complex-valued support added.

    Examples
    --------
    >>> from scipy import ndimage, misc
    >>> import matplotlib.pyplot as plt

    >>> fig = plt.figure()
    >>> ax1 = fig.add_subplot(121)  # left side
    >>> ax2 = fig.add_subplot(122)  # right side
    >>> ascent = misc.ascent()
    >>> result = ndimage.zoom(ascent, 3.0)
    >>> ax1.imshow(ascent, vmin=0, vmax=255)
    >>> ax2.imshow(result, vmin=0, vmax=255)
    >>> plt.show()

    >>> print(ascent.shape)
    (512, 512)

    >>> print(result.shape)
    (1536, 1536)