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https://github.com/wassname/scikit-image.git
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Stefan van der Walt
117 lines
2.9 KiB
Python
117 lines
2.9 KiB
Python
"""
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:author: Damian Eads, 2009
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:license: modified BSD
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"""
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import numpy as np
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def square(width, dtype=np.uint8):
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"""
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Generates a flat, square-shaped structuring element. Every pixel
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along the perimeter has a chessboard distance no greater than radius
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(radius=floor(width/2)) pixels.
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Parameters
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----------
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width : int
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The width and height of the square
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Other Parameters
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----------------
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dtype : data-type
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The data type of the structuring element.
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Returns
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-------
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selem : ndarray
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A structuring element consisting only of ones, i.e. every
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pixel belongs to the neighborhood.
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"""
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return np.ones((width, width), dtype=dtype)
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def rectangle(width, height, dtype=np.uint8):
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"""
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Generates a flat, rectangular-shaped structuring element of a
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given width and height. Every pixel in the rectangle belongs
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to the neighboorhood.
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Parameters
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----------
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width : int
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The width of the rectangle
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height : int
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The height of the rectangle
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Other Parameters
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----------------
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dtype : data-type
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The data type of the structuring element.
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Returns
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-------
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selem : ndarray
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A structuring element consisting only of ones, i.e. every
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pixel belongs to the neighborhood.
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"""
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return np.ones((width, height), dtype=dtype)
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def diamond(radius, dtype=np.uint8):
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"""
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Generates a flat, diamond-shaped structuring element of a given
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radius. A pixel is part of the neighborhood (i.e. labeled 1) if
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the city block/manhattan distance between it and the center of the
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neighborhood is no greater than radius.
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Parameters
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----------
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radius : int
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The radius of the diamond-shaped structuring element.
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dtype : data-type
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The data type of the structuring element.
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Returns
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-------
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selem : ndarray
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The structuring element where elements of the neighborhood
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are 1 and 0 otherwise.
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"""
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half = radius
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(I, J) = np.meshgrid(range(0, radius * 2 + 1), range(0, radius * 2 + 1))
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s = np.abs(I - half) + np.abs(J - half)
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return np.array(s <= radius, dtype=dtype)
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def disk(radius, dtype=np.uint8):
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"""
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Generates a flat, disk-shaped structuring element of a given radius.
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A pixel is within the neighborhood if the euclidean distance between
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it and the origin is no greater than a radius.
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Parameters
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----------
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radius : int
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The radius of the disk-shaped structuring element.
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dtype : data-type
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The data type of the structuring element.
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Returns
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-------
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selem : ndarray
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The structuring element where elements of the neighborhood
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are 1 and 0 otherwise.
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"""
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L = np.linspace(-radius, radius, 2 * radius + 1)
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(X, Y) = np.meshgrid(L, L)
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s = X**2
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s += Y**2
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return np.array(s <= radius * radius, dtype=dtype)
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