mirror of
https://github.com/wassname/scikit-image.git
synced 2026-07-06 05:16:40 +08:00
Tony S Yu
49 lines
1.3 KiB
Python
49 lines
1.3 KiB
Python
import numpy as np
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from scipy import ndimage
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def peak_local_max(image, min_distance=10, threshold=0.1):
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"""Return coordinates of peaks in an image.
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Peaks are the local maxima in a region of `2 * min_distance + 1`
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(i.e. peaks are separated by at least `min_distance`).
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Parameters
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----------
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image: ndarray of floats
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Input image.
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min_distance: int, optional
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Minimum number of pixels separating peaks and image boundary.
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threshold: float, optional
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Candidate peaks are calculated as `max(image) * threshold`.
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Returns
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-------
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coordinates : (N, 2) array
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(row, column) coordinates of peaks.
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"""
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image = image.copy()
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# Non maximum filter
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size = 2 * min_distance + 1
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image_max = ndimage.maximum_filter(image, size=size, mode='constant')
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mask = (image == image_max)
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image *= mask
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# Remove the image borders
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image[:min_distance] = 0
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image[-min_distance:] = 0
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image[:, :min_distance] = 0
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image[:, -min_distance:] = 0
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# find top corner candidates above a threshold
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corner_threshold = np.max(image.ravel()) * threshold
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image_t = (image >= corner_threshold) * 1
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# get coordinates of peaks
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coordinates = np.transpose(image_t.nonzero())
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return coordinates
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