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scikit-image/skimage/feature/tests/test_template.py
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Python

import numpy as np
from numpy.random import randn
from numpy.testing import assert_array_almost_equal as assert_close
from skimage.feature import match_template, peak_local_max
def test_template():
size = 100
# Type conversion of image and target not required but prevents warnings.
image = np.zeros((400, 400), dtype=np.float32)
target = np.tri(size) + np.tri(size)[::-1]
target = target.astype(np.float32)
target_positions = [(50, 50), (200, 200)]
for x, y in target_positions:
image[x:x + size, y:y + size] = target
image += randn(400, 400) * 2
for method in ["norm-corr", "norm-coeff"]:
result = match_template(image, target, method=method)
delta = 5
positions = peak_local_max(result, min_distance=delta)
if len(positions) > 2:
# Keep the two maximum peaks.
intensities = result[tuple(positions.T)]
i_maxsort = np.argsort(intensities)[::-1]
positions = positions[i_maxsort][:2]
# Sort so that order matches `target_positions`.
positions = positions[np.argsort(positions[:, 0])]
for xy_target, xy in zip(target_positions, positions):
yield assert_close, xy, xy_target
if __name__ == "__main__":
from numpy import testing
testing.run_module_suite()