mirror of
https://github.com/wassname/scikit-image.git
synced 2026-06-28 08:08:05 +08:00
Juan Nunez-Iglesias
fac8fde9dc
- images are displayed within their native dtype range, - unless they are outside of their range (e.g. a float image with values greater than 1) or they are of an unsupported dtype (e.g. a uint64 image), in which case the dynamic range of the display corresponds to the image range, - which is also done for images with extremely low contrast for their native range (e.g. float images in [1e-7, 5e-7]. In the latter two cases, a colorbar is also displayed and a warning is raised. Finally, we return the axes object on which the image is plotted, to enable further plotting in the matplotlib new OO style.
71 lines
2.3 KiB
Python
71 lines
2.3 KiB
Python
import numpy as np
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import warnings
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import matplotlib.pyplot as plt
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from skimage.util import dtype as dtypes
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def imshow(im, *args, **kwargs):
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"""Show the input image and return the current axes.
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Images are assumed to have standard range for their type. For
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example, if a floating point image has values in [0, 0.5], the
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most intense color will be gray50, not white, as would be the
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default in matplotlib.
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In contrast, if the image exceeds the standard range, this
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function defaults back to displaying exactly the range of the
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input image.
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Parameters
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----------
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im : array, shape (M, N[, 3])
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The image to display.
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*args, **kwargs : positional and keyword arguments
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These are passed directly to `matplotlib.pyplot.imshow`.
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Returns
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-------
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ax : `matplotlib.pyplot.Axes`
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The axes showing the image.
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"""
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if plt.gca().has_data():
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plt.figure()
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immin, immax = np.min(im), np.max(im)
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supported_dtype = im.dtype in dtypes._supported_types
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if supported_dtype:
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lo, hi = dtypes.dtype_range[im.dtype.type]
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if immin >= 0:
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# display range starts at 0 for nonnegative images
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lo = 0
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else:
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warnings.warn("Non-standard image type; displaying image with "
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"stretched contrast.")
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out_of_range_float = (np.issubdtype(im.dtype, np.float) and
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(immin < lo or immax > hi))
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if out_of_range_float:
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warnings.warn("Float image out of standard range; displaying image "
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"with stretched contrast.")
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low_dynamic_range = (immin != immax and
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(float(immax - immin) / (hi - lo)) < (1. / 255))
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if low_dynamic_range:
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warnings.warn("Low image dynamic range; displaying image with "
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"stretched contrast.")
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if not supported_dtype or out_of_range_float or low_dynamic_range:
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lo, hi = immin, immax
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kwargs.setdefault('interpolation', 'nearest')
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kwargs.setdefault('cmap', 'gray')
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kwargs.setdefault('vmin', lo)
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kwargs.setdefault('vmax', hi)
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ax = plt.imshow(im, *args, **kwargs)
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if not supported_dtype or out_of_range_float or low_dynamic_range:
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ax.colorbar()
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return ax
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imread = plt.imread
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show = plt.show
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def _app_show():
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show()
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