Scikit-image 简明教程

Scikit Image - Using Plugins

plugin 指扩展或外部软件组件，它可以通过为程序添加特定功能从而增强程序功能，从而提高其功能。

Plugins in Python Scikit Image

Python scikit-image (skimage) 库提供了多种插件，可以用来处理图像 I/O 操作，如读取、写入和显示图像。scikit-image 库中的可用插件包括如 Matplotlib、PIL（Python 图像库）、GDAL、SimpleITK、tiffile、PyFITS 和 ImageIO 等流行的库。每个插件都专门用于一项特定的图像 I/O 操作。

scikit-image 库根据需要加载插件，以确保最佳性能并实现有效的资源利用。这意味着只有在明确需要或设为默认值时才加载插件。这种动态加载机制确保仅加载必需的插件，具体取决于特定的图像 I/O 操作。

此外，scikit-image 库还提供了一系列功能工具来处理和操作插件。这些工具允许用户自定义其图像 I/O 操作，让我们讨论一下 skimage.io 模块中一些重要的插件函数。

Listing the available plugins

函数 io.find_available_plugins(loaded=False) 用于列出 scikit-image（skimage.io）中的可用插件。它返回一个字典，以插件名称作为键，以公开函数作为值。以下是该函数的语法：

skimage.io.find_available_plugins(loaded=False)

参数 "loaded" 接受一个布尔值。如果将其设为 True ，只显示已加载的插件。默认情况下，显示所有插件。

Example 1

以下示例演示了如何使用 *io.find_available_plugins() *函数列出所有可用插件及其对应的公开函数。

import skimage.io as io
# List all available plugins
available_plugins = io.find_available_plugins()
# Display the plugin names and their exposed functions
for plugin_name, exposed_functions in available_plugins.items():
   print('Plugin:', plugin_name)
   print("Exposed Functions:", exposed_functions)
   print()

Plugin: fits
Exposed Functions: ['imread', 'imread_collection']
Plugin: gdal
Exposed Functions: ['imread', 'imread_collection']
Plugin: gtk
Exposed Functions: ['imshow']
Plugin: imageio
Exposed Functions: ['imread', 'imsave', 'imread_collection']
Plugin: imread
Exposed Functions: ['imread', 'imsave', 'imread_collection']
Plugin: matplotlib
Exposed Functions: ['imshow', 'imread', 'imshow_collection',
'imread_collection']
Plugin: pil
Exposed Functions: ['imread', 'imsave', 'imread_collection']
Plugin: qt
Exposed Functions: ['imshow', 'imsave', 'imread', 'imread_collection']
Plugin: simpleitk
Exposed Functions: ['imread', 'imsave', 'imread_collection']
Plugin: tifffile
Exposed Functions: ['imread', 'imsave', 'imread_collection']

Example 2

我们仅获取有关加载的插件的信息。

from skimage import io
# List loaded plugins only
available_plugins = io.find_available_plugins(loaded=True)
# Display the loaded plugin names and their exposed functions
for plugin_name, exposed_functions in available_plugins.items():
   print('Plugin:', plugin_name)
   print("Exposed Functions:", exposed_functions)
   print()

Plugin: imageio
Exposed Functions: ['imread', 'imsave', 'imread_collection']
Plugin: matplotlib
Exposed Functions: ['imshow', 'imread', 'imshow_collection',
'imread_collection']
Plugin: tifffile
Exposed Functions: ['imread', 'imsave', 'imread_collection']

Retrieving Info about a specific plugin

函数 io.plugin_info(plugin) 用于检索特定插件的信息。它返回一个字典，其中包含有关插件的信息，如描述，并且只提供可用函数名称。以下是该函数的语法：

skimage.io.plugin_info(plugin)

参数 "plugin" 接受一个字符串，表示要检索其信息的插件名称。

Example 1

以下示例演示了如何使用 io.plugin_info() 函数检索 'pil' 插件的信息。

from skimage import io
# Get information about the 'pil' plugin
plugin_info = io.plugin_info('pil')
# Print the plugin information
print("Description:", plugin_info['description'])
print("Available Functions:", plugin_info['provides'])
print()

Description: Image reading via the Python Imaging Library
Available Functions: imread, imsave

Example 2

在此示例中，我们将获取有关 'matplotlib' 插件的信息。

from skimage import io
# Get information about the 'matplotlib' plugin
plugin_info = io.plugin_info('matplotlib')
# Print the plugin information
print("Description:", plugin_info['description'])
print("Available Functions:", plugin_info['provides'])
print()

Description: Display or save images using Matplotlib
Available Functions: imshow, imread, imshow_collection, _app_show

Retrieving the plugin order

io.plugin_order() 函数用于获取当前首选的插件顺序。以下为此函数的语法 −

skimage.io.plugin_order()

该函数返回一个字典，其中函数名称作为键，对应值是按优先顺序排列的插件列表。

Example

以下是如何使用 plugin_order() 函数获取当前首选的插件顺序的示例。

from skimage import io
# Get the currently preferred plugin order
order_dict = io.plugin_order()
# Print the plugin loading order
print("Preferred Plugin Order:")
for function_name, plugins in order_dict.items():
   print("Function:", function_name)
   print("Plugins in order of preference:", plugins)
   print()

Preferred Plugin Order:
Function: imread
Plugins in order of preference: ['imageio', 'matplotlib']
Function: imsave
Plugins in order of preference: ['imageio']
Function: imshow
Plugins in order of preference: ['matplotlib']
Function: imread_collection
Plugins in order of preference: ['imageio', 'matplotlib']
Function: imshow_collection
Plugins in order of preference: ['matplotlib']
Function: _app_show
Plugins in order of preference: ['matplotlib']

Setting the default plugin

io.use_plugin() 函数用于设置指定操作的默认插件。

如果尚未加载指定的插件，则将加载它。以下为此函数的语法 −

skimage.io.use_plugin(name, kind=None)

以下是此函数的参数 −

name − 表示要作为默认值设置的插件名称的字符串。
kind (optional) − 表示正在为其设置插件的特定函数的字符串。它可以采用以下值之一：“imsave”、“imread”、“imshow”、“imread_collection”、“imshow_collection”。默认情况下，插件适用于所有函数。

Example

以下示例显示了在设置默认插件后插件加载顺序的更改。

from skimage import io

# Get the currently preferred plugin order
order_dict_1 = io.plugin_order()

# Print the plugin loading order
print("Plugin Order before Setting the default plugin:")
for function_name, plugins in order_dict_1.items():
    print(function_name)
    print("Plugin order:", plugins)

    print()

# Set the default plugin for all functions
io.use_plugin('qt')

# Get the preferred plugin order after setting the default plugin
order_dict_2 = io.plugin_order()

# Print the plugin loading order
print("Plugin Order after setting the default plugin: ")
for function_name, plugins in order_dict_2.items():
    print(function_name)
	print("Plugin order:", plugins)

    print()

Plugin Order before Setting the default plugin:
imread
Plugin order: ['imageio', 'matplotlib']

imsave
Plugin order: ['imageio']

imshow
Plugin order: ['matplotlib']

imread_collection
Plugin order: ['imageio', 'matplotlib']

imshow_collection
Plugin order: ['matplotlib']

_app_show
Plugin order: ['matplotlib']

Plugin Order after setting the default plugin:
imread
Plugin order: ['qt', 'imageio', 'matplotlib']

imsave
Plugin order: ['qt', 'imageio']

imshow
Plugin order: ['qt', 'matplotlib']

imread_collection
Plugin order: ['qt', 'imageio', 'matplotlib']
imshow_collection
Plugin order: ['matplotlib']

_app_show
Plugin order: ['qt', 'matplotlib']

Resetting the plugin to its default state

io.reset_plugins() 函数用于将插件状态重置为其默认/初始状态。即，没有加载任何插件。以下为此函数的语法 −

skimage.io.reset_plugins()

Example

以下示例演示如何使用 io.reset_plugins() 函数将插件状态重置为其默认状态。并在将插件状态重置为默认状态之前和之后检索插件顺序。

from skimage import io

# Get the currently preferred plugin order
order_dict_1 = io.plugin_order()

# Print the plugin loading order
print("Plugin Order before Resetting to the default state:")
for function_name, plugins in order_dict_1.items():
   if function_name == 'imread':
      print('Function',function_name)
      print("Plugin order:", plugins)

      print()

# Reset the plugin state to the default
io.reset_plugins()

# Get the preferred plugin order after Resetting to the default state
order_dict_2 = io.plugin_order()
# Print the plugin loading order
print("Plugin Order after Resetting to the default state: ")
for function_name, plugins in order_dict_2.items():
   if function_name == 'imread':
      print('Function',function_name)
      print("Plugin order:", plugins)
      print()

Plugin Order before Resetting to the default state:
Function imread
Plugin order: ['pil', 'imageio', 'matplotlib']

Plugin Order after Resetting to the default state:
Function imread
Plugin order: ['imageio', 'matplotlib']

Appropriate plugin for a specific function

io.call_plugin() 函数用于查找特定函数的适当插件并执行它。以下为此函数的语法 −

skimage.io.call_plugin(kind, *args, **kwargs)

以下是此函数的参数 −

kind (str) − 要查找的函数。它可以采用以下值之一：“imshow”、“imsave”、“imread”、“imread_collection”。
plugin (str, optional) − 要加载的特定插件。如果未提供（默认值为 None），则将使用第一个匹配的插件。
args, *kwargs − 将传递给插件函数的其他参数和关键字参数。

Example

以下示例演示如何使用 io.call_plugin() 函数使用图像读取函数的相应插件加载图像文件。

import numpy as np
from skimage import io

img_array = io.call_plugin('imread', 'Images_/black rose.jpg')
print("Image Arary Shape:",img_array.shape)

Image Arary Shape: (2848, 4272, 3)

该函数加载图像文件并将其作为 NumPy 数组返回，该数组被分配给 img_array 变量。