2017-07-27 212 views
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我想创建一个给定半径的圆形中值滤波器,而不是数组中的方形滤波器。 这里是我的尝试至今:python中的圆形中值滤波器

# Apply median filter to each image 
import matplotlib.pyplot as plt 
radius = 25 
disk_filter = plt.fspecial('disk', radius) 
w1_median_disk = plt.imfilter(w1data, disk_filter, 'replicate') 

w2_median_disk = plt.imfilter(w2data, disk_filter, 'replicate') 

w1dataw2data是我想要的过滤器适用于2-d numpy的阵列。 fspecial模块来自Matlab,但我想在我的Python代码中使用它(或其他类似的东西)。有任何想法吗?

我得到错误信息“

disk_filter = plt.fspecial('disk', radius)
AttributeError: 'module' object has no attribute 'fspecial'"

我想知道,如果有任何一个模块,我可以导入包含fspecial,或在Python等效的命令。

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这段代码有什么问题? – Julien

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编辑原始帖子以澄清错误。 – Jim421616

回答

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刮‘摄影师’从图像:
https://www.mathworks.com/help/images/ref/fspecial.html

enter image description here

import numpy as np 
import matplotlib.pyplot as plt 

import os 
from scipy import misc 
path = 'D:/My Pictures/cameraman.bmp' 
cameraman = misc.imread(path, flatten=0) 

cameraman = np.average(cameraman, axis=2) 

r = 10 
y,x = np.ogrid[-r: r+1, -r: r+1] 
disk = x**2+y**2 <= r**2 
disk = disk.astype(float) 

from scipy import signal 
blur = signal.convolve2d(cameraman, disk, mode='full', boundary='fill', fillvalue=0) 

import matplotlib 
f, (ax1, ax2) = plt.subplots(1, 2, sharey=True) 
ax1.imshow(cameraman, cmap = matplotlib.cm.Greys_r) 
ax1.set_title('cameraman') 
ax2.imshow(blur, cmap = matplotlib.cm.Greys_r) 
ax2.set_title('signal.convolve2d(cameraman, disk..') 

,或者您可能需要使用scipy.ndimage.filters.convolve其“反映”边缘处理

from scipy.ndimage.filters import convolve 
blur = convolve(cameraman, disk) 
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如果你愿意安装/使用额外的包,我强烈推荐惊人skimage在Python中任何一种的图像处理!与圆盘状的过滤器过滤只是两行代码:

import skimage 
import skimage.data 
import skimage.morphology 
import skimage.filters 

# load example image 
original = skimage.data.camera() 

# create disk-like filter footprint with given radius 
radius = 10 
circle = skimage.morphology.disk(radius) 

# apply median filter with given footprint = structuring element = selem 
filtered = skimage.filters.median(original, selem = circle) 
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这里的东西我发现,似乎做的工作:

from scipy.ndimage.filters import generic_filter as gf 

# Define physical shape of filter mask 
def circular_filter(image_data, radius): 
    kernel = np.zeros((2*radius+1, 2*radius+1)) 
    y, x = np.ogrid[-radius:radius+1, -radius:radius+1] 
    mask = x**2 + y**2 <= radius**2 
    kernel[mask] = 1     
    filtered_image = gf(image_data, np.median, footprint = kernel) 
    return filtered_image 

但我不知道我完全理解这是怎么回事上。特别是,究竟什么行

 y, x = np.ogrid[-radius:radius+1, -radius:radius+1] 
    mask = x**2 + y**2 <= radius**2 
    kernel[mask] = 1 

呢?