四、图像形态学操作

1. 腐蚀操作

import cv2 # OpenCV 读取的格式是 BGR
import matplotlib.pyplot as plt
import numpy as np
%matplotlib inline

img = cv2.imread('jswyn.jpg')

# cv2.imshow('img', img)
# cv2.waitKey(0)
# cv2.destroyAllWindows()
plt.imshow(cv2.cvtColor(img, cv2.COLOR_BGR2RGB))

<matplotlib.image.AxesImage at 0x2917d142438>

1.1original.png

kernel = np.ones((3, 3), np.uint8)
erosion = cv2.erode(img, kernel, iterations=2)

# cv2.imshow('erosion', erosion)
# cv2.waitKey(0)
# cv2.destroyAllWindows()
plt.imshow(cv2.cvtColor(erosion, cv2.COLOR_BGR2RGB))

<matplotlib.image.AxesImage at 0x2917e451dd8>

1.2iterations=2.png

yuan = cv2.imread('yuan.jpg')

# cv2.imshow('yuan', yuan)
# cv2.waitKey(0)
# cv2.destroyAllWindows()
plt.imshow(cv2.cvtColor(yuan, cv2.COLOR_BGR2RGB))

<matplotlib.image.AxesImage at 0x2917df154a8>

2.1original.png

kernel = np.ones((3, 3), np.uint8)

erosion_1 = cv2.erode(yuan, kernel, iterations=1)
plt.imshow(cv2.cvtColor(erosion_1, cv2.COLOR_BGR2RGB))

<matplotlib.image.AxesImage at 0x2917e749828>

2.2iterations=1.png

erosion_2 = cv2.erode(yuan, kernel, iterations=2)
plt.imshow(cv2.cvtColor(erosion_2, cv2.COLOR_BGR2RGB))

<matplotlib.image.AxesImage at 0x2917e791048>

2.3iterations=2.png

erosion_3 = cv2.erode(yuan, kernel, iterations=3)
plt.imshow(cv2.cvtColor(erosion_3, cv2.COLOR_BGR2RGB))

<matplotlib.image.AxesImage at 0x2917e7caa58>

2.4iterations=3.png

2. 膨胀操作

img = cv2.imread('jswyn.jpg')

# cv2.imshow('img', img)
# cv2.waitKey(0)
# cv2.destroyAllWindows()
plt.imshow(cv2.cvtColor(img, cv2.COLOR_BGR2RGB))

<matplotlib.image.AxesImage at 0x2917e80f358>

3.1original.png

kernel = np.ones((3, 3), np.uint8)
erosion = cv2.dilate(img, kernel, iterations=2)

# cv2.imshow('erosion', erosion)
# cv2.waitKey(0)
# cv2.destroyAllWindows()
plt.imshow(cv2.cvtColor(erosion, cv2.COLOR_BGR2RGB))

<matplotlib.image.AxesImage at 0x2917fd32048>

3.2iterations=2.png

yuan = cv2.imread('yuan.jpg')

# cv2.imshow('yuan', yuan)
# cv2.waitKey(0)
# cv2.destroyAllWindows()
plt.imshow(cv2.cvtColor(yuan, cv2.COLOR_BGR2RGB))

<matplotlib.image.AxesImage at 0x2917fd747b8>

4.1original.png

kernel = np.ones((6, 6), np.uint8)

erosion_1 = cv2.dilate(yuan, kernel, iterations=1)
plt.imshow(cv2.cvtColor(erosion_1, cv2.COLOR_BGR2RGB))

<matplotlib.image.AxesImage at 0x2917fdcc438>

4.2iterations=1.png

erosion_2 = cv2.dilate(yuan, kernel, iterations=2)
plt.imshow(cv2.cvtColor(erosion_2, cv2.COLOR_BGR2RGB))

<matplotlib.image.AxesImage at 0x2917fecd6a0>

4.3iterations=2.png

erosion_3 = cv2.dilate(yuan, kernel, iterations=3)
plt.imshow(cv2.cvtColor(erosion_3, cv2.COLOR_BGR2RGB))

<matplotlib.image.AxesImage at 0x2917ff28320>

4.4iterations=3.png

3. 开运算与闭运算

jswyn1 = cv2.imread('jswyn1.jpg')

# cv2.imshow('jswyn1', jswyn1)
# cv2.waitKey(0)
# cv2.destroyAllWindows()
plt.imshow(cv2.cvtColor(jswyn1, cv2.COLOR_BGR2RGB))

<matplotlib.image.AxesImage at 0x2917df080b8>

5.1original.png

# 开运算：先腐蚀，再膨胀
kernel = np.ones((5, 5), np.uint8)
open = cv2.morphologyEx(jswyn1, cv2.MORPH_OPEN, kernel)

# cv2.imshow('open', open)
# cv2.waitKey(0)
# cv2.destroyAllWindows()
plt.imshow(cv2.cvtColor(open, cv2.COLOR_BGR2RGB))

<matplotlib.image.AxesImage at 0x291410e8e48>

5.2open.png

# 闭运算：先膨胀，再腐蚀
kernel = np.ones((5, 5), np.uint8)
close = cv2.morphologyEx(jswyn1, cv2.MORPH_CLOSE, kernel)

# cv2.imshow('close', close)
# cv2.waitKey(0)
# cv2.destroyAllWindows()
plt.imshow(cv2.cvtColor(close, cv2.COLOR_BGR2RGB))

<matplotlib.image.AxesImage at 0x2914114a860>

5.3close.png

4.梯度运算

# 梯度运算：膨胀 - 腐蚀
img = cv2.imread('yuan.jpg')
kernel = np.ones((5, 5), np.uint8)
gradient = cv2.morphologyEx(img, cv2.MORPH_GRADIENT, kernel)

# cv2.imshow('gradient', gradient)
# cv2.waitKey(0)
# cv2.destroyAllWindows()
plt.imshow(cv2.cvtColor(gradient, cv2.COLOR_BGR2RGB))

<matplotlib.image.AxesImage at 0x291412e8da0>

6.梯度运算.png

5.礼帽与黑帽

礼帽：原始输入 - 开运算结果
黑帽：闭运算结果 - 原始输入

# 礼帽
img = cv2.imread('jswyn1.jpg')
kernel = np.ones((3, 3), np.uint8)
top_hat = cv2.morphologyEx(img, cv2.MORPH_TOPHAT, kernel)

# cv2.imshow('top_hat', top_hat)
# cv2.waitKey(0)
# cv2.destroyAllWindows()
plt.imshow(cv2.cvtColor(top_hat, cv2.COLOR_BGR2RGB))

<matplotlib.image.AxesImage at 0x291415164e0>

7.1礼帽.png

# 黑帽
black_hat = cv2.morphologyEx(img, cv2.MORPH_BLACKHAT, kernel)

# cv2.imshow('black_hat', black_hat)
# cv2.waitKey(0)
# cv2.destroyAllWindows()
plt.imshow(cv2.cvtColor(black_hat, cv2.COLOR_BGR2RGB))

<matplotlib.image.AxesImage at 0x2914253fb00>

7.2黑帽.png