July 2019
Intermediate to advanced
365 pages
8h 13m
Chinese
Content preview from Python机器学习手册：从数据预处理到深度学习
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142
｜
第
8
章
图像处理
最后，使用
bitwise_and
方法将掩模应用于图像，并将图像转换为所需的输出格式。
8.9
图像二值化
问题描述
将一张图像转换成仅包含黑色和白色的简化版本。
解决方案
图像二值化是指对图像进行
阈值处理
（
thresholding
），即将强度大于某个阈值的像素设
置为白色并将小于该值的像素设置为黑色的过程。还有一种更先进的技术，叫作
自适应
阈值处理
（
adaptive thresholding
），在这种方法中，一个像素的阈值是由其相邻像素的强
度决定的。当图像中不同区域的光照条件有差异时，用这种方法处理会很有帮助。
#
加载库
import cv2
import numpy as np
from matplotlib import pyplot as plt
#
以灰度图像格式加载图像
image_grey = cv2.imread("images/plane_256x256.jpg", cv2.IMREAD_GRAYSCALE)
#
应用自适应阈值处理
max_output_value = 255
neighborhood_size = 99
subtract_from_mean = 10
image_binarized = cv2.adaptiveThreshold(image_grey,
max_output_value,
cv2.ADAPTIVE_THRESH_GAUSSIAN_C,
cv2.THRESH_BINARY,
neighborhood_size, ...
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