Python OpenCV cv2.imread()用法及代码示例

OpenCV-Python是旨在解决计算机视觉问题的Python绑定库。
cv2.imread()方法从指定的文件加载图像。如果无法读取图像(由于缺少文件，权限不正确，格式不受支持或格式无效)，则此方法将返回一个空矩阵。

用法： cv2.imread(path, flag)

注意：该映像应位于工作目录中，或者应提供完整的映像路径。

所有三种类型的标志描述如下：

cv2.IMREAD_COLOR: It specifies to load a color image. Any transparency of image will be neglected. It is the default flag. Alternatively, we can pass integer value 1 for this flag.
cv2.IMREAD_GRAYSCALE: It specifies to load an image in grayscale mode. Alternatively, we can pass integer value 0 for this flag.
cv2.IMREAD_UNCHANGED: It specifies to load an image as such including alpha channel. Alternatively, we can pass integer value -1 for this flag.

用于以下所有示例的图像：

示例1:使用默认标志

# Python program to explain cv2.imread() method 
  
# importing cv2  
import cv2 
  
# path 
path = r'C:\Users\Rajnish\Desktop\geeksforgeeks.png'
  
# Using cv2.imread() method 
img = cv2.imread(path) 
  
# Displaying the image 
cv2.imshow('image', img)

输出：

示例2:
以灰度模式加载图像

# Python program to explain cv2.imread() method 
  
# importing cv2  
import cv2 
  
# path 
path = r'C:\Users\Rajnish\Desktop\geeksforgeeks.png'
  
# Using cv2.imread() method 
# Using 0 to read image in grayscale mode 
img = cv2.imread(path, 0) 
  
# Displaying the image 
cv2.imshow('image', img)

输出：