Python OpenCV | cv2.imread() 方法

OpenCV-Python是一个Python绑定库，旨在解决计算机视觉问题。
cv2.imread()方法从指定文件加载图像。如果无法读取图像（由于缺少文件、权限不正确、格式不受支持或无效），则此方法返回一个空矩阵。

Syntax: cv2.imread(path, flag)

Parameters:
path: A string representing the path of the image to be read.
flag: It specifies the way in which image should be read. It’s default value is cv2.IMREAD_COLOR

Return Value: This method returns an image that is loaded from the specified file.

注意：图像应在工作目录中或应给出图像的完整路径。

所有三种类型的标志如下所述：

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：