Python [plt 和 cv] 图片读取、显示和保存

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原创最新推荐文章于 2026-06-21 13:00:40 发布 4.3k 阅读 AI 写同款· GEO 优化 ›

cv2和plt读取显示图像问题——Python+Opencv学习系列一、问题阐述我们一般利用cv2.imread来读取彩色图像和灰度图像，并可利用cv2.imshow来显示图像；但在特殊场合下，我们为了方便对比区分，需采用matplotlib.pyplot来显示图像，就如下图所示。本次遇到的问题是两种方法显示彩色和灰度图像的结果有差异，当利用cv2.imshow显示读取彩色图像时，会“偏黄”；当利用cv2.imshow显示读取的灰度图像时符合我们正常的灰度图像，但利用plt.show显示读取的灰度图像时更像是彩色的，代码和图像如... 阅读详情

1. 图片读取方式

读取图片，并设置图片大小

keras 导入

img = load_img(image_path, target_size=target_input) # 设置导入尺寸

plt.imshow(img)

opencv 导入

img = cv2.imread(image_path)
img = cv2.resize(img, target_input[:2])   # cv.resize 值只接受（h, w）

2. 绘图

2.1 图片显示

opencv 绘制（默认 gbr）

cv2.imshow(windown, img)  # window 可以随意命名

若不能正常显示：

cv2.waitKey(0)  # 键盘绑定函数，等待按键
cv2.destroyAllWindows() # 按下键盘中的按键，启动该程序销毁所有窗口

plt 显示

使用 img = cv2.cvtColor(img,cv2.COLOR_BGR2RGB) 可以先将opencv读取的bgr转化为plt可以读取的bgr格式
```
plt.imshow()
plt.show()
```

2.2 关闭坐标显示

plt.xticks([]) # 关闭x坐标显示
plt.yticks([]) # 关闭y坐标显示

3. 保存图片

保存在当前目录下（或者使用绝对地址）

plt.savefig('./result.jpg')

4. 实例

矩阵边线

# Python program to explain cv2.rectangle() method 

# importing cv2 
import cv2 

# path 
path = r'C:\Users\Rajnish\Desktop\geeksforgeeks\geeks.png'

# Reading an image in default mode 
image = cv2.imread(path) 

# Window name in which image is displayed 
window_name = 'Image'

# Start coordinate, here (5, 5) 
# represents the top left corner of rectangle 
start_point = (5, 5) 

# Ending coordinate, here (220, 220) 
# represents the bottom right corner of rectangle 
end_point = (220, 220) 

# Blue color in BGR 
color = (255, 0, 0) 

# Line thickness of 2 px 
thickness = 2

# Using cv2.rectangle() method 
# Draw a rectangle with blue line borders of thickness of 2 px 
image = cv2.rectangle(image, start_point, end_point, color, thickness) 

# Displaying the image 
cv2.imshow(window_name, image)

实心矩阵

# Python program to explain cv2.rectangle() method 
	
# importing cv2 
import cv2 
	
# path 
path = r'C:\Users\Rajnish\Desktop\geeksforgeeks\geeks.png'
	
# Reading an image in grayscale mode 
image = cv2.imread(path, 0) 
	
# Window name in which image is displayed 
window_name = 'Image'

# Start coordinate, here (100, 50) 
# represents the top left corner of rectangle 
start_point = (100, 50) 

# Ending coordinate, here (125, 80) 
# represents the bottom right corner of rectangle 
end_point = (125, 80) 

# Black color in BGR 
color = (0, 0, 0) 

# Line thickness of -1 px 
# Thickness of -1 will fill the entire shape 
thickness = -1

# Using cv2.rectangle() method 
# Draw a rectangle of black color of thickness -1 px 
image = cv2.rectangle(image, start_point, end_point, color, thickness) 

# Displaying the image 
cv2.imshow(window_name, image)