plt.plot(…)没有显示窗口。我错过了什么吗？

huangapple
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英文:

plt.plot(...) doesn't show a window. what am I missing?

问题

Here's the translated code portion:

  1. 我正在使用VScode进行OpenCV练习。
  3. 我习惯于使用以下结构显示图像：
  5.     import cv2
  6.     import numpy as np
  7.     import matplotlib.pyplot as plt
  9.     puppy = cv2.imread('./DATA/00-puppy.jpg')
  10.     horse = cv2.imread('./DATA/horse.jpg')
  11.     rainbow = cv2.imread('./DATA/rainbow.jpg')
  13.     # 对这些图像进行“inplace”操作，例如
  14.     # puppy = cv2.cvtColor(puppy, cv2.COLOR_BGR2RGB)
  15.     # 等...
  17.     img_to_show_1 = puppy
  18.     img_to_show_2 = horse
  19.     img_to_show_3 = rainbow
  21.     # ---> 开始“while True ... - if 0xFF == 27: break”结构
  23.     cv2.namedWindow(winname='window_1')
  24.     cv2.namedWindow(winname='window_2')
  25.     cv2.namedWindow(winname='window_3')
  27.     while True:
  28.         cv2.imshow('window_1', img_to_show_1)
  29.         cv2.imshow('window_2', img_to_show_2)
  30.         cv2.imshow('window_3', img_to_show_3)
  32.         if cv2.waitKey(1) & 0xFF == 27: # 当按下'esc'键时停止循环
  33.             break
  35.     cv2.destroyAllWindows()
  37.     # ---> 结束“while True ... - if 0xFF == 27: break”结构
  39. 现在，我已计算存储在“puppy”变量中的图像的值的直方图：
  41.     hist_values = cv2.calcHist([puppy], channels=[0], mask=None, histSize=[256], ranges=[0,256])
  43. 在Jupyter笔记本上，可以通过简单执行以下操作来显示它：
  45.     plt.plot(hist_values)
  47. 但在VScode上，这不会显示任何内容。
  49. 是否有一种方法可以在VScode上显示此图像，而不需要安装任何其他图形扩展？
  51. 是否有一种方法可以利用相同的“while True ... - if 0xFF == 27: break”结构，以便在按下'esc'键时也使此图像消失，就像其他图像一样？

This is the translated code portion you requested.

英文:

I am practicing with open cv on VScode.

I am used to display images by using the following structure:

  1. import cv2
  2. import numpy as np
  3. import matplotlib.pyplot as plt
  5. puppy = cv2.imread('./DATA/00-puppy.jpg')
  6. horse = cv2.imread('./DATA/horse.jpg')
  7. rainbow = cv2.imread('./DATA/rainbow.jpg')
  9. # "inplace" operations on these images such as
  10. # puppy = cv2.cvtColor(puppy, cv2.COLOR_BGR2RGB)
  11. # etc...
  13. img_to_show_1 = puppy
  14. img_to_show_2 = horse
  15. img_to_show_3 = rainbow
  17. # ---> beginning of the "while True ... - if 0xFF == 27: break" structure
  19. cv2.namedWindow(winname='window_1')
  20. cv2.namedWindow(winname='window_2')
  21. cv2.namedWindow(winname='window_3')
  24. while True:
  25. 	cv2.imshow('window_1', img_to_show_1)
  26. 	cv2.imshow('window_2', img_to_show_2)    
  27. 	cv2.imshow('window_3', img_to_show_3)
  29. 	if cv2.waitKey(1) & 0xFF == 27: # stop loop when 'esc' key is pressed
  30. 		break
  32. cv2.destroyAllWindows()
  34. # ---> end of the "while True ... - if 0xFF == 27: break" structure

Now I have calculated the histogram of the values of an image stored in puppy variable

  1. hist_values = cv2.calcHist([puppy], channels=[0], mask=None, histSize=[256], ranges=[0,256])

On jupyter notebooks, this can be showed by simply doing:

  1. plt.plot(hist_values)

But on VScode, this does not show anything.

Is there a way to show this image on VScode and without intalling any other graphical extention?

Is there a way to exploit the same "while True ... - if 0xFF == 27: break" structure, in order to have this image also disappear with the others as I press 'esc' key?

答案1

得分: 0

我找到了一个解决方法。

这基于使用OpenCV模块方法保存图像，然后使用Matplotlib方法重新加载图像：

  1. import cv2
  2. import numpy as np
  3. import matplotlib.pyplot as plt
  5. puppy = cv2.imread('./DATA/00-puppy.jpg')
  6. horse = cv2.imread('./DATA/horse.jpg')
  7. rainbow = cv2.imread('./DATA/rainbow.jpg')
  9. hist_values = cv2.calcHist([puppy], channels=[0], mask=None, histSize=[256], ranges=[0, 256])
  11. plt.plot(hist_values)
  12. plt.plot([1, 2])
  13. mypath = 'my/path/hist_values.jpg'
  14. plt.savefig(mypath)
  16. hist_values_img = cv2.imread(mypath)
  18. import os
  19. try:
  20.     os.remove(mypath)
  21. except:
  22.     print("无法删除{}".format(mypath))
  24. img_to_show_1 = puppy
  25. img_to_show_2 = hist_values_img
  26. img_to_show_3 = rainbow
  28. cv2.namedWindow(winname='window_1')
  29. cv2.namedWindow(winname='window_2')
  30. cv2.namedWindow(winname='window_3')
  32. while True:
  33.     cv2.imshow('window_1', img_to_show_1)
  34.     cv2.imshow('window_2', img_to_show_2)
  35.     cv2.imshow('window_3', img_to_show_3)
  36.     plt.show()
  38.     if cv2.waitKey(1) & 0xFF == 27:  # 如果按下esc键
  39.         break
  41. cv2.destroyAllWindows()

通过这种方式，我没有混合GUI，并且当我按下'esc'键时，直方图图像会与其他图像一起关闭。

感谢@ChristophRackwitz。

另外，将Matplotlib格式的元素转换为OpenCV格式的元素的代码段可以缩短为以下函数：

  1. def convert_matplotlib_to_opencv_img(matplotlib_format_img, clear=False, transitory_img_path='my_transitory_img.jpg'):
  3.     if clear:
  4.         plt.clf()
  6.     plt.plot(matplotlib_format_img)
  8.     try:
  9.         plt.savefig(transitory_img_path)
  10.     except:
  11.         raise OSError("无法保存图像到{}".format(transitory_img_path))
  13.     cv2_imread_format_img = cv2.imread(transitory_img_path)
  15.     import os
  16.     try:
  17.         os.remove(transitory_img_path)
  18.     except:
  19.         print("无法删除{}".format(transitory_img_path))
  21.     return cv2_imread_format_img

希望这对你有所帮助。

英文:

I found a workaround to do it.

This is based on saving the image with opencv module method and to reload it with the matplotlib method:

  1. import cv2
  2. import numpy as np
  3. import matplotlib.pyplot as plt
  5. puppy = cv2.imread('./DATA/00-puppy.jpg')
  6. horse = cv2.imread('./DATA/horse.jpg')
  7. rainbow = cv2.imread('./DATA/rainbow.jpg')
  9. # "inplace" operations on these images such as
  10. # puppy = cv2.cvtColor(puppy, cv2.COLOR_BGR2RGB)
  11. # etc...
  13. hist_values = cv2.calcHist([puppy], channels=[0], mask=None, histSize=[256], ranges=[0,256])
  15. plt.plot(hist_values)
  16. plt.plot([1, 2])
  17. mypath = 'my/path/hist_values.jpg'
  18. plt.savefig(mypath)
  20. hist_values_img = cv2.imread(mypath)
  22. import os
  23. try: 
  24.     os.remove(hist_values_path)
  25. except: 
  26.     print("could not remove {}".format(hist_values_path))
  28. img_to_show_1 = puppy
  29. img_to_show_2 = hist_values_img
  30. img_to_show_3 = rainbow
  32. # ---> beginning of the "while True ... - if 0xFF == 27: break" structure
  34. cv2.namedWindow(winname='window_1')
  35. cv2.namedWindow(winname='window_2')
  36. cv2.namedWindow(winname='window_3')
  38. while True:
  39. 	cv2.imshow('window_1', img_to_show_1)
  40. 	cv2.imshow('window_2', img_to_show_2)    
  41. 	cv2.imshow('window_3', img_to_show_3)
  42. 	plt.show()
  44. 	if cv2.waitKey(1) & 0xFF == 27: # se premo esc
  45. 		break
  47. cv2.destroyAllWindows()
  49. # ---> end of the "while True ... - if 0xFF == 27: break" structure

In this way I am not mixing GUIs and as I press 'esc', the histogram image closes together with the other images.

Credits to @ChristophRackwitz

Also, the snippet to convert a matplotlib-format element to a opencv-format element can be shrinked to this function:

  1. def convert_matplotlib_to_opencv_img(matplotlib_format_img, clear=False, transitory_img_path='my_transitory_img.jpg'):
  3. 	if clear:
  4. 		plt.clf()
  6. 	plt.plot(matplotlib_format_img)
  8. 	try:
  9. 		plt.savefig(transitory_img_path)
  10. 	except: 
  11. 		raise OSError("could not save img to {}".format(transitory_img_path))
  13. 	cv2_imread_format_img = cv2.imread(transitory_img_path)
  15. 	import os
  16. 	try: 
  17. 		os.remove(transitory_img_path)
  18. 	except: 
  19. 		print("could not remove {}".format(transitory_img_path))
  21. 	return cv2_imread_format_img

huangapple
  • 本文由 发表于 2023年6月18日 20:12:41
  • 转载请务必保留本文链接：https://go.coder-hub.com/76500476.html
  • jupyter-notebook
  • matplotlib
  • python
  • visual-studio-code
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