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pythonrgbopencvgrayscale

RGb to gray conversion in CV2

I am trying to convert an image from RGB to grayscale. My image looks like this after reading

img = cv2.imread('sample.png')
plt.imshow(img)

enter image description here

I tried converting this to grayscale using cv2 function and the image looks as below after conversion:

gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
plt.imshow(gray)

enter image description here

As you can see image is not converted to grayscale properly. What could be the reason? Am I missing something here?

Solution

  • The default option for cmap in plt.imshow is viridis. Use plt.imshow(gray, cmap='gray') for grayscale images. If you save the image using cv2.imwrite you can see the image has been converted to grayscale.