为什么使用 OpenCV 将 RGB 图像转换为灰度图像时会得到绿色图像？

Question

When I tried to convert an RGB image with OpenCV function cv2.cvtColor(), I got a green-like image.

I've converted the raw image read by OpenCV to RGB-format, again converted it to gray scale using cv2.cvtColor(), and tried to display it using pyplot.imshow() function.

image = cv2.cvtColor(image, cv2.COLOR_RGB2GRAY)
plt.imshow(image)

Answer 1

plt.imgshow() uses a color map for a single-channel images. You have two possible solutions, convert your grayscale to rgb (basically duplicate the grayscale 3 times), or choose a proper colormap as explained here: https://matplotlib.org/3.1.0/tutorials/colors/colormaps.html