subplot-mosaic-13-post.py

import matplotlib.pyplot as plt

image = plt.imread("gardens.jpg")

# Create a figure
mosaic = """
    aaab
    aaac
    aaad
    efg.
"""

fig, axs = plt.subplot_mosaic(
    mosaic
)

axs["a"].imshow(image)
axs["a"].axis("off")

# Create red channel image. I'll keep these images as 3D arrays
# and set the second and third layers, which represent the green
# and blue channels, to 0
image_red = image.copy()
image_red[:, :, 1:] = 0

# Same for the green image, but now the first and third layers
# are set to 0
image_green = image.copy()
image_green[:, :, 0] = 0
image_green[:, :, 2] = 0

image_blue = image.copy()
image_blue[:, :, 0:2] = 0

# Plot the separate channels
axs["e"].imshow(image_red)
axs["e"].axis("off")
axs["f"].imshow(image_green)
axs["f"].axis("off")
axs["g"].imshow(image_blue)
axs["g"].axis("off")

# Plot the histograms
axs["b"].hist(image[:, :, 0].ravel(), bins=50, color="red")
axs["b"].axis("off")
axs["c"].hist(image[:, :, 1].ravel(), bins=50, color="green")
axs["c"].axis("off")
axs["d"].hist(image[:, :, 2].ravel(), bins=50, color="blue")
axs["d"].axis("off")

plt.show()