You want to create a grayscale image by averaging the red, green, and blue channels of an image array img. Which code correctly does this and keeps the result as a 2D array?

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Matplotlib - Image Display

You want to create a grayscale image by averaging the red, green, and blue channels of an image array img. Which code correctly does this and keeps the result as a 2D array?

Agray = img.mean(axis=2)

Bgray = img.mean(axis=0)

Cgray = img[:, :, 0] + img[:, :, 1] + img[:, :, 2]

Dgray = img.sum(axis=1)

Step-by-Step Solution

Solution:

Step 1: Understand axis for color channels
Color channels are in the last dimension (axis=2) of img.
Step 2: Average across color channels
Using img.mean(axis=2) averages red, green, and blue for each pixel, resulting in a 2D array.
Final Answer:
gray = img.mean(axis=2) -> Option A
Quick Check:
Mean over axis=2 gives grayscale 2D image [OK]

Quick Trick: Use mean(axis=2) to average RGB channels [OK]

Common Mistakes:

Averaging over wrong axis
Summing channels without dividing
Resulting in 3D array instead of 2D

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You want to create a grayscale image by averaging the red, green, and blue channels of an image array img. Which code correctly does this and keeps the result as a 2D array?

Step 1: Understand axis for color channels

Step 2: Average across color channels

Final Answer:

Quick Check:

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