Displaying images with imshow in Matplotlib - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the imshow function do in matplotlib?

The imshow function displays an image on a plot using pixel data, showing the image as it appears in an array or matrix form.

beginner

Which data types can imshow display as images?

It can display 2D arrays for grayscale images and 3D arrays for color images (like RGB), where pixel values represent brightness or color intensity.

beginner

How do you add a color map to an image displayed with imshow?

Use the cmap parameter in imshow, for example, imshow(image, cmap='gray') to show a grayscale color map.

intermediate

What does the interpolation parameter control in imshow?

It controls how pixel values are smoothed or stretched when the image is resized, affecting the sharpness or blur of the displayed image.

beginner

Why might you use plt.axis('off') after imshow?

To hide the axis ticks and labels, making the image display cleaner and focusing only on the image itself.

What type of array does imshow expect for a color image?

A 3D array with RGB values

B 2D array with grayscale values

C 1D array of pixel intensities

D 4D array with alpha channel

imshow expects a 3D array for color images, where the last dimension represents RGB color channels.

Which parameter changes the color scheme of an image in imshow?

A palette

B color

C color_map

D cmap

The cmap parameter sets the color map for the image display.

What does plt.axis('off') do after showing an image?

A Removes axis ticks and labels

B Changes image brightness

C Turns off the image

D Saves the image

It hides the axis ticks and labels for a cleaner image display.

If you want a sharper image display with imshow, which parameter should you adjust?

A dpi

B interpolation

C resolution

D sharpness

The interpolation parameter controls how pixels are smoothed or sharpened.

Which library provides the imshow function?

A pandas

B numpy

C matplotlib

D seaborn

imshow is part of the matplotlib.pyplot module.

Explain how to display a grayscale image using imshow and how to remove axis labels for a cleaner look.

Think about the image data shape and how to hide axes.

Describe the role of the interpolation parameter in imshow and how it affects image appearance.

Consider what happens when you resize an image.