Displaying images (cv2.imshow, matplotlib) in Computer Vision - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to display an image using OpenCV.

Computer Vision

import cv2
img = cv2.imread('image.jpg')
cv2.[1]('Image Window', img)
cv2.waitKey(0)
cv2.destroyAllWindows()

Drag options to blanks, or click blank then click option'

Aimread

Bimwrite

Cimshow

DwaitKey

Attempts:

3 left

💡 Hint

Common Mistakes

Using cv2.imread instead of cv2.imshow to display the image.

Forgetting to call cv2.waitKey to keep the window open.

cv2.imshow is used to display an image in a window.

2fill in blank

medium

Complete the code to display an image using matplotlib.

Computer Vision

import matplotlib.pyplot as plt
import cv2
img = cv2.imread('image.jpg')
img_rgb = cv2.cvtColor(img, cv2.COLOR_BGR2[1]RGB)
plt.imshow(img_rgb)
plt.show()

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A0

B3

C1

D2

Attempts:

3 left

💡 Hint

Common Mistakes

Not converting BGR to RGB before displaying with matplotlib, causing wrong colors.

Using cv2.COLOR_RGB2BGR instead of cv2.COLOR_BGR2RGB.

OpenCV loads images in BGR format, so we convert from BGR to RGB using cv2.COLOR_BGR2RGB.

3fill in blank

hard

Fix the error in the code to properly display the image using OpenCV.

Computer Vision

import cv2
img = cv2.imread('image.jpg')
cv2.imshow('Window', img)
cv2.[1]()

Drag options to blanks, or click blank then click option'

AwaitKey(0)

BwaitKey

CdestroyAllWindows

Dimwrite

Attempts:

3 left

💡 Hint

Common Mistakes

Calling cv2.waitKey without parentheses or argument.

Calling cv2.destroyAllWindows before waitKey.

cv2.waitKey(0) waits for a key press to keep the window open until you press a key.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps image filenames to their grayscale images.

Computer Vision

import cv2
filenames = ['img1.jpg', 'img2.jpg', 'img3.jpg']
grayscale_images = {filename: cv2.[1](filename, [2]) for filename in filenames}

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Aimread

Bimwrite

CCOLOR_BGR2GRAY

DIMREAD_GRAYSCALE

Attempts:

3 left

💡 Hint

Common Mistakes

Using imwrite instead of imread to read images.

Using COLOR_BGR2GRAY as a flag in imread, which is incorrect.

cv2.imread with flag cv2.IMREAD_GRAYSCALE loads images in grayscale mode.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps image filenames to their RGB images using OpenCV and matplotlib.

Computer Vision

import cv2
filenames = ['img1.jpg', 'img2.jpg']
images_rgb = {filename: cv2.cvtColor(cv2.[1](filename), cv2.[2]) for filename in filenames if filename.endswith('.jpg') and filename != [3]

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Aimread

BCOLOR_BGR2RGB

C'img2.jpg'

D'img1.jpg'

Attempts:

3 left

💡 Hint

Common Mistakes

Using COLOR_RGB2BGR instead of COLOR_BGR2RGB.

Not excluding the correct filename in the condition.

We read images with imread, convert from BGR to RGB, and exclude 'img2.jpg' from the dictionary.