Cropping images in Computer Vision - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to crop the image using slicing.

Computer Vision

cropped_img = img[[1]:100, 50:150]

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

A50

B0

C20

D100

Attempts:

3 left

💡 Hint

Common Mistakes

Using column index first instead of row index.

Starting slice at 0 which crops from the top instead of desired position.

The code slices the image from row 20 to 100 and columns 50 to 150, cropping the desired area.

2fill in blank

medium

Complete the code to crop the image to a square of size 50x50 pixels starting at (30, 40).

Computer Vision

cropped_img = img[[1]:[1]+50, 40:90]

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

A30

B40

C50

D20

Attempts:

3 left

💡 Hint

Common Mistakes

Using the column index as the first slice index.

Not adding 50 to the start index for the end index.

The crop starts at row 30 and goes 50 pixels down, so the slice is from 30 to 80.

3fill in blank

hard

Fix the error in the code to correctly crop the image region from (10, 20) to (60, 70).

Computer Vision

cropped_img = img[10:[1], 20:70]

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

A60

B70

C50

D80

Attempts:

3 left

💡 Hint

Common Mistakes

Using 70 as the end row index which is beyond the desired crop.

Using 50 which crops less than intended.

The row slice should end at 60 to crop from row 10 to 60.

4fill in blank

hard

Fill both blanks to crop a 40x40 pixel square starting at (15, 25).

Computer Vision

cropped_img = img[[1]:[2], 25:65]

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

A15

B55

C65

D40

Attempts:

3 left

💡 Hint

Common Mistakes

Using 65 as the end row index which is too large.

Using 40 as the start index instead of 15.

The crop starts at row 15 and ends at 55 (15 + 40) to get a 40 pixel height.

5fill in blank

hard

Fill all three blanks to crop the image from (10, 20) to (60, 70) and convert to grayscale.

Computer Vision

cropped_img = img[[1]:[2], [3]:70]
gray_img = cv2.cvtColor(cropped_img, cv2.COLOR_BGR2GRAY)

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

A10

B60

C20

D50

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up row and column indices.

Not converting to grayscale after cropping.

The crop rows go from 10 to 60, columns from 20 to 70, then convert to grayscale.