Geometric transforms (rotate, flip, crop) in Computer Vision - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to rotate the image by 90 degrees clockwise using OpenCV.

Computer Vision

rotated_image = cv2.rotate(image, [1])

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Acv2.ROTATE_90_COUNTERCLOCKWISE

Bcv2.ROTATE_180

Ccv2.ROTATE_90_CLOCKWISE

Dcv2.FLIP_HORIZONTAL

Attempts:

3 left

💡 Hint

Common Mistakes

Using the counterclockwise rotation constant instead.

Using flip constants instead of rotate.

To rotate an image 90 degrees clockwise in OpenCV, use cv2.ROTATE_90_CLOCKWISE as the flag.

2fill in blank

medium

Complete the code to flip the image vertically using OpenCV.

Computer Vision

flipped_image = cv2.flip(image, [1])

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A2

B1

C-1

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using 1 which flips horizontally instead.

Using -1 which flips both axes.

In OpenCV, flipping with 0 flips the image vertically (upside down).

3fill in blank

hard

Fix the error in the code to crop the image correctly using NumPy slicing.

Computer Vision

cropped_image = image[[1]:[1]+100, 50:150]

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A0

B50

C100

D150

Attempts:

3 left

💡 Hint

Common Mistakes

Starting crop at row 100 which may be outside image bounds.

Using column indices for row slicing.

To crop starting from the top, use 0 as the starting row index.

4fill in blank

hard

Fill both blanks to create a horizontal flip and then crop the center 100x100 pixels of the image.

Computer Vision

flipped = cv2.flip(image, [1])
cropped = flipped[[2]:[2]+100, 100:200]

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A1

B0

C50

D100

Attempts:

3 left

💡 Hint

Common Mistakes

Using vertical flip code 0 instead of horizontal.

Starting crop at 100 which is too low for center crop.

Flip code 1 flips horizontally. Cropping starts at row 50 to get center 100 pixels vertically.

5fill in blank

hard

Fill all three blanks to rotate the image 180 degrees, flip vertically, and then crop the top-left 50x50 pixels.

Computer Vision

rotated = cv2.rotate(image, [1])
flipped = cv2.flip(rotated, [2])
cropped = flipped[[3]:[3]+50, 0:50]

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

Acv2.ROTATE_180

B0

Dcv2.ROTATE_90_CLOCKWISE

Attempts:

3 left

💡 Hint

Common Mistakes

Using 90 degree rotation instead of 180.

Using horizontal flip code 1 instead of vertical.

Starting crop at wrong row index.

Rotate 180 degrees uses cv2.ROTATE_180. Flip vertically uses code 0. Crop starts at row 0 for top-left corner.