Chapter 6 Quiz

Question 1 of 11

1. Question

Translation: What is the correct line of code that defines a translation matrix that shifts an image 10 pixels up and 20 pixels to the right?

M = np.float32([[1, 0, 20], [0, 1, -10]])
M = np.float32([[1, 0, 10], [0, 1, -20]])
M = np.float32([[1, 0, -20], [0, 1, 10]])
M = np.float32([[1, 0, -10], [0, 1, 20]])

Question 2 of 11

2. Question

Translation: What is the correct line of code that defines a translation matrix that shifts an image 30 pixels down and 180 pixels to the left?

M = np.float32([[1, 0, -180], [0, 1, -30]])
M = np.float32([[1, 0, -180], [0, 1, 30]])
M = np.float32([[1, 0, -30], [0, 1, -180]])
M = np.float32([[1, 0, 30], [0, 1, 180]])

Question 3 of 11

3. Question

Rotation: Positive values of theta (the angle we rotate an image by) will rotate an image:

Counter-clockwise
Clockwise

Question 4 of 11

4. Question

Rotation: Negative values of theta will rotate an image:

Counter-clockwise
Clockwise

Question 5 of 11

5. Question

Rotation: What is the correct line of code to construct a matrix that will rotate an image 177 degrees clockwise?

M = cv2.getRotationMatrix2D(center, -177, 1.0)
M = cv2.getRotationMatrix2D(center, 177, 1.0)
M = cv2.getRotationMatrix2D(center, 1.0, -177)
M = cv2.getRotationMatrix2D(center, 1.0, 177)

Question 6 of 11

6. Question

Resizing: Modify the resize.py script to resize our trex.png image to have a width of 66 pixels. What is the height that maintains the aspect ratio?

42
99
48
67

Question 7 of 11

7. Question

Resizing: Modify the resize.py script to resize our trex.png image to have a height of 110 pixels. What is the width that maintains the aspect ratio?

168
197
202
203

Question 8 of 11

8. Question

Flipping: What is the correct line of code to flip an image horizontally?

flipped = cv2.flip(image, 1)
flipped = cv2.flip(image, 0)
flipped = cv2.flip(image, -1)

Question 9 of 11

9. Question

Flipping: What is the correct line of code to flip an image vertically?

flipped = cv2.flip(image, 1)
flipped = cv2.flip(image, 0)
flipped = cv2.flip(image, -1)

Question 10 of 11

10. Question

Cropping: I want to extract a rectangular region from my image starting at x=9, y=47 and ending at x=97, y=96. What is the correct line of code to perform this cropping?

crop = image[47:96, 9:97]
crop = image[9:97, 47:96]
crop = image[9:47, 97:96]
crop = image[97:96, 9:47]

Question 11 of 11

11. Question

Cropping: Now, suppose I want to extract a second rectangular region from my image starting at x=1, y=48 and ending at x=80, y=69. What is the correct line of code to perform this cropping?

crop = image[48:69, 1:80]
crop = image[48:80, 48:69]
crop = image[1:48, 80:69]
crop = image[80:69, 1:48]

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