Color transforms (brightness, contrast, hue) in Computer Vision - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to increase the brightness of an image by adding a value to all pixels.

Computer Vision

bright_img = img + [1]

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

A50

B0.5

C-50

D255

Attempts:

3 left

💡 Hint

Common Mistakes

Using a value less than 1 like 0.5 which is too small for brightness increase

Using negative values which decrease brightness

Adding 50 to all pixel values increases brightness by a fixed amount.

2fill in blank

medium

Complete the code to adjust contrast by multiplying pixel values by a factor.

Computer Vision

contrast_img = img * [1]

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A0

B0.5

C-1

D1.5

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 or negative values which remove or invert the image

Using values less than 1 which reduce contrast

Multiplying by 1.5 increases contrast by making bright pixels brighter and dark pixels darker.

3fill in blank

hard

Fix the error in the code to correctly convert an RGB image to HSV and adjust the hue.

Computer Vision

hsv_img = cv2.cvtColor(img, [1])
hsv_img[:, :, 0] = (hsv_img[:, :, 0] + 10) % 180

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Acv2.COLOR_BGR2HSV

Bcv2.COLOR_HSV2BGR

Ccv2.COLOR_RGB2HSV

Dcv2.COLOR_BGR2GRAY

Attempts:

3 left

💡 Hint

Common Mistakes

Using BGR to HSV conversion when image is RGB

Using HSV to BGR conversion which is backward

Use cv2.COLOR_RGB2HSV to convert from RGB to HSV color space before adjusting hue.

4fill in blank

hard

Fill both blanks to create a function that adjusts brightness and contrast of an image.

Computer Vision

def adjust_brightness_contrast(img, brightness, contrast):
    return img * [1] + [2]

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

Acontrast

Bbrightness

Cimg

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping brightness and contrast

Adding brightness before multiplying contrast

The formula for brightness and contrast adjustment is: new_img = img * contrast + brightness.

5fill in blank

hard

Fill all three blanks to adjust hue, saturation, and value in an HSV image.

Computer Vision

hsv_img[:, :, 0] = (hsv_img[:, :, 0] + [1]) % 180
hsv_img[:, :, 1] = hsv_img[:, :, 1] * [2]
hsv_img[:, :, 2] = hsv_img[:, :, 2] * [3]

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

A10

B1.2

C0.8

D180

Attempts:

3 left

💡 Hint

Common Mistakes

Using 180 instead of 10 for hue shift

Multiplying saturation or value by values greater than 1 incorrectly

Hue is shifted by 10 degrees (mod 180), saturation is increased by 20%, and value is decreased by 20%.