Virtual Labs

Image Histogram

1. What does an image histogram represent?

a: The distribution of pixel intensities in an image Explanation

Explanation

b: The spatial coordinates of every pixel Explanation

Explanation

c: The physical size of the image Explanation

Explanation

d: The order in which pixels are stored Explanation

Explanation

2. In a grayscale image histogram, the horizontal axis normally represents

a: The number of pixels Explanation

Explanation

b: Gray level or intensity value Explanation

Explanation

c: Image width Explanation

Explanation

d: Image height Explanation

Explanation

3. If an image is rotated by

180^\circ

, what happens to its gray-level histogram, assuming the image contents are unchanged?

a: The histogram is rotated by

180^\circ

Explanation

b: The histogram is shifted toward higher gray levels Explanation

Explanation

c: The histogram remains the same Explanation

Explanation

d: The histogram is shifted toward lower gray levels Explanation

Explanation

4. If a constant value

c

is added to every pixel value

r

in an image, so that the new value is

s = r + c

for

c > 0

, how does the histogram generally change?

a: It shifts toward higher gray levels Explanation

Explanation

b: It shifts toward lower gray levels Explanation

Explanation

c: It remains unchanged Explanation

Explanation

d: It is rotated by

180^\circ

Explanation

5. A grayscale image has a histogram that is spread approximately uniformly across its available gray levels. What can be concluded from the histogram alone?

a: The image must have poor visual quality Explanation

Explanation

b: The image must have low contrast Explanation

Explanation

c: The image must contain only dark pixels Explanation

Explanation

d: The image uses a broad range of gray levels Explanation

Explanation

6. An 8-bit grayscale image has pixel values from

0

255

. If every pixel value is increased by

20

, what happens to a pixel with original value

100

, before considering the upper limit?

80

Explanation

100

Explanation

120

Explanation

275

Explanation

7. A negative image is formed by replacing each pixel value

r

with

s = L - 1 - r

, where

L

is the number of possible gray levels. What happens to the histogram?

a: Its gray-level ordering is reversed Explanation

Explanation

b: It remains at exactly the same gray-level positions Explanation

Explanation

c: It is shifted only toward higher gray levels Explanation

Explanation

d: It is shifted only toward lower gray levels Explanation

Explanation

8. For a grayscale image with bit depth

b

, what is the maximum number of distinct gray-level values that can be represented?

2b

Explanation

b^2

Explanation

2^b

Explanation

2^{b-1}

Explanation

9. Two images have identical histograms but different spatial arrangements of their pixels. Which statement is correct?

a: The images must be identical pixel by pixel Explanation

Explanation

b: The images have the same gray-level distribution but can have different spatial content Explanation

Explanation

c: The images must have different numbers of pixels Explanation

Explanation

d: One image must be a rotated version of the other Explanation

Explanation