Computer Graphics Multiple Choice Questions & Answers (MCQs) on “Area Sampling”.
1. We can think a line as a _____________________ in the grid.
a) Parallelogram
b) Rectangle
c) Circle
d) Triangle
Answer: b
Clarification: A line can be viewed as a rectangle of defined thickness. It covers a desired area in the grid. Even the thinnest horizontal line has a thickness of one pixel.
2. Line should set an intensity of only a single pixel in a column to black.
a) True
b) False
Answer: b
Clarification: A line should not set an intensity of a single pixel in a column to black, but rather should contribute some amount of intensity to each pixel in the column, whose area it intersects.
3. A signal can also be represented as ____________________
a) Amplitude domain
b) Signal domain
c) Frequency domain
d) Phase domain
Answer: c
Clarification: The signal can also be represented as a frequency domain, that is why we may represent it as a sum of two different sine waves.
4. What is lower bound on the sampling rate known as?
a) Syquist rate
b) Nyquist rate
c) Hartley rate
d) Sampling rate
Answer: b
Clarification: Sampling theory tells us that a signal can be reconstructed by its samples. The original signal is sampled at a frequency larger than twice. This sampling rate is called Nyquist rate.
5. The equal area in area sampling contributes _______________
a) Equal intensity
b) Greater intensity
c) Lower intensity
d) Area is not dependent on the intensity
Answer: a
Clarification: The equal area contributes to equal intensity in area sampling. Only the total amount of overlapped area matters, regardless of the distance between the pixel’s centre.
6. Which of the following is NOT a type of area sampling?
a) Weighted area sampling
b) Unweighted area sampling
c) Anti-aliasing
d) Point sampling
Answer: d
Clarification: Weighted and unweighted area sampling are types of area sampling classified on the basis of proportionality of intensity. Anti-aliasing is another name of unweighted area sampling whereas, point sampling is not a type of area sampling.
7. The technique of setting the intensity proportional to the amount of area covered is used in weighted area sampling.
a) True
b) False
Answer: b
Clarification: The technique of setting the intensity proportional to the amount of area covered is used in unweighted area sampling. This technique produces noticeably better results than others.
8. What happens to intensity if an area of overlapping increases?
a) Intensity remains same
b) Intensity decreases
c) Intensity increases
d) Can’t say anything
Answer: c
Clarification: When the line covers pixel completely the intensity is a maximum while when the line doesn’t touch the pixel the intensity is zero. Hence we can say, the intensity is directly proportional to the overlapping area.
9. What is the effect of weighted area sampling on adjacent pixels?
a) Intensity is increased
b) Intensity is decreased
c) Contrast is increased
d) Contrast is decreased
Answer: d
Clarification: The net effect of weighted area sampling is to decrease the contrast of adjacent pixels. This gives a lot of help in order to provide smooth transactions.
10. What is the name of the effect that causes different signals to become indistinguishable?
a) Aliasing
b) Anti-aliasing
c) Sampling
d) Staircase effect
Answer: a
Clarification: When the resolution is too low, visual stair-stepping of edges occurs in an image. That effect is called aliasing.