Computer Graphics multiple choice questions on Anti Aliasing.
1. The distortion of information due to low-frequency sampling is known as
a) Sampling
b) Aliasing
c) Inquiry function
d) Anti-aliasing
Answer: b
Clarification: The distortion of information is called aliasing.
2. To avoid losing information from periodic objects we need
a) Sampling frequency twice
b) Nyquist sampling frequency
c) Both a or b
d) Neither a nor b
Answer: c
Clarification: Because nyquist sampling frequency means sampling frequency twice.
3. Nyquist sampling frequency formula is
a) fs=2fmax
b) fs=2fmin
c) fs=fmax
d) fs=fmin
Answer: a
Clarification: None.
4. The sampling of object characteristic at a high resolution and displaying the result at a lower resolution is called?
a) Super-sampling
b) Post-filtering
c) Anti-aliasing
d) a or b
Answer: d
Clarification: Super-sampling is also called Post-filtering by computing intensities and combines results to obtain the pixel intensities.
5. Anti-aliasing by computing overlap areas is referred to as
a) Area-sampling
b) Super-sampling
c) Pixel phasing
d) Only b
Answer: a
Clarification: The intensity of pixel as a whole is determined without calculating sub-pixel intensity.
6. Area-sampling is also known as
a) Pre-filtering
b) Pixel phasing
c) Post-filtering
d) Anti-aliasing
Answer: a
Clarification: None.
7. Raster objects can also be anti-aliased by shifting the display location of pixel areas is known as
a) Super-sampling
b) Pixel shaping
c) Pixel phasing
d) Any of these
Answer: c
Clarification: This technique is applied by micro-positioning the electron beam in relation to object geometry.
8. If we want to use more intensity levels to anti-alias the line, then
a) We increase the number of sampling positions
b) We decrease the number of sampling positions
c) We increase the number of pixels
d) Only c
Answer: a
Clarification: We increase the number of sampling positions across each pixel to use more intensity levels.
9. The procedure that increases the number of intensity levels for each pixel to total number of sub-pixels is
a) Area-sampling
b) Anti-aliasing
c) Super-sampling procedure
d) Only c
Answer: d
Clarification: The super-sampling procedure increases the number of intensity levels for each pixel to total number of sub-pixels.
10. For a 45% line, the line path is________ on the polygon area.
a) Horizontal
b) Centered
c) Vertical
d) Any of these
Answer: b
Clarification: The line path is centered on the polygon area only if a line is 45%.
11. An array of values specifying the relative importance of sub-pixel is referred as________ of sub-pixel weights.
a) Sub-mask
b) Mask
c) Pixel phasing
d) Pixel weighting
Answer: c
Clarification: None.
12. The technique that is more accurate method for anti-aliasing lines is
a) Filtering
b) Area-sampling
c) Super-sampling
d) None
Answer: a
Clarification: In this technique we can imagine a continuous weighting surface covering the pixel.
13. Super-sampling methods can be applied by
a) Sub-dividing the total area
b) Determining the number of sub-pixels inside the area
c) Both a and b
d) Only b
Answer: c
Clarification: Super-sampling methods can be applied by sub-dividing the total area and determining the number of sub-pixels inside the area boundary.
14. Another method for determining the percentage of pixel area within a boundary is
a) Mid-print algorithm
b) Mid-point algorithm
c) Pixel intensity
d) By using inquiry functions
Answer: b
Clarification: This algorithm selects the next pixel along a line by determining which of 2 pixels is closer to the line between 2 pixels.
15. What is the use of Coherence techniques along and between scan lines?
a) To simplify the calculations
b) To determine the area edges
c) To find polygon region
d) To correct interior area
Answer: a
Clarification: Coherence techniques are used along and between scan lines to simplify the calculations.