1. Intro + Fundamentals

Question 1

What is an image?

Answer 1

• An image can be defined as a two dimensional function f(x,y).
• x and y are spatial coordinates.
• The amplitude of f at any given point = graylevel
• Digital Image = when x and y are finite and discrete.

Question 2

What are the two types of receptors in the eye and what are they sensitive to?

Answer 2

1. cones - color (bright-light vision)
2. rods - low light

Question 3

What is contrast?

Answer 3

• The difference in intensities between the highest and lowest values.
• High dynamic range = high contrast

Question 4

When an image is digitized it is sampled in…(2)

Answer 4

1. Space (x,y) - image sampling
2. Amplitude f(x,y) - graylevel quantization

Question 5

What is resolution in an image?

Answer 5

The amount of detail an image holds.

Question 6

What is spatial resolution?

Answer 6

Measure of the smallest distinct detail of an image

Question 7

What is resolution in an image?

Answer 7

The amount of detail an image holds.

Question 7

What is gray level / intensity resolution?

Answer 7

The smallest identifiable change in the gray/intensity levels

Question 8

The number of bits used to quantize intensity can be known as ___?

Answer 8

Intensity resolution

Question 9

• What does the quantization level of an image determine?
• How do humans perceive high levels of quantization?

Answer 9

• The number of gray levels in a digital image
• It helps observe finer details

Question 10

What are the 3 types of relationships between pixels?

Answer 10

1) N4(p) - Edge neighbours
2) ND(p) - Diagonal neighbours
3) N8(p) - 8 neighbours

Question 11

What are the 3 types of adjacency between pixels?

Answer 11

1) 4-adjacency –> q is in set N4(p)
2) 8-adjacency –> q is in set N8(p)
3) m-adjacency –> q is in N4(p)
OR q is in ND(p) and N4(p) and N4(q) have no values in common.

Question 12

What is connectivity? (connected)

Answer 12

For a subset of pixels S, p and q are connected in S, if there exists a path between them consisting entirely of pixels in S.

Question 13

What is adjacent and disjoint in two subsets of pixels R1 and R2?

Answer 13

• R1 and R2 are adjacent if their union forms a connected set.
• If not adjacent R1 and R2 are disjoint

Question 14

How can a subset of pixels (R) be a region?

Answer 14

If the R is a connected set, it will be a region.

Question 15

Define the boundary/ border/ contour of a region R.

Answer 15

The set of pixels in R that have one or more neighbours that are not in R.

Question 16

What are 3 ways pixel distance can be measured?

Answer 16

1) Euclidian distance (disk)
2) City-block distance (D4)
3) Chessboard distance (D8)

Question 17

Define euclidian distance

Answer 17

The pixels having a distance less than or equal to
some value r from (x, y) are the points contained
in a disk of radius r centered at (x, y).

Question 18

Define city-clock distance

Answer 18

Pixels having D4 distance from (x,y) that is less than or equal to some value from d from a diamond centered at (x,y)

Question 19

Define chessboard distance

Answer 19

Pixels with D8 distance from (x, y) less than or
equal to some value d form a square centered at
(x, y)