Neighbor of pixels prepared by students of institute of management sciences peshawar and course instructor is Dr imran Mughal

1. Digital Image
Processing.
COURSE INSTRUCTOR
DR IMRAN MUGHAL.
PREPARED BY
RAJA OSAMA
RAJA RAHEEL

2. Content
• Basic Relationship between pixels.
• Pixel adjacency
• Pixel connectivity
• Pixel region
• Region adjacency
• Region boundary.

3. Neighbors of pixels.
• A pixel p at location (x , y) has two horizontal and two vertical
neighbors.
• This set of four pixels (vertical & horizontal) is called 4 neighbors of
pixel. p=N4(p)
• If the p is boundary pixel then it will have less number of neighbor
pixels.
p(x , y-1)
p(x -1 , y) p(x , y) p(x+1 , y)
P(x , y+1)

4. Neighbors of pixel
• A pixel p at location ( x ,y ) has 4 diagonal neighbors. P=ND(p)
• If p is neighbor pixel then it will have less number of neighbor pixels.
p(x-1 , y+1) p(x+1 , y-1)
P(x , y)
p(x-1 , y-1) P(x+1 , y+1)

5. Neighbors of pixels
• Union of all 4 (vertical & horizontal ) and 4 ( diagonal ) neighbors is
called 8 neighbors.
• N8(p) =N4(p) U PD(p)
• If p is boundary pixel then it will have less number of neighbor pixels.
p(x-1 , y+1) p(x , y-1) p(x+1 , y-1)
p(x-1 , y) p(x , y) p(x+1 , y)
p(x-1 , y-1) p(x , y+1) P(x+1 , y+1)

6. Adjacency
4-Adjacency:-
• Two pixels are adjacent if they have same intensity value and they are
neighbors in set of p = N4(p).
• In binary image two pixels are adjacent if they are neighbors and have
same intensity either 0 or 1.
1 0 0
0 0 1
1 1 1

7. Adjacency
Two pixels are adjacent if they have same intensity value and they are
neighbors in set of p = N8(p).
1 0 0
0 0 1
1 1 1

8. Connectivity
• Two pixels are said to be connected if a path exist between them.
• Pixel connectivity based on 4 connectivity

9. Pixel Region & Region adjacency
• Region can be a subset image made by pixels.
• Region can be grow according to your need.
• impixelregion is function to set pixel region in an image.

10. Pixel Region and Region Adjacency

11. Pixel Region and Region Adjacency
Region adjacency
• R1 and R2 will said to be Region adjacent if their union form a
connected set.
• Regions that are not adjacent are called disjoint.
• There can be two type of region adjacency 4&8 adjacency.

12. Pixel Region and Region Adjacency
EXAMPLE:
R1
R2
Above regions are adjacent using only 8-adjacency.
1 1 1
0 0 1
0 1 0
0 0 1
0 0 1
0 1 0

13. Boundary of Region
• The boundary of the region R is the set of pixels in the region that
have one or more neighbors that are not in R.
0 0 0 0 0
1 0 1 0 1
0 1 0 1 0
1 0 1 0 0
1 0 1 1 1
0 1 0 1 0

14. Thank you!