Sharp IV-C35M User Manual page 122

Glossary
[An example of detecting a point using the edge detection function and user specified criteria]
- Horizontal transition point
from light to dark (moving
from left to right)
Edge detection point
A
Detection direction
- Horizontal transition point
from light to dark (moving
from right to left)
A
Detection direction
- Center (dark), horizontal (left and right)
- Edge detection of the inside and outside edges of a two circles
A: Moving right horizontally
G
from light to dark
Edge emphasis
See "Space filter."
Edge extraction
See "Space filter."
Expansion
See "Expansion and contraction to eliminate binary noise in the image."
Expansion and contraction to eliminate binary noise in the image
When an image is converted to black and white, a number of unwanted dots may appear in the
image. These noises can be eliminated during the preliminary processing. Dot control processing of
binary values is used to eliminate this problem, as described below.
Expansion
If a white area contains a single, isolated black point, the system will interrupt the black point to
white.
Contraction
If a black area contains a single, isolated white point, the system will convert the white point to
black.
- Vertical transition point from
light to dark (moving from top
to bottom)
Detection area
B
- Vertical transition point from
light to dark (moving from
bottom to top)
Detection area
B
Edge detection
point
Edge detection point
Detection area
B: Moving right horizontally
from dark to light
Detection area
Edge detection
Light
point
A
Brightness
level
Dark
B
Light
A
Brightness
level
B
Dark
C: Moving left horizontally
from dark to light
D: Moving left horizontally
from light to dark
Internal diameter (between B and C)
External diameter (between A and D)
G-4
Edge Flat
width width
Difference
in level
A Direction B
Edge Flat
width width
Difference
in level
Direction
A B