Sharp IV-S30J User Manual page 61

Setting Measurement Conditions
(7) Edge detection
The "edge" refers to the boundaries between the brighter (white) and darker (black) parts in an image.
The "edge detection" function is used to detect this boundary by processing the image.
An example of detecting a point using the edge detection function and user specified
criteria
• Horizontal transition point
from light to dark (moving
3
from left to right)
Edge detection point
Detection direction
• Horizontal transition point
from light to dark (moving
from right to left)
Detection direction
• Center (dark), horizontal (left and right)
• Edge detection of the inside and outside edges of a two circles
A: Moving right horizontally
from light to dark
- The edge detection point coordinates are used as a reference point to detect an out of position
condition.
- Edge detection in binary images is much quicker than in a gray scale search. However, the binary
image detection process is less precise at detecting position.
• Vertical transition point
Detection area
A B
• Vertical transition point
Detection area
A B
Edge detection
point
Edge detection point
Detection area
B: Moving right horizontally
from dark to light
Detection area
from light to dark (moving
from top to bottom)
Edge detection
point
A
Brightness
B
from light to dark (moving
from bottom to top)
A
Brightness
B
C: Moving left horizontally
from dark to light
3-14
Edge Flat
width width
Light
level
Dark
A Direction
Edge Flat
Light
width width
level
Dark
A Direction
D: Moving left horizontally
from light to dark
Internal diameter (between B and C)
External diameter (between A and D)
Difference
in level
B
Difference
in level
B