Chapter 4: Positional Deviation Measurement; Outline - Sharp IV-S30J User Manual

Chapter 4: Positional Deviation Measurement

4-1 Outline

The gray scale search function and edge detection function* make possible measuring
positional deviation as well as the absolute position.
Purpose
- It is also possible to detect the position of sub-pixel units with great accuracy.
- A rotation angle of 360 can be detected. (When a one point gray search is selected).
Application Used to determine the position of machine parts and substrates.
[Determining the location of the positioning (the fiducial mark) mark that
identifies the position of the substrate]
(1) 1 point search: Detecting the deviation in position in X and Y directions
(2) 2 point search: Determining positional deviation in X and Y directions as well
as rotational deviation
Reference image a: Center coordinates (Xa1,Ya1)
Example
[Measured results]
- Center coordinates of image a: (Xa2,Ya2)
- Amount of deviation of image a: Xa2-Xa1, Ya2-Ya1
- Center coordinates of image b: (Xb2,Yb2)
- Amount of deviation of image b: Xb2-Xb1, Yb2-Yb1
- Deviation angle:
* Gray scale search / edge detection function
Gray scale search: Compares a workpiece image with the 256-level gray-scale
Edge detection:
- The deviation angle
rotation of the image for measurements 1 to 4.
Reference image: Center coordinates (X1,Y1)
Inspection Image: Center coordinates (X2,Y2)
Y2-Y1
Search area
X2-X1
Search area
(image a)
Xa2-Xa1
reference image to find an area that matches the reference image.
- See page G-6 of the User's Manual (Instruction & Hardware).
Finds the boundary between light and dark areas in an image.
- See page G-3 of the User's Manual (Instruction & Hardware).
, determined in the 2-point search, is used to readjust the
Positional Deviation Measurement
[Measured result]
Center coordinates: (X2,Y2)
Amount of deviation: X2-X1, Y2-Y1
Inspection image a: Center coordinates (Xa2,Ya2)
Reference image b: Center coordinates (Xb1,Yb1)
Ya2-Ya1
Inspection image b: Center coordinates (Xb2,Yb2)
Angular deviation:
Xb2-Xb1 Search area (image b)
4-1
4
Yb2-Yb1