|
The table shows the performance of the system without offset correction
| Method |
Mean |
Std Deviation |
| Distance using ruler calibration |
29,28 mm
|
0,0478 mm |
| Distance using calibrator - 1.
derivative edge |
30,14 mm |
0,0097 mm |
| Distance using calibrator - 2.
derivative edge |
29,90 mm |
0,0103 mm |
The following conclusion can be drawn from these measurements:
- The offset of a ruler calibration is approximately 3%
- The offset using calibrator is less; approximately 0.3%
- The offset is caused by the fact that the detected grayscale edge is
not the caliper edge
- In gauging systems with Scorpion, it is always needed to adjust the
measured value with an offset to improve the absolute precision
- With an offset corrected calibrator the accuracy with a Scorpion is
about one pixel or better. A pixel in this application is 0.058 mm.
- The Accuracy can be estimated using the formula : Accuracy = 3 * std
deviation =
The table shows the performance of the system with offset correction
| Method |
Mean |
Std Deviation |
Accuracy |
| Distance using ruler calibration |
30,02 mm
|
0,0478 mm |
0,150 mm |
Distance using calibrator
2. derivative edge |
30.00 mm |
0,0103 mm |
0.035 mm |
The Accuracy is improved by a factor of 4 to 5 using the 5. order camera
and lens calibration. The system can further be improved by using a
backlight and a better lens.
|
