For this report we meansured all the dot spacing in the target as shown in the below:

Item No.: WMH-050-40-G   

pattern size: 40x40mm

array size: 7x7

dot spacing: 5.0mm

dot diameter: 2.5mm

type: chrome-on-glass

To generate the results we meassured the horizontal and vertical spacing of the dots. The test system fits a ellipse at each dot position to detect its centre to report the 3D position of the dot. Using the 3D space the system automatical corrects any lense distortion using an instrisic and extrensic calibration to get metrically calibrated coordinates with the quality of the powerfull GOM system. Based on these points you can calculate the distance of any dots. This are the results:

1) Horizontal spacing error in um

2) Vertical spacing error in um

3) Overall  dot spacing error in um

4) Conclusion

As you can see the accuracy of the spacing in horizontal and vertical direction are reporting similar values. The mean error is roughly 0.8um. The standard deviation of the error in spacing is less than 0.2um allowing precise measurements of your system. You can archive similar results of your optical measurement system by using our precise calibration targets or use our targets to generate highly sophisticated AR or VR systems.