Target Grid Distortion Glass- Clear Glass Useful for measuring video system distortion. Known dot diameters and spacing used to quantify Actual image distances versus Predicted. Corrections result for image processing or direct readings.Pattern: Five (5) square dot arrays on 3” X 3” soda lime glass.(1) Dot spacing: 2.00mm. Dot dia.: 1.00mm. Square length (center to center): 50.00mm(2) Dot spacing: 1.00mm. Dot dia.: 0.50mm. Square length (center to center): 34.00mm.(3) Dot spacing: 0.50mm Dot dia.: 0.25mm. Square length (center to center): 20.00mm.(4) Dot spacing: 0.25mm. Dot dia.: 0.125mm. Square length (center to center): 10.00mm.(5) Dot spacing: 0.125mm. Dot dia.: 0.0625mm. Square length (center to center): 5.00mm.Reticle on stable glass substrate etched in Low Reflection Chrome. Pattern is on top surface (right-reading looking at).Includes N.I.S.T. traceable certificate of accuracy. Click here to download drawing