Target Grid Distortion Glass On White 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” white 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 White glass substrate etched in Low Reflection Chrome for viewing in diffuse light. Pattern is on top surface (right-reading looking at).Includes N.I.S.T. traceable certificate of accuracy. Click here to download drawing