Device for measurement of distances from a central reference point has an optical or opto-electronic technique using a hand held lens with central cross hairs and lines of equal distance, for use in games such as bowls etc.

摘要

Device has optical lens marked with reference cross- hairs (A) and lines marking equal distances (B) calculated using an optical transformation of the lens. The lens can be marked, printed or glued with colored and opaque areas. Alternately as an opto-electronic device it can have an electronic camera or laser device. Lens can have a handle for holding.