1. A system, comprising a measuring tool, a fixture, and a rotatable target, wherein said measuring tool includes a light source, an imaging device, and an electronic circuit, wherein said fixture allows said rotatable target to rotate about an axis, wherein said rotatable target includes a surface having microscopic asperities, wherein said imaging device is mounted to provide a sequence of images derived from said microscopic asperities, wherein said electronic circuit is connected to said imaging device for measuring rotation of said rotatable target from said sequence of images.