US Patent 10900781 Increment measuring device and process

A device for measuring an increment on a surface comprises a housing having a left light source, a right light source and center light source each configured to project a light beam onto a target surface. Each light source is independently rotatable, and in communication with a rotation measuring element configured to measure a degree of rotation of each respective light source. A computing unit is configured to receive a measured degree of rotation value from the rotation measuring element for each of the left light source and the right light source, and to calculate a rotation target value for the center light source corresponding to a desired incremental point on the target surface between a projected left light beam from the left light source and a projected right light beam from the right light source, such that the center light source can be rotated according to the rotation target value and project a center light beam at the desired incremental point.