CPC Subgroup
G01B 11/14 for measuring distance or clearance between spaced objects or spaced apertures (G01B11/26 takes precedence; rangefinders G01C3/00)
Full Title
Measuring arrangements characterised by the use of optical techniques > for measuring distance or clearance between spaced objects or spaced apertures (G01B11/26 takes precedence; rangefinders G01C3/00)