The error of coaxiality measurement for bearings of crank shaft of large-scale marine diesel engine is analyzed in this paper,then the influences of random errors and system errors are discussed,finally the error formula of the measuring system is presented.

A CMOS method of coaxiality measurement for bearings of crank shaft of large-scale marine diesel engine is presented in this paper,in which installation reference line uses laser diode with single mode fiber pigtail and position sensor of center of crank shaft bearings is composed of a CMOS image sensor and a rotating inductance displacement transducer.