This method makes use of the data acquired from measure site and multiple-unit successive regression method to build up a model that is fit for the local condition at that time. An adaptive noise-reducing technique and monitoring of temp gradient of measured area are used to eliminate the measure error caused by the shift, flutter and bend of the light beam itself, so as to ensure the stability of measuring reference and to increase the precision of straight line measurement. In the device provided by this invention, more than two fixed monitor targets and a measuring target connected with the object to be measured are arranged on the way of a collimated light beam. These targets are sampled multiple times and acquired data are averaged. A computer is used for data processing to output real-time measured result. |