When using scanner to measure the diameter of microbe bacteriostatic rings

the system error is very big because of the principle of scanner.Method for auto modification of measurement result is discussed.By Visual C++ 6.0 programming

the position of the scanned object that is placed on the work plane of scanner at will is determined by technology without an interesting name（TWAIN） protocol.Using a circular object

whose diameter is measured manually using high accurate tool

modifying coefficients are determined in advance.In real measuring

measurement result can be modified automatically according to the object position to reduce the influence of position error.Experiment maximum error is 0.18 percent.