Method for precisely measuring width of steel plate at finish rolling outlet

The invention discloses a method for precisely measuring the width of a steel plate at a finish rolling outlet. The method comprises the steps that (1) a width gauge is used for measuring width data Wi of the steel plate, and a flatness gauge is used for measuring wave height data Yij of the steel plate; (2) an evaluation coefficient P is calculated according to a model formula, and abnormal wave height data with P higher than 100 are removed; (3) the wave height data after data removal are divided according to the formula in the specification to obtain n sets of wave shape error amounts and tilt error amounts; (4) tilt error correction delta Wbi is calculated according to the formula in the specification; (5) wave shape error correction delta Wai is calculated according to the formula in the specification; (6) precise strip steel width measuring data Wact_i are determined. According to the method for precisely measuring the width of the steel plate at the finish roller outlet, the wave height data after meas