Image measuring instrument and non-linear error correcting method and correcting plate thereof

Abstract

The invention discloses an image measuring instrument and a non-linear error correcting method and a correcting plate thereof. The correcting plate is provided with a plurality of standard circles and a plurality of concentric circles which are arranged in the form of a matrix, wherein the plurality of concentric circles are divided into two groups; in a first group of concentric circles, a standard circle at a leftmost lowermost corner is taken as a standard; in a second group of concentric circles, a standard circle at a rightmost uppermost corner is taken as a standard; and the plurality of concentric circles are arranged at intervals on the basis of the standard circles. In the correcting plate provided by the invention, the coordinate of a circle center is selected by measuring in a point taking way instead of aligning the edges of a line, so that a point taking error caused by the width factor of the line is reduced. In the non-linear error correcting method for the image measuring instrument provided, twice non-linear error correction is performed on a workbench, and two non-linear error correcting values are averaged, so that the measuring accuracy is increased; and moreover, non-linear error correction is performed along longitudinal and transverse directions at the intervals of 10 millimeters in the measuring range of the workbench, so that mechanical errors are effectively eliminated or reduced.

Description

technical field

[0001] The invention relates to an image measuring instrument, in particular to an image measuring instrument, a nonlinear error correction method and a correction plate thereof. Background technique

[0002] During the production and assembly process of the image measuring instrument, measurement errors will be caused by factors such as mechanical errors and microscope distortion. Therefore, in order to reduce the measurement error and improve the measurement accuracy of the image measuring instrument, nonlinear error correction will be performed. The entire nonlinear error correction process of the existing image measuring instrument is manually operated. A glass line ruler is placed on the workbench to measure the lines on the glass line ruler, and then the measurement results are input into the image measurement In the system, the image measurement system then corrects the nonlinear error of the measurement results. The specific method is to use a standa...

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