Standard Gauge Based Reference Measuring Technologies For Geometric Parameters

The online detection technology for geometry is essential to protect the quality of the production. With the development of high-precision systems, this requires products with higher accuracy and eligibility. Outer diameter is one of the most important parameters of the products,which needs high-precision on-line measurement, however, the existing measuring equipment often occurs with the issues between the decreasing measurement accuracy and increasing range. Rely solely on improving measuring equipment to improve accuracy resolution itself is not advisable, and it will be affected by objective conditions such as industrial technology,testing conditions and manufacturing cost.For the high accuracy measurement of the large diameter of axisymmetric components, this paper proposes a method of reference measuring based on standard gauge, transformed the diameter measurement into the slit measurement between the goals and the standard gauges. Application of machine vision technology, the system using high-resolution image sensor array and image processing techniques to realize the precise measurement of slit. This paper first studied the principle of the measuring system, which includes the principles of conversion between the slit size and the target size, and gives the system error analysis, Get the main factors that affecting system precision, including the camera calibration precision and positioning accuracy of image measurement; Secondly, this paper proposed a new two-steps calibration method of linear array camera through the separates between internal and external parameters, and the two-step method not only makes full use of high-precision calibration laboratory equipments, but also makes it easy to industrial field application. Experiments prove the camera's measurement precision has been largely improved after calibrated. Finally, the image processing application of system is studied, and the image quality evaluation function and edge correction algorithm are proposed which is suitable for linear array image sensor online real-time measuring system, and verifies the proposed algorithm in the paper through simulation experiments. Experimental results show that the image measurement method can achieve high precision measurement of the slit,which Meet the design requirements of the system.