Measurement Of Key Geometric Parameters Of Grin Lens Based On 3D Imaging Principle

Grin lens is an optical device whose refractive index gradually changes in the radial direction.Due to its compact structure,small size,excellent focusing and collimating performance,and easy installation,it becomes one of the irreplaceable components in the field of optical communication.Meanwhile,the grin lens has important applications in the fields of fax machines,scanners,and medical optics.The geometric parameters of the grin lens,such as wire diameter,length,ellipticity,and eight degree angle,have an important influence on the performance of the products.Whether these parameters meet the standard determines the qualified rate of the product,so it's important to detect products rapidly and precisely.At present,most of the geometric parameter measurement methods on the grin lens production line adopt the contact measurement method,which is not only time-consuming but also causes secondary damage during the measurement process.Therefore,the high-precision rapid non-contact measurement of the Grin Lens geometry can not only achieve rapid product inspection and classification,but also reduce secondary damage during the test,which is of great significance for improving production efficiency.According to this actual demand,this paper uses 3D structured light imaging combined with multi-vision rendezvous stereo measurement to measure the key parameters required by the Grin Lens production line.This measurement method is non-contact and can minimizes the damage as much as possible.Besides,all the data needed can be obtained with one measurement.In this paper,the geometric parameters and optical characteristics of the grin lens are analyzed in detail.Based on this,several commonly used measurement methods are introduced and compared from the form and error of themself.Finally,the 3D structured light imaging principle combined with the multi-vision rendezvous stereo measurement method is adopted and it can obtain all the key geometric parameters of the Grin Lens by one measurement.The experimental results show that the accuracy of the measurement method can reach the order of micrometers and have a high consistency of its results.The main contents of this paper are as follows:1.The structure and optical characteristics of the grin lens are analyzed and different measurement schemes are compared and selected.The combination of 3D structured light imaging and multi-vision rendezvous measurement is adopted to achieve highly precise and fast non-contact measurement of Grin Lens.2.A mathematical model is established based on the principle of 3D measurement,the error model is deduced,the key error sources are analysed and simulated,and the key parameters such as baseline length and measurement angle in the test plan are determined;3.The work mainly focuses on the image intersection matching algorithm based on 3D multi-vision imaging,determines the 3D structured light form and builds an experimental platform to verify the measurement principle;4.According to the image data obtained by the experimental platform,detailed analysis and calculation are obtained.Besides,the algorithm and core parameters are adjusted according to the actual working conditions.Finally,the experiment rapidly and precisely measures the geometric parameters of Grin Lens such as diameter,ellipticity,cylindricity,octave angle,and length.