Reflective stripe three-dimensional shape measuring method based on multi-field view splice

A technology of three-dimensional surface shape and measurement method, which is applied in the direction of measuring devices, instruments, and optical devices, etc., can solve the problems of limited field of view, inability to fully measure and accurately measure the three-dimensional shape of the reflective workpiece surface, and inaccurate phase measurement. Achieve the effects of avoiding low measurement accuracy, fast three-dimensional surface measurement, and solving matching errors

Active Publication Date: 2018-06-22
南通钜子光电科技有限公司
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AI Technical Summary

Problems solved by technology

[0004] However, in actual optical processing and precision inspection, when the surface shape of the device under test is relatively complex or the curvature of the workpiece surface changes greatly, the previous fringe reflection measurement method cannot measure the complete and accurate three-dimensional surface topography of the reflective workpiece.
Especially for parts where the surface curvature changes rapidly, the measurement data is either missing or the accuracy is very low
This is mainly due to the limited field of view of a single camera, and the fringe cannot enter the effective acquisition area of ​​the camera after being reflected by the mirror area with a large curvature change, or even if it can be acquired by the camera, the image is severely deformed and the phase measurement is inaccurate

Method used

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  • Reflective stripe three-dimensional shape measuring method based on multi-field view splice
  • Reflective stripe three-dimensional shape measuring method based on multi-field view splice
  • Reflective stripe three-dimensional shape measuring method based on multi-field view splice

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Experimental program
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Effect test

Embodiment 1

[0038] In this embodiment, four cameras are used to splice and measure the three-dimensional surface topography of the workpiece under test. Image 6 As shown, the reflective fringe three-dimensional surface measurement method based on multi-field stitching, the measurement steps are:

[0039] (a) Mount each camera (including No. 1 camera 2, No. 2 camera 4, No. 3 camera 6 and No. 4 camera 36) with a camera lens (including No. 1 camera lens 3, No. camera lens 7 and camera lens 4 37). All cameras are known to have a pixel size of 4.8 µm. If the focal length and distortion of the installed camera lenses are unknown, the focal length and distortion of the four camera lenses are first calibrated; if known, the pre-calibrated focal length and distortion can be used. In this embodiment, we first calibrate the focal length and distortion of the four camera lenses using checkerboard calibration boards. as attached image 3 As shown, in the calibration process, the checkerboard cali...

Embodiment 2

[0048] Different from Example 1, after obtaining the normal vector matrix ( Mx m , My m ) and synthesize them directly to obtain the normal vector matrix ( Mx , My ). During the compositing process, the average value of the normal vectors measured by multiple cameras is used when the overlapping parts are composited, and the normal vector value measured by a single camera is used when the non-overlapping parts are composited. Then the normal vector matrix ( Mx , My ) to perform a gradient integral operation to obtain the overall three-dimensional topography of the surface of the workpiece 12 under test. in, m =1,2,3,4.

Embodiment 3

[0050] Different from Example 1, in order to improve the three-dimensional shape in its step (h) S 1 , S 2 , S 3 with S 4 The synthesis accuracy of the 3D shape is corrected by the feature matching algorithm before the synthesis of the 3D shape S 1 , S 2 , S 3 with S 4 The small displacement and angle difference between them can contain the small displacement and angle difference in the three-dimensional surface shape measurement results of each part introduced by the calibration error of the principal point coordinates of the camera lens and the optical axis direction.

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Abstract

The invention belongs to the technical field of optical precision measurement and relates to a reflective stripe three-dimensional shape measuring method based on multi-field view splice. According tothe method, multiple cameras are used for measuring the three-dimensional shape of different parts of the tested piece at the same time, to solve the problem of incomplete measuring data of the single camera caused by the self-shielding of the curved surface. In order to ensure that the coordinate system of the plurality of camera measuring data is consistent, the invention uniformly corrects multiple cameras and strip display screens to establish a unified spatial coordinate system. In addition, the invention corrects the fine inclination and the motion error between the measuring data of each camera by utilizing fine beam labeling method and the like to further improve the measuring precision. The invention integrates the multi-camera and multi-field synchronous measuring idea into thereflective strip three-dimensional shape measuring technology with high-reflective surface for the first time, which has the advantages of high measurement precision, fast measurement speed and stronganti-environment interference capability, and can be used for rapid three-dimensional shape measurement on a high-reflective surface with large bending degree.

Description

technical field [0001] The invention belongs to the technical field of optical precision measurement and can be used for high-precision measurement of three-dimensional topography of high-reflection surfaces. Background technique [0002] High-precision three-dimensional surface measurement technology plays an important role in the fields of precision instrument manufacturing, precision optical processing and product testing. Measuring and evaluating the surface topography of precision-machined devices is of great significance for studying the relationship between the surface geometric characteristics and performance of precision devices, improving processing quality and product performance. With the continuous increase and deepening of application requirements, highly reflective curved surface devices such as mirrors and mirror-like surfaces, as key components of the system, have received more and more attention in the fields of aerospace, automotive industry, communication...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01B11/25
CPCG01B11/254
Inventor 杨佳苗龚雷
Owner 南通钜子光电科技有限公司
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