CN200962029Y - 3D Deformation Measurement System Based on Split Fiber - Google Patents

Abstract

The utility model relates to a three-dimensional strain measuring system based on splitting optical fibers, comprising an optical maser providing light source, a graphic receiving system with a CCD camera, and a light splitting, conducting and phase-shift system, wherein the light splitting, conducting and phase-shift system is a light splitting, conducting and phase-shift system that splits the light into five beams. Through switching the shielding switch on the output of the fibers, the strain measuring the object in the direction perpendicular to the plane of the object, the horizontal direction and the anti-central direction can be achieved. The utility model has a rational compact construction, easy operation, which is applicable to the three-dimensional strain real-time measurement of the object surface.

Description

3D Deformation Measurement System Based on Split Fiber

technical field

The utility model relates to an optical three-dimensional deformation measurement system, in particular to a three-dimensional deformation measurement system based on a split optical fiber.

Background technique

With the development of work, people's research requirements on performance parameters such as deformation, stress, and strain after materials are stressed are also increasing. From the metal stress gauge that can only be applied to object point measurement in the past to the application of speckle technology that can measure the object surface area. There are already many methods in terms of hardware systems and algorithm processing such as deformation processing for two-dimensional or three-dimensional deformation measurement of objects using speckle technology.

In the current domestic literature, the technology of electronic speckle interferometry to measure the three-dimensional deformation system of the object surface is: three lasers are used to irradiate from three different directions to provide the illumination light source, and the object to be measured and the laser placed beside it are irradiated. reference. A PZT phase shifter is used to push the three mirrors pasted on the reference object to provide reference light corresponding to the interference of the three beams of object light and introduce phase shift. Place a large dislocation prism in front of the CCD camera, so that the information on the surface of the object and the information on the reference object enter the CCD. Combined with the four-step phase shift technology, the three lasers irradiate the measured object in turn, and calculate the collected speckle pattern. And separate to get three independent deformation fields. However, due to the large number of lasers and the large structure of this system, it is difficult to adjust the direction of the three plane mirrors on the reference object, and the separation effect of the large misalignment prism may affect the quality of the speckle image, and this system cannot be used alone for one-dimensional or two-dimensional Measurement.

In the patent US 6188483 B1, in the system for measuring the surface deformation of three-dimensional objects, a laser is used to provide the light source, and the characteristics of the beam splitter and the mirror are used to split and transmit light. Combining two double-beam electronic scattered interferometry systems and an out-of-plane deformation detection system into one system, relying on the outgoing four laser beams to complete the in-plane deformation detection, and using one of the four laser beams and the other internal The beams of light constitute an out-of-plane deformation detection system. The electronic speckle images obtained before and after deformation are processed by direct subtraction algorithm to obtain three-dimensional deformation data. This system can measure one-dimensional, two-dimensional or three-dimensional deformation independently. The disadvantage is that discrete components are used for light splitting and light transmission, there are many optical devices, the positioning accuracy of optical devices is high, the system debugging requires high precision, and the adjustment operation is difficult.

Utility model content

The purpose of the utility model is to provide an improved three-dimensional deformation measurement system based on split optical fiber, which is simple in structure, easy to operate, and can ensure measurement accuracy against the defects in the prior art.

In order to achieve the above object, the design of the present utility model is:

The utility model mainly improves and innovates the hardware system, adopts a one-point five-type optical fiber to split and transmit light, and takes four branch optical fibers to form two pairs of in-plane deformation detection, and through the predetermined divergence angle parameters of the optical fiber exit port, The divergent beam that meets the system requirements can be directly obtained without a beam expander. In order to improve the accuracy of deformation measurement, the four-step phase shift algorithm is still used, and the traditional method of introducing phase shift is adopted. In the above two pairs of coherent beams, a PZT phase shifter is respectively pasted on the exit port of one of the branched optical fibers, through the PZT The push of the phase shifter drives the branch fiber to move slightly, so that a phase shift can be introduced in this beam. One of the beams introduced with phase shift is shared and combined with the fifth branch fiber to obtain a coherent beam that meets the system requirements. Therefore, due to the use of optical fiber, the structure of the system is greatly simplified, and the debugging operation is convenient. Due to the use of the blocking switch, the system can independently measure one-dimensional, two-dimensional or three-dimensional deformation, and the software structure for image post-processing is simple. And ensure the measurement accuracy.

According to above-mentioned utility model design, the utility model adopts following technical scheme:

A three-dimensional deformation measurement system based on a split optical fiber, consisting of a laser providing a light source, an image receiving system with a CCD camera, and a spectroscopic light transmission and phase shift system, characterized in that the spectroscopic light transmission and phase shift The system is a one-to-five optical fiber splitting light transmission and phase shifting system; the structure of the above-mentioned one-fifth optical fiber splitting light transmission and phase shifting system is: the main optical fiber from the laser is connected to a One-to-five fiber coupler input ports, the output port of the fiber coupler is connected to five optical fiber branches for light splitting and light transmission: one branch optical fiber is connected to the image receiving system with CCD camera described above, and the output port of four branch beams Each beam irradiator is aimed at the object to be measured, and a PZT phase shifter is pasted on each of the two beam irradiators. The expansion and movement of the PZT phase shifter drives the beam irradiator pasted to move, and the phase shift is introduced. In the light beam; the structure of the image receiving system with the CCD camera is: the outgoing light beam from the laser (1) passes through a microscope (2) and an optical fiber adjustment frame (3), and is transmitted by the optical fiber (11), and the light beam After passing through the beam guard collimator (10) and the blocking switch (9), the light is split by the beam splitter (7), and the beam splitter (7) is placed between the CCD camera (6) and the CCD lens (8).

The structure of the above-mentioned beam irradiator is: after the branch optical fiber is fixed on an optical fiber adjustment frame, the outgoing beam passes through an attenuation plate to adjust the light intensity, and passes through a variable aperture and a blocking switch to irradiate on the surface of the measured object.

The above CCD camera is connected to a computer.

Compared with the existing three-dimensional electronic speckle deformation detection system, the utility model has the following obvious features and advantages: the system of the utility model adopts a one-to-five optical fiber splitting and transmitting light; shares one beam of split beams; passes through two The PZT phase shifter obtains two laser beams that can be phase shifted to meet the experimental requirements. The three pairs of coherent light beams required by the system can be obtained through optical fiber splitting. The utility model requires few optical devices, has a reasonable and compact structure, and is easy to operate, and is suitable for quasi-real-time three-dimensional deformation measurement of object surfaces.

Description of drawings

Fig. 1 is a schematic diagram of the system structure of an embodiment of the present invention.

FIG. 2 is a schematic structural diagram of the one-to-five optical fiber splitting and transmission and phase shifting system in the example in FIG. 1 .

Fig. 3 is a schematic structural diagram of the beam irradiator in the example of Fig. 1 .

Detailed ways

A preferred embodiment of the present utility model is: referring to Fig. 1, this three-dimensional deformation measurement system based on beam-splitting optical fiber consists of a laser 1 providing a light source, an image receiving system with a CCD camera 6, and a light splitting light transmission and phase shifting system Composition, the light splitting, light transmission and phase shifting system is a one-to-five fiber optic light splitting, light transmission and phase shifting system.

The structure of the above-mentioned one-to-five optical fiber splitting light transmission and phase shift system is: the main optical fiber from the laser 1 is connected to a one-to-five fiber coupler 4 input port through a fiber adjustment frame 3, and the fiber coupler The output port of 4 is connected with five bundles of optical fiber branches 11, 12, 13, 14, 15 for light splitting and light transmission: a bundle of branched optical fibers 11 is connected to the image receiving system with the CCD camera 6, and four bundles of branched light beams 12, 13, The output ports of 14 and 15 each have a beam irradiator 20, 21, 19, 18 aimed at the measured object 22 respectively, wherein the two beam irradiators 19, 18 are respectively pasted with a PZT phase shifter 17, 16, through the PZT The expansion movement of the phase shifters 17, 16 drives the beam irradiators 19, 18 attached to them to move, and introduces the phase shift into the beam.

The structure of above-mentioned light beam irradiator 19,18 is: after branch optical fiber 14,15 is fixed on an optical fiber adjustment frame 23, its outgoing light beam is adjusted light intensity by an attenuation sheet 24, passes through an iris diaphragm 25 and a blocking The switch 26 shines on the surface of the measured object 22 .

The structure of the image receiving system with the above-mentioned band CCD camera 6 is: the outgoing light beam from the laser 1 passes through a microscope 2 and the optical fiber adjustment frame 3, and is transmitted by the optical fiber 11, and the light beam passes through the beam expander collimating mirror 10, the blocking switch 9 After that, the light is split by the beam splitter 7, and the beam splitter 7 is placed between the CCD camera 6 and the CCD lens 8.

The above-mentioned CCD camera 6 is connected with a computer 5 .

All components of the above-mentioned laser 1 , image receiving system with CCD camera and one-to-five optical fiber splitting light transmission and phase shifting system are installed on a base plate 27 .

The above-mentioned fiber coupler 4 is also called a splitter, which is a component for splitting an optical signal from one optical fiber to multiple optical fibers. We mainly use it to split and transmit light in the system. In this system, a star-shaped/tree-shaped fiber coupler is used, and five optical fibers are burnt and stretched together through the sintering method, so that the cores are aggregated together to achieve optical coupling. By adjusting the length of the taper and controlling the sintering temperature, the energy ratio of the optical fiber splitting is realized, so as to meet the requirements of the system that the energy ratio of the five branch beams is close to equal.

Working principle of the utility model

As shown in Figure 1, the laser 1 provides a laser light source. After the laser beam is focused by the microscope 2, the beam enters the main optical fiber of the 1/5 fiber coupler 4 through the adjustment of the optical fiber adjustment frame 3 to obtain 11, 12, 13, 14, 15 five beams. The beam 11 is expanded and collimated by the beam expander and collimator 10 and enters the beam splitter 7 through the blocking switch 9; the beams 12 and 14 are placed in the horizontal plane and irradiate the measured object 22 symmetrically with respect to the normal line of the object surface, wherein the output of the beam 14 The port is pasted with a PZT phase shifter 17 so that the phase shift is introduced into the light beam 14 to form an in-plane horizontal direction deformation detection system; the light beams 13 and 15 are placed in the vertical plane and irradiate the measured object 22 symmetrically with respect to the normal line of the object surface, Wherein the output port of the beam 15 is pasted with a PZT phase shifter 16 to introduce the phase shift into the beam 15 to form an in-plane vertical deformation detection system. At the output ends of the light beams 12, 13, 14, 15, there are respectively blocking switches 26 of the light beam irradiators 20, 21, 19, 18 to control the sequence of deformation detection.

In the above system, after the branch beams 12 , 13 , 14 , 15 exit the beams, they respectively pass through the beam irradiators 20 , 21 , 19 , 18 with the same structure, and then irradiate the measured object. As shown in Figure 3, the branched light beams 12, 13, 14, 15 are fixed on the optical fiber adjustment frame 23, and the emitted divergent light beams pass through the attenuation plate 24 to adjust the light intensity, pass through the diaphragm 25 and the blocking switch 26, and then irradiate on the surface of the object superior.

In the above system, the data acquisition operation steps are as follows: first, carry out in-plane vertical deformation detection, open the shielding switch 26 on the beam irradiators 18, 21, close the shielding switch 9 and the shielding switches 26 on the beam irradiators 19, 20 , so that the light beams 13 and 15 constitute an in-plane vertical deformation detection system; then, carry out in-plane horizontal deformation detection, close the shielding switch 26 on the beam irradiators 18, 21, and open the shielding switches on the beam irradiators 19, 20 26. The shielding switch 9 is still in the closed state, so that the beams 12 and 14 constitute an in-plane horizontal deformation detection system; finally, the out-of-plane deformation detection is performed, and the shielding switch 26 on the beam irradiators 18, 20, 21 is turned off, and the shielding is turned on The switch 9 makes the light beams 11 and 14 constitute an out-of-plane deformation detection system. The light beam reflected from the measured object is imaged on the target surface of the CCD camera 6 through the CCD lens 8, and then the image is transmitted to the computer 5 for data processing.

Claims (3)

1. A three-dimensional deformation measurement system based on beam splitting optical fiber is composed of a laser (1) providing a light source, an image receiving system with a CCD camera (6) and a split light transmission and phase shifting system, characterized in that the The light splitting and light transmission and phase shifting system described above is a one-to-five-type optical fiber splitting and light transmission and phase shifting system; the structure of the one-to-five-type optical fiber light splitting and light transmission and phase shifting system is: from the laser (1 ) is connected to the input port of a one-to-five fiber coupler (4) through a fiber adjustment frame (3), and the output port of the fiber coupler (4) is connected to five optical fiber branches (11, 12, 13, 14 , 15) Carry out light splitting and light transmission: a branch optical fiber (11) connects the described image receiving system with CCD camera (6), and the output ports of four branch light beams (12, 13, 14, 15) each have one The beam irradiators (20, 21, 19, 18) are respectively aimed at the object to be measured (22), and two of the beam irradiators (19, 18) are respectively pasted with a PZT phase shifter (17, 16). The expansion movement of shifter (17,16) drives the beam irradiator (19,18) that it sticks to move, and phase shift is introduced in the beam; The structure of the image receiving system of described band CCD camera is: from described The output beam of the laser (1) passes through a microscope (2) and optical fiber adjustment frame (3), and is transmitted by the optical fiber (11). ) beam splitter, the beam splitter (7) is placed between the CCD camera (6) and the CCD lens (8). 2. The three-dimensional deformation measurement system based on split optical fiber according to claim 1, characterized in that the structure of the beam irradiator (19, 18) is: the branch optical fiber (14, 15) is fixed on an optical fiber adjustment frame After (23) is on, its outgoing light beam is adjusted light intensity by an attenuation sheet (24), passes through an iris diaphragm (25) and a blocking switch (26) and irradiates on the surface of the measured object (22). 3. The three-dimensional deformation measurement system based on split optical fiber according to claim 1, characterized in that said CCD camera (6) is connected to a computer (5).

Images