阅读说明：本技术 微细孔内壁缺陷自动检测装置 (Automatic detection device for inner wall defects of micro-holes ) 是由 吴斌 吉逸喆 王航 张祖光 薛婷 于 2019-09-27 设计创作，主要内容包括：本发明涉及一种微细孔内壁缺陷自动检测装置,分为两个部分：固定部分和旋转部分,固定部分包括相机和镜头、环形光源、连接件、遮光筒和转台固定部分；旋转部分包括光信息传输部件、夹持件、托板和转台旋转部分；光信息传输部件包括遮光罩、磨砂面、锥形进光面、导光柱、平面透镜、底端45°反射镜,其中,遮光罩位于上端,其中间开设有透光孔,磨砂面为倒锥形,设置在遮光罩的下部,遮光罩和磨砂面共同防止环境光从上端进入光信息传输部件；在磨砂面的下部设置有锥形进光面,环形光源产生的光经过锥形进光面,沿导光柱照亮被测孔内壁,被测孔内壁局部图像经过平面透镜和底端45°反射镜被反射至上端,经过透光孔,进入镜头,在相机成像。(The invention relates to an automatic detection device for defects of the inner wall of a micro-hole, which is divided into two parts: the device comprises a fixed part and a rotating part, wherein the fixed part comprises a camera, a lens, an annular light source, a connecting piece, a shading cylinder and a turntable fixed part; the rotating part comprises an optical information transmission component, a clamping piece, a supporting plate and a turntable rotating part; the optical information transmission component comprises a light shield, a frosted surface, a conical light inlet surface, a light guide column, a planar lens and a bottom 45-degree reflector, wherein the light shield is positioned at the upper end, a light hole is formed in the middle of the light shield, the frosted surface is in an inverted cone shape and is arranged at the lower part of the light shield, and the light shield and the frosted surface jointly prevent ambient light from entering the optical information transmission component from the upper end; the lower part of the frosting surface is provided with a conical light inlet surface, light generated by the annular light source passes through the conical light inlet surface and illuminates the inner wall of the hole to be measured along the light guide column, a local image of the inner wall of the hole to be measured is reflected to the upper end through the planar lens and the 45-degree reflector at the bottom end, passes through the light hole, enters the lens and is imaged by the camera.)

1. An automatic detection device for inner wall defects of micro-holes is divided into two parts: the device comprises a fixed part and a rotating part, wherein the fixed part comprises a camera, a lens, an annular light source, a connecting piece, a shading cylinder and a turntable fixed part; the rotating part includes an optical information transmission member, a holder, a pallet, and a turntable rotating part. Wherein the content of the first and second substances,

the camera, the lens and the annular light source are fixedly connected with the fixed part of the turntable through connecting pieces; the shading cylinder is fixed on the periphery of the lens and is not contacted with the optical information transmission component so as to prevent stray light from entering the lens;

the optical information transmission component comprises a light shield, a frosted surface, a conical light inlet surface, a light guide column, a planar lens and a bottom 45-degree reflector, wherein the light shield is positioned at the upper end, a light hole is formed in the middle of the light shield, the frosted surface is in an inverted cone shape and is arranged at the lower part of the light shield, and the light shield and the frosted surface jointly prevent ambient light from entering the optical information transmission component from the upper end; a conical light inlet surface is arranged at the lower part of the frosted surface, light generated by the annular light source passes through the conical light inlet surface and illuminates the inner wall of the measured hole along the light guide column, a local image of the inner wall of the measured hole is reflected to the upper end through the planar lens and the 45-degree reflector at the bottom end, passes through the light hole, enters the lens and is imaged by the camera;

the supporting plate and the clamping piece are fixedly connected with the rotating part of the rotary table, the optical information transmission component is fastened on the rotation of the rotary table by the clamping piece and the supporting plate, and the supporting plate is provided with a hole allowing the light guide column to pass through.

Technical Field

The invention relates to a defect detection method, in particular to an automatic detection device for defects of the inner wall of a micro-hole based on optical measurement.

Background

The micro holes are more and more widely applied in the fields of aerospace, automobiles, energy sources, chemical engineering and the like, and in the precision casting process of devices such as automobile engine cylinder covers, aerospace aircraft radiating pipes and the like, the inner wall surfaces of the micro holes often generate defects such as a few of micro cracks, air holes, pits and the like, and the defects can cause the leakage of high-pressure gas or liquid inside parts, particularly at joints, so that the performance of equipment is reduced, and even safety accidents are caused.

At present, the commonly used detection technology for the defects of the inner wall of the pipeline comprises an ultrasonic method, an eddy current method, a magnetic leakage method and the like, but can only be used for pipe holes with large diameters. For small holes with the diameter of less than 10mm, an industrial endoscope with a small outer diameter can be used, but the defect can be judged only by manual operation, and the size and the position of the defect cannot be automatically and quantitatively given. In addition, the existing measuring device based on the 360-degree cylindrical surface annular panoramic image optical transmission component can realize the automatic detection of the defects of the inner wall of the small hole with the inner diameter of 10 mm. In summary, in several conventional schemes for detecting micro-duct, both the light source and the sensing component must enter the duct. Although the size of optical devices and other devices can be continuously reduced along with the development of technology and the improvement of manufacturing level, the miniaturization of the tested pipeline and the further miniaturization of the system structure face certain technical difficulties due to the complexity of the measurement function of the system. At present, no automatic detection device for the defects of the inner wall of the hole with the inner diameter of 4mm-10mm exists.

Micro-hole internal surface defect inspection research related documents (① Wu, Shaozhou, Zhang Yunhao. micro-channel inner wall defect Measurement system construction and Technology [ J ]. photoelectron. laser, 2014,25(02): 293) 298; ② Zhang. micro-hole wall defect flexible visual inspection system critical Technology research [ D ]. Tianjin university, 2014; ③ Enhong, Hongwei Zhang, Reuven Katz, John S.Agap. non-contact inspection of internal throdes of mechanical fasteners [ J ]. The mechanical fasteners, technical Manufacturing Manual, 2012,62(1-4), ④ Enhong, Reuven Katz, an of which, John of John applied to surface of inner wall, technical, and The requirements for small inner wall defect inspection based on The optical transmission Technology [ 2010 ] of The micro-hole inspection Technology [ 10mm ] were not satisfied even more with The development of The small inner wall defect inspection Technology [ 10 ] of The panoramic annular ring-wall inspection Technology [ 2010 ] of The optical inspection Technology [ 10 mm.

Disclosure of Invention

In order to overcome the defects of the prior art and meet the detection requirement of smaller pipe holes generated along with the development of casting technology, the invention provides an automatic detection device for realizing high-precision measurement of the defects of the inner wall of a micro-hole by a method of traversing the panorama of the inner wall of a detected hole through an automatic rotating and lifting optical information transmission part and provides a detection method. The technical scheme is as follows:

an automatic detection device for defects of the inner wall of a micro-hole is divided into two parts, namely a fixed part and a rotating part, wherein the fixed part comprises a camera, a lens, an annular light source, a connecting piece, a shading cylinder and a turntable fixed part; the rotating part includes an optical information transmission member, a holder, a pallet, and a turntable rotating part, wherein,

the camera, the lens and the annular light source are fixedly connected with the fixed part of the turntable through connecting pieces; the shading cylinder is fixed on the periphery of the lens and is not contacted with the optical information transmission component so as to prevent stray light from entering the lens;

the optical information transmission component comprises a light shield, a frosted surface, a conical light inlet surface, a light guide column, a planar lens and a bottom 45-degree reflector, wherein the light shield is positioned at the upper end, a light hole is formed in the middle of the light shield, the frosted surface is in an inverted cone shape and is arranged at the lower part of the light shield, and the light shield and the frosted surface jointly prevent ambient light from entering the optical information transmission component from the upper end; a conical light inlet surface is arranged at the lower part of the frosted surface, light generated by the annular light source passes through the conical light inlet surface and illuminates the inner wall of the measured hole along the light guide column, a local image of the inner wall of the measured hole is reflected to the upper end through the planar lens and the 45-degree reflector at the bottom end, passes through the light hole, enters the lens and is imaged by the camera;

the supporting plate and the clamping piece are fixedly connected with the rotating part of the rotary table, the optical information transmission component is fastened on the rotation of the rotary table by the clamping piece and the supporting plate, and the supporting plate is provided with a hole allowing the light guide column to pass through.

The device can realize non-contact full-automatic high-precision defect detection and shape measurement of the inner wall of the micro hole with the diameter of 4-10 mm, is simple to use, convenient to assemble, high in measurement speed and high in automation degree, and has the detection precision reaching 0.01 mm. The method can meet the high-precision requirement of automatic detection of the defects of the inner walls of the micro-holes in parts such as aerospace, military equipment and the like.

Drawings

FIG. 1 is a schematic diagram showing an image of an optical information transmission member of an apparatus for automatically detecting defects in the inner wall of a micro hole.

FIG. 2 is a schematic diagram illustrating the optical path transmission principle of an optical information transmission member of the apparatus for automatically detecting the defect in the inner wall of a micro hole.

FIG. 3 is a schematic structural view of a separated illumination system of an automatic inspection apparatus for inner wall defects of micro-holes.

FIG. 4 is a flowchart illustrating an automatic inspection of defects in the inner wall of a micro hole.

1. Light shield 2, light hole 3, frosted surface 4, annular light source 5, annular 45-degree conical light inlet surface 6, light guide column 7, inner wall 8 of measured hole, planar lens 9.45-degree reflector 10, camera 11, lens 12, connecting piece 13, turntable fixing part 14, light shield tube 15, turntable rotating part 16, optical information transmission part 17, clamping piece 18, supporting plate rotating part 16

Detailed Description

The invention provides an automatic detection device for realizing high-precision measurement of defects of the inner wall of a micro-hole with the diameter of less than 10mm by a method of traversing the panorama of the inner wall of a measured hole through an automatic rotating and lifting optical information transmission part, and provides a detection method. The automatic detection device for the defects of the inner wall of the micro-hole adopts the ideas of external light source introduction and internal image derivation, improves the resolution ratio by locally acquiring images, and realizes the image acquisition of the whole inner wall of the micro-hole by rotation and depth. The detection system is characterized in that an illumination system, an image acquisition device and an optical information transmission component are separated, the optical information transmission component rotates independently, external illumination light is guided into an area to be detected in a hole through reasonable design of the optical information transmission component, an optical image of the area to be detected is guided out by the same optical information transmission component, the technical problems of design of an illumination light source system in the hole, optimal design of a transmission optical system, local area imaging, local area image information processing and the like are solved by combining an image information processing technology and the like, and a micro-hole inner wall defect detection system with the detection precision reaching 0.01mm is established.

The present invention will be described with reference to examples.

The embodiment designs a mechanical device for traversing the inner surface of a small hole by lifting and rotating an optical information transmission part by utilizing the principle that the optical information transmission part is used for locally imaging the inner surface of the small hole and illuminating through an external annular light source, and realizes the quick, automatic and high-precision detection of the defects of the inner wall of the micro-hole with the inner diameter of 4-10 mm by matching with an automatic control program and an image processing program. The technical scheme is realized by means of an optical information transmission component (such as SP-730 of SIGHT-PIPE company), an annular light source (a current visual photoelectric annular machine vision light source), a camera (such as REV-50AM industrial camera of Yuan-Qizhi company), a lens (such as an AFT-ZL0910 microscope lens), a lifting table (such as a high-precision electric lifting table of PSA200-11-Z of Zhuo Han, Beijing), a turntable (such as a RAK200 high-precision electric rotating table of Zhuo Han, Beijing), and a computer.

1. The automatic detection device structure for the defects of the inner wall of the micro-hole comprises:

as shown in fig. 1 and 2, the optical information transmission member 16 includes a light shield 1, a light hole 2, a frosted surface 3, an annular 45 ° tapered light inlet surface 5, a light guide column 6, a planar lens 8, and a 45 ° reflector 9. The light shield 1 made of black rubber is sleeved on the upper end light-transmitting part of the optical information transmission component 16, and prevents stray light from entering the optical information transmission component 16 from the upper end together with the frosted surface 3. The light generated by the annular light source 4 passes through the annular 45-degree conical light inlet surface 5 and illuminates the inner wall 7 of the measured hole along the light guide column 6. The local image of the inner wall 7 of the detected hole is reflected to the upper end through the plane lens 8 and the bottom end 45-degree reflector 9, passes through the light hole 2, enters the lens 11 and is imaged by the camera 10. Since each position can only acquire an image of the inner wall 7 of the hole to be measured at a fixed depth by a certain angle, it is necessary to rotate the optical information transmission member 16 by one rotation to acquire an image of the entire circumference at that depth.

As shown in fig. 3, the structure of the automatic detection device for the defect of the inner wall of the micro-hole is divided into two parts, a fixed part and a rotating part:

the fixed portion includes a camera 10, a lens 11, an annular light source 4, a connector 12, a light-shielding cylinder 14, and a turntable fixed portion 13. The connector 12 is inserted into the inside of the turntable fixing portion 13 to be engaged with the turntable fixing portion 13. Wherein the camera 10 and the lens 11 are connected by screw threads; the light-shielding cylinder 14 and the lens 11 are connected by screw threads and the light-shielding cylinder 14 is not in contact with the optical information transmission member 16; a stepped hole is formed in the connecting piece 12 and is respectively matched with the diameters of the lens 11 and the annular light source 4, and the lower end of the lens 11 is inserted into the connecting piece 12 from the upper part and is fastened by adding a top thread on the side surface; the ring light source 4 is inserted into the connector 12 from below and fastened by means of a lateral topping wire.

The rotating portion includes an optical information transmission member 16, a holder 17, a pallet 18, and a turntable rotating portion 15. Wherein the pallet 18 is coupled to the turntable rotating portion 15 by screws, the clamp 17 is coupled to the pallet 18 by screws, and the optical information transmission member 16 is fastened to the turntable rotating center by the clamp 17 and the pallet 18, and rotates together with the turntable rotating portion 15 by means of friction between the optical information transmission member 16 and the clamp 17.

Firstly, the separation design of the fixed part and the rotating part ensures that the optical information transmission part 16 is not influenced by the annular light source 4, the camera 10 and the lens 11, keeps good coaxiality when rotating in the inner wall 7 of the measured hole, and avoids the danger caused by the collision of the optical information transmission part with the wall in the narrow hole. Meanwhile, the ring light source 4 and the lens 11, the camera 10 are still to avoid the control wire from being wound.

Secondly, the secondary light shielding structure comprises a light shielding cover 1 and a light shielding tube 14, the light shielding cover 1 can prevent stray light from entering the tested hole along the optical information transmission component 16 to affect the imaging effect, and the light shielding tube 14 can prevent the stray light from entering the lens 11 to cause the over-bright field of vision and prevent the over-bright field of vision from being imaged.

Thirdly, the device is mounted on a lifting platform, wherein the lifting platform and the rotary platform are connected on a control box and are controlled by a computer together with the camera 10. The lifting platform drives the hole to move up and down to enter and exit the hole to be measured, the image of the full length in the hole is firstly realized in the same direction, then the rotary table is rotated to repeat the full-length acquisition in the other direction, and the acquisition of the panoramic image of the inner wall of the small hole is finished by analogy.

2. As shown in fig. 3, the method for automatically detecting the defect of the inner wall of the micro-hole comprises the following steps:

(1) the automatic detection device for the defects of the inner wall of the micro-hole is installed, the annular light source 4 is turned on, the control boxes of the rotary table and the lifting table are connected to a computer, and the camera 10 is connected to the computer.

(2) Serial ports for connecting control boxes of the rotary table and the lifting table with a computer are selected to ensure successful connection with the control boxes;

(3) controlling the optical information transmission component 16 to enter the tested hole, collecting an inner wall image to calibrate the initial direction, and using the inner wall image as a reference for unifying the directions of the collected images, thereby facilitating the later judgment of the defect position;

(4) starting an automatic acquisition mode, enabling the lifting platform to descend at a constant speed and simultaneously enabling the camera 10 to acquire images at a fixed frame rate, rotating the rotary platform by an angle after reaching a specified depth, continuing to ascend and acquire the images, and repeating the process until the acquisition of the panoramic images in the hole is completed;

(5) after image acquisition is finished, the image rises and leaves a tested hole, the image is uniformly turned to the initial direction through software processing, and the effective area extraction, defect size, position detection and other targets are realized by utilizing the digital image processing technology, and the specific implementation method comprises the following steps:

a) and converting the RGB image into a gray image for the acquired original image. And preprocessing the image by adopting a circular mean filter, and enhancing the image contrast by adopting a histogram equalization method.

b) And performing Gaussian filtering on the image, detecting the edge of the effective region by using a standard Canny algorithm, and extracting the ROI region. And rotating the ROI area according to the initial direction until the directions are consistent.

c) And processing the image by using a Wiener filter, extracting a defect area by using a Suzuki algorithm, and calculating the number of contained pixels to obtain the size of the defect.

d) According to the sequence of obtaining the images, the images are numbered, and the images can correspond to the positions of the inner wall 7 of the hole to be detected one by one. And combining the coordinates of the defect center on the image to acquire the position of the defect on the inner wall 7 of the detected hole.

(6) And generating a detection report, wherein the content comprises the defect number, the defect size and the defect coordinate.