CN-122023223-A - Method and device for detecting divergence angle of beam-splitting optical fiber

CN122023223ACN 122023223 ACN122023223 ACN 122023223ACN-122023223-A

Abstract

The invention belongs to the technical field of laser welding, and particularly relates to a beam-splitting optical fiber divergence angle detection method and device, wherein the method comprises the following steps of S1, collecting a spot image of a laser welding line through a CCD; the method comprises the steps of S2, preprocessing a light spot image of a laser welding line to obtain a gray level image of the light spot, S3, carrying out binarization processing on the gray level image to obtain a binarized image, S4, analyzing and calculating a boundary curve on the binarized image, determining the center position and the radius of the light spot, further calculating the divergence angle corresponding to each optical fiber leg, S5, determining the height of an optical waveguide device and the distance between each optical fiber leg according to the divergence angle and the welding line width of each optical fiber leg, and collecting the laser coaxial light spot image by using a CCD (charge coupled device), wherein the laser divergence angle is automatically calculated according to the light spot brightness by using a detection principle based on Hough transformation.

Inventors

ZHOU HONGJIAN
YIN XIAOTONG
LI ZHIPENG
LEI JUN

Assignees

无锡骄成智能科技有限公司

Dates

Publication Date: 20260512
Application Date: 20241111

Claims (6)

1. The method for detecting the divergence angle of the beam-splitting optical fiber is characterized by comprising the following steps of: s1, acquiring a facula image of a laser welding line through a CCD; S2, preprocessing the light spot image of the laser welding seam to obtain a gray level image of the light spot; S3, performing binarization processing on the gray level image to obtain a binarized image; S4, calculating a boundary curve through analysis of the binarized image, determining the circle center position and the radius of the light spot, and further calculating the divergence angle corresponding to each optical fiber leg; s5, determining the height of the optical waveguide and the distance between the optical fiber legs according to the divergence angle and the weld joint width of each optical fiber leg.
2. The method according to claim 1, wherein the step S2 includes: the gray level image of the light spot is obtained by sequentially carrying out filtering, image segmentation and homogenization treatment on the light spot image of the laser welding seam.
3. The method according to claim 1, wherein the step S3 includes: S31, acquiring a position set with the largest gradient change in the gray image, and taking the average value of gray values in the set as a binarization processing threshold; S32, carrying out binarization processing on the gray level image according to the binarization processing threshold value to obtain a binarized image.
4. The method according to claim 1, wherein the step S4 includes: S41, traversing all radius values in a radius range in an edge set to form a circular accumulation space; s42, obtaining the point with the maximum count in the round accumulation space, namely the center of a facula circle; s43, determining a circle with the largest radius in the circle accumulation space as a spot circle, and extracting the center coordinates and the radius of the spot circle; S44, calculating an actual divergence angle of the corresponding optical fiber leg according to the radius of the light spot circle, judging whether the actual divergence angle belongs to the laser divergence angle range, outputting the divergence angle if the actual divergence angle belongs to the laser divergence angle range, and adjusting the light spot radius range if the actual divergence angle belongs to the laser divergence angle range.
5. The method according to claim 1, wherein the step S5 includes: S51, calculating the distance between each two optical fiber legs according to the width of the welding line; S52, calculating the setting height of the waveguide according to the interval between the optical fiber legs and the divergence angle of the optical fiber legs.
6. The beam splitting optical fiber divergence angle detection device is characterized by comprising a frame, a detection module and an analysis module, wherein the frame comprises an optical fiber fixing disc, a beam splitter positioning block, a photosensitive positioning block and a bottom plate, and the detection module comprises a beam splitter, a CCD camera and photosensitive test paper.

Description

Method and device for detecting divergence angle of beam-splitting optical fiber Technical Field The invention belongs to the technical field of laser welding, and particularly relates to a method and a device for detecting a divergence angle of a beam-splitting optical fiber. Background In the field of synchronous laser plastic welding, because the shape of a welded part is complex and the welding line is long, in order to ensure that the welding line of the welded part can finish welding in a shorter welding time and reduce the number of lasers as much as possible, a beam splitting optical fiber and a light-adding waveguide are generally adopted to arrange a light-emitting area above the welding line, for example, the laser with the beam splitting ratio of 1 to 10 is split into 10 optical fiber legs, and each optical fiber leg is inserted into an optical waveguide for homogenization and focusing. In consideration of the complexity of the design and processing of the optical waveguide, accurate divergence angle data of the beam splitting optical fiber must be used as the basis of optical design and simulation. The number of output legs of the beam splitting optical fiber is large, the traditional and accurate method is low in test efficiency one by one, the traditional and extensive test method is poor in precision, and extremely high requirements are placed on detection of the divergence angle of the beam splitting optical fiber, so that a measuring tool is required to be simple and efficient, and the precision of a measuring result is required to be high. For example, patent document CN113074912a discloses a laser divergence angle detection device and method, which make a power receiver receive light intensity in a set range by moving a diaphragm position, so as to calculate a laser divergence angle according to a fixed diaphragm size and diaphragm position. However, when the method is actually used, if the power receiving range is set to be wider, the diaphragm is moved in a larger range, so that the laser power can meet the receiving range, and if the power range is set to be narrower, the position difference of the diaphragm is larger during repeated testing, so that the testing is inaccurate. Moreover, the application of the method requires repeated movement of the diaphragm position, and the efficiency is low. As another example, patent document CN115753010a discloses a device and a method for measuring the off-axis degree and the divergence angle of the outgoing beam of the lens optical fiber, and the method is to mark the outgoing position by a horizontal and vertical vision monitoring unit, and calculate the off-axis degree of the outgoing beam of the lens optical fiber in the directions of the fast axis and the slow axis. However, in terms of calculation of the divergence angle, the analysis calculation is essentially performed by using a beam analyzer. The image receiving end of the beam analyzer is a digital camera, and can only receive mw-level laser output no matter a CMOS or a CCD, and w-level laser output used in laser synchronous plastic welding cannot be directly transmitted to the beam analyzer for calculation. Moreover, the detection means still needs to repeatedly move the five-axis sliding table, and the efficiency is low. Based on this, there is a need to improve the drawbacks of the prior art to overcome the deficiencies in practical use. Disclosure of Invention In view of the foregoing drawbacks and disadvantages of the prior art, it is an object of the present invention to at least solve one or more of the above-mentioned problems with the prior art, in other words, to provide a method and apparatus for detecting divergence angle of a split-beam optical fiber that satisfies one or more of the above-mentioned needs. In order to achieve the aim of the invention, the invention adopts the following technical scheme: the invention provides a beam splitting optical fiber divergence angle detection method, which comprises the following steps: s1, acquiring a facula image of a laser welding line through a CCD; S2, preprocessing the light spot image of the laser welding seam to obtain a gray level image of the light spot; S3, performing binarization processing on the gray level image to obtain a binarized image; S4, calculating a boundary curve through analysis of the binarized image, determining the circle center position and the radius of the light spot, and further calculating the divergence angle corresponding to each optical fiber leg; s5, determining the height of the optical waveguide and the distance between the optical fiber legs according to the divergence angle and the weld joint width of each optical fiber leg. Preferably, the step S2 includes: the gray level image of the light spot is obtained by sequentially carrying out filtering, image segmentation and homogenization treatment on the light spot image of the laser welding seam. Preferably, the step S3 includes: S31, acquiri