CN-122015707-A - Program-controlled phase-shift structured light source, control method and industrial line scanning detection method

CN122015707ACN 122015707 ACN122015707 ACN 122015707ACN-122015707-A

Abstract

The invention relates to the technical field of visual detection, and provides a program-controlled phase-shift structured light source, a control method and an industrial line scanning detection method. The light source comprises a lamp bead module formed by a plurality of lamp beads which are arranged in a matrix, and a total reflection lens module corresponding to the lamp bead module, wherein the diameter of a light spot of a single lamp bead on a working surface is set so that the lamp beads with the same phase in each array can be spliced seamlessly to form sine stripes when the lamp beads are synchronously lightened. The control module rapidly switches the lighted lamp bead groups according to the phase shift time sequence to realize the transverse phase shift and the longitudinal phase shift of the stripes. The industrial line scanning detection method is based on the method, the object to be detected is moved, the light source mode is synchronously switched, the line scanning camera is used for collecting images, the object to be detected is supported to reciprocate, the phase separation is complete to shoot, the object to be detected is unidirectionally and continuously moved, the light emitting mode is rapidly switched to synchronously collect the phase images, and the high-speed, high-precision and compact phase-shift illumination solution is realized while the high-brightness requirement of line scanning detection is met.

Inventors

YANG YUAN
SHI QIANG
GUO SHIZE
Ou changdong

Assignees

武汉精测电子集团股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260214

Claims (13)

1. The utility model provides a program-controlled phase shift structure light source which characterized in that includes lamp pearl module, lens module and control module, wherein: The lamp bead module comprises a plurality of lamp bead arrays which are periodically arranged according to rows and/or columns, wherein each lamp bead array comprises a plurality of lamp beads which are arranged in m multiplied by m, and m is more than 1; The lens module comprises a plurality of lenses which are arranged in one-to-one correspondence with the lamp beads and are used for collimating the light rays emitted by the corresponding lamp beads and then projecting the light rays to the same working plane; The control module is electrically connected with the lamp beads and used for independently controlling the opening and closing of each lamp bead; The control module is configured to control the synchronous lighting of the lamp beads with the same phase in different lamp bead arrays according to a preset phase shift time sequence so as to form periodic bright and dark stripes on a working plane; The diameter of the light spot of the single lamp bead on the working plane is equal to the stripe spacing of the bright and dark stripes.
2. The programmable phase shift structured light source of claim 1, wherein the lateral spacing and the longitudinal spacing of adjacent light beads in the light bead module are the same.
3. The programmable phase shift structured light source of claim 1, wherein the phase difference between adjacent light beads at the time of light bead ignition is 2 pi/m.
4. A programmable phase shift structured light source as claimed in claim 3 wherein the light intensity across the spot diameter of a single bead is sinusoidal and the light intensity across the center of the spot in the bright-dark stripe is sinusoidal.
5. A programmable phase shift structured light source as claimed in claim 1, wherein the lens is a total reflection lens.
6. A programmable phase shift structured light source as claimed in claim 5 wherein said lens comprises a centrally located transmissive region and a reflective region circumferentially located in the transmissive region.
7. A programmable phase shift structured light source as claimed in claim 1 wherein all of said beads are in the same plane.
8. A method for controlling a programmable phase shift structured light source, characterized in that the programmable phase shift structured light source according to any one of claims 1 to 7 comprises: according to the phase shift time sequence of the m-step phase shift method, controlling the lamp beads with the same phase in different lamp bead arrays to be synchronously lightened so as to form periodic bright and dark stripes on a working plane; And the phase shift of the bright and dark stripes is realized by sequentially switching the lighted lamp beads.
9. The method of claim 8, wherein the m-step phase shift method comprises performing a lateral phase shift sub-step and a longitudinal phase shift sub-step; the lateral phase shift sub-step comprises: sequentially and synchronously lighting the lamp beads positioned at the same sequence position in different lamp bead arrays according to a first preset time sequence to realize the phase shift of the bright and dark stripes in the transverse direction, wherein the phase difference of each transverse phase shift is 2 pi/m; the longitudinal phase shift sub-step comprises: And sequentially and synchronously lighting the lamp beads positioned at the same row sequence position in different lamp bead arrays according to a second preset time sequence to realize the phase shift of the bright and dark stripes in the longitudinal direction, wherein the phase difference of each longitudinal phase shift is 2 pi/m.
10. An industrial wire sweep detection method, characterized in that based on the control method according to claim 8 or 9, the industrial wire sweep detection method comprises: s1, enabling a to-be-detected object to move along a preset direction relative to a line scanning camera and the program-controlled phase shift structure light source; S2, switching the light emitting mode of the light source according to the phase shift time sequence of the m-step phase shift method in the moving process of the object to be detected, and synchronously acquiring a plurality of images of the object to be detected, which contain bright and dark stripes with different phases, by the line scanning camera; s3, reconstructing the three-dimensional morphology of the object to be detected according to the acquired multiple images.
11. The industrial wire sweep detection method according to claim 10, wherein step S2 specifically comprises: controlling the object to be detected to execute a plurality of reciprocating strokes; in each reciprocating movement stroke, keeping a light source in a fixed-phase light emitting mode in the m-step phase shift method unchanged, and acquiring an image of the object to be detected, which is matched with the current phase, in the unidirectional movement process of the object to be detected by the line scanning camera; And after each reciprocating movement stroke is finished, resetting the object to be detected to a starting position, switching a light source to a light emitting mode corresponding to the next phase in the m-step phase shift method, and repeating the image acquisition process until all the images of the object to be detected with different phases are obtained.
12. The industrial wire sweep detection method according to claim 10, wherein step S2 specifically comprises: Controlling the object to be detected to start to continuously move; in the moving process of the object to be detected, the first light-emitting mode and the second light-emitting mode of the light source are rapidly and circularly switched according to the phase shift time sequence, and each time the light-emitting mode is switched, the line scanning camera synchronously acquires the image of the object to be detected; wherein the lateral phase shift sub-step is performed in the first light emitting mode and the longitudinal phase shift sub-step is performed in the second light emitting mode, or, Performing the longitudinal phase shift sub-step in the first light emission mode and the transverse phase shift sub-step in the second light emission mode; And splicing a plurality of continuously acquired images of the object to be detected into a composite image, and separating images with different phases required by the m-step phase shift method from the composite image according to the switching sequence of the luminous modes.
13. The method for industrial wire sweep detection of claim 12, it is characterized in that the method comprises the steps of, The switching time of the light source between the first light-emitting mode and the second light-emitting mode is less than 100 microseconds, so that image rows acquired by the line scanning camera in different light-emitting modes correspond to areas at the same position on the surface of the object to be detected.

Description

Program-controlled phase-shift structured light source, control method and industrial line scanning detection method Technical Field The invention relates to the technical field of visual detection, in particular to a program-controlled phase-shift structured light source, a control method and an industrial line scanning detection method. Background Industrial vision inspection plays a key role in modern manufacturing industry, and in particular, it is required to accurately reflect the height change of the object to be inspected through three-dimensional information so as to improve the detection precision and efficiency. The structured light phase shift method is used as a common 3D imaging technology, is widely applied to the fields of quality control, reverse engineering and the like by projecting periodic stripe light spots and moving specific phases (such as 90 degrees, 180 degrees and 270 degrees) and combining a plurality of images to jointly solve the height information. The industrial vision detection is mainly divided into two modes of area array detection and line scanning detection, wherein the line scanning detection is particularly suitable for 3D modeling of products such as television display screens and the like in large-size and high-speed detection scenes by virtue of the advantages of high acquisition frequency (line frequency can reach 20 KHz), high resolution and long measurable length. However, the high line frequency of the line scan camera requires that the illumination source has a brightness much higher than that of the area array detection, otherwise it is difficult to obtain a clear image in a short exposure time, which becomes a main bottleneck for popularization of the line scan detection technology. Currently, there are two main prior art schemes applied to structured light phase shift methods. The first scheme adopts the projector to project the structured light, and has the advantages of good controllability and higher stripe definition, but the brightness of the projector is limited, so that the illumination requirement of the line scanning camera under high line frequency can not be met, and the signal to noise ratio of the image is insufficient. The second scheme uses a special light source for linear scanning to irradiate the black-white transparent grating, and the physical grating is used for generating stripes, so that the brightness can meet the requirement, but the positions of the stripes are fixed, and a displacement device (such as a precise mechanical structure) is additionally arranged to realize stripe movement (phase shift). The displacement equipment has extremely high requirements on the movement speed and precision, and causes the system to be bulky and the cost to be increased, and meanwhile, the delay of the mechanical movement is difficult to match with the high-frequency acquisition of the wire scanning camera, so that the application of the displacement equipment in a high-speed detection scene is limited. Therefore, a new illumination scheme is needed to realize the fast program-controlled phase shift of high-brightness stripe light without complex mechanical structure, so as to overcome the limitation of the prior art and promote the further development of the line scanning detection technology. Disclosure of Invention Aiming at the technical problems in the prior art, the invention provides a program-controlled phase-shift structured light source, a control method and an industrial line scanning detection method, which provide a structured light source scheme capable of meeting the high brightness requirement and realizing rapid and accurate phase shift for industrial line scanning detection so as to overcome the defects of insufficient light source brightness, equipment bulkiness and low response speed in the prior art. According to a first aspect of the present invention, there is provided a programmable phase shift structured light source comprising a lamp bead module, a lens module and a control module, wherein: The lamp bead module comprises a plurality of lamp bead arrays which are periodically arranged according to rows and/or columns, wherein each lamp bead array comprises a plurality of lamp beads which are arranged in m multiplied by m, and m is more than 1; The lens module comprises a plurality of lenses which are arranged in one-to-one correspondence with the lamp beads and are used for collimating the light rays emitted by the corresponding lamp beads and then projecting the light rays to the same working plane; The control module is electrically connected with the lamp beads and used for independently controlling the opening and closing of each lamp bead; The control module is configured to control the synchronous lighting of the lamp beads with the same phase in different lamp bead arrays according to a preset phase shift time sequence so as to form periodic bright and dark stripes on a working plane; The diameter of the light spot