CN113252557B

CN113252557B - Light source device for detecting stripe structure light spraying flaw

Info

Publication number: CN113252557B
Application number: CN202110375313.5A
Authority: CN
Inventors: 曹海川
Original assignee: Chengdu Xiaosong Technology Co ltd
Current assignee: Chengdu Xiaosong Technology Co ltd
Priority date: 2021-04-08
Filing date: 2021-04-08
Publication date: 2023-02-03
Anticipated expiration: 2041-04-08
Also published as: CN113252557A

Abstract

The invention provides a stripe structure light spraying flaw detection light source device, which comprises an arc-shaped lamp trough, an LED array light source, a diffusion plate and a light-transmitting film, wherein the arc-shaped lamp trough is provided with a plurality of light sources; the arc-shaped lamp groove is used for ensuring the uniform integral illumination of the detected product; the LED array light source comprises an aluminum substrate fixed inside the arc-shaped lamp trough and an LED lamp fixed on the aluminum substrate; the diffusion plate is used for carrying out light equalizing treatment on the LED array light source so as to ensure the uniformity of light; the light-transmitting film is printed with a sampling pattern for flaw collection, the light source can project a structured light pattern on a detected product through projection, and a spraying flaw sample is shot through the image collection system. The invention has the advantages that the light source device ensures that the image acquisition system can clearly acquire different types of flaws, has higher discrimination with the background, and lays a good image quality foundation for subsequent flaw detection. And the device is simple and convenient to install and has a great economic and applicable value.

Description

Light source device for detecting stripe structure light spraying flaw

Technical Field

The invention particularly relates to a light source device for detecting stripe structure optical spraying flaws.

Background

In recent years, intelligent spray flaw detection has received much attention. Wherein, polishing is a very important ring in the detection of the coating defects, and the design of the light source directly influences the detection effect.

Currently, there are two main ways of polishing for detecting the spraying defects. The first mode of polishing is to project several groups of sine stripe lights with different phases through a liquid crystal display screen, and three-dimensional reconstruction is carried out on the surface of the car body by adopting a host phase unwrapping algorithm to position the flaw. The disadvantages of this mode are: the method has certain limitation on the flaws with no deformation on the surface, and cannot accurately detect the flaws; the light source only can detect static objects by integrally moving the mechanical arm, is high in manufacturing cost and has certain limitation on popularization. The second type of polishing mode is to adopt a uniform polishing mode, and to collect images by completely utilizing the reflected light characteristic of the coating surface flaws, the polishing mode has extremely strict requirements on the position placement and the algorithm of a camera, and the problem that clear shooting cannot be carried out on flaws with small deformation exists. The two polishing modes are combined, the defects are eliminated, the advantages are exerted, and a novel light source device is invented by combining the light source effect.

Disclosure of Invention

The present invention is directed to a light source device for detecting a stripe-structured light-spraying defect, which can solve the above-mentioned problems.

In order to meet the requirements, the technical scheme adopted by the invention is as follows: a light source device for detecting a stripe structure optical spraying defect is provided, which includes

The stripe structure light spraying flaw detection light source device has the advantages that:

the visual light source plays a very important role in detecting the flaws. The good light source system can enable the flaw to present clear characteristics, and the subsequent algorithm detection is convenient. The invention has the advantages that the light source device ensures that the image acquisition system can clearly acquire different types of flaws, has higher discrimination with the background, and lays a good image quality foundation for subsequent flaw detection. And the device is simple and convenient to install and has higher economic and applicable values.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

fig. 1 schematically shows a structural view of a stripe-structured light-coating defect detection light source device according to an embodiment of the present application in use.

Fig. 2 schematically shows a uniform light defect diagram.

Fig. 3 schematically shows a uniform light defect diagram.

FIG. 4 schematically illustrates a sampling pattern of a stripe-structured optical spray defect detection light source apparatus according to one embodiment of the present application.

Fig. 5 schematically shows a schematic diagram of a sampling example of a stripe-structured light-spraying defect detecting light source device according to an embodiment of the present application.

FIG. 6 schematically shows a raw image detected by the stripe-structured light-coating defect detecting light source device according to one embodiment of the present application.

FIG. 7 is a schematic diagram illustrating the defect results detected by the stripe-structure photo-spraying defect detection light source device according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be described in further detail with reference to the accompanying drawings and specific embodiments.

In the following description, references to "one embodiment," "an embodiment," "one example," "an example," etc., indicate that the embodiment or example so described may include a particular feature, structure, characteristic, property, element, or limitation, but every embodiment or example does not necessarily include the particular feature, structure, characteristic, property, element, or limitation. Furthermore, repeated use of the phrase "one embodiment according to the present application" does not necessarily refer to the same embodiment, although it may.

Certain features that are well known to those skilled in the art have been omitted from the following description for the sake of simplicity.

According to an embodiment of the present application, there is provided a stripe-structured light-spraying defect detection light source device, as shown in fig. 1 to 5, including the following structures:

1) Arc light trough: the reasonable appearance size structure is designed according to the appearance structure of the detection product, and the whole illumination of the detected product is ensured to be relatively uniform.

2) LED array light source: the LED array surface light source is used as a light source, the LED array surface light source is provided with an aluminum substrate and is fixed in the lamp trough in consideration of heat dissipation requirements, and the power and the arrangement density of the LED light source need to be designed according to illumination requirements and uniformity conditions, which is not described herein.

3) And (3) diffusion plate: the PC diffusion plate is used for carrying out light equalizing treatment on the LED luminous source, and the uniformity of light is ensured.

4) A light-transmitting film: the light-transmitting film is printed with a design pattern for flaw collection, a specific structured light pattern can be projected on a detected product through projection of a light source, and a spraying flaw sample is clearly shot through an image collection system. The innovative point of the device lies in that clear sample collection can be carried out on deformation defects and non-deformation defects at the same time. The traditional fringe light (sine wave and square wave) can be mainly used for detecting deformation defects, and can only be projected by using a liquid crystal screen or a projector, and the uniform light focuses on detecting the defects with the type of reflectivity change. The film can better combine the two into one, and the specific description and scheme are shown in the part 3.

According to an embodiment of the present application, a design concept of a specific light-transmitting film of a stripe-structured light-spraying defect detection light source device is as follows:

defects are largely classified into two types according to the type of image formation. One is when the surface varnish is damaged, and is mainly expressed in the form of hair, scratches, abrasions, and the like. Such imperfections, due to the greatly altered reflectivity of the reflective surface, are easily picked up by the image acquisition system by uniform illumination and present high contrast and sharp edge information for subsequent processing by the algorithm, as shown in fig. 2.

And the other types of defects such as particles, shrinkage holes, bulges and depressions only have certain deformation because the reflectivity of the sprayed surface is not changed by the defects, the reflection direction of the sprayed surface is changed, and the defects are large and small, so that the uniform polishing mode is difficult to photograph clearly. As shown in fig. 3, the particle defect features in the map are very weak and are not easy to detect by the following algorithm.

By combining the above conditions, the design of the stripe structured light needs to consider that the first type of defects can be clearly photographed, and also needs to make the second type of defects have obvious characteristic photographing, so that the subsequent deep learning target detection is facilitated. However, since the second type of defect does not change the reflection coefficient, it is difficult to photograph a defect only by changing the direction of reflected light. As shown in fig. 4, for illustration, only the concave defects and two light beams are considered, and it can be seen from the figure that the reflected light beams may cross due to the deformation of the sprayed surface, and if the intensities of the light beams 1 and 2 are not equal, images with different brightness are formed on the target surface of the camera, and specific image shape characteristics are presented due to different reflection microstructures at different depths of the concave plus different incident light intensities of the light source.

Summarizing the analysis results, a flaw sampling model with half uniform light and half stripe light is designed, non-deformation flaws such as scratches can be well sampled by the uniform light, deformation flaws such as pits can be clearly sampled by the stripe light, and the model and an actual sampling graph are shown in fig. 4 to 5.

It can be seen that the features of the pits in fig. 5 are not obvious enough near the uniform light, and both the conventional algorithm and the deep learning-based method are easy to miss detection. But the pits are very well characterized within the structured band of fringes. One benefit of this is that if we use deep learning, we can label only deformation-like flaws as positive samples, so that we have sufficient feature discrimination. In the same way, only non-deformation defects such as scratches and the like are marked in a uniform light band to be used as a positive sample. Through the calibration, all positive samples and the background can be guaranteed to have good identification degree, and the deep learning framework can better learn.

The stripe structure optical film can be printed and adjusted according to the size of an actual light source, so that high flexibility is provided, and the stripe structure optical film can be easily adapted to large-scale surface flaw detection or surface flaw detection with a small area without changing the whole system light source framework.

Since the larger the lateral luminance change slope is, the more distinctive the characteristic is for detecting the deformation-like stain, the intensity difference between black and white stripes can be set to the maximum (depending on the printing accuracy). The period design of the stripe structure light depends on the actual size of the detected flaw, and the minimum size of the flaw detection is assumed to be min _flaw One period of the stripe is T, and then T needs to be satisfied

I.e. keeping the edge sampling period less than or equal to the minimum defect to be detected.

1. Detection of striped structured light defect shots

As shown in fig. 6, due to the obvious features, after deep learning, the defects of the target detection class can be accurately located after learning by using a deep learning framework of the target detection class. The left image is the original image, and the right image is the detected flaw and is displayed by the minimum bounding rectangle. It can be seen that the dent defect in the figure can be accurately detected. Simultaneously, can also accurately detect the scratch class flaw that appears in the even light when detecting sunken, it is completely coincided with the original intention of our design this type of light source.

By utilizing the novel light source device, two types of defects of deformation and non-deformation (including all defect types basically) can be clearly collected, and the defects can be accurately detected and positioned by a deep learning method, so that the novel light source device has great engineering applicability.

The above-mentioned embodiments only show several embodiments of the present invention, and the description thereof is specific and detailed, but should not be construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the claims.

Claims

1. The utility model provides a stripe structure light spraying flaw detects light source device which characterized in that: comprises an arc-shaped lamp trough, an LED array light source, a diffusion plate and a light-transmitting film;

the arc-shaped lamp groove is used for ensuring the uniform integral illumination of the detected product;

the LED array light source comprises an aluminum substrate fixed inside the arc-shaped lamp trough and LED lamps fixed on the aluminum substrate;

the diffusion plate is used for carrying out light equalizing treatment on the LED array light source so as to ensure the uniformity of light;

a sampling pattern for flaw collection is printed on the light-transmitting film, a structured light pattern can be projected on a detected product through projection of a light source, and a sprayed flaw sample is shot through an image collection system;

half of the structured light pattern is uniform light and half of the structured light pattern is stripe light;

the light-transmitting film is used for realizing that half of uniform light is uniform light and half of stripe light is stripe light when in light emitting.

2. The streak-structured light coating defect detection light source device according to claim 1, wherein: the diffuser plate is a PC diffuser plate.

3. The streak-structured light coating defect detection light source device according to claim 1, wherein: the stripe light satisfies the following condition:

the minimum size for defect detection is minflaw, and one period width of the stripe is T, then T needs to satisfy T <2 minflaw.