An optical inspection method to distinguish between dirt and real defects

Abstract

The present invention discloses an optical detection method for distinguishing dirt from real defects. First, a scanning channel constructed by setting up a line scanning camera group is used to scan the surface of a workpiece to be detected to obtain its three-dimensional configuration. Then, a visual inspection is performed to mark the defect position. Subsequently, a laser reflection type flaw detection light source is set up in the scanning channel to perform near-point flaw detection on the marked defect position. During the near-point flaw detection, the laser reflection type flaw detection light source is pulled to the top of the defect position to emit a plurality of parallel laser rays perpendicular to the section at the defect position. A matching reflected light receiving surface is configured at the bottom of the laser reflection type flaw detection light source. When the reflected light receiving surface receives the laser reflected from the defect position, the size of the received reflected light range is judged. When the received reflected light range is smaller than the emission range of the parallel laser rays, it indicates that the defect position here is a real defect, otherwise it is a dirt defect. The present invention has the advantage that dirt and real defects can be directly distinguished during the detection process.

Description

Technical Field

[0001] The present invention relates to the field of optical detection, in particular to an optical detection method for distinguishing dirt from real defects. Background Art

[0002] In existing industrial quality inspection technologies, defect detection of workpieces usually involves fixing the workpieces on an inspection machine, and using an industrial camera to scan and identify them in sequence along a specific trajectory under fields of view of different sizes. The defects identified by the scans are then categorized through an integrated algorithm, and most defects can be correctly identified and their defect categories can be detected.

[0003] However, when using industrial cameras to identify processing defects, since the recognition action is performed in a two-dimensional environment, the position and area of ​​the defect area can be clearly identified, but the depth of the defect, that is, the degree of explicitness, is relatively weak.

[0004] Especially for substantial defects and dirt defects, the defect patterns obtained under the detection of industrial cameras with flat framing are all flat patterns. For the substantial damage of defect type, its degree of damage cannot be reflected in the vertical direction, and it cannot be effectively distinguished from dirt defects. Therefore, subsequent targeted processing requires manual re-inspection of the defect area to confirm the subsequent defect repair method. The process is complicated and reduces work efficiency. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to provide an optical detection method for distinguishing dirt from real defects in view of the shortcomings of the prior art.

[0006] Technical solution: The optical detection method for distinguishing dirt from real defects described in the present invention comprises the following steps:

[0007] S1. Setting up a line scan camera group to construct a scanning channel and visually scanning the surface of the workpiece to be inspected through the scanning channel to obtain a three-dimensional configuration of the surface of the workpiece to be inspected;

[0008] S2. Visually inspect the surface of the three-dimensional configuration and mark the defect locations;

[0009] S3. Set up a laser reflection flaw detection light source in the scanning channel to perform near-point flaw detection on the marked defect position;

[0010] S4. During near-point flaw detection, the laser reflection flaw detection light source is pulled to the top of the defect position, and several parallel laser rays are emitted perpendicular to the section where the defect is located;

[0011] S5. A reflected light receiving surface is configured at the bottom of the laser reflection type flaw detection light source. When the reflected light receiving surface receives the laser reflected from the defect position, the size of the received reflected light range is determined. When the received reflected light range is smaller than the emission range of the parallel laser beam, it indicates that the defect position is a real defect. When the received reflected light range is larger than the emission range of the parallel laser beam, it indicates that the defect position is a dirty defect.

[0012] Preferably, the scanning channel constructed in S1 is customized according to the surface configuration of the workpiece to be inspected.

[0013] Preferably, while obtaining the three-dimensional configuration in S1, a matching projection plane of the three-dimensional configuration is retained in the horizontal direction, and in S2, the obtained defect position is auxiliary marked on the projection plane.

[0014] Preferably, the laser reflection flaw detection light source in S4 uses an auxiliary mark as a positioning point in traction.

[0015] Compared with the prior art, the present invention has the following beneficial effects: dirt and real defects can be directly distinguished during the detection process, without the need for manual re-inspection to confirm whether they are dirt and real defects after visual inspection, which effectively improves the detection and repair efficiency. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] In the description of the present invention, it is necessary to understand that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships are for the purpose of facilitating the description of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0018] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0019] The technical solution of the present invention is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0020] Embodiment 1: An optical detection method for distinguishing dirt from real defects, comprising the following steps:

[0021] S1. Setting up a line scan camera group to construct a scanning channel and visually scanning the surface of the workpiece to be inspected through the scanning channel to obtain a three-dimensional configuration of the surface of the workpiece to be inspected;

[0022] S2. Visually inspect the surface of the three-dimensional configuration and mark the defect locations;

[0023] S3. Set up a laser reflection flaw detection light source in the scanning channel to perform near-point flaw detection on the marked defect position;

[0024] S4. During near-point flaw detection, the laser reflection flaw detection light source is pulled to the top of the defect position, and several parallel laser rays are emitted perpendicular to the section where the defect is located;

[0025] S5. A reflected light receiving surface is configured at the bottom of the laser reflection type flaw detection light source. When the reflected light receiving surface receives the laser reflected from the defect position, the size of the received reflected light range is determined. When the received reflected light range is smaller than the emission range of the parallel laser beam, it indicates that the defect position is a real defect. When the received reflected light range is larger than the emission range of the parallel laser beam, it indicates that the defect position is a dirty defect.

[0026] Embodiment 2: An optical detection method for distinguishing dirt from real defects, comprising the following steps:

[0027] S1. Set up a line scan camera group to build a scanning channel. The scanning channel is customized to match the surface configuration of the workpiece to be inspected. The surface of the workpiece to be inspected is visually scanned through the scanning channel to obtain the three-dimensional configuration of the surface of the workpiece to be inspected, and at the same time, a matching projection plane is retained for the three-dimensional configuration in the horizontal direction;

[0028] S2. Visually inspect the surface of the three-dimensional configuration, mark the defect position, and auxiliary mark the obtained defect position on the projection plane;

[0029] S3. Set up a laser reflection flaw detection light source in the scanning channel to perform near-point flaw detection on the marked defect position;

[0030] S4. During near-point flaw detection, the laser reflection flaw detection light source is pulled to the position directly above the defect. The laser reflection flaw detection light source uses an auxiliary mark as a positioning point during pulling and emits several parallel laser rays perpendicular to the section where the defect is located.

[0031] S5. A reflected light receiving surface is configured at the bottom of the laser reflection type flaw detection light source. When the reflected light receiving surface receives the laser reflected from the defect position, the size of the received reflected light range is determined. When the received reflected light range is smaller than the emission range of the parallel laser beam, it indicates that the defect position is a real defect. When the received reflected light range is larger than the emission range of the parallel laser beam, it indicates that the defect position is a dirty defect.

[0032] The advantage of the present invention is that dirt and real defects can be directly distinguished during the detection process, without the need for manual re-inspection to confirm whether they are dirt and real defects after visual inspection, which effectively improves the detection and repair efficiency.

[0033] In the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first feature is in direct contact with the second feature, or the first feature and the second feature are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature. In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example.

[0034] Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples without contradicting each other.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An optical detection method for distinguishing dirt from real defects, characterized in that: The following steps are involved: S1. Setting up a line scan camera group to construct a scanning channel and visually scanning the surface of the workpiece to be inspected through the scanning channel to obtain a three-dimensional configuration of the surface of the workpiece to be inspected; S2. Visually inspect the surface of the three-dimensional configuration and mark the defect locations; S3. Set up a laser reflection flaw detection light source in the scanning channel to perform near-point flaw detection on the marked defect position; S4. During near-point flaw detection, the laser reflection flaw detection light source is pulled to the top of the defect position, and several parallel laser rays are emitted perpendicular to the section where the defect is located; S5. A reflected light receiving surface is configured at the bottom of the laser reflection type flaw detection light source. When the reflected light receiving surface receives the laser reflected from the defect position, the size of the received reflected light range is determined. When the received reflected light range is smaller than the emission range of the parallel laser beam, it indicates that the defect position is a real defect. When the received reflected light range is larger than the emission range of the parallel laser beam, it indicates that the defect position is a dirty defect.

2. The optical detection method for distinguishing dirt from real defects according to claim 1, characterized in that: The scanning channel constructed in S1 is customized according to the surface configuration of the workpiece to be inspected.

3. The optical detection method for distinguishing dirt from real defects according to claim 1, characterized in that: In S1, while obtaining the three-dimensional configuration, a matching projection plane of the three-dimensional configuration is retained in the horizontal direction, and in S2, the obtained defect position is auxiliary marked on the projection plane.

4. The optical detection method for distinguishing dirt from real defects according to claim 3, characterized in that: The laser reflection flaw detection light source in S4 uses auxiliary marks as positioning points during traction.