3D laser cameras for curved surface inspection

Abstract

The present application discloses a three-dimensional laser camera suitable for curved surface detection, including: a parallel light source device, used to generate and output laser light located in a laser plane and with the emission direction parallel to the first direction; a first optical device, used to change the direction of the laser light so that the laser light intersects at multiple internal light intersections after passing through the first optical device; a second optical device, used to change the direction of the laser light again so that the laser light has a gradually changing and different emission direction after passing through the second optical device; wherein the first optical device is arranged between the parallel light source device and the second optical device so that the part of the laser light located at the edge that is finally emitted from the second optical device is tilted toward the direction close to the center. The benefit of the present application is that it provides a three-dimensional laser camera suitable for curved surface detection that can obtain sufficient reflected light for imaging during curved surface detection.

Description

Technical Field

[0001] The present application relates to the field of three-dimensional laser cameras, and in particular, to a three-dimensional laser camera suitable for curved surface detection. Background Art

[0002] 3D laser cameras are widely used in industrial production. For example, in consumer electronic products such as mobile phones, more and more curved glass displays are appearing. This places higher demands on the quality inspection of curved glass during production and manufacturing. Such inspection requirements mainly include inspection of the surface quality of curved edges, such as scratches, and inspection of the cutting quality of curved edges, such as missing corners and edge size tolerance exceeding limits.

[0003] The reflected light on the surface of general objects can be divided into ambient light, specular reflection light and diffuse reflection light. Generally, rough and matte surfaces mainly show diffuse reflection, while objects with high surface gloss such as glass mainly show specular reflection in addition to transmitted light.

[0004] like Figure 1 As shown, from the Phong model, it can be seen that as the angle α increases, the observable light intensity at the observation point gradually weakens.

[0005] In existing 3D laser cameras, the laser emits light in a single direction, such as parallel light. Because the local normal of the scanned object is uncertain, when scanning an object with a relatively high mirror reflection coefficient, if the angle of the observation point (CMOS camera) deviates greatly from θ (that is, the angle α is too large), the light received by the camera end will be too weak to form an image.

[0006] For example, when scanning curved glass, if parallel light is incident, the light on both sides of the laser line (corresponding to the two sides of the curved surface) will be reflected by the glass surface to the two sides of the camera and cannot be well received by the CMOS sensor.

[0007] For example Figure 2 As shown in the figure below, because laser is monochromatic, local interference is easy to occur on the surface of the object, resulting in severe speckle. As shown in the figure below, it seriously affects the image processing and extraction of laser lines. Summary of the invention

[0008] In order to address the shortcomings of the prior art, the present application provides a three-dimensional laser camera suitable for curved surface detection, including: a parallel light source device, used to generate and output laser light located in a laser plane and with an emission direction parallel to a first direction; a first optical device, used to change the direction of the laser light so that the laser light intersects at multiple internal light intersections after passing through the first optical device; a second optical device, used to change the direction of the laser light again so that the laser light has a gradually changing and different emission direction after passing through the second optical device; wherein the first optical device is arranged between the parallel light source device and the second optical device so that the portion of the laser light located at the edge that is finally emitted from the second optical device is tilted toward a direction close to the center.

[0009] Furthermore, the first optical device has or forms a plurality of first-type exit interfaces, and the first-type exit interfaces are curved surfaces whose generatrix is ​​perpendicular to the laser plane.

[0010] Furthermore, the first type of exit interfaces are repeatedly arranged along a second direction, and the first direction is perpendicular to the second direction.

[0011] Furthermore, the first type of exit interfaces have the same curved surface shape.

[0012] Furthermore, the first optical device has or forms a first type of incident interface, and the first type of incident interface is a plane perpendicular to the laser plane.

[0013] Furthermore, one of the first-type incident interfaces corresponds to a plurality of the exit interfaces.

[0014] Furthermore, the curved surface of the first type of exit interface protrudes toward the second optical device so that the internal light intersection point of the laser light is located between the first type of optical device and the second type of optical device.

[0015] Furthermore, the second optical device has or forms a second type of exit interface, and the second type of exit interface is a curved surface whose generatrix is ​​perpendicular to the laser plane.

[0016] Furthermore, the second optical device has or forms a second type of incident interface, and the second type of incident interface is a plane perpendicular to the laser plane.

[0017] Further, in the second direction, the size of the second type of incident interface is greater than or equal to the size of two or more of the first type of exit interfaces.

[0018] The benefit of the present application lies in that it provides a three-dimensional laser camera suitable for curved surface detection, which can obtain sufficient reflected light for imaging during curved surface detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting a part of this application are used to provide a further understanding of this application, so that other features, purposes and advantages of this application become more obvious. The schematic embodiment drawings and their descriptions of this application are used to explain this application and do not constitute an improper limitation on this application. In the drawings:

[0020] Figure 1 This is a schematic diagram of the principle of the Phong model;

[0021] Figure 2 This is a schematic diagram of speckle caused by interference when detecting a curved surface;

[0022] Figure 3 is a schematic diagram of the stereoscopic structure of a three-dimensional laser camera suitable for curved surface detection and an object to be detected according to an embodiment of the present application;

[0023] Figure 4 yes Figure 3 The internal structure diagram of a 3D laser camera suitable for curved surface detection is shown;

[0024] Figure 5 yes Figure 3 The schematic diagram of the optical structure of the laser module and the laser light in the three-dimensional laser camera suitable for curved surface detection is shown;

[0025] Figure 6 is a schematic diagram of the dimensions of a laser module according to an embodiment of the present application;

[0026] Figure 7 is a partial structural schematic diagram of a laser module according to a second embodiment of the present application;

[0027] Figure 8 is a partial structural schematic diagram of a laser module according to a third embodiment of the present application;

[0028] Fig. 9 is a partial structural schematic diagram of a laser module according to a fourth embodiment of the present application;

[0029] Fig.10 It is a partial structural schematic diagram of a laser module according to the fifth embodiment of the present application.

[0030] Meaning of the reference symbols:

[0031] A three-dimensional laser camera 100 suitable for curved surface detection, a camera housing 101, a laser module 102, a lens module 103, an image sensor 104, a parallel light source device 105, a first optical device 106, a second optical device 107, a laser source 108, a collimating lens 109, a beam expander lens 110, a parallel light lens 111, a unit lens 112, a converging lens 113, a first type of exit interface 114, a first type of incident interface 115, a second type of exit interface 116, and a second type of incident interface 117;

[0032] Curved object 200;

[0033] A first optical device 301, a second optical device 302, a second type of exit interface 303, an exit arc surface 3031, and an exit plane 3032;

[0034] A first optical device 401, a second optical device 402, a central lens 4021, and an edge lens 4022;

[0035] A first optical device 501, a second optical device 502, a second type of exit interface 503, an exit inclined surface 5031, and an exit plane 5032;

[0036] A first optical device 601 , a second optical device 602 , a second type of incident interface 603 , and a second type of exit interface 604 . DETAILED DESCRIPTION

[0037] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0038] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0039] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0040] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0041] In addition, the terms "installed", "set", "provided with", "connected", "connected", and "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0042] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0043] like Figure 1 As shown, the three-dimensional laser camera suitable for curved surface detection of the present application includes: a camera housing, a laser module, a lens module and an image sensor. Among them, the laser module, the lens module and the image sensor are fixedly installed in the camera housing. The central axis of the laser module and the central axis of the lens module are obliquely intersected, that is, arranged into a triangular structure of a general three-dimensional laser camera to realize the function of laser line scanning imaging detection.

[0044] like Figures 3 to 5 As shown, the specific improvement of the present application lies in the laser module. Specifically, the laser module of the present application includes: a parallel light source device, a first optical device and a second optical device.

[0045] The parallel light source device is used to generate and output a laser beam located in a laser plane and having an emission direction parallel to the first direction ( Figure 5The first optical device is used to change the direction of the laser light so that the laser light intersects at multiple internal light intersections after passing through the first optical device; the second optical device is used to change the direction of the laser light again so that the laser light has a gradually changing and different exit direction after passing through the second optical device.

[0046] As a preferred solution, the parallel light source device includes: a laser source, a collimating lens, a beam expanding lens and a parallel light lens.

[0047] The laser light generated by the laser source passes through the collimating lens to form a laser beam, and the laser beam passes through the beam expanding lens to be diffused into scattered laser lines, and the scattered laser lines pass through the parallel light lens to form parallel laser light. The laser source collimating lens, beam expanding lens and parallel light lens in the parallel light source device are all well known to those skilled in the art, and will not be described in detail here. As a further preferred embodiment, the parallel light lens is constructed as a cylindrical mirror.

[0048] As an alternative, the laser source, the collimating lens, and the beam expander lens can be constructed as a whole, and the collimating light lens is constructed as a whole with the first optical device and the second optical device.

[0049] Reference Figure 5 As shown, the first optical device is arranged between the parallel light source device and the second optical device so that a portion of the laser light emitted from the second optical device and located at the edge is tilted toward a direction close to the center.

[0050] Specifically, the first optical device has or forms a plurality of first-type exit interfaces, and the first-type exit interfaces are curved surfaces whose generatrix is ​​perpendicular to the laser plane. The first-type exit interfaces are along the second direction ( Figure 5 The first optical device has or forms a first type of incident interface, which is a plane perpendicular to the laser plane.

[0051] As a specific implementation scheme, the first optical device is composed of a plurality of unit lenses repeatedly arranged in the second direction, each unit lens is constructed as a part of a cylindrical mirror (referring to the whole cylinder), specifically, a section plane parallel to the central axis of the cylindrical mirror (perpendicular to Figure 5 After the cylindrical mirror is divided by the plane of the paper, the part with smaller curvature is the unit lens (it can also be the case of equal curvature), and the cylindrical surface of the unit lens is used as the first type of exit interface, and the cross section formed after cutting is used as part of the first type of incident interface. The end faces of multiple unit lenses are aligned as an overall plane to form the first type of incident interface. In this way, it is equivalent to one first type of incident interface corresponding to multiple exit interfaces.

[0052] Specifically, the curved surface of the first type of exit interface protrudes toward the second optical device so that the internal light intersection point of the laser light is located between the first type of optical device and the second type of optical device.

[0053] In addition, by setting the distance from the first type of exit interface to the second type of incident interface, the intersection point (internal light intersection point) of the laser light for the first time is located between the first type of exit interface and the second type of incident interface. Figure 5 As shown, the laser light incident on the second type of incident interface is divergent.

[0054] As a preferred solution, Figure 6 As shown, in the first direction, the distance L3 from the first type of exit interface to the second type of incident interface ranges from 10 mm to 100 mm.

[0055] As an optional option, the value range of L3 is 10 mm to 20 mm, 20 mm to 30 mm, 30 mm to 40 mm, and 40 mm to 50 mm.

[0056] As an optional option, the value range of L3 is 20 mm to 80 mm, 30 mm to 70 mm, or 40 mm to 60 mm.

[0057] As a preferred solution, the value range of L3 is 10 mm to 15 mm, and the specific value of L3 is 13.2 mm.

[0058] On the other hand, the second optical device has or forms a second type of exit interface, the second type of exit interface is a generatrix (perpendicular to Figure 5 The second optical device has or forms a second type of incident interface, which is a plane perpendicular to the laser plane.

[0059] As a specific solution, the second optical device is constructed as a converging lens similar in shape to the unit lens, that is, a part of a cylindrical lens, the difference being that the converging lens is larger in size.

[0060] As a preferred solution, in the second direction, the size of the second type incident interface is greater than or equal to the size of two or more first type exit interfaces. As a preferred solution, in the second direction, all unit lenses fall within the converging lens range.

[0061] As a preferred solution, Figure 5 and Figure 6 As shown, the dimension L1 of the cross section of the converging lens in the second direction (ie, the dimension of the second type incident interface in the second direction) ranges from 5 mm to 50 mm.

[0062] As an optional solution, the value range of L1 is 10 mm to 20 mm, 20 mm to 30 mm, 30 mm to 40 mm, and 40 mm to 50 mm.

[0063] As an optional solution, the value range of L1 is 10 mm to 50 mm, 20 mm to 40 mm, or 25 mm to 35 mm.

[0064] As a preferred solution, the value range of L1 is 25 mm to 30 mm, and the specific value of L3 is 26 mm.

[0065] The dimension L2 of the converging lens in the first direction ranges from 5 mm to 50 mm.

[0066] As an optional solution, the value range of L2 is 10 mm to 20 mm, 20 mm to 30 mm, 30 mm to 40 mm, and 40 mm to 50 mm.

[0067] As an optional option, the value range of L2 is 10 mm to 50 mm, 20 mm to 40 mm, or 25 mm to 35 mm.

[0068] As a preferred solution, the value range of L2 is 5 mm to 10 mm, and the specific value of L3 is 5 mm.

[0069] As a preferred solution, a dimension L5 of the cross section of the unit lens in the second direction ranges from 0.5 mm to 5 mm.

[0070] As an optional option, the value range of L5 is 0.5 mm to 1 mm, 1 mm to 2 mm, 2 mm to 3 mm, 3 mm to 4 mm, and 4 mm to 5 mm.

[0071] As an optional option, the value range of L5 is 1 mm to 5 mm, 2 mm to 4 mm, or 2.5 mm to 3.5 mm.

[0072] As a preferred solution, the value range of L5 is 3 mm to 3.5 mm, and the specific value of L3 is 3.2 mm.

[0073] As a further preferred solution, the dimension L4 of the first type incident interface in the second direction ranges from 5 mm to 50 mm.

[0074] As an optional option, the value range of L4 is 5 mm to 20 mm, 20 mm to 30 mm, 30 mm to 40 mm, and 40 mm to 50 mm.

[0075] As an optional option, the value range of L4 is 10 mm to 50 mm, 20 mm to 40 mm, and 25 mm to 35 mm.

[0076] As a preferred solution, the value range of L4 is 20 mm to 25 mm, and the specific value of L4 is 22.4 mm.

[0077] In addition, the dimension L6 of the unit lens in the first direction ranges from 0.2 mm to 3 mm.

[0078] As an optional option, the value range of L4 is 0.2 mm to 0.5 mm, 0.55 mm to 1.0 mm, 1.05 mm to 1.5 mm, and 1.6 mm to 3 mm.

[0079] As an optional option, the value range of L4 is 0.25 mm to 2.8 mm, 0.3 mm to 2 mm, and 0.35 mm to 1.5 mm.

[0080] As a preferred solution, the value range of L4 is 0.25 mm to 0.37 mm, and the specific value of L4 is 0.3 mm.

[0081] As an optional scheme, the radius of curvature of the cylindrical surface of the unit lens ranges from 1 mm to 10 mm; as a further optional scheme, the radius of curvature of the unit lens ranges from 1 mm to 2 mm, 2.1 mm to 3.5 mm, 3.7 mm to 5 mm, 5.5 mm to 7 mm, 7.5 mm to 8 mm, and 8.5 mm to 10 mm.

[0082] As an optional solution, the radius of curvature of the unit lens ranges from 1 mm to 9 mm, 2 mm to 8 mm, 3 mm to 7 mm, 4 mm to 6 mm, or 5 mm to 5.5 mm.

[0083] As a preferred solution, the curvature radius of the unit lens ranges from 1.1 mm to 1.8 mm, and a more specific value of the curvature radius of the unit lens is 1.6 mm.

[0084] As an optional scheme, the radius of curvature of the cylindrical surface of the converging lens ranges from 5 mm to 100 mm; as a further optional scheme, the radius of curvature of the converging lens ranges from 5 mm to 15 mm, 16 mm to 24 mm, 25 mm to 40 mm, 41 mm to 55 mm, 56 mm to 70 mm, 71 mm to 80 mm, and 80 mm to 100 mm.

[0085] As a limited solution, the curvature radius of the cylindrical surface of the converging lens ranges from 7 mm to 20 mm, 9 mm to 15 mm, 10 mm to 14 mm, 11 mm to 13.5 mm, and 12.5 mm to 13 mm; the specific curvature radius of the cylindrical surface of the converging lens is 13 mm.

[0086] The function of the converging lens is to make the laser light converge and converge to a certain extent, and at the same time, the converging lens makes the laser light emission angle gradually change. The converging and convergence formed here is mainly because the cylindrical interface at the edge of the converging lens makes the laser light at the edge of the laser light set emitted by the converging lens tilt towards the center at different angles, thus producing the converging and convergence effect.

[0087] So in, for example Figure 5 The laser light indicated by the middle arrow will be projected onto the curved object in a more vertical manner. Moreover, the laser light is evenly irradiated on the surface of the object. For the curved object, the optical paths of multiple laser lights are superimposed, and each projection point can be irradiated by laser lights at different angles, thereby solving the above-mentioned technical problems.

[0088] like Figure 7 As shown, as a preferred solution, the first optical device in this solution still adopts the technical solution introduced above, and the difference of this solution is that the second type of exit interface of the second optical device is composed of an exit plane in the central part and exit arc surfaces on both sides thereof, and the exit plane is different from the above solution. The exit plane is a plane parallel to the first direction. When the area is arc-shaped relative to the area, the plane solution can reduce the divergence of the laser light, so that within the preset detection area, the laser line passing through the exit plane can intersect more with the laser line passing through the exit arc surfaces on both sides in the arc surface area to be detected.

[0089] like Figure 8 As shown in the second preferred solution, the first optical device in this solution still adopts the technical solution introduced above, and the difference is that the second optical device, compared with Figure 7 The scheme shown, Figure 8 The second optical device in the solution shown can be composed of multiple optical elements. Specifically, the original whole lens can be replaced by a central lens and edge lenses on both sides. This has the advantage of facilitating the production and processing of parts.

[0090] like Fig. 9 As shown in the third preferred solution, the first optical device in this solution still adopts the technical solution introduced above, and the difference is that the second optical device, compared with Figure 7 The scheme shown, Fig. 9 The second type of exit interface of the second optical device in the scheme shown is composed of an exit plane and exit inclined planes on both sides. The exit inclined plane is a plane that intersects the first direction left and right. Figure 7The curved exit surface of the middle exit arc surface and the plane of the exit inclined surface are firstly easy to process, and secondly, because the first optical device has a certain arc angle, the deflection of the inclined exit plane is more regular than that of the arc plane laser line, which is convenient for establishing an algorithm model. Of course, the exit arc surfaces on both sides are more conducive to eliminating speckles and adapting to more irregular arc detection surfaces.

[0091] like Fig.10 As shown in the fourth preferred solution, the first optical device in this solution still adopts the technical solution introduced above, and the second type of exit interface of the second optical device in this solution still adopts the solution introduced above, the difference is that the second type of incident interface of the second type of optical device adopts a curved surface convex toward the first optical device, and of course, it can also adopt a similar Fig. 9 The second type of exit interface shown is composed of Fig.10 The second type of incident interface in the illustrated solution, of course, protrudes in the opposite direction. The use of the second type of optical device protruding toward the first optical device can make the central and side light overlap more in the preset detection area.

[0092] Fig. 9 and Fig.10 The scheme shown can also be adopted such as Figure 8 The split scheme shown.

[0093] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A three-dimensional laser camera suitable for curved surface detection, characterized in that: The three-dimensional laser camera suitable for curved surface detection includes: A parallel light source device, used to generate and output laser light located in a laser plane and with the emission directions all parallel to the first direction; A first optical device, used to change the direction of the laser light so that the laser light intersects at a plurality of internal light intersection points after passing through the first optical device; A second optical device, used to change the direction of the laser light again so that the laser light has a gradually changing and different emission direction after passing through the second optical device; Wherein, the first optical device is arranged between the parallel light source device and the second optical device so that the portion of the laser light located at the edge finally emitted from the second optical device is tilted toward the center; The first optical device has or forms a plurality of first-type exit interfaces, wherein the first-type exit interfaces are curved surfaces whose generatrix is ​​perpendicular to the laser plane; The first type of exit interfaces are repeatedly arranged along a second direction, and the first direction is perpendicular to the second direction; The first type of exit interfaces have the same curved surface shape; The first optical device has or is formed with a first type of incident interface, and the first type of incident interface is a plane perpendicular to the laser plane; One of the first-type incident interfaces corresponds to a plurality of the exit interfaces; The curved surface of the first type of exit interface protrudes toward the second optical device so that the internal light intersection point of the laser light is located between the first optical device and the second optical device; The second optical device has or forms a second type of exit interface, and the second type of exit interface is a curved surface whose generatrix is ​​perpendicular to the laser plane; The second optical device has or is formed with a second type of incident interface, and the second type of incident interface is a plane perpendicular to the laser plane; In the second direction, the size of the second-type incident interface is greater than or equal to the size of two or more of the first-type exit interfaces.

Images