A thickness measurement method for warped plate-like objects based on area array structured light

Abstract

The present invention relates to a method for measuring the thickness of a warped plate-like object based on planar array structured light. The method for measuring the thickness of an object using a measuring device sequentially comprises the following steps: step 1, placing the object to be measured on optical glass; step 2, ensuring that the object to be measured is in the common field of view of an upper camera and a lower camera; step 3, fitting the center data of all standard calibration spheres using the upper camera and the lower camera respectively; step 4, calculating the relative coordinate relationship between the upper camera and the lower camera; step 5, obtaining point cloud data of two surfaces through three-dimensional reconstruction by the upper camera and the lower camera; step 6, selecting an area on the point cloud data of the upper camera, obtaining its normal vector, and obtaining a mapping point cloud with the lower camera in the normal direction; step 7, fitting the plane equation of the mapping point cloud of the lower camera, and obtaining the average distance from the upper camera point cloud to the plane equation of the lower camera, which is the thickness. The present invention can accurately and efficiently measure the thickness of a warped plate-like object, and is simple to operate and easy to use.

Description

Technical Field

[0001] The present invention relates to the technical field related to stereoscopic vision detection, specifically the technical field related to size detection of warped plate-like objects, and in particular to a method for measuring the thickness of warped plate-like objects based on area array structured light. Background Art

[0002] Industrial products often feature warped plate-like objects, such as mobile phone heat sinks and chassis. High-precision, real-time thickness inspection of these objects on the production line is challenging due to their inherent warping, making it difficult to find a flat, horizontal surface to use as a reference. Furthermore, the true thickness along the curved surface relies on the calculation of the local normal vector passing through the point cloud. Traditional methods such as multi-camera vision, mechanical height gauges, line scanning, and laser measurement struggle to accurately and efficiently measure thickness.

[0003] In view of the above-mentioned defects, the designers have actively carried out research and innovation in order to create a method for measuring the thickness of warped plate-like objects based on area array structured light, making it more valuable for industrial use. Summary of the Invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a method for measuring the thickness of a warped plate-like object based on area array structured light.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for measuring the thickness of a warped plate-like object based on area array structured light, wherein the measuring device includes an upper camera, a glass stage, a machine platform, and a lower camera. The upper camera is mounted on the top of the machine platform via a camera bracket, and the lower camera is mounted on the bottom of the machine platform via a camera bracket. A glass stage is provided on the machine platform between the upper and lower cameras, and optical glass is provided on the top of the glass stage. The method for measuring the thickness of an object using the measuring device sequentially includes the following steps:

[0007] Step 1: Place the object to be measured on the optical glass;

[0008] Step 2: Place an upper camera above the object to be measured and a lower camera below the object to be measured, and ensure that the object to be measured is in the common field of view of the upper and lower cameras;

[0009] Step 3: Place several standard calibration spheres into the common field of view of the upper camera and the lower camera, and use the upper camera and the lower camera to fit the center data of all standard calibration spheres respectively;

[0010] Step 4: Calculate the relative coordinate relationship between the upper camera and the lower camera, and unify the coordinates to the coordinate system of the upper camera;

[0011] Step 5: Obtain point cloud data of the two surfaces through 3D reconstruction of the upper camera and the lower camera;

[0012] Step 6: Select an area on the upper camera point cloud data, calculate its normal vector, and obtain the mapping point cloud with the lower camera in the normal direction;

[0013] Step 7: Fit the plane equation of the lower camera mapping point cloud and calculate the average distance from the upper camera point cloud to the lower camera plane equation, which is the thickness.

[0014] As a further improvement of the present invention, the object to be measured is a warped plate-shaped object.

[0015] As a further improvement of the present invention, the optical glass is an optical glass with a uniform refractive index at all locations.

[0016] As a further improvement of the present invention, both the upper camera and the lower camera are area array structured light cameras.

[0017] As a further improvement of the present invention, the number of standard calibration balls is 1 to 12.

[0018] As a further improvement of the present invention, the number of standard calibration balls is 9.

[0019] By means of the above solution, the present invention has at least the following advantages:

[0020] The present invention provides a method for measuring the thickness of a warped plate-like object based on area array structured light, which can accurately and efficiently measure the thickness of the warped plate-like object and is simple to operate and easy to use.

[0021] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 It is a structural schematic diagram of a method for measuring the thickness of a warped plate-like object based on area array structured light according to the present invention;

[0024] Figure 2 Schematic diagram of the positional relationship between the object to be measured and the standard calibration sphere in the present invention;

[0025] Figure 3 This is a schematic diagram of obtaining the mapping point cloud in the present invention.

[0026] The meanings of the reference numerals in the figures are as follows.

[0027] 1 Upper camera 2 Glass stage

[0028] 3 Object under test 4 Optical glass

[0029] 5. Machine 6. Camera bracket

[0030] 7 Lower camera 8 Standard calibration sphere DETAILED DESCRIPTION

[0031] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0032] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0033] Example

[0034] like Figures 1 to 3 As shown,

[0035] A method for measuring the thickness of a warped plate-like object based on area array structured light, wherein the measuring device includes an upper camera 1, a glass stage 2, a machine platform 5, and a lower camera 7. The upper camera 1 is mounted on the top of the machine platform 5 via a camera bracket 6, and the lower camera 7 is mounted on the bottom of the machine platform 5 via a camera bracket 6. A glass stage 2 is provided on the machine platform 5 between the upper camera 1 and the lower camera 7, and an optical glass 4 is provided on the top of the glass stage 2. The method for measuring the thickness of an object using the measuring device sequentially includes the following steps:

[0036] Step 1: Place the object to be measured 3 on the optical glass 4;

[0037] Step 2: Place an upper camera 1 above the object 3 and a lower camera 7 below the object 3, ensuring that the object 3 is in the common field of view of the upper camera 1 and the lower camera 7;

[0038] Step 3: Place several standard calibration spheres 8 into the common field of view of the upper camera 1 and the lower camera 7, and use the upper camera 1 and the lower camera 7 to fit the center data of all standard calibration spheres 8 respectively;

[0039] Step 4: Calculate the relative coordinate relationship between the upper camera 1 and the lower camera 7, and unify the coordinates to the coordinate system of the upper camera 1;

[0040] Step 5: Obtain point cloud data of the two surfaces through 3D reconstruction using upper camera 1 and lower camera 7;

[0041] Step 6: Select an area on the point cloud data of the upper camera 1, calculate its normal vector, and obtain the mapping point cloud with the lower camera 7 in the normal direction;

[0042] Step 7: Fit the plane equation of the point cloud mapped by lower camera 7, and calculate the average distance from the point cloud of upper camera 1 to the plane equation of lower camera 7, which is the thickness.

[0043] Preferably, the object to be measured 3 is a warped plate-shaped object.

[0044] Preferably, the optical glass 4 is an optical glass with a uniform refractive index at all locations.

[0045] Preferably, the upper camera 1 and the lower camera 7 are both area array structured light cameras.

[0046] Preferably, the number of standard calibration balls 8 is 1 to 12.

[0047] Preferably, the number of standard calibration balls 8 is 9.

[0048] The present invention provides a method for measuring the thickness of a warped plate-like object based on area array structured light, which can accurately and efficiently measure the thickness of the warped plate-like object and is simple to operate and easy to use.

[0049] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like to indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the devices or elements referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly referring to the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0050] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be internal communication between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for measuring the thickness of a warped plate-like object based on area array structured light, characterized in that: The measuring device comprises an upper camera (1), a glass carrier (2), a machine platform (5) and a lower camera (7), wherein the upper camera (1) is mounted at the top of the machine platform (5) via a camera bracket (6), and the lower camera (7) is mounted at the bottom of the machine platform (5) via a camera bracket (6), a glass carrier (2) is arranged on the machine platform (5) between the upper camera (1) and the lower camera (7), and an optical glass (4) is arranged on the top of the glass carrier (2). A method for measuring the thickness of an object using the measuring device comprises, in sequence: Step 1: placing the object to be measured (3) on the optical glass (4); Step 2: Place an upper camera (1) above the object to be measured (3) and a lower camera (7) below the object to be measured (3), and ensure that the object to be measured (3) is in the common field of view of the upper camera (1) and the lower camera (7); Step 3: Place several standard calibration spheres (8) into the common field of view of the upper camera (1) and the lower camera (7), and use the upper camera (1) and the lower camera (7) to fit the center data of all standard calibration spheres (8); Step 4: Calculate the relative coordinate relationship between the upper camera (1) and the lower camera (7), and unify the coordinates to the coordinate system of the upper camera (1); Step 5: Obtain point cloud data of the two surfaces through three-dimensional reconstruction using the upper camera (1) and the lower camera (7); Step 6: Select an area on the point cloud data of the upper camera (1), calculate its normal vector, and obtain the mapping point cloud with the lower camera (7) in the normal direction; Step 7: Fit the plane equation of the point cloud mapped by the lower camera (7), and calculate the average distance from the point cloud of the upper camera (1) to the plane equation of the lower camera (7), which is the thickness.

2. The method for measuring thickness of a warped plate-like object based on area array structured light according to claim 1, wherein: The object to be measured (3) is a warped plate-shaped object.

3. The method for measuring thickness of a warped plate-like object based on area array structured light according to claim 1, wherein: The optical glass (4) is an optical glass with a uniform refractive index at all locations.

4. The method for measuring thickness of a warped plate-like object based on area array structured light according to claim 1, wherein: The upper camera (1) and the lower camera (7) are both area array structured light cameras.

5. The method for measuring thickness of a warped plate-like object based on area array structured light according to claim 1, wherein: The number of the standard calibration balls (8) is 1 to 12.

6. The method for measuring thickness of a warped plate-like object based on area array structured light according to claim 5, wherein: The number of the standard calibration balls (8) is 9.

Images