Inspection device

Abstract

The invention provides an inspection device which can easily and accurately grasp the shape and the surface state of a measurement object while realizing miniaturization. Green light, blue light, and red light are emitted from light sources (111-113) to generate white light. The white light is reflected from the pattern generation unit (118), and a plurality of structured light beams of white light are sequentially projected onto a measurement object. The imaging unit (120) receives the light reflected from the measurement object and generates a plurality of pattern image data. Height data is generated based on the plurality of pattern image data. Green light, blue light, and red light are sequentially emitted from the light sources (111-113), these light are reflected from the pattern generation unit (118), and uniform light of the green light, uniform light of the blue light, and uniform light of the red light are sequentially projected onto an object to be measured. The imaging unit (120) receives the uniform light reflected by the object to be measured, and sequentially generates a plurality of pieces of texture image data. The plurality of texture image data is synthesized, thereby generating color texture image data.

Description

[0001] (This application is a divisional application of an application filed on February 5, 2020, with application number 2020100807618 and invention title “Inspection Device”.) Technical Field

[0002] The present invention relates to an inspection device for inspecting the height of a measurement object. Background Art

[0003] In the inspection device of the triangulation method, a light projection unit irradiates the surface of the measurement object with light, and a light receiving unit including pixels arranged one-dimensionally or two-dimensionally receives the reflected light. Height data representing a height image of the measurement object is generated based on data related to the distribution of the amount of received light obtained by the light receiving unit. In some cases, such height data is used to inspect the height of the measurement object produced at a production site such as a factory (online inspection).

[0004] On the other hand, in the above inspection apparatus, if texture image data representing an image of the measurement object can be acquired in addition to the height data, more information about the measurement object can be grasped.

[0005] For example, in the inspection device described in Japanese Patent Laid-Open No. 2006-284215, in a state where a three-dimensional measurement irradiation unit irradiates the measurement object with three-dimensional measurement light, a charge coupled device (CCD) camera is used to capture an image of the measurement object. Three-dimensional data related to the measurement object is generated based on the image data to be acquired through the imaging. In addition, in the inspection device, in a state where a two-dimensional imaging irradiation unit irradiates the measurement object with imaging light, an image of the measurement object is captured by a CCD camera. Two-dimensional data representing the surface of the measurement object is generated based on the image data to be acquired through the imaging.

[0006] The two-dimensional data is mapped with respect to the three-dimensional data, thereby displaying a height image including brightness and darkness information on a display unit.

[0007] The height image displayed in this way makes it easy to grasp the texture and realism of the measured object.

[0008] In order to use the inspection device described in Japanese Patent Laid-Open No. 2006-284215 to inspect a measurement object flowing on a belt conveyor, for example, it is necessary to ensure installation space for a three-dimensional measurement irradiation unit, a two-dimensional imaging irradiation unit, and a CCD camera above the belt conveyor. In this case, it is desirable to miniaturize the inspection device to increase the flexibility of the layout of the inspection device.

[0009] Furthermore, in the above-mentioned inspection apparatus, imaging for acquiring three-dimensional data and imaging for acquiring two-dimensional data are performed separately using two different irradiation units. Therefore, there is a possibility that a difference in the irradiation possible area on the surface of the measurement object may occur between one of the irradiation units and the other irradiation unit. In this case, the unmeasurable area in the generated three-dimensional data does not match the unmeasurable area in the two-dimensional data. This makes it difficult to grasp accurate information about the shape and surface state of the measurement object. Summary of the invention

[0010] An object of the present invention is to provide an inspection device which makes it easy to accurately grasp the shape and surface state of a measurement object while achieving miniaturization thereof.

[0011] (1) An inspection device according to the present invention is equipped with: a plurality of light sources configured to respectively emit a plurality of lights having mutually different wavelengths and cause the emitted plurality of lights to travel in a common optical path set in advance; a pattern generating unit arranged on the common optical path and configured to receive the light traveling in the common optical path and selectively generate structured light and uniform light based on the received light so that the generated structured light or uniform light travels in the common optical path and is projected onto a measurement object; a light projection control unit configured to cause light to be emitted from at least one of the plurality of light sources, control the plurality of light sources and the pattern generating unit to generate a plurality of structured lights using the light emitted from the at least one light source while shifting in phase, and control the plurality of light sources and the pattern generating unit to sequentially emit light from the plurality of light sources. generating a plurality of uniform lights each having a plurality of wavelengths; an imaging unit configured to sequentially generate a plurality of pattern image data for representing an image of the measuring object by sequentially receiving a plurality of structured lights reflected from the measuring object, and sequentially generate a plurality of texture image data for representing an image of the measuring object by sequentially receiving a plurality of uniform lights reflected from the measuring object; an image data generating unit configured to generate height data for representing a height image of the measuring object based on the plurality of pattern image data, and to generate color texture image data for representing an image of the measuring object using a plurality of colors corresponding to a plurality of wavelengths by synthesizing the plurality of texture image data; and an inspection unit configured to perform inspection of the measuring object based on the height data and the color texture image data.

[0012] In the inspection device, light is emitted from at least one of a plurality of light sources. The emitted at least one light is incident on a pattern generating unit, thereby sequentially irradiating a measurement object by a plurality of structured lights generated while being phase-shifted. In the process, an imaging unit sequentially receives a plurality of structured lights reflected from the measurement object, and sequentially generates a plurality of pattern image data. Height data is generated based on the generated plurality of pattern image data.

[0013] In addition, a plurality of lights having mutually different wavelengths are sequentially emitted from the plurality of light sources, and these lights are incident on the pattern generating unit. Therefore, the measurement object is sequentially irradiated by a plurality of uniform lights having mutually different wavelengths from the pattern generating unit. The imaging unit sequentially receives a plurality of uniform lights reflected from the measurement object, and sequentially generates a plurality of texture image data. The generated plurality of texture image data are synthesized, thereby generating color texture image data. Inspection of the measurement object is performed based on the height data and the color texture image data.

[0014] In this case, the pattern generating section and the imaging section are used together to generate the height data and the color texture image data. Therefore, there is no need to separately prepare a structure for generating the height data and a structure for generating the color texture image data. Specifically, there is no need to separately prepare a light projection system for irradiating the measuring object with structured light and a light projection system for irradiating the measuring object with uniform light. In addition, there is no need to separately prepare a light receiving system for receiving the structured light reflected from the measuring object and a light receiving system for receiving the uniform light reflected from the measuring object. This can reduce the number of components in the multiple light projection and receiving systems for generating the height data and the color texture image data. This allows the inspection device to be reduced in size and reduced in cost.

[0015] Furthermore, by the above-described structure, the structured light used in the generation of the height data and the uniform light used in the generation of the color texture image data travel in a common optical path and are projected onto the measurement object. Therefore, there is no difference in the area such as a shadow to be formed on the measurement object between the generation of the height data and the generation of the color texture image data. Therefore, the unmeasurable area in the height data and the unmeasurable area in the color texture image data are maintained in a state where they match each other. As a result, accurate information on the shape and surface state of the measurement object can be easily grasped based on the height data and the color texture image data.

[0016] (2) The plurality of light sources may include a light source for emitting green light, a light source for emitting blue light, and a light source for emitting red light, and the light projection control unit may control the plurality of light sources and the pattern generating unit to emit green light, blue light, and red light from the plurality of light sources, and generate a plurality of structured lights while shifting the phases using white light obtained from the emitted green light, blue light, and red light.

[0017] Depending on the color of the measuring object, if light having a specified wavelength is projected onto the measuring object, the projected light is absorbed on the surface of the measuring object in some cases. In this case, even if a plurality of structured lights are projected onto the measuring object, there is a possibility that height data cannot be acquired due to a small amount of structured light reflected in the measuring object.

[0018] By the above structure, in the case of generating height data, a plurality of structured lights of white color including components of a plurality of wavelengths are projected onto the measuring object. Therefore, independent of the color of the measuring object, at least a portion of the components of the wavelengths can be reflected on the surface of the measuring object. As a result, height data can be generated within an expanded range on the measuring object.

[0019] (3) The inspection device is also configured with: a light receiving optical system, which is configured to include a light receiving lens having an optical axis extending in the up-down direction and guides the structured light or uniform light reflected upward from the measuring object to the camera unit; a holding member, which is configured to hold the multiple light sources so that the multiple lights respectively emitted from the multiple light sources travel from the upper direction to the lower direction in the common optical path; and a reflecting member, which is configured to reflect the multiple lights respectively emitted from the multiple light sources and traveling from the upper direction to the lower direction in an oblique upward direction to move away from the optical axis of the light receiving lens, wherein the pattern generating unit may include a light generating surface, which is used to selectively generate the structured light and the uniform light by reflecting at least a portion of the multiple lights reflected by the reflecting member in an oblique downward direction to be closer to the optical axis of the light receiving lens.

[0020] In this case, each of the multiple lights emitted from the multiple light sources held by the holding member travels from the upper direction to the lower direction in the common optical path, and is reflected by the reflecting member in an oblique upward direction to be away from the optical axis of the light receiving lens. At least a portion of the light reflected by the reflecting member is reflected by the light generating surface in an oblique downward direction to be closer to the optical axis of the light receiving lens. In this process, the light reflected in the light generating surface is projected onto the measuring object as structured light or uniform light. The structured light or uniform light reflected upward from the measuring object is incident on the imaging unit through the light receiving optical system.

[0021] With the above structure, the optical path common to a plurality of lights is bent. This prevents the structure for irradiating the measurement object with structured light and uniform light from being enlarged in the irradiation direction of these lights. In addition, with the above structure, a plurality of light sources, a holding member, and a reflecting member are located between the pattern generating unit and the optical axis of the light receiving optical system in a direction perpendicular to the optical axis of the light receiving optical system. Therefore, the space between the pattern generating unit and the optical axis of the light receiving optical system in a direction perpendicular to the optical axis of the light receiving optical system can be effectively utilized.

[0022] Therefore, the structure of the plurality of light projecting and receiving systems including the plurality of light sources, the holding member, the reflecting member, the pattern generating section, the light receiving optical system, and the imaging section can be further miniaturized.

[0023] (4) The inspection device is also configured with: a light projection optical system, which is configured to include a light projection lens having an optical axis extending obliquely downward to be closer to the optical axis of the light receiving lens, and guides the structured light or uniform light generated by the light generating surface to the measurement object, wherein the measurement object can be placed on a pre-set placement surface, and the pattern generating unit and the light projection optical system can be arranged so that the light generating surface of the pattern generating unit and the placement surface follow the Scheimpflug principle relative to the main plane of the light projection optical system.

[0024] In this case, the structured light or uniform light generated in the light generating surface is projected onto the measuring object through the light projection optical system. Here, the light generating surface of the pattern generating part and the placement surface follow the Scheimpflug principle relative to the main plane of the light projection optical system, so that the focus of the entire light generating surface can be focused on the placement surface. Therefore, even in the case where the light projection lens has a small f-value, the focus of the entire light generating surface is focused on the placement surface, so that the lighting can be designed to be brighter.

[0025] (5) The inspection device may further include a housing configured to accommodate the plurality of light sources, the holding member, the reflecting member, the pattern generating section, the light projecting optical system, the light receiving optical system, and the imaging section.

[0026] In this case, a plurality of light projection and receiving systems including a plurality of light sources, a holding member, a reflecting member, a pattern generating unit, a light projection optical system, a light receiving optical system, and an imaging unit can be compactly accommodated in the housing. This can miniaturize the housing and reduce the installation space of the housing. In addition, processing such as installation of the inspection device becomes easy.

[0027] According to the present invention, the inspection device can be miniaturized, and the shape and surface state of the measurement object can be accurately grasped easily. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a block diagram showing the structure of an inspection device according to an embodiment of the present invention;

[0029] Figure 2 It is used to illustrate Figure 1 A schematic diagram of the basic internal structure of the head in;

[0030] Figure 3 It is a diagram used to illustrate the principle of triangulation;

[0031] Figure 4 It is shown Figure 1 A flowchart of an example of an inspection process performed by the inspection device in;

[0032] Figure 5A and Figure 5B is a diagram for explaining the relationship between the irradiation direction of structured light and the irradiation direction of uniform light and the unmeasurable area on the measurement object;

[0033] Figure 6 is a diagram showing a preferred positional relationship between a pattern generating unit and a light projection lens;

[0034] Figure 7 is a block diagram showing a structure of an inspection device according to a first modification; and

[0035] Figure 8 : is a block diagram showing the structure of an inspection device according to a second modification. DETAILED DESCRIPTION

[0036] An inspection device according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0037] (1) Inspection device structure

[0038] Figure 1 1 is a block diagram showing the structure of an inspection device according to an embodiment of the present invention. Figure 1 As shown, the inspection device 300 is equipped with a head 100, a controller portion 200, an operation portion 310, and a display portion 320. The controller portion 200 is connected to an external device 400 such as a programmable logic controller or the like.

[0039] like Figure 1As shown by the thick arrows, a plurality of measuring objects S are sequentially conveyed by the belt conveyor 301 to pass through the space below the head 100. When each measuring object S passes through the space below the head 100, the belt conveyor 301 stops for a certain period of time, so that the relevant measuring object S temporarily stops at a specified position below the head 100.

[0040] The head 100 is, for example, an imaging device in which light emission and light reception are integrated, and has a structure in which an illumination unit 110, an imaging unit 120, and a computing unit 130 are accommodated in a head housing 100c. The illumination unit 110 is configured to allow light between red, blue, green, or white light having an arbitrary pattern and red, blue, green, or white light having no pattern and being uniform to be selectively irradiated to the measuring object S from an oblique upward direction. Hereinafter, light having an arbitrary pattern is referred to as structured light, and uniform light is referred to as uniform light. The structure of the illumination unit 110 is described later.

[0041] The imaging unit 120 includes an imaging element 121 and light receiving lenses 122 and 123. At least the light receiving lens 122 of the light receiving lenses 122 and 123 is a telecentric lens. The structured light or uniform light reflected upward by the object S to be measured is converged and imaged by the light receiving lenses 122 and 123 of the imaging unit 120, and then received by the imaging element 121. The imaging element 121 is, for example, a monochrome charge coupled device (CCD), and outputs an analog electrical signal corresponding to the amount of light received from each pixel, thereby generating image data. The imaging element 121 may be other imaging elements such as a complementary metal oxide semiconductor (CMOS) image sensor.

[0042] In the present embodiment, image data representing an image of the measuring object S when the measuring object S is irradiated with structured light is referred to as pattern image data. On the other hand, image data representing an image of the measuring object S when the measuring object S is irradiated with uniform light having any wavelength of red, blue, or green is referred to as texture image data.

[0043] The calculation unit 130 is implemented by, for example, a field programmable gate array (FPGA), and includes an image processing unit 131, an image data generating unit 132, a storage unit 133, and an output processing unit 134. In the present embodiment, the calculation unit 130 is implemented by the FPGA, but the present invention is not limited thereto. The calculation unit 130 may be implemented by a central processing unit (CPU) and a random access memory (RAM), or may be implemented by a microcomputer.

[0044] The imaging processing unit 131 controls the operations of the lighting unit 110 and the imaging unit 120. The image data generating unit 132 generates height data representing a height image of the measuring object S based on a plurality of pattern image data. In addition, the image data generating unit 132 generates color texture image data representing a color image of the measuring object S by synthesizing red, blue, and green texture image data generated from uniform light of red, blue, and green. The storage unit 133 temporarily stores the plurality of pattern image data and the plurality of texture image data generated by the imaging unit 120 internally. In addition, the storage unit 133 temporarily stores the height data and the color texture image data generated by the image data generating unit 132 internally. The output processing unit 134 outputs the height data or the color texture image data stored in the storage unit 133. The details of the calculation unit 130 will be described later.

[0045] The controller section 200 includes a head control section 210, an image memory 220, and an inspection section 230. The head control section 210 controls the operation of the head 100 based on a command given by the external device 400. The image memory 220 stores the height data or the color texture image data output by the calculation section 130 internally.

[0046] The inspection section 230 performs processing such as edge detection or size measurement on the height data or color texture image data stored in the image memory 220 based on the inspection content specified by the user. In addition, the inspection section 230 judges the quality of the measuring object S by comparing the measured value with a prescribed threshold value, and provides the judgment result to the external device 400.

[0047] The operation unit 310 and the display unit 320 are connected to the controller unit 200. The operation unit 310 includes a keyboard, a pointing device, or a dedicated console. As the pointing device, a mouse or a joystick is used. The user can specify the desired inspection content to the controller unit 200 by operating the operation unit 310.

[0048] The display unit 320 includes, for example, a liquid crystal display (LCD) panel or an organic electroluminescent (EL) panel. The display unit 320 displays a height image based on the height data stored in the image memory 220. In addition, the display unit 320 displays a color image of the measuring object S based on the color texture image data stored in the image memory 220. In addition, the display unit 320 displays the judgment result of the inspection unit 230 on the measuring object S.

[0049] (2) Basic Internal Structure of Head 100

[0050] Figure 2 It is used to illustrate Figure 1 Schematic diagram of the basic internal structure of the head 100. Figure 2As shown, the imaging unit 120 is fixed inside the head housing 100c so that the common optical axis ax0 of the light receiving lenses 122 and 123 extends in the up-down direction. The imaging element 121 is fixed above the light receiving lenses 122 and 123 to receive light traveling from the lower direction to the upper direction along the common optical axis ax0 of the light receiving lenses 122 and 123. In addition, in this example, the calculation unit 130 is fixed inside the head housing 100c in a state where it is mounted to the substrate so as to be located above the imaging unit 120.

[0051] In the head housing 100c, the lighting unit 110 is provided in a manner adjacent to the imaging unit 120 in the horizontal direction. The lighting unit 110 includes light sources 111, 112, and 113, dichroic mirrors 114 and 115, an illumination lens 116, a reflection mirror 117, a pattern generator 118, a light projection lens 119, a first holding member 110a, and a second holding member 110b.

[0052] The first holding member 110a integrally holds the light sources 111, 112 and 113, the dichroic mirrors 114 and 115, and the illumination lens 116. The second holding member 110b integrally holds the reflection mirror 117, the pattern generating unit 118 and the light projection lens 119. The first holding member 110a is connected to the second holding member 110b in such a manner as to be located above the second holding member 110b. The first holding member 110a and the second holding member 110b connected to each other are fixed in the head housing 100c in such a manner as to have a certain positional relationship with the imaging unit 120.

[0053] The light sources 111, 112, and 113 are, for example, light emitting diodes (LEDs), and emit green light, blue light, and red light, respectively. Each of the light sources 111 to 113 may be a light source other than an LED.

[0054] The dichroic mirror 114 is held by the first holding member 110a in such a manner that the green light emitted by the light source 111 and the blue light emitted by the light source 112 overlap each other. The dichroic mirror 115 is held by the first holding member 110a in such a manner that the light overlapped by the dichroic mirror 114 and the red light emitted by the light source 113 overlap each other. Therefore, the green light, the blue light, and the red light simultaneously emitted from the light sources 111 to 113 overlap each other on a common optical path, thereby generating white light.

[0055] Furthermore, in the present embodiment, the light sources 111 to 113 and the dichroic mirrors 114 and 115 are held by the first holding member 110 a so that a plurality of lights respectively emitted by the light sources 111 to 113 travel from the upper direction to the lower direction in a common optical path.

[0056] The illumination lens 116 is held by the first holding member 110a at a position below the dichroic mirror 115 to collect light having passed through or reflected from the dichroic mirror 115. In the head housing 100c, the light collected by the illumination lens 116 further travels from the upper direction to the lower direction.

[0057] The reflector 117 is held by the second holding member 110b in such a manner that the light passing through the illumination lens 116 is kept away from the optical axis ax0 of the imaging unit 120 while reflecting the light in an oblique upward direction. The pattern generating unit 118 is held by the second holding member 110b in such a manner that the light reflected by the reflector 117 is received. The pattern generating unit 118 is, for example, a digital micromirror device (DMD), and includes a light generating surface that reflects at least a portion of the received light in an oblique downward direction to be closer to the optical axis ax0 of the imaging unit 120, thereby selectively generating structured light and uniform light. The pattern generating unit 118 may be an LCD or a reflective liquid crystal element (LCOS).

[0058] The light projection lens 119 is held by the second holding member 110b such that the optical axis ax1 of the light projection lens 119 extends obliquely downward while being closer to the optical axis ax0 of the imaging unit 120. In this embodiment, the light projection lens 119 expands the light from the pattern generating unit 118 and irradiates the image with the light. Figure 1 Note that the light projection lens 119 may include a telecentric optical system, and may be configured to expand and collimate the structured light or uniform light from the pattern generation section 118 and allow the structured light or uniform light to be irradiated to the measurement object S.

[0059] By the above structure, the optical path common to the plurality of lights emitted from the light sources 111, 112, and 113 is bent, and the measuring object S is irradiated with the light on the optical path. Therefore, the respective optical systems held by the first holding member 110a are not arranged on the optical axis ax1 of the light projection lens 119 held by the second holding member 110b. This prevents the structure for irradiating the measuring object S with structured light and uniform light from being enlarged in its irradiation direction.

[0060] Furthermore, by the above-described structure, each optical system held by the first holding member 110a is located between the pattern generating section 118 and the optical axis ax0 of the imaging section 120 in a direction perpendicular to the optical axis ax0 of the imaging section 120. Therefore, the space between the pattern generating section 118 and the optical axis ax0 of the imaging section 120 in a direction perpendicular to the optical axis ax0 of the imaging section 120 can be effectively utilized. Therefore, the compact configuration of the illumination section 110 and the imaging section 120 in the head housing 100c realizes miniaturization of the head 100 and improves the flexibility of the layout of the head 100.

[0061] Figure 1 The imaging processing unit 131 of the calculation unit 130 in the embodiment individually controls the emission of light from the light sources 111 to 113 according to the flow of the inspection process described later. In addition, the imaging processing unit 131 controls the pattern generation unit 118 so that the desired pattern is assigned to the light emitted from the illumination unit 110. Through this control, the illumination unit 110 selectively emits structured light of white including a prescribed pattern, and uniform light of green, blue, or red. In addition, the imaging processing unit 131 controls the imaging unit 120 according to the flow of the inspection process described later to capture the measurement object S in synchronization with the emission of structured light or uniform light in the illumination unit 110.

[0062] (3) Generation of height data

[0063] In the inspection device 300, a unique three-dimensional coordinate system (hereinafter referred to as the device coordinate system) is defined for the head 100. The device coordinate system in this example includes an origin, and an X-axis, a Y-axis, and a Z-axis that are perpendicular to each other. In the following description, the direction parallel to the X-axis of the device coordinate system is referred to as the X-direction, the direction parallel to the Y-axis of the device coordinate system is referred to as the Y-direction, and the direction parallel to the Z-axis of the device coordinate system is referred to as the Z-direction. The X-direction and the Y-direction are perpendicular to each other in a plane parallel to the top surface of the belt conveyor 301 (hereinafter referred to as the reference plane). The Z-direction is perpendicular to the reference plane.

[0064] In the head 100 , height data representing a height image of the measuring object S is generated by triangulation. Figure 3 This is a diagram used to illustrate the principle of triangulation. Figure 3 In FIG. 1 , the X direction, Y direction and Z direction are indicated by arrows. Figure 3 As shown, the optical system ( Figure 2 The optical axis ax1 of the light projection lens 119 in the imaging unit 120 and the optical system ( Figure 2 The angle α between the optical axes ax0 of the light receiving lenses 122 and 123 in FIG. 1 is preset. The angle α is greater than 0 degrees and less than 90 degrees.

[0065] In the case where the measuring object S does not exist below the head 100, the light emitted from the illumination section 110 is reflected by the point O on the reference surface R and is incident on the imaging section 120. In contrast, in the case where the measuring object S exists below the head 100, the light emitted from the illumination section 110 is reflected by the point A on the surface of the measuring object S and is incident on the imaging section 120. This causes the measuring object S to be imaged, and image data representing an image of the measuring object S is generated.

[0066] When the distance in the X direction between the point O and the point A is set to d, the height h of the point A in the measuring object S relative to the reference surface R is given by h=d÷tan(α). The calculation unit 130 calculates the distance d based on the image data generated by the imaging unit 120. In addition, the calculation unit 130 calculates the height h of the point A on the surface of the measuring object S based on the calculated distance d. By calculating the heights of all points on the surface of the measuring object S, the coordinates represented by the device coordinate system can be identified for all points irradiated with light. Through this identification, the height data of the measuring object S is generated.

[0067] In order to illuminate all points on the surface of the measuring object S with light, various types of structured light are emitted from the illumination section 110. In the present embodiment, the illumination section 110 emits a plurality of stripe structured light (hereinafter referred to as stripe light) having a linear cross section parallel to the Y direction and arranged in the X direction while changing the spatial phase of the stripe structured light. In addition, the illumination section 110 emits a plurality of coded structured light (hereinafter referred to as coded light) having a linear cross section parallel to the Y direction and having a bright portion and a dark portion arranged in the X direction while changing the bright portion and the dark portion of the coded structured light (hereinafter referred to as coded light) into a Gray coded portion.

[0068] (4) Inspection and processing

[0069] Figure 4 It is shown Figure 1 FIG. 1 is a flowchart of an example of an inspection process performed by the inspection device 300 in FIG. Figure 1 The various components of the inspection device 300 and Figure 4 The inspection process is described with reference to the flowchart in FIG. First, in the head 100, the imaging processing unit 131 controls the lighting unit 110 to emit white structured light including a prescribed pattern (step S1). In addition, the imaging processing unit 131 controls the imaging unit 120 to image the measuring object S in synchronization with the emission of the structured light in step S1 (step S2). Therefore, the imaging unit 120 generates pattern image data of the measuring object S.

[0070] Next, the image processing unit 131 causes the storage unit 133 to internally store the pattern image data generated in the previous step S2 (step S3). In addition, the image processing unit 131 determines whether the image capturing has been performed a predetermined number of times (step S4). If the image capturing has not been performed a predetermined number of times, the image processing unit 131 controls Figure 2The pattern generating unit 118 in the memory 133 changes the pattern of the structured light (step S5), and the process returns to step S1. Here, changing the pattern of the structured light includes shifting the phase of the pattern of the structured light. The processes of steps S1 to S5 are repeated until the prescribed number of imaging is performed. Therefore, a plurality of pattern image data when the measuring object S is sequentially irradiated with striped light and coded light while changing the pattern are stored in the storage unit 133. Note that either the striped light or the coded light may be emitted first.

[0071] When the predetermined number of imaging is performed in step S4, the image data generation unit 132 generates height data by performing calculations on the plurality of pattern image data stored in the storage unit 133 (step S6). Thereafter, the output processing unit 134 outputs the height data generated in step S6 to the controller unit 200 (step S7). Thus, the height data is accumulated in the image memory 220 of the controller unit 200.

[0072] Next, the image processing unit 131 Figure 2 The image processing unit 131 selects one light source from the plurality of light sources 111, 112, and 113, and controls the illumination unit 110 to emit uniform light of a color corresponding to the selected one light source (step S8). Furthermore, the image processing unit 131 controls the image capturing unit 120 to capture an image of the measuring object S in synchronization with the emission of uniform light in step S8 (step S9). Thus, the image capturing unit 120 generates texture image data of a color corresponding to the one light source.

[0073] Subsequently, the imaging processing unit 131 causes the storage unit 133 to internally store the texture image data generated in the previous step S9 (step S10). In addition, the imaging processing unit 131 determines whether imaging using all the light sources 111 to 113 has been performed (step S11). In the case where imaging using all the light sources 111 to 113 has not been performed, the imaging processing unit 131 determines a light source to emit light from one or more light sources that have not emitted light after the previous process of step S7 (step S12), and returns the process to step S8. Before imaging using all the light sources 111 to 113 is performed, the processes of steps S8 to S12 are repeated. Therefore, a plurality of texture image data when the measuring object S is sequentially irradiated with uniform light while changing the color of the light used to irradiate the measuring object S is stored in the storage unit 133.

[0074] When the image capturing using all the light sources 111 to 113 is performed in step S11, the image data generating unit 132 generates color texture image data by synthesizing the plurality of texture image data stored in the storage unit 133 (step S13). Thereafter, the output processing unit 134 outputs the color texture image data generated in step S13 to the controller unit 200 (step S14). Thus, the color texture image data is accumulated in the image memory 220 of the controller unit 200.

[0075] Next, in the controller section 200, the inspection section 230 performs image processing on the height data and the color texture image data accumulated in the image memory 220 in steps S7 and S14 (step S15). Thus, based on the inspection content pre-specified by the user, measurement of a predetermined portion in the height data or the color texture image data is performed. Specifically, the height data is used to perform measurement related to the height direction (Z direction), and the color texture image data is used to perform measurement related to the X direction or the Y direction.

[0076] Subsequently, the inspection section 230 determines the quality of the measuring object S by comparing the measurement value obtained in step S15 with a prescribed threshold value (step S16 ), and ends the measurement process.

[0077] Here, the inspection section 230 may display the judgment result in step S16 on the display section 320, or may provide the judgment result to the external device 400. In addition, the inspection section 230 may cause the display section 320 to display a height image based on the height data generated in the process of the above-mentioned step S6. In addition, the display section 320 may cause the display section 320 to display a color image of the measuring object S based on the color texture image data generated in the above-mentioned step S13.

[0078] In the above-mentioned inspection process, after the processes of steps S1 to S7 are performed, the processes of steps S8 to S14 are performed, but the present invention is not limited thereto. The processes of steps S1 to S7 may be performed after the processes of steps S8 to S14 are performed. In addition, the processes of steps S7 and S14 may be performed at any time point before the measurement is performed, and may be performed in parallel with other processes.

[0079] (5) Effects of the Embodiment

[0080] (a) In the head 100 described above, green light, blue light, and red light are emitted from the plurality of light sources 111, 112, and 113, and white light is generated. The generated white light is incident on the pattern generating unit 118, whereby the measuring object S is sequentially irradiated with the plurality of structured lights to be generated. In this process, the imaging unit 120 sequentially receives the plurality of structured lights reflected from the measuring object S, and sequentially generates a plurality of pattern image data. Height data is generated based on the plurality of pattern image data generated.

[0081] In addition, green light, blue light, and red light are sequentially emitted from the plurality of light sources 111, 112, and 113, and these lights are incident on the pattern generation unit 118. In this process, the pattern generation unit 118 reflects the incident green light, blue light, and red light, thereby sequentially irradiating the measuring object S with uniform light of green light, uniform light of blue light, and uniform light of red light. The imaging unit 120 sequentially receives the plurality of uniform lights reflected from the measuring object S, and sequentially generates a plurality of texture image data. The generated plurality of texture image data are synthesized, thereby generating color texture image data. Based on the height data and the color texture image data, the inspection of the measuring object S is performed.

[0082] In this case, the pattern generation unit 118 and the imaging unit 120 are used together to generate height data and color texture image data. Therefore, there is no need to separately prepare a structure for generating height data and a structure for generating color texture image data. Specifically, there is no need to separately prepare a light projection system for irradiating the measuring object S with structured light and a light projection system for irradiating the measuring object S with uniform light. In addition, there is no need to separately prepare a light receiving system for receiving structured light reflected from the measuring object S and a light receiving system for receiving uniform light reflected from the measuring object S. This can reduce the number of components in multiple light projection and receiving systems for generating height data and color texture image data. This allows the head 100 of the inspection device 300 to be reduced in size and cost.

[0083] (b) Furthermore, with the above configuration, the structured light used in the generation of height data and the uniform light used in the generation of color texture image data travel in a common optical path and are projected onto the measuring object S. The effects obtained from the above will be described.

[0084] Figure 5A and Figure 5B 1 is a diagram for explaining the relationship between the irradiation direction of structured light and the irradiation direction of uniform light, and the unmeasurable area on the measurement object S. Figure 5A An example in which the height data and the texture image data are generated using the illumination section 110P for illuminating the measuring object S with structured light and the illumination section 110Q for illuminating the measuring object S with uniform light separately is shown as a reference example.

[0085] exist Figure 5A In the example of , in order to prevent the illumination units 110P and 110Q and the imaging unit 120 from interfering with each other, the illumination units 110P and 110Q and the imaging unit 120 are arranged to be aligned in the horizontal direction. With such a structure, the area to be formed on the measuring object S is different between the case where the structured light is projected for the measuring object S and the case where the uniform light is projected for the measuring object S, depending on the shape of the measuring object S. In this case, the unmeasurable area in the height data does not match the unmeasurable area in the color texture image data.

[0086] Figure 5B An example of generating height data and texture image data using the illumination section 110 for selectively illuminating the measuring object S with structured light and uniform light in the inspection device 300 according to the present embodiment is shown. Figure 5B As shown, with the illumination section 110 according to the present embodiment, the structures for applying structured light and uniform light to the measuring object S, respectively, are made common. Therefore, the irradiation directions of the structured light and the uniform light with respect to the measuring object S coincide with each other. With such a structure, independently of the shape of the measuring object S, the areas of the shadow to be formed on the measuring object S match each other between the case where the structured light is projected with respect to the measuring object S and the case where the uniform light is projected with respect to the measuring object S. Therefore, the unmeasurable area in the height data and the unmeasurable area in the color texture image data are maintained in a state where they are made to match each other. As a result, accurate information on the shape and surface state of the measuring object S can be easily grasped based on the height data and the color texture image data.

[0087] (c) In the lighting unit 110 , when generating height data, structured light of white light is projected onto the measuring object S.

[0088] Depending on the color of the measuring object S, if light having a specified wavelength is projected onto the measuring object S, the projected light is absorbed at the surface of the measuring object S in some cases. In this case, even if structured light having a specified wavelength is projected onto the measuring object S, there is a possibility that height data cannot be acquired due to a small amount of structured light reflected in the measuring object S.

[0089] By the above-described structure, in the case of generating height data, a plurality of structured lights of white color including components of a plurality of wavelengths are projected onto the measuring object S. Therefore, independently of the color of the measuring object S, at least a portion of the components of the wavelengths can be reflected on the surface of the measuring object S. As a result, the range on the measuring object S in which the height data can be generated is expanded.

[0090] (d) In the above-mentioned head 100, a plurality of light projection and receiving systems for height data and color texture image data are compactly accommodated in the head housing 100c. This can miniaturize the head 100 and reduce the installation space of the head 100. In addition, processing such as installation of the head 100 becomes easy.

[0091] (6) Preferred Positional Relationship between Pattern Generator 118 and Light Projection Lens 119

[0092] In the following description, a region on the top surface of the belt conveyor 301 irradiated with structured light or uniform light from the illumination section 110 in a state where the measuring object S is not placed on the top surface of the belt conveyor 301 is referred to as an irradiated region.

[0093] In the head 100, in order to perform shape measurement using the triangulation method, the optical axis ax1 of the illumination unit 110 is tilted relative to the optical axis ax0 of the imaging unit 120. In such a structure, when the focal planes on the image side and the object side of the light projection lens 119 are perpendicular to the optical axis ax1, the focus of the entire light generating surface of the pattern generating unit 118 cannot be focused on the top surface of the belt conveyor 301.

[0094] Therefore, in the above-described head 100 , the pattern generating section 118 and the light projecting lens 119 may be preferably arranged with respect to the top surface of the belt conveyor 301 on which the measuring object S is placed according to the Scheimpflug principle.

[0095] Figure 6 1 is a diagram showing a preferred positional relationship between the pattern generating unit 118 and the light projection lens 119. Figure 6 In the example of , the arrangement of the light generating surface 118S of the pattern generating unit 118, the light projection lens 119, and the top surface of the belt conveyor 301 is determined according to the Scheimpflug principle.

[0096] Specifically, the pattern generating unit 118 and the light projection lens 119 are arranged so that: the surface PP including the main plane of the light projection lens 119, the surface IS including the light generating surface 118S of the pattern generating unit 118, and the surface SS including the top surface of the belt conveyor 301 intersect each other on a common straight line LP.

[0097] In the case where the light generating surface 118S is included in the focal plane on the image side of the light projection lens 119, and the top surface of the belt conveyor 301 is included in the focal plane on the object side of the light projection lens 119, the focus of the entire light generating surface 118S is focused on the irradiation area 301S on the top surface of the belt conveyor 301. Therefore, even in the case where the light projection lens 119 has a small f-value, the focus of the entire light generating surface 118S is focused on the irradiation area 301S, so that the lighting can be designed to be brighter.

[0098] (7) Modification

[0099] (a) The head 100 includes an illumination unit 110 and an imaging unit 120, but the present invention is not limited thereto. Figure 7 is a block diagram showing the structure of the inspection device 300 according to the first modification. Figure 7 As shown, the head 100 in the first variant includes four lighting units 110. Figure 7 , the illustration of the calculation unit 130 is omitted.

[0100] In the following description, when distinguishing the four lighting units 110 from each other, the four lighting units 110 are respectively referred to as lighting units 110A to 110D. The lighting units 110A to 110D have the same structure as each other, and are arranged to surround the camera unit 120 at intervals of 90 degrees. Specifically, the lighting unit 110A and the lighting unit 110B are arranged to face each other by clamping the camera unit 120 between the two. In addition, the lighting unit 110C and the lighting unit 110D are arranged to face each other by clamping the camera unit 120 between the two. In addition, the four lighting units 110A to 110D and the camera unit 120 are accommodated in the head housing 100c together with the calculation unit 130.

[0101] In this structure, the four lighting units 110A to 110D can emit light to the measuring object S from four different directions. Therefore, even if there is an unmeasurable portion using the light emitted from any one of the lighting units 110, the shape of the unmeasurable portion can be measured by the light emitted from the other lighting units 110. Therefore, by synthesizing the height data corresponding to each of the four lighting units 110A to 110D, synthesized height data with a further reduction in the unmeasurable portion can be generated. In addition, by synthesizing the color texture image data generated corresponding to each of the four lighting units 110A to 110D, color texture image data with a further reduction in the unmeasurable portion can be generated.

[0102] (b) In the above-mentioned head 100, the optical axis ax0 of the imaging unit 120 extends in the up-down direction, and the optical axis ax1 of the lighting unit 110 is inclined relative to the optical axis ax0, but the present invention is not limited thereto. The head 100 may be configured such that the positional relationship between the lighting unit 110 and the imaging unit 120 is opposite to that in the above-mentioned example. In other words, the head 100 may be configured such that: the optical axis ax1 of the lighting unit 110 extends in the up-down direction, and the optical axis ax0 of the imaging unit 120 is inclined relative to the optical axis ax1.

[0103] In this case, a plurality of imaging units 120 may be provided for one illumination unit 110 . Figure 8 is a block diagram showing the structure of an inspection device 300 according to a second modification. Figure 8 As shown, the head 100 in the second variant includes four camera units 120. Figure 8 , the illustration of the calculation unit 130 is omitted.

[0104] In the following description, when distinguishing the four imaging units 120, the four imaging units 120 are respectively referred to as imaging units 120A to 120D. The imaging units 120A to 120D have the same structure as each other, and are arranged to surround the lighting unit 110 at intervals of 90 degrees. Specifically, the imaging unit 120A and the imaging unit 120B are arranged to face each other by clamping the lighting unit 110 therebetween. In addition, the imaging unit 120C and the imaging unit 120D are arranged to face each other by clamping the lighting unit 110 therebetween. In addition, the four imaging units 120A to 120D and the lighting unit 110 are accommodated in the head housing 100c together with the calculation unit 130.

[0105] In this configuration, the four imaging units 120A to 120D can capture images of the measurement object S from four different directions. Therefore, even if there is a portion that cannot be captured by any of the imaging units 120, the portion that cannot be captured can be captured by the other imaging units 120. Therefore, by synthesizing the height data corresponding to each of the four imaging units 120A to 120D, synthesized height data with a further reduction in the unmeasurable portion can be generated. In addition, by synthesizing the color texture image data corresponding to each of the four imaging units 120A to 120D, synthesized color texture image data with a further reduction in the unmeasurable portion can be generated.

[0106] (8) Other embodiments

[0107] (a) In the above embodiment, in order to generate height data, white structured light is projected onto the measuring object S, but the present invention is not limited to this. The structured light used to generate height data is not limited to white structured light, and red, blue, green, or structured light of a combination of two of these colors can be used. In this case, the color of the structured light can be user-selectable. This allows the user to check the height of the measuring object S using light with a suitable wavelength according to the color, surface state, shape, etc. of the measuring object S.

[0108] In this way, in the case where the color of the structured light is selectable, calibration of the inspection device 300 can be preferably performed according to the selected color. This makes it possible to generate height data with the influence of, for example, chromatic aberration removed.

[0109] (b) In the illumination section 110 according to the above embodiment, the optical path common to the light sources 111 , 112 , and 113 is bent by the reflection mirror 117 and the pattern generating section 118 , but the present invention is not limited thereto.

[0110] The common optical path of the light sources 111, 112 and 113 can be extended linearly without being bent. In this case, the reflector 117 becomes unnecessary from the above-mentioned illumination unit 110. In addition, in this case, a transmissive element such as an LCD is used as the pattern generating unit 118. This simplifies the structure of the illumination unit 110.

[0111] (9) Correspondence between the components in the claims and the units in the embodiments

[0112] In the following, the correspondence between the components in the claims and the units in the embodiments is explained. In the above-described embodiments, the measuring object S is an example of the measuring object, the light sources 111, 112, and 113 are examples of a plurality of light sources, the pattern generating section 118 is an example of a pattern generating section, the imaging processing section 131 is an example of a light projection control section, the imaging section 120 is an example of an imaging section, the image data generating section 132 is an example of an image data generating section, the inspection section 230 is an example of an inspection section, and the inspection device 300 is an example of an inspection device.

[0113] In addition, the light receiving lenses 122 and 123 are examples of light receiving lenses and light receiving optical systems, the first holding member 110a is an example of a holding member, the reflector 117 is an example of a reflecting member, the light generating surface 118S of the pattern generating unit 118 is an example of a light generating surface, the light projection lens 119 is an example of a light projection lens and a light projection optical system, the top surface of the belt conveyor 301 is an example of a placement surface, and the head shell 100c is an example of a shell.

[0114] As various components in the claims, other various elements having the structures or functions described in the claims may also be used.

Claims

1. An inspection device, comprising: A plurality of light sources configured to respectively emit a plurality of lights having mutually different wavelengths and to cause the emitted plurality of lights to travel in a preset common optical path; a pattern generating section disposed on the common optical path and configured to receive light traveling in the common optical path and selectively generate structured light and uniform light based on the received light, so that the generated structured light or uniform light travels in the common optical path and is projected onto a measurement object; a light projection control section configured to cause light to be emitted from at least one of the plurality of light sources, control the plurality of light sources and the pattern generation section to generate a plurality of structured lights using the light emitted from the at least one light source while shifting in phase, and control the plurality of light sources and the pattern generation section to sequentially generate a plurality of uniform lights each having a plurality of wavelengths from the plurality of light sources; an imaging unit configured to sequentially generate a plurality of pattern image data representing an image of the measuring object by sequentially receiving a plurality of structured lights reflected from the measuring object, and sequentially generate a plurality of texture image data representing an image of the measuring object by sequentially receiving a plurality of uniform lights reflected from the measuring object; an image data generating section configured to generate height data for representing a height image of the measurement object based on the plurality of pattern image data, and to generate color texture image data for representing an image of the measurement object using a plurality of colors corresponding to a plurality of wavelengths by synthesizing the plurality of texture image data; as well as An inspection section is configured to perform an inspection of the measurement object based on the height data and the color texture image data.

2. The inspection device according to claim 1, wherein: The plurality of light sources include a light source for emitting green light, a light source for emitting blue light, and a light source for emitting red light, and The light projection control section controls the plurality of light sources and the pattern generation section to emit green light, blue light, and red light from the plurality of light sources, and generates a plurality of structured lights while shifting phases using white light obtained from the emitted green light, blue light, and red light.

3. The inspection device according to claim 1, further comprising: a light receiving optical system configured to include a light receiving lens having an optical axis extending in the up-down direction and to guide the structured light or the uniform light reflected upward from the measuring object to the imaging section; a holding member configured to hold the plurality of light sources so that a plurality of lights respectively emitted from the plurality of light sources travel from an upper direction to a lower direction in the common optical path; as well as a reflecting member configured to reflect a plurality of lights respectively emitted from the plurality of light sources and traveling from an upper direction toward a lower direction in an obliquely upward direction to be away from an optical axis of the light receiving lens, The pattern generating portion includes a light generating surface for selectively generating structured light and uniform light by reflecting at least a portion of the plurality of lights reflected by the reflecting member in an obliquely downward direction to be closer to an optical axis of the light receiving lens.

4. The inspection device according to claim 3, further comprising a light projection optical system configured to include a light projection lens having an optical axis extending obliquely downward to be closer to the optical axis of the light receiving lens, and to guide the structured light or uniform light generated by the light generating surface to the measuring object, in, The measuring object is placed on a preset placement surface, and The pattern generating section and the light projection optical system are arranged so that the light generating surface and the placement surface of the pattern generating section follow the Scheimpflug principle with respect to a principal plane of the light projection optical system. 5 . The inspection device according to claim 4 , further comprising a housing configured to accommodate the plurality of light sources, the holding member, the reflecting member, the pattern generating section, the light projecting optical system, the light receiving optical system, and the imaging section.

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