Device and method for testing an object

Abstract

Device (201, 301) for testing an object (205), comprising: a first camera (101) for capturing a first image (607) of an object (205) to be examined located in an image field (105) of the first camera (101) with a first relative image resolution, a second camera (103) for taking a second image (617) of the object (205) to be examined, which is located in an image field (107, 303) of the second camera (103), with a second relative image resolution, where the second relative image resolution is greater than the first relative image resolution, Funding for moving the object to be tested (205) from the image field (105) of the first camera (101) to the image field (107, 303) of the second camera (103), a drive device (215) for driving the conveying means, a processor (217) which is designed to detect a feature (207) of the object (205) to be inspected in the first image (607), wherein the processor (217) is further configured to determine a test position for the conveying means, such that the detected feature (207) lies in the image field (107, 303) of the second camera (103) when the conveying means are in the test position, wherein the drive device (215) is designed to move the conveying means into the test position, wherein the second camera (103) is configured to capture a second image (617) of the object (205) with the second relative image resolution when the conveying means are in the test position, wherein the second image (617) includes the captured feature (207) so that the captured feature (207) can be tested based on the second image (617), characterized in that The conveying means are formed by a first carriage (401) movably arranged on a stationary running rail (203) and a second carriage (403) arranged on the running rail (203), which are driven by means of the drive device (215), wherein the drive device (215) is a linear motor drive device (215), wherein the first slide (401) is connected to a plate (405) by means of a first linear bearing (412) which defines a first linear displacement direction (417), on which the object (205) to be inspected can be arranged, and wherein the second slide (403) is connected to the plate (405) by means of a second linear bearing (414) which defines a second linear displacement direction (419), wherein the first (417) and the second displacement direction (419) form an angle greater than 0°, in particular an angle of 45°, so that by changing a distance between the two slides (401, 403) the plate (405) can be displaced relative to the two slides (401, 403), so that a cross table (415) is formed by means of the two slides (401, 403), the two linear bearings (412, 414) and the plate (405), wherein the processor (217) is configured to determine a respective inspection position for the two slides (401, 403), so that the detected feature (207) is displayed in the image field (107, 303) of the second camera (103) is located when the two carriages (401, 403) are in their respective test positions,wherein the linear motor drive unit (215) is designed to move the two slides (401, 403) into the respective test position.

Description

[0001] The invention relates to a device for testing an object. The invention further relates to a method for testing an object. The invention further relates to a computer program product.

[0002] A generic device for testing an object is known from US 6,236,735 B1. EP 0 554 811 B1 discloses a device for detecting printing defects in a rotary printing press. DE 10 2005 018 855 A1 discloses a device for inspecting printed products. WO 2014 / 117870 A1 discloses a measuring arrangement for inspecting a three-dimensional object. DE 10 2007 033 793 A1 discloses a device for microscopically examining a sample.

[0003] The object underlying the invention is to provide a concept for the efficient testing of an object.

[0004] This problem is solved by means of the respective subject matter of the independent claims. Advantageous embodiments of the invention are the subject matter of dependent claims.

[0005] A device for testing an object includes: - a first camera for capturing a first image of an object to be examined located in an image field of the first camera with a first relative image resolution, - a second camera for capturing a second image of the object to be inspected, which is located in the image field of the second camera, with a second relative image resolution, - where the second relative image resolution is greater than the first relative image resolution, - at least one carriage movably arranged on a stationary guide rail for moving the object to be inspected from the field of view of the first camera to the field of view of the second camera, - a linear motor drive device for driving at least one slide, - a processor trained to detect a feature of the object to be examined in the first image, - wherein the processor is further configured to determine a test position for the at least one slide, such that the detected feature lies in the image field of the second camera when the at least one slide is in the test position, - wherein the linear motor drive device is designed to move at least one slide into the test position, - wherein the second camera is configured to capture a second image of the object with the second relative image resolution when the at least one slide is in the inspection position, wherein the second image includes the captured feature so that the captured feature can be inspected based on the second image.

[0006] A procedure for testing an object using the object testing device comprises the following steps: - Capturing a first image of the object to be inspected with the first relative image resolution using the first camera, - Capturing a feature of the object to be inspected in the first image using the processor, - Determining a test position for at least one slide using the processor, such that the detected feature lies in the field of view of the second camera when at least one slide is in the test position, - Moving at least one slide into the test position using the linear drive device, - Taking a second image of the object to be inspected with the second relative image resolution using the second camera when at least one slide is in the inspection position, wherein the second image includes the captured feature, so that the captured feature can be inspected based on the second image.

[0007] A computer program product is stored in a medium usable in a computer, wherein the computer program product comprises computer-readable programming means by which a computer can perform the procedure for checking an object.

[0008] The second camera can capture images with a higher relative image resolution than the first camera. Therefore, the images captured with the second camera can be used more efficiently for examining the object, as they reveal more detail than images captured with the first camera.

[0009] The images from the first camera, however, can be used efficiently to capture an overview of the object without necessarily capturing all the details with the same high level of detail as the second camera. Furthermore, the images from the first camera can be used to identify a specific feature of the object, which can then be examined more closely, i.e., with a higher relative resolution, using the second camera.

[0010] This means, in particular, that the first camera serves to locate a specific feature of the object, while the second camera then takes an image of the feature.

[0011] The first camera can be described as an overview camera.

[0012] The second camera can be described as an inspection camera.

[0013] The linear motor drive device makes it possible to efficiently move the object from the field of view of the first camera to the field of view of the second camera, so that the feature captured by the first camera lies in the field of view of the second camera, allowing the second camera to record the captured feature.

[0014] This allows, for example, for dynamic adaptation of the inspection to the object being inspected. Regardless of the object's dimensions, the linear motor drive unit can always move the object into the field of view of the second camera (at least within the limits of the available degrees of freedom) so that the feature captured by the first camera lies within the field of view of the second camera.

[0015] This allows details in unknown components to be examined.

[0016] Since the first camera has a lower resolution compared to the second camera, and the second camera only captures relevant areas—in this case, the captured feature—data overhead can be efficiently kept low. This is because high-resolution images generally have a larger file size than relatively low-resolution images.

[0017] In particular, it is advantageous to capture a specific feature, which is to be recorded in high resolution by the second camera, efficiently and time-savingly using the processor in the first image. This is because, typically, evaluating an image of a defined image area with a lower relative resolution to capture a specific feature takes less time than evaluating an image of the same image area with a relatively higher relative resolution.

[0018] In particular, the use of the stationary guide rail, on which the carriage is movably arranged and which can be driven by means of the linear motor drive device, enables efficient positioning of the object both in the field of view of the first camera and in the field of view of the second camera with high spatial accuracy.

[0019] The phrase "at least one sled" includes in particular several sleds, especially two sleds.

[0020] The image field of the first camera can be specifically referred to as the first image field.

[0021] The image field of the second camera can be specifically referred to as the second image field.

[0022] An object within the meaning of the present invention is, for example, a component. More generally, the object can also be referred to as a test specimen.

[0023] The term "image resolution," specifically the first relative and / or second relative image resolution as used in this description, indicates a point density, also called pixel density. Point density is the resolution (in pixels, [px]) of a camera sensor (specifically the first and / or second camera) divided by the camera's field of view ([m]). Even if the term "image resolution" is used alone, without the suffix "relative," the suffix "relative" should always be understood as implied.

[0024] This means, in particular, that the first camera has a first sensor with a first sensor resolution. The first relative image resolution is then the first sensor resolution divided by the size of the first image field.

[0025] This means, in particular, that the second camera has a second sensor with a second sensor resolution. The second relative image resolution is then the second sensor resolution divided by the size of the second image field.

[0026] In one embodiment, the first sensor is a surface sensor or a line sensor.

[0027] In one embodiment, the second sensor is provided to be an area sensor or a line sensor.

[0028] In one embodiment, it is provided that the relative image resolution, i.e., in particular the first and / or the second image resolution, in a first dimension, for example in the x-direction, of a planar Cartesian coordinate system is different from the relative image resolution, i.e., in particular the first and / or the second image resolution, in a second dimension, for example in the y-direction, of the planar Cartesian coordinate system.

[0029] This means, in particular, that a relative image resolution in the x-direction can be different from a relative image resolution in the y-direction.

[0030] "Different" means smaller or larger.

[0031] For example, the pixel count of the first and / or second sensor in the x-direction differs from the pixel count of the first and / or second sensor in the y-direction.

[0032] This means, in particular, that the first sensor resolution in the x-direction can be different from the first sensor resolution in the y-direction. This also means, in particular, that the second sensor resolution in the x-direction can be different from the second sensor resolution in the y-direction.

[0033] For example, the sensor resolution of the first image field in the x-direction is intended to be different from the sensor resolution of the first image field in the y-direction. Similarly, the sensor resolution of the second image field in the x-direction is intended to be different from the sensor resolution of the second image field in the y-direction.

[0034] The above descriptions illustrate embodiments in which the relative image resolutions, image fields, and sensor resolutions can differ in the x-direction and the y-direction. It should be noted that in further embodiments, the term "different" can also be replaced by the term "same." This means, in particular, that the (first and / or second) relative image resolution in the x-direction can be equal to the (first and / or second) image resolution in the y-direction.

[0035] The main characteristic of the inspection camera (the second camera) is therefore not necessarily that it has a higher pixel count than the overview camera. Rather, the intention is that the pixel density, i.e., the relative image resolution, is higher. In fact, the pixel count of the second camera's sensor can even be lower than that of the first camera, and yet the second camera can still deliver more detailed images (i.e., images with a higher pixel density). In this case, this is achieved primarily through a specific lens to create a corresponding second field of view.

[0036] If both cameras each include an area sensor, the respective point density can differ in the x and y directions. To provide more detailed images, the relative image resolution, which, as explained above, can also be referred to as point density, of the second camera must be higher in at least one dimension. In one embodiment, the respective point density, i.e., the respective relative image resolution, of the second camera is higher in both dimensions, i.e., in both the x and y directions, than the corresponding point densities of the first camera.

[0037] In the case that both cameras each have a line sensor, the respective dot density in the line direction and direction of movement can differ, for example.

[0038] Even if only one of the two cameras is a line scan camera, i.e., a camera with a line sensor, it is provided, for example, that the respective dot density of the line scan camera is different in the line direction and direction of movement.

[0039] In one embodiment, the second camera is a line scan camera, wherein the point density of the second camera is higher in at least one direction than the corresponding point density of the first camera. The above descriptions relating to an area scan camera (camera having an area sensor) apply analogously to a line scan camera.

[0040] In one embodiment, the second camera is a line scan camera, wherein the respective point density of the second camera is higher than the corresponding point densities of the first camera in both the direction of movement and in the line direction.

[0041] Therefore, because the point density of the second camera is higher in at least one direction (x and / or y direction) than the corresponding point density of the first camera, the second camera can advantageously provide more detailed images than the first camera.

[0042] A camera that has an area sensor can also be called an area camera.

[0043] A camera having a line sensor can also be called a line camera.

[0044] If a sensor is described below or above, the corresponding statements should apply to both the first and the second sensor, even if this is not explicitly mentioned.

[0045] In one embodiment, the sensor is provided to be an optical sensor.

[0046] In one embodiment, the sensor is a depth sensor. This provides, for example, the technical advantage of being able to measure the distance to the object relative to the camera.

[0047] In one embodiment, the sensor is an ultrasonic sensor, a microwave sensor, or an X-ray sensor. The corresponding images are therefore ultrasonic images, microwave images, or X-ray images, respectively.

[0048] In one embodiment, the sensor is an imaging sensor.

[0049] In one embodiment, at least one of the two cameras, and in particular both cameras, comprises multiple sensors. These multiple sensors are configured, for example, like one of the sensors described above. If there are multiple sensors, they may be configured differently or identically.

[0050] In one embodiment, at least one of the two cameras, in particular both cameras, is designed as a stereo camera.

[0051] In one embodiment, a laser triangulation device is provided, which is designed for laser triangulation. This allows, for example, the advantageous measurement of a distance from the first and / or the second camera to the object.

[0052] In the case of a line sensor, one embodiment provides that the object is moved through the image field of the corresponding line camera by means of at least one carriage, while the corresponding line camera captures an image. The speed of the at least one carriage is preferably constant and / or at least predetermined during the process, i.e., known.

[0053] This means, in particular, that the object is moved through the first image field of the first camera by means of at least one carriage having a line sensor, whereby the first camera detects the object by means of the line sensor while the object is moved through the first image field, and takes the first image based on the detection.

[0054] This means, in particular, that the object is moved through the second image field of the second camera by means of at least one carriage having a line sensor, whereby the second camera detects the object by means of the line sensor while the object is moved through the second image field, and takes the second image based on the detection.

[0055] The speed is determined, for example, by means of the processor. The linear motor drive unit is specifically designed to move at least one carriage through the first and / or the second image field at the determined speed.

[0056] In one embodiment, a so-called "ROI" area is defined for at least one of the two cameras, and in particular for both cameras, whereby only pixels of the sensor corresponding to the ROI area are read out. "ROI" stands for "Region of Interest" and can be translated as "area of ​​interest." The ROI area of ​​the first camera can also be referred to as a first area of ​​interest. The ROI area of ​​the second camera can also be referred to as a second area of ​​interest.

[0057] By providing a ROI range, for example, the technical advantage is achieved that the effort required for data transmission, storage and processing can be efficiently reduced.

[0058] Furthermore, it is possible, and in one embodiment provided for, to adjust the ROI of the second camera depending on the data acquired by the first camera. For example, if a feature of a certain size is detected using the first camera, such as a hole with a specific diameter, the ROI of the second camera can be adjusted to the detected size of this feature when capturing a detailed image of it. Thus, a detected feature receives an optimal ROI, typically slightly larger than the feature itself, which again leads to increased efficiency in image processing.

[0059] A feature within the meaning of the present invention is, for example, a bore, in particular a through bore. A bore can also be referred to as a drilled hole.

[0060] In particular, the processor is designed to capture several features of the object under inspection in the first image. The statements made in connection with one feature apply analogously to multiple features.

[0061] The captured features may be different or identical. For example, several holes are captured in the first image. The second camera then takes multiple images of these holes with a second relative image resolution to inspect them.

[0062] According to one embodiment, the image field of the second camera is smaller than the image field of the first camera.

[0063] This results in the particular technical advantage of efficiently reducing the storage requirements for images taken with the second camera.

[0064] It is provided that a first and second slide are arranged to be movable on the guide rail, wherein the first slide is connected to a plate on which the object to be tested can be arranged by means of a first linear bearing which defines a first linear displacement direction, and wherein the second slide is connected to the plate by means of a second linear bearing which defines a second linear displacement direction, wherein the first and the second displacement directions form an angle greater than 0°, in particular an angle of 45°, so that by changing a distance between the two slides the plate can be moved relative to the two slides, so that a cross table is formed by means of the two slides, the two linear bearings and the plate, wherein the processor is configured to determine a respective test position for the two slides.so that the detected feature lies within the field of view of the second camera when the two carriages are in their respective test positions, wherein the linear motor drive device is designed to move the two carriages into their respective test positions.

[0065] This results in the particular technical advantage of enabling efficient positioning of the object being tested. Specifically, it allows the object to be advantageously shifted or moved within a plane, the plane of the cross table. This efficiently achieves a high degree of freedom.

[0066] Since the positions of the two slides in a linear motor drive device can usually be determined efficiently and with high accuracy, it is advantageously possible to move the object to be tested into a specific position with high accuracy.

[0067] According to a further embodiment, the second displacement direction is provided to run orthogonally to a direction of travel specified by means of the running rail.

[0068] This results in the particular technical advantage of enabling efficient movement of the cross table. Specifically, it advantageously allows the second linear bearing to efficiently support, i.e., guide, the movement of the plate perpendicular to the direction of travel.

[0069] In a further embodiment, it is provided that the two linear bearings each comprise a bearing slide and a linear guide guided in the respective bearing slide, wherein the bearing slide of the first linear bearing is arranged on the first slide and the linear guide of the first linear bearing is arranged on the plate or vice versa, wherein the bearing slide of the second linear bearing is arranged on the second slide and the linear guide of the second linear bearing is arranged on the plate or vice versa.

[0070] This results in the particular technical advantage of enabling efficient relocation of the plate.

[0071] According to a further embodiment, the second camera has a line sensor comprising several pixels, wherein the processor is configured to identify those pixels of the line sensor that capture the detected feature in the image field of the second camera, and wherein the processor is configured to read out only the identified pixels of the line sensor when the detected feature is located in the image field of the second camera.

[0072] This results in the particular technical advantage of efficiently reducing the amount of data. Specifically, this means that the storage requirements for the second image can be significantly reduced. This is because pixels that cannot capture the desired feature are not read.

[0073] According to a further embodiment, a first lighting device is provided for illuminating the object with a first illumination light when the object is in the image field of the first camera, and a second lighting device is provided for illuminating the object with a second illumination light when the object is in the image field of the second camera.

[0074] This results in the particular technical advantage of efficient image capture. This allows for efficient adjustment of shooting conditions, especially lighting, ensuring sufficient brightness, which in turn effectively reduces image noise in the captured images.

[0075] According to a further embodiment, it is provided that the first and / or the second lighting device each comprise an incident light illumination for illuminating the object with incident light, wherein the respective incident light illumination is designed as a bright-field illumination and / or as a dark-field illumination, so that the first camera and / or the second camera can take an incident light bright-field image of the object and / or an incident light dark-field image of the object.

[0076] This results in the particular technical advantage that the properties of the feature can be efficiently recorded.

[0077] According to a further embodiment, it is provided that the first and / or the second lighting device each comprise a transmitted light illumination for illuminating the object with transmitted light, wherein the respective transmitted light illumination is designed as a bright-field illumination and / or as a dark-field illumination, so that the first camera and / or the second camera can take a transmitted light bright-field image of the object and / or a transmitted light dark-field image of the object.

[0078] This results in the particular technical advantage that the properties of the recorded characteristic can be efficiently captured.

[0079] The properties of a feature include, for example, its size (dimensions) and / or roundness. This means, for instance, that the diameter of a bore is checked. Specifically, the roundness of a bore is tested. By using different types of illumination (dark-field illumination as transmitted or reflected light, and / or bright-field illumination as transmitted or reflected light), different properties of a feature, or different features in general, can be optimally captured for efficient imaging.

[0080] According to another embodiment, the first and / or the second lighting device is designed to illuminate the object using UV light and / or IR light.

[0081] This results in the particular technical advantage that details of the feature can be efficiently captured.

[0082] According to a further embodiment, it is provided that the first and / or the second lighting device is designed to illuminate the object by means of a pulsed light.

[0083] This provides the particular technical advantage of efficiently reducing the influence of ambient light.

[0084] According to one embodiment, the second lighting device is designed to illuminate the object depending on the detected feature.

[0085] This provides the particular technical advantage of efficiently illuminating the object, allowing the feature to be efficiently captured using the second camera, thus enabling subsequent efficient inspection of the feature.

[0086] Depending on the feature or property to be tested, one of the illuminations described above (incident light, transmitted light, bright field, dark field) is used to illuminate the feature.

[0087] For example, the object includes a UV code as a feature, meaning a code that is only visible under UV light. In this case, it is planned, for instance, that the object will be illuminated with UV light when the second camera takes a picture of it.

[0088] For example, the feature is a bore that is illuminated with transmitted light when the second camera takes an image of the object.

[0089] According to another embodiment, the first and second cameras are each configured to capture a calibration image of a calibration object having a reference feature, wherein the processor is configured to detect the reference feature in the respective calibration image, and wherein the processor is further configured to determine a respective transformation matrix for converting image coordinates of the first and second cameras into world coordinates based on the respective detected reference feature.

[0090] For example, the calibration provides the technical advantage that the test position can be approached with high accuracy.

[0091] According to a further embodiment, the processor is designed to detect a different feature of each of the objects, each having several features, in successive inspections, where the objects should be identical, in the first images of the objects taken by means of the first camera, and to determine corresponding inspection positions for the at least one slide.

[0092] This results in the particular technical advantage that the multiple objects can be checked efficiently and in a time-saving manner.

[0093] This means that, especially for objects with multiple holes, only one hole is inspected for each object, with a different hole being inspected for each object. This allows, for example, checking whether the drill bits used by the drilling machine that created the holes in the objects are defective, such as broken. The inspection process is designed so that after each object has been inspected, at least one drill bit has been indirectly tested.

[0094] In another embodiment, it is provided that one or both cameras are arranged in a stationary position.

[0095] This results in the particular technical advantage of enabling an efficient arrangement of the cameras. Specifically, this results, for example, in the efficient setup of cable routing for the cameras.

[0096] According to a further embodiment, the processor is configured to determine the spatial position of the object based on the first image of the object, and the processor is further configured to determine the test position based on the determined spatial position.

[0097] This results, for example, in the technical advantage that the test position can be determined efficiently.

[0098] According to one embodiment, the device is designed or configured to perform or carry out the procedure for testing an object.

[0099] The technical functionalities of the device for testing an object result analogously from corresponding technical functionalities of the method for testing an object and vice versa.

[0100] This means that device features result from corresponding process features and vice versa.

[0101] According to one embodiment, it is provided that the at least one slide, in particular the two slides, comprises one or more permanent magnets which are operatively connected to the linear motor drive device.

[0102] In one embodiment, the linear motor drive unit comprises several coils connected in series, each of which can be individually energized. When a coil is energized, local magnetic fields are generated, creating a force flow between the coil and the permanent magnet(s) of the carriage. By intelligently controlling and energizing the individual coils, a "traveling" magnetic field can be generated, which can move each individual carriage independently of the others.

[0103] The coils are arranged along the running rail, for example.

[0104] According to one embodiment, the at least one slide comprises one or more rollers that can roll or do roll on one or more running surfaces of the track.

[0105] According to one embodiment, the guide rail is mounted on the linear motor drive unit.

[0106] This results, for example, in the technical advantage of creating an efficient flow of power.

[0107] A computer program product is understood to be, in particular, a computer program stored on a medium. The medium is, for example, a CD, a DVD, a ROM, a RAM, a BD (Blu-ray Disc), or an electronic device.

[0108] A computer program product is understood to be, in particular, an embedded system with a computer program, for example, an electronic device with a computer program.

[0109] A computer program product is understood to be, in particular, a computer on which a computer program is loaded, for example running, preferably stored, executed, or developed.

[0110] In one embodiment, it is provided that the detected feature is checked based on the second image.

[0111] The inspection process includes, in particular, a target-actual comparison. This means that it is checked whether the feature depicted in the second image corresponds to a reference feature. For example, the diameter of a hole is determined based on the second image, and the determined diameter is compared to a reference diameter. Similarly, the roundness of a hole is determined based on the second image, and the determined roundness is compared to a reference roundness.

[0112] In one embodiment, the processor is configured to check the detected feature based on the second image. The processor is specifically designed for a target-actual comparison. For example, the processor is configured to determine the diameter of a bore based on the second image and compare the determined diameter with a reference diameter. Similarly, the processor is configured to determine the roundness of a bore based on the second image and compare the determined roundness with a reference roundness.

[0113] In one embodiment, the processor is designed to detect an object type, object material, or object property based on the first image.

[0114] In one embodiment, the second lighting device is designed to illuminate and record the object depending on the type of object detected, the object material detected, or a detected object property.

[0115] In one embodiment, it is provided that one or more recording parameters of the second camera are adapted or set depending on the type of object being recorded, the object material being recorded, or a property of the object being recorded.

[0116] In one embodiment, the processor is designed to adapt or set one or more recording parameters of the second camera, depending on the type of object detected, the object material detected, or a detected object property.

[0117] The one or more recording parameters of the second camera include, for example, an exposure time and / or an aperture and / or a sensor sensitivity.

[0118] The term “respectively” includes in particular the term “and / or”,

[0119] The invention will be explained in more detail below with reference to preferred embodiments. Here, we will show... Fig. 1 a first and a second camera, Fig. 2 a first device for testing an object, Fig. 3 a second device for testing an object, Fig. 4 a cross table in first position, Fig. 5 the cross table according to Fig. 4 in a second position, Fig. 6. A flowchart of a procedure for testing an object, Fig. 7 a top view of a calibration object and Fig. 8 a perspective view of the calibration object according to Fig. 7.

[0120] The same reference symbols can be used for identical features in the following.

[0121] Fig. Figure 1 shows a first camera 101 and a second camera 103, as they can be used for a device for checking an object and for a method for checking an object, respectively, as described above and below.

[0122] The first camera 101 has an image field 105. The image field 105 of the first camera 101 can also be referred to as a first image field in the following.

[0123] The second camera 103 also has an image field 107. The image field 107 of the second camera 103 can be referred to below as a second image field.

[0124] The first image field 105 of the first camera 101 is larger than the second image field 107 of the second camera 103.

[0125] The first camera 101 has a first relative image resolution. This means that the first camera 101 can capture images with the first relative image resolution.

[0126] The second camera 103 has a second relative image resolution. This means that the second camera 103 can capture images with the second relative image resolution.

[0127] The second relative image resolution is higher than the first relative image resolution. This means that the second camera 103 has a higher resolution compared to the first camera 101.

[0128] In contrast, the first camera 101, due to its larger field of view, can capture more of an object or even the object as a whole compared to the second camera 103.

[0129] Therefore, the first camera, 101, can also be described as an overview camera. The second camera, 103, can also be described as an inspection camera.

[0130] According to one embodiment, at least one of the two cameras 101, 103, in particular both cameras 101, 103, are arranged in a stationary position.

[0131] In a further embodiment, it is provided that at least one of the two cameras 101, 103, in particular both cameras 101, 103, are arranged in a mobile manner.

[0132] It is intended that the first camera 101 will take a first picture of an object to be inspected when it is located in the first image field 105 of the first camera 101.

[0133] Furthermore, it is provided that the second camera 103 takes a second picture of the object to be inspected if it is located in the second image field 107.

[0134] The two image fields 105, 107 are formed separately from each other, therefore they do not overlap, i.e. they are non-overlapping.

[0135] Thus, it is provided that the object to be tested, which can generally and in the following also be referred to as a test specimen, is moved from the first image field 105 to the second image field 107 after the first image has been taken by means of the first camera 101.

[0136] For this movement, at least one carriage, and in particular two carriages, are provided, which can be moved on a stationary guide rail. The carriage(s) are driven by means of a linear motor drive unit.

[0137] Fig. Figure 2 shows a first device 201 for testing an object in a schematic top view.

[0138] The device 201 comprises the first camera 101 and the second camera 103, as described above in connection with the Fig. 1 are described. For clarity, the two cameras 101 and 103 are in the Fig. 2 not shown. Only the respective image fields 105 and 107 are shown.

[0139] The first device 201 further comprises a guide rail 203, which is fixedly arranged. Two carriages (not shown) are movably arranged on the guide rail 203.

[0140] The first image field 105, for example, is dimensioned such that it completely covers one width of the guide rail 203. The second image field 107, for example, is dimensioned such that it is smaller than one width of the guide rail 203.

[0141] Using the two cameras 101, 103, a first and second image of an object 205 to be examined are taken respectively.

[0142] The test specimen 205 comprises four bores 207.

[0143] The first image field 105 is, for example, dimensioned such that the test specimen 205 can be completely captured by the first camera 101.

[0144] The second image field 107 is dimensioned, for example, in such a way that the test subject 205 can only be partially captured by the second camera 103.

[0145] The test specimen 205 can be moved in a first displacement direction 211. The test specimen 205 can be moved in a second displacement direction 213, the second displacement direction being perpendicular to the first displacement direction 211. The manner in which this is achieved will be described below in connection with the Fig. 4 and Fig. 5 described in detail.

[0146] One direction of travel for the carriages on the track 203 is symbolically indicated by an arrow with the reference symbol 209. The carriages can also be moved in the opposite direction to the arrow 209. The first displacement direction 211 runs parallel to the direction of travel 209.

[0147] To drive the carriages, the first device 201 comprises a linear motor drive unit 215. The linear motor drive unit includes, for example, several coils arranged in series along the guide rail 203, which can be individually energized. The carriages each include, for example, one or more permanent magnets. When an energized coil is powered, local magnetic fields are generated, thus creating a force flow between the coil and the permanent magnet(s) of the carriage. By intelligently controlling and energizing the individual coil, a "traveling" magnetic field can be generated, which can move one of the carriages independently of the other carriages.

[0148] The device 201 further comprises a processor 217.

[0149] The following measures are specifically planned to examine candidate 205.

[0150] The first camera 101 takes a first picture of the test subject 205 when it is located in the first image field 105.

[0151] Processor 217 evaluates the first image and performs, for example, an image analysis of the first image. The goal of this image analysis is, in particular, to detect or record the four bores 207. These four bores 207 are therefore features of the test specimen 205 that are to be checked. For example, the roundness of the four bores 207 is to be checked. For example, the diameter of the four bores 207 is to be checked.

[0152] The second camera 103, the inspection camera, is used for this inspection. It can record the boreholes 207 at a higher resolution than the first camera 101, so that details, in this case the boreholes 207, are more clearly visible compared to the images taken with the overview camera, i.e., the first camera 101.

[0153] However, since the image field 107 of the second camera 103 is not large enough to capture all four bores 207 in a single image, the four bores 207 must be moved one after the other into the second image field 107. The two carriages are provided for this purpose.

[0154] Based on the bores 207 detected in the first image, the processor 217 determines a test position for each of the two slides, so that when the two slides are in their test position, one of the bores 207 lies in the second image field 107.

[0155] By means of the linear motor drive unit 215, the two slides are moved one after the other into their respective test position, so that a second image of the respective bore 207 is taken by means of the second camera 103.

[0156] Based on the second images of the bores 207, a verification of these bores 207 can then be carried out, for example by means of a target-actual comparison, so that ultimately an efficient test of the test specimen 205 can be carried out.

[0157] Fig. Figure 3 shows a second device 301 for testing an object in a schematic top view.

[0158] Device 301 is essentially designed analogously to device 201 according to Fig. 2.

[0159] One difference is that device 301 includes an inspection camera, i.e., a second camera, which has a line-shaped image field. This image field is in Fig. 3 is marked with reference numeral 303. This means that in the device 301 according to Fig. 3 the second camera is a line scan camera, i.e. it has a line sensor.

[0160] In this case, the second image field 303 extends over the entire width of the guide rail 203, whereby in an embodiment not shown it may be provided that the image field 303 is shorter than the width of the guide rail 203.

[0161] For example, it is intended that only those pixels of the line sensor that can detect a bore 207 are read by the processor 217. This means that those pixels of the line sensor that do not detect a bore 207 are not read by the processor 217. This significantly speeds up the inspection process and allows it to be carried out more efficiently.

[0162] Fig. Figure 4 shows a schematic top view of the two slides of the device 201 and 301 respectively, by means of which the test specimen 205 is moved both longitudinally (corresponding to the direction of movement 211 according to Fig. 2 and Fig. 3) as well as transversely (corresponds to the direction of movement 213 according to the Fig. 2 and Fig. 3) can be shifted relative to the direction of travel 209.

[0163] It should be noted here that the exemplary embodiments described above and below are explained with reference to test specimen 205. Test specimen 205 does not imply any limitation. Other test specimens may also be used in the explained exemplary embodiments. Test specimen 205 should therefore be considered a placeholder for illustrative purposes. For example, an object to be tested may have more or fewer than four bores.

[0164] For moving the test specimen 205, a first slide 401 is provided, which is movably arranged on the guide rail 203. Furthermore, a second slide 403 is provided, which is also movably arranged on the guide rail 203. Both slides 401, 403 can be moved by means of the linear motor drive unit 215 (in Fig. 4 and Fig. 5 (not shown) are driven and thus moved.

[0165] Furthermore, a plate 405 is provided on which the test specimen 205 can be arranged.

[0166] A first bearing slide 407 is arranged on the first slide 401. A first linear guide 411 is arranged on the underside of the plate 405, i.e., on the side of the plate 405 facing the two slides 401 and 403, and can be guided by means of the first bearing slide 407. This means that the first linear guide 411 is guided linearly within the first bearing slide 407.

[0167] Thus, a first linear bearing 412 is formed from the first bearing slide 407 and the first linear guide 411, which connects the first slide 401 with the plate 405.

[0168] A second bearing slide 409 is provided on the second slide 403. A second linear guide 413 is provided on the underside of the plate 405, which is guided linearly in the second bearing slide 409.

[0169] Thus, a second linear bearing 414 is provided, formed from the second bearing slide 409 and the second linear guide 413, which connects the second bearing slide 409 with the plate 405.

[0170] This means that the plate 405 is supported by means of the two linear bearings 412, 414 respectively on the two slides 401, 403.

[0171] The two linear bearings 412 and 414 thus provide for two linear displacement directions. The first linear bearing 412 defines a first linear displacement direction 417. The second linear bearing 414 defines a second linear displacement direction 419.

[0172] The second direction of movement 419 is provided for to run orthogonally or perpendicularly to the direction of travel 209, which is defined by the guide rail 203. The first direction of movement 417, defined by the first linear bearing 412, forms an angle of 45° with the second direction of movement 419.

[0173] If the distance between the two carriages 401, 403 changes, the plate 405 is forced to deflect laterally via the first linear guide 411. The second linear guide 413 supports this lateral deflection, so that the plate is deflected laterally relative to the direction of travel 209.

[0174] This lateral deflection or evasive movement is symbolically indicated by an arrow with the reference numeral 421.

[0175] Thus, a cross table 415 is formed by means of the plate 405 and the two linear bearings 412, 414.

[0176] The cross table 415 can be moved by changing the distance between the two slides 401, 403.

[0177] Fig. Figure 5 shows a schematic top view of the cross table 415 in relation to the in Fig. The distance between the two slides 401 and 403 shown in position 4 is smaller than in the other position. Fig. The distance shown is 4. Plate 405 has moved upwards relative to the plane of the paper.

[0178] This means that during synchronous movement of the two slides 401, 403, the plate 405 is only moved in the direction of travel 209. Thus, the test specimen 205 can move in the first displacement direction 211, as in Fig. 2 and Fig. 3. The procedure is shown using the corresponding arrow.

[0179] However, if the distance between the two slides 401, 403 is changed, the plate is displaced orthogonally to the direction of travel 209, i.e., in the direction of movement 421. Thus, the test specimen 205 can be moved along the second displacement direction 213, as in Fig. 2 and Fig. 3 can be symbolically represented by the double arrow and moved.

[0180] Thus, any desired position can be reached within the scope of a corresponding travel or displacement path of the two linear bearings 412, 414. This advantageously enables the four bores 207 of the test specimen 205 to be moved successively into the second image field 107 or 303 of the second camera 103.

[0181] The positions that the two slides 401, 403 must move to in order to reach these positions for the four bores 207 in the second image field 107 and 303 respectively are referred to here as test positions, whereby these test positions are determined by the processor 217 (in the Fig. 4 and Fig. 5 (also not shown) are determined or calculated based on an image analysis of the images taken by the overview camera 101 of the test subject 205.

[0182] In one embodiment, it is provided that at least one, in particular both, of the cameras 101, 103 is a monochrome camera, i.e., for example, has a monochrome sensor.

[0183] In a further embodiment, it is provided that at least one, in particular both, of the cameras 101, 103 is a color camera, i.e., for example, includes a color sensor.

[0184] In one embodiment, at least one, and in particular both, of the two cameras 101, 103 comprise a telecentric lens for imaging the object to be inspected onto the image sensor of the respective camera. In particular, the second camera 103 has such a telecentric lens.

[0185] A telecentric lens is a lens that always renders an object the same size within a defined depth of field, regardless of distance. Telecentric lenses typically exhibit minimal distortion, making them ideal for measurement and inspection applications. The primary reason for this is that the lens's entrance pupil is located at infinity, ensuring that the principal rays of a light beam travel parallel to the optical axis within the object space.

[0186] A particularly important advantage of telecentric lenses is that they do not exhibit perspective distortion.

[0187] According to one embodiment, incident light illumination is provided to illuminate the bores 207 using incident light.

[0188] In another embodiment, transmitted light illumination is provided to illuminate the bores 207 by means of transmitted light.

[0189] This means that the boreholes 207, for example, are illuminated using reflected light or transmitted light.

[0190] To efficiently detect the boreholes 207, indirect brightfield illumination is provided, for example. A ring light can be used for this purpose.

[0191] For example, instead of or in addition to indirect brightfield illumination, darkfield illumination is provided to illuminate the bores 207.

[0192] This means, in particular, that at least one of the lighting methods described above is required for taking the first or second image.

[0193] In one embodiment, a flash, for example a pulsed light, is used to capture the first and second images, respectively. This efficiently minimizes the influence of ambient light during image capture. Furthermore, it advantageously increases the lifespan and maximum power or luminous intensity of the light source.

[0194] Fig. Figure 6 shows a flowchart of a procedure for testing an object using the device 201 or 301 for testing an object.

[0195] The procedure starts with the element with reference numeral 601.

[0196] According to step 603, the cross table 415 is moved into the first image field 105 of the first camera 101 by means of synchronous movement of the two carriages 401, 403, so that the test specimen 205 is located, for example, in the center of the image field 105 of the first camera 101. In an embodiment not shown, step 603 provides for an asynchronous movement of the two carriages 401, 403 instead of or in addition to the synchronous movement. This allows, for example, the technical advantage that the test specimen can be moved transversely to the direction of movement into the image field 105 of the first camera 101.

[0197] In step 605, it is provided that a first image of the test object 205 is taken using the first camera 101. This means that in step 605 an image of the test object 205 is created or generated. Thus, a first image 607 of the test object 205 is available.

[0198] According to step 609, processor 217 performs image processing of the first image 607 to capture the four bores 207 as features of the test piece 205. Processor 217 determines, for example, the respective coordinates of the bores 207. Processor 217 also determines test positions for the two slides 401 and 403, such that one of the bores 207 is always located in the second image field 107 or 303 of the second camera 103 when the two slides 401 and 403 are in their test positions.

[0199] Step 609 therefore includes a step 609a (not represented by a separate element) in which the processor 217 detects the four bores 207 of the test specimen 205 based on the first image 607.

[0200] Step 609 further includes a step 609b (not shown by means of a separate element) in which the processor 217 determines a respective test position for the two carriages 401, 403, such that one of the bores 207 lies in the second image field 107 or 303 of the second camera 103 when the two carriages 401, 403 are in the respective test position.

[0201] Step 609 thus provides the test positions 611 as a result, in order to move the four bores 207 one after the other into the second image field 107 or 303 respectively.

[0202] In step 613, it is provided that the two slides 401, 403 are driven or moved to those test positions in which a first of the four bores 207 is located in the second image field 107 or 303 of the second camera 103.

[0203] In step 615, a second image is then taken using the second camera 103 to obtain a second image 617 of the first of the four bores 207.

[0204] In step 619, further image processing of the second image 617 takes place using processor 217. This step 619 also includes an inspection of the corresponding bore. Thus, one result of step 619 is an inspection result 621. Such an inspection result includes, for example, the result of a target-actual comparison. Processor 217 determines, for example, the diameter or roundness of the first of the four bores 207 and compares this or this with a reference diameter or reference roundness.

[0205] In a subsequent step 623, it is checked whether further test positions need to be visited, i.e., whether further boreholes need to be recorded using the second camera 103. If it is determined in step 623 that further test positions need to be visited, the next test positions are selected in step 625, and the procedure is continued in step 613.

[0206] If, in step 623, it was determined that all test positions had been reached, meaning that the four bores 207 had also been recorded by the second camera 103, the two slides 401, 403 are moved to a predetermined end position in step 627. This means that the test specimen 205 is moved to the predetermined end position. In an embodiment not shown, it is provided that, after all test positions have been reached, the test specimen 205 is removed from the cross table 415, for example, by means of a picker. The test specimen 205 can then, for example, be further processed.

[0207] In one embodiment, the guide rail forms a closed curve, for example a circle.

[0208] The individual test results 621 are then provided as a total test result 629.

[0209] The procedure ends at the element with reference numeral 631.

[0210] According to one embodiment, bright-field illumination is provided for the overview camera 101, by means of which the object is illuminated. In particular, according to one embodiment, monochrome dark-field illumination is provided for the inspection camera 103, which can advantageously highlight the contours of bores efficiently.

[0211] In one embodiment, both lights are pulsed.

[0212] In reflected light darkfield imaging, the contour of a borehole opening, including any defects, is particularly efficient at being identified, detected, or captured by the processor in the corresponding image. Everything inside the borehole typically remains invisible in reflected light darkfield imaging. In brightfield imaging, defects within the borehole are efficiently identified, detected, or captured based on the contour in the corresponding image. The choice of specific illumination depends, for example, on the objective, i.e., what is to be detected. The term "contours of boreholes" specifically refers to "contours of the openings of boreholes."

[0213] In summary, the cross table 415 is moved into the first image field 105 of the overview camera 101 by simultaneously moving both carriages 401 and 403, so that the test piece 205 is located, for example, in the center of the first image field 105. A first image is then captured, in which the bores 207 are located, and from this, the coordinates (inspection positions) to be approached in the second image field 107 of the inspection camera 103 are calculated. Subsequently, the test piece is moved to the first determined target coordinates by means of a corresponding movement of the two carriages 401 and 403, at which point the inspection camera 103 captures a second image of the bore, which has a higher resolution than the first image. This second image is analyzed, and the coordinates of the next bore are then approached. This process is repeated for each bore.For example, a target-actual comparison is carried out, the results of which are entered, for example, in the first image, whereby the test object is moved to a defined end position.

[0214] Fig. Figure 7 shows a calibration object 701 in a top view. Fig. Figure 8 shows the calibration object 701 in a perspective view from a slanted top view.

[0215] Using such an exemplary calibration object 701, for example, a respective transformation matrix is ​​determined for converting image coordinates of the first and second cameras into world coordinates.

[0216] The calibration object 701 comprises four bores 703 with a first diameter and four second bores 705 with a second diameter, the second diameter being smaller than the first diameter. The diameters and positions of the bores 703 and 705 are known. In one embodiment not shown, the first diameter is smaller than or equal to the second diameter. For example, in another embodiment not shown, a mask is used so that the overview camera uses the outer holes for calibration instead of, as in the illustrated embodiment, performing the calibration via the hole sizes, i.e., the diameters.

[0217] Distances 707, 709 between boreholes 703 and distances 711, 713 between boreholes 705 are also known.

[0218] The calibration object 701 is captured analogously to a test specimen 205 using the two cameras 101 and 103, whereby the position and diameter of the bores 703 and 705 are determined in the correspondingly captured images using the processor. If the diameters and positions of the bores 703 and 705 are known, a transformation matrix from image coordinates to world coordinates can thus be efficiently determined.

[0219] This transformation matrix is ​​then used for an object to be tested, where the diameters or the positions of the holes need to be checked.

[0220] In another embodiment, further calibration (including correction of lens distortion in a camera lens) is provided. For this purpose, for example, a calibration object with a checkerboard pattern is used.

[0221] In summary, the invention provides a concept for the efficient inspection of an object using, for example, two slides that are movably arranged on a guide rail and can be moved by means of a linear motor drive. In particular, a plate is provided which is connected to the two slides by means of two linear bearings, thus forming a cross table as described above. Two cameras are used for the inspection. The first camera is specifically responsible for locating the holes in the test object. By converting (using the transformation matrix) the hole coordinates determined in pixels in the image coordinate system into the world coordinate system, it is advantageously possible to center the individual holes in the field of view of the second camera by correspondingly moving the slides to the target positions (inspection positions).Using the second camera, which, for example, has a smaller field of view but a higher sensor resolution, the holes can be individually examined, for example, with regard to their diameter and / or roundness. In particular, the system is designed to determine the position of a hole's center point based on the second image and compare or calculate it with the position value already determined by the first camera. This advantageously enables a target-actual comparison, the results of which can be clearly presented to the user.

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