EP4176580A1

EP4176580A1 - Modular multi-camera system

Info

Publication number: EP4176580A1
Application number: EP21742082.7A
Authority: EP
Inventors: Lothar Howah; Marco BRINKER
Original assignee: Xaptec GmbH
Current assignee: Xaptec GmbH
Priority date: 2020-07-06
Filing date: 2021-07-05
Publication date: 2023-05-10
Also published as: WO2022008425A1; DE102020117791A1

Abstract

The invention relates to a modular multi-camera system (30) for industrial image processing, comprising at least one beam-shaped girder section (31) and a plurality of equipping modules (20, 40, 41) fastened thereto, at least some of said equipping profiles being camera modules (20) which each have an image sensor (6a, 6b) and a lens (21). The equipping modules (20, 40, 41) are individually arranged in removable fashion at discrete module positions on the outside of the girder profile (31) and are able to be strung together so as to be flush. Moreover, in the direction of the longitudinal axis (39) of the girder profile (31), they have a width corresponding to one or more base units (B). Moreover, the invention relates to a method for positioning the equipping modules (20, 40, 41) on the beam-shaped girder section (31), within the scope of which they are individually arranged in removable fashion at discrete module positions on the outside of the girder profile (31) by virtue of being placed flush against one another or by virtue of being aligned with markings on the girder profile (31) along the longitudinal axis (39) thereof or by virtue of being put into a latching connection at the module position.

Description

Modular multi-camera system

The invention generally relates to a contribution to the optimization of production processes. In particular, the invention relates to a multi-camera system for industrial image processing with at least one beam-shaped carrier profile and a plurality of camera modules with image sensor and lens mounted thereon, and a method for positioning the modules.

The optimization of industrial production processes is a concrete challenge from the multitude of all applications of industrial production measurement technology and offers as a result the reduction of rejects or the primary raw materials used as well as secondary factors such as energy use and environmental pollution. With the use of powerful measurement methods, an increase in quality and productivity of the production facilities is aimed at, which is reflected in an increase in profitability, international competitiveness and job security.

In the control or quality control of industrial systems, an elementary task is often to inspect the surface of an object or to determine a dimensional variable such as an object dimension or a relative position of the object in relation to a reference point and to compare it with a reference variable, for example to check compliance with tolerances or to detect faulty objects. Primary dimensional measurements such as the position, length, width or height of the object are used to determine secondary quantities such as area, volume, dimensional accuracy, completeness or the like. Solving these metrological tasks quickly and without contact, and therefore without wear, is one of the features of a special technology that uses cameras to record images of a measurement object in a scene and evaluates them using methods and algorithms of digital image data processing. Technologies of this type are summarized under the title industrial image data processing (IIP) and have a wide range of technical applications.

A simple machine vision camera system 1 for measuring and checking a measurement object 2a is shown in FIG. The object 2a is captured by a camera 3 whose image data is transmitted to an evaluation computer 5 via a data line 4 . Appropriate software runs on the evaluation computer 5 for the use, in particular the evaluation, of the image data. The camera 3 is a digital camera and forms the combination of an image sensor with an optical imaging system (lens) and digital evaluation and transmission electronics, which result in a sub-functional unit in a camera housing. CCD or CMOS image sensors are predominantly used as image sensors 6a, 6b. The image data from the camera 3 are transmitted via standard interfaces such as GigE, USB, CoaX, IEEE1384, etc. using standardized protocols (e.g. GeniCam, etc.). A large number of software packages, so-called machine vision libraries, with the appropriate algorithms are available on the market for digital image data evaluation, such as the proprietary HALCON program library developed by MVTec Software GmbH.

The image sensors of the camera 3 record and evaluate the light reflected from the surface of the measurement object 2a (test object). Both LEDs and lasers can be used as light sources, which are arranged either as a spot, point or line. Likewise, emitters in the near infrared spectrum (NIR) are used.

In the technology of the camera 3, a basic distinction is made between two variants, the arrangement of the light-sensitive picture elements (pixels). Image sensors 6a, 6b concerned. This arrangement may be in a row or in a matrix as Figures 2 and 3 illustrate.

If the pixels are in a single row, one speaks of a line image sensor 6a, or line sensor 6a for short. The line image sensor 6a forms a line camera 3a together with the imaging system (lens) and analog/digital electronics installed in a housing. This is illustrated in FIG. Line scan cameras 3a are characterized by a high line refresh rate and are mainly used for measurement tasks on moving objects 2a, where the movement of the measurement object 2 and continuously recorded image lines enable an evaluation of 2D images.

If, on the other hand, the pixels are arranged in a matrix, one speaks of a matrix image sensor 6b or matrix sensor 6b for short or a matrix camera 3b. This is illustrated in FIG. Matrix cameras 3b differ in their design from line cameras 3a only in that the image sensor is a matrix image sensor 6b, which acts as the primary image recorder. Matrix cameras 6b are the components primarily installed in machine vision. The image points (pixels) of the matrix image sensors 6b arranged in the form of a matrix supply a two-dimensional image which can also be recorded and evaluated when the measuring objects 2a are stationary.

In many technical applications it is not sufficient to view a scene with just one camera 3 . A higher resolution of the image scene or of the measurement area can be achieved, for example, with a plurality of cameras 3 directed at a scene, which together form a multi-camera system 30 . The overall scene is divided into sub-scenes, each of which is assigned to one of the cameras 3 and is captured by it. Specifically for the inspection of material 2b in the form of a strip or web, cameras 3 are arranged next to one another transversely to the direction of travel of the strip (cross direction, CD). Figure 4 illustrates this using the example of a conveyor system. In this case, a strip material 2a, which forms the measurement object 2b here, is monitored by means of a camera bar 12 installed above the strip material 2b transversely to the strip running direction (CD). A technology developed by the applicant is based on the fact that the camera bar 12 is a tubular housing for a large number of image sensors, each with its own lens, which are arranged side by side in a row. By definition, the camera bar 12 is a single multi-lens camera. Such a camera bar 12 can have, for example, 80 integrated image sensors and a single data interface 15 to a PLC (programmable logic controller). Camera bars with up to 176 matrix image sensors and an equal number of lenses and image processors with a total length of over 4400 mm are known, which are probably the largest cameras in the world to date.

Below the band 2a is a light bar 13 corresponding to the camera bar 12 with light sources in a housing which is also designed as a hollow profile and is arranged parallel to the camera bar 12 . This makes it possible to identify geometric characteristics of the strip material 2a, such as the strip width, position, e.g. strip center position or features such as defects 14 or strip edge cracks on the running strip 2a. The measurement system 30 shown in FIG. 4 has significant advantages over other known camera systems, such as in particular

- a small distance between camera bar 12 and band 2b

- a high geometry resolution transverse to the tape running direction (CD)

- a simple mechanical installation

- A data evaluation within the camera bar 12, wherein an interface 15 allows a connection to a PLC, and

- a minimization of calibration tasks.

By linking the camera data with the current belt speed, belt features and their geometry can also be assigned to a geometric location in the direction of belt travel (Machine Direction, MD, x coordinate) and transverse to the direction of belt travel (Cross Direction, CD, y coordinate). This method corresponds to a 2D recording of measured values, with the assessment of the product quality being able to be assigned to a section of the strip 2a online (in real time) or offline (after a recording sequence) using the xy coordinates. A suitable arrangement of the cameras 3, including suitable lighting, also makes it possible to determine geometric data of the object 2 in three-dimensional space (3D scan). So-called laser triangulation, for example, can be used for this purpose, the basic principle of which is illustrated in FIG. A vertical change between the measuring arrangement or the camera 3 and the reference plane 10, and thus a change in height Dz, is transformed into a change Dg on the imaging plane 11 of the image sensor or the camera 3. A laser 8 is used here as the light source, the light beam 9 of which falls perpendicularly onto the reference plane 10 . The optical axis 7 of the camera 3, to which the imaging plane 11 is orthogonal, lies at the angle a to the light beam 9. The change in height Dz corresponds to the distance between the reference plane 10 and the point of intersection of the light beam 9 and the optical axis 7, where Dz is approximately equal to Ay/sin(a).

If a laser line 16 is directed at the strip 2b transversely to the strip running direction MD, height information (z-direction) can also be determined for a strip feature with the aid of the triangulation method illustrated in FIG. measured value recording) are assigned. A multi-camera system 30 developed by the applicant and using this principle is shown in FIG. It uses laser triangulation to determine extensive 3D geometry data from a scene. Here, too, many image sensors are combined to form a camera bar 12 in a tubular housing 32 . There is also a row of line lasers in another bar 13 which, in contrast to FIG. 4, is above the strip 2b. This arrangement of a camera bar 12 and a laser bar 13 according to FIG. 6 over a strip 2a can determine and record the geometry of the strip 2a in xyz coordinates and thus, for example, the flatness of the strip 2a without gaps even at high strip speeds. In the same way, for example, a piece of goods 2a as in FIG. 1 can be geometrically recorded and checked in its three dimensions on a flat conveyor belt.

What the measurement methods mentioned have in common is that their measured value uncertainty depends on the precise and known position of the cameras and the lighting components is known absolutely to each other and relative to the 3D observation or coordinate system.

Today's multi-camera systems can only be precisely scaled, reproduced, assembled and calibrated to a limited extent. Scaling takes place by increasing or reducing the number of cameras in the system. In this case, an increase in the measured value resolution is possible with an increase in the number of cameras in the system. However, expanding a system from three to four cameras, for example, requires repositioning and consequently recalibration of all cameras. In addition, this often fails because the cameras cannot be arranged arbitrarily close to each other because their structural dimensions or brackets on mounting flanges do not allow this. Any scaling is therefore not possible. The reproducibility of a camera system is primarily about the exact resumption of the original camera position after a repair or service case. If a camera fails in a multi-camera system, it must be possible to replace it with a new camera at exactly the same point, which is difficult to do with today's camera systems, so that a complex recalibration of all cameras is required. This is associated with a corresponding expenditure of time.

In the previously outlined machine vision measuring systems for strip inspection, it is of great importance that the exact position of all cameras and all lasers or

Light sources in the plant coordinate system is known exactly. In conventional systems, installing and adjusting the components on site involves a great deal of effort. This effort is significantly reduced in the case of the measuring or camera bar 12 according to FIGS. 4 and 6, because all image sensors are mounted with high precision in a common assembly or on a printed circuit board and installed in a common housing ex works. However, the architecture of this camera bar always has a fixed number of cameras per unit of length, which cannot be changed afterwards. In the event of repairs, individual cameras cannot be replaced individually on site, but can only be repaired in the factory. It is therefore the object of the present invention to provide a multi-camera measuring system for industrial image processing that overcomes the aforementioned disadvantages, in particular is highly scalable, enables the cameras of the system to be positioned precisely and requires minimal effort for mechanical adjustment and software calibration . Furthermore, it is the object of the invention to provide a method for the exact positioning of the cameras.

This object is achieved by the multi-camera system having the features of claim 1 and a method according to claim 16. Advantageous developments are set out in the dependent claims and are addressed below.

According to the invention, a modular multi-camera system for industrial image processing is proposed with at least one beam-shaped carrier profile and a plurality of assembly modules attached to it, at least some of which are camera modules each with an image sensor and a lens, the assembly modules being arranged individually on the carrier profile at discrete module positions so that they can be removed and can be lined up flush and have a width in the direction of the longitudinal axis of the carrier profile which corresponds to one or a multiple of a base unit.

A core idea of the invention is therefore to use defined module positions along the longitudinal extent of the carrier profile, to which the assembly modules are intended to be mounted in order to assume a specific and therefore known position relative to the carrier profile and its surroundings. This is achieved through a uniform shape and width of the assembly modules, which is a single or a multiple of the defined base unit. For example, the base unit is 1cm. Exact positioning of each individual assembly module, including those that are at a greater distance from the longitudinal ends of the carrier module, can then be achieved by aligning the assembly modules flush with one another. Thus, a first assembly module can serve to align a second assembly module without tilting, which rests against the first assembly module comes. The first placement module thus forms a reference. The second assembly module is then automatically also given the necessary exact position in relation to the longitudinal extension of the carrier profile, at least if the first assembly module is positioned exactly, since the width of the assembly module corresponds to one or a multiple of the base unit. If a third assembly module is attached flush to the second assembly module, the second assembly module forms the reference. This assembly process can be carried out without any expense or difficulty. Positioning accuracies of less than 1mm, in particular a few tenths of a millimeter, can be achieved with this.

However, it is not absolutely necessary for all the assembly modules to remain on the carrier profile after they have been lined up. Rather, a flush juxtaposition can also only take place for the purpose of exact positioning along the longitudinal extension.

For example, an assembly module can be a spacer plate on which another assembly module is placed flush. The other assembly module can also be a spacer plate or an assembly module with more functions, such as a camera module or a lighting module, which then assumes its desired module position exactly. The spacer plate or plates can remain on the carrier profile or be removed.

In addition to the flush application of a second assembly module to a first assembly module, whereby the position of the second assembly module is fixed along the longitudinal axis of the carrier profile, the second assembly module can also be precisely aligned transversely to the longitudinal axis of the carrier profile thanks to the identical length of the assembly module.

In principle, the assembly modules can be arranged arbitrarily along the longitudinal extension of the carrier profile, ie mechanically the positionability of the assembly modules is not necessarily limited to the defined module positions. Nevertheless, it is advantageous if there is a snap-in option at each module position. The carrier profile and the assembly modules can be designed in this way be that an assembly module can enter into a latching connection with the carrier profile at each module position in order to assume the module position. The release of such a latching connection by longitudinal displacement of the assembly module relative to the carrier profile is then only possible by overcoming a certain force.

The locking connection can be mechanical. At least one cavity in the form of a depression or a hole can be provided on the carrier profile at each module position, in which a spring-loaded latching means such as a ball or a pin on the assembly module can engage. Alternatively, the cavity can be present on the part of the assembly module and the spring-loaded latching means can be present on the part of the carrier profile, but this variant does not make economic sense with regard to a possible partial assembly of the carrier profile.

In addition or as an alternative, the carrier profile can have the discrete module positions by predetermined markings at regular intervals, with the distance between two markings corresponding to the base unit. A placement module can then be aligned with one marker or two adjacent markers. The markings thus also ensure, alternatively or additionally, an exact positioning of the assembly modules at the module positions, both when they are arranged at a distance from one another and when they are flush with one another.

In one embodiment variant, the assembly modules can also have a marking, preferably at the edge, in particular in the middle of their width, so that this marking can be aligned with a marking on the carrier profile.

The markings can be, for example, lines that are applied to or introduced into the carrier profile at regular intervals, for example in the form of notches. Additionally or alternatively, position numbers or symbols can be applied to the carrier profile as markings assigned to the module positions, with a position number clearly defining a specific module position. The position numbers allow in the absence of a further marking a rough positioning of an assembly module, the fine positioning being possible via one or more spacer plates lined up next to one another and/or via the latching connection.

The modularity of the multi-camera system according to the invention is achieved in that any assembly module can be arranged at each of the module positions, it also being possible for each module position to remain free of an assembly module. Thus, the multi-camera system according to the invention is not only scalable, but can be adapted to any application as required and on site.

An assembly module can be a camera module, a lighting module or a spacer plate. Furthermore, it is also possible for an assembly module to be a combination of a camera module and an illumination module. Furthermore, an assembly module can include two or more image sensors or lighting units. This results in different assembly variants for the carrier profile.

The carrier profile can be fully equipped within a section, i.e. have an assembly module at each defined module position of this section. According to another embodiment variant, the carrier profile can only be partially equipped, i.e. only part of the module positions are occupied with assembly modules, whereas the remaining module positions of the section are free. A continuous area between the axial ends of the carrier profile is to be considered as a section.

According to the invention, at least some of the assembly modules are camera modules. Preferably, however, all existing assembly modules can be camera modules. If all of the mounting modules are camera modules in the fully equipped version of the carrier profile, a maximum resolution of the observed scene is achieved. There is therefore no mixed shoring with lighting modules. The carrier profile with its camera modules then functionally forms a camera bar, as mentioned above in relation to the prior art. In an embodiment variant, some of the assembly modules can be formed by camera modules and another part by spacer plates. This applies to both the fully equipped and the partially equipped version. A spacer plate is used on the one hand to provide a defined system for another placement module in order to position it precisely and to bridge gaps between placement modules that are not directly adjacent, or between a placement module and the edge of the carrier profile. On the other hand, a spacer plate is used to cover sections of the carrier profile in order to protect the side and rear of a camera module or lighting module from foreign objects.

According to an embodiment variant, some of the assembly modules can be camera modules and another part can be lighting modules. Thus, camera modules and lighting modules are commonly arranged in a single carrier profile. No additional light bar is therefore required, which simplifies the installation work for the camera system. In this embodiment variant, too, the carrier profile can be partially or fully equipped. A lighting module serves to illuminate the scene captured by a camera module. For this purpose, an illumination module can have a light source in the form of a light-emitting diode (LED) or a laser, preferably a line laser.

According to an embodiment variant, some of the assembly modules can be camera modules, another part can be lighting modules and another part can be spacer plates. The spacer plates can be arranged between camera modules, between a camera module and a lighting module, between two lighting modules or between the edge of the carrier profile and a camera or lighting module.

According to another embodiment variant, a second carrier profile identical to the first carrier profile can be provided, in which all assembly modules are lighting modules. This also applies to both a fully equipped and a partially equipped variant of the second carrier profile, with a section of the second carrier profile being fully equipped with lighting modules in practice will not be required. This second carrier profile is then to be installed in addition to the first carrier profile. However, it has the advantage that the light emission direction of the light source can be aligned independently of the first carrier profile and simultaneously for all lighting modules.

Finally, in one embodiment variant, part of the assembly modules can be formed by lighting modules and another part by spacer plates. The spacer plates can be arranged between two lighting modules or between the edge of the carrier profile and a lighting module.

A camera module represents a digital camera with an image sensor, a lens, a processor and a data interface to transmit the image data to an external evaluation unit. The image sensor can be a line image sensor or a matrix image sensor, for example a CCD or CMOS image sensor. In an embodiment variant, all camera modules can have line image sensors or matrix image sensors. In another embodiment variant, some of the camera modules can have line image sensors and another part of the camera modules can have matrix image sensors. Thus, the multi-camera system can be optimally adapted to the corresponding application as required.

It is also possible that one of the camera modules is a thermal imaging camera. In this way, heat sources can be detected or, in the case of objects that need to have a certain temperature, the temperature can be checked and monitored.

The carrier profile can preferably have a longitudinal groove in which the assembly modules lie at least partially and can be displaced in the direction of the longitudinal axis of the carrier profile. The longitudinal groove thus serves as a receptacle for the assembly modules according to the principle of a tongue and groove connection, so that they can only be moved in the direction along the carrier profile axis. Alternatively, the longitudinal groove can form an undercut form fit at least on one longitudinal side. This has the advantage that attachment is only required on the opposite long side. By using an undercut form fit on both long sides, for example in the form of a dovetail profile, attachment can be dispensed with entirely, since a holder via the form closure. However, the assembly modules must then be inserted from one longitudinal end and pushed to the appropriate position and can therefore no longer be dismantled individually. In order to overcome this disadvantage, the form fit can be formed by a retractable projection on at least one longitudinal side. In order to release the form fit and to remove the individual module, the projection simply has to be pulled back.

If an assembly module is placed on the carrier profile, the carrier profile forms a housing in the form of a rear cover for the assembly module.

The assembly modules can be attached to the carrier profile in any way that causes a detachable connection, for example by means of screws, a detachable form fit such as a detachable snap-in connection, or by means of a clamp connection with an eccentric.

It is advantageous if the carrier profile is a hollow profile. The hollow profile can thus be used to guide individual lines to the assembly modules in a cavity inside the carrier profile and thus accommodate them in a protected manner. The lines can be data lines to the camera modules, control lines to the lighting units, supply lines or combinations of the lines mentioned. If necessary, further electronic components for digital image data processing, e.g. for pre-processing of the image data, can also be accommodated in the hollow profile. In order to lead the lines to the individual module positions out of the cavity, openings can be made in the carrier profile at the module positions.

It is ideal if the carrier profile is a so-called construction profile. Structural profiles have many inner chambers and grooves on the outer circumference, which extend over the entire axial length and for different purposes, e.g. for fastening components to the carrier profile, for fastening the carrier profile itself or for coolant to flow through in order to cool the carrier profile. Suitably, the carrier profile consists of a metal, preferably aluminium.

The assembly modules preferably have a rectangular, in particular elongated, basic shape with flat, parallel longitudinal sides. This allows them to be lined up flush against each other.

In one embodiment variant, an assembly module can have a carrier plate with which it is attached to the carrier profile, with a circuit board being held on the rear side of the carrier plate facing the carrier profile, for example by means of a screw connection. The carrier plate preferably forms the only mechanical component of the placement module, which to this extent has a very simple structural design. The carrier plate also protectively covers the electronics of the camera modules or lighting modules on the printed circuit board.

According to a further development, the carrier plate can be part of a housing body, within which electronics of the camera modules or lighting modules are arranged. For example, a frame can protrude from the carrier plate on the underside facing the carrier profile and laterally enclose the electronics, the housing body being formed, in particular consisting of, the carrier plate and the frame. Thus, the housing body can be open on its rear side facing the carrier profile and the printed circuit board can close the housing body. The printed circuit board thus forms part of the housing. This is possible because the carrier profile also acts as a housing for the assembly modules and in turn protects the circuit board. A completely closed housing for a camera or lighting module can therefore be dispensed with. This has the advantage that weight and material costs can be saved for each assembly module.

It is also advantageous if the carrier profile is used as a heat sink for the assembly modules. Although a camera module or a lighting module itself generates comparatively little heat loss and therefore does not have to be cooled in practice, forced cooling may or may not be necessary in certain applications of the multi-camera system according to the invention be advantageous in order to increase the service life of the camera modules and/or lighting modules. This is the case, for example, when the multi-camera system is operated at high ambient temperatures or for monitoring or measuring hot objects. For cooling, an assembly module can be in thermally conductive connection with the carrier profile via a thermal bridge. A heat-conducting paste, for example, can be used as a thermal bridge.

According to a further advantageous development, a seal can be arranged between two adjacent assembly modules and can rest against them in a sealing manner. This prevents dust or other dirt particles from getting into the electronics.

In the case of a camera module, the printed circuit board preferably has a data interface on its side facing the carrier profile in order to transmit image data. Power is preferably supplied to the camera module at the same time via the data interface. The interface can be a GigE (Gigabit Ethernet), a USB, CoaX or IEEE1384 interface.

According to the invention, a method for positioning assembly modules on a beam-shaped carrier profile for the production of a modular multi-camera system for industrial image processing is also proposed, in which the assembly modules are individually arranged in a removable manner on the carrier profile at discrete module positions on the outside, in which they are flush with one another, or on markings aligned on the carrier profile along its longitudinal axis or brought into a snap-in connection at the module position.

Further features, properties and advantages of the invention are explained in more detail below using exemplary embodiments and the attached figures. In the figures, elements that are identical or have the same function retain the same reference number from figure to figure.

It should be noted that, in the context of the present description, the terms “have”, “comprise” or “include” in no way imply the presence exclude other features. Furthermore, the use of the indefinite article with an object does not exclude its plural form.

Show it:

Figure 1: an IBV measuring arrangement for checking the completeness of an object Figure 2: a line image sensor (left) and line camera (right)

Figure 3: a matrix image sensor (left) and matrix camera (right)

Figure 4: a camera bar and opposing light bar in a belt inspection system

Figure 5: the functional principle of a laser triangulation

FIG. 6: a measuring bar arrangement for uninterrupted 3D measurement transverse to the strip FIG. 7: a camera module according to the invention in a side view FIG. 8: the camera module according to the invention in a perspective view from below

FIG. 9: the camera module according to the invention mounted on a carrier profile in a side view

FIG. 10: a multi-camera system according to the invention with a large number of camera modules on the carrier profile (fully equipped)

FIG. 11: a multi-camera system according to the invention with individual

camera modules on the carrier profile in all three module positions (partial assembly)

Figure 12: Six camera modules at the longitudinal ends of the carrier profile as a camera bar

Figure 13: Mixed assembly of the carrier profile with different camera modules Figure 14: Camera modules on the carrier profile with intermediate spacer plates

Figure 15: spacer plates of different widths as spacers Figure 16: a fully equipped carrier profile with an alternating sequence of three camera modules and one lighting module Figure 17: a fully equipped carrier profile with camera and lighting modules and spacer plates

FIG. 18: Partially equipped carrier profile with markings and cavities for a snap-in connection Figure 19: Top view of the beginning section of a partially equipped carrier profile with markings and cavities for a snap-in connection Figure 20: Cross section along section line BB in Figure 19

Figure 21: Perspective view of the beginning section of a carrier profile according to Figure 19

Figure 22: Partially equipped carrier profile with markings and spacer plates Figure 23: Perspective view of the beginning section of the carrier profile according to Figure 22

Figure 24: Perspective view of the spacer plate according to Figure 22 Figure 25: Side view of a spacer plate with eccentric attachment not within a hollow profile as in the prior art, but individually mounted or mounted precisely on the outside of a carrier profile 31 at discrete module positions, can be individually dismantled again, for example for repair purposes, and then can be repositioned exactly on the carrier profile. As an alternative to the camera modules 20, lighting modules and spacer plates can be mounted identically. The camera modules 20, lighting modules 41 and spacer plates 40 form assembly modules for the carrier profile 31.

FIGS. 7 and 8 show a camera module 20 according to the invention in a side view. The camera module 20 has a housing body 22 , 23 , a lens 21 , electronics on a printed circuit board 25 and a data interface 28 . The housing body 22, 23 consists of a support plate 22, from the underside of which a frame 23 protrudes, which encloses an interior space of the housing body 22, 23. The housing body 22, 23 is thus open to the underside. The printed circuit board 25 closes the interior so that the electronics lie protected in the interior.

Support plate 22 and frame 23 are in one piece. The housing body 22, 23 consists of metal, preferably aluminum. However, it can also be made of plastic and manufactured by injection molding. The interior may have been created by milling. Additive manufacturing (3D printing) of the housing body 22, 23 is also possible, for example by selective laser sintering (SLS). The electronics include at least one image sensor and one processor, and may have additional components. The printed circuit board 25 is held on the carrier plate 22 by means of screws 26 . However, the attachment can also be designed differently, for example by means of a clamp or snap-in connection. Furthermore, the printed circuit board 25 has the data interface 28 on its rear side in the form of a plug connection, via which the camera module 20 can be plugged into a data line 29 . The data line 29 also supplies the camera module 20 with power. It is a coaxial line, but can also be designed differently. The data is transmitted in serial form.

The housing body 22, 23, more precisely its support plate 22, has an elongated rectangular basic shape of constant height and with a width which corresponds to twice the base unit B. The longitudinal ends of the support plate 22 are chamfered on the upper side. The frame 23 is set back from the longitudinal ends, so that the support plate 22 protrudes beyond the frame 23 with the formation of mounting wings 24 . The underside of the mounting wings 24 forms a mounting surface that comes to rest on the carrier profile 31 . Bores for accommodating screws or pins 27 are provided in the mounting wings 24 in order to fasten the camera module 20 on the carrier profile 31 .

Due to the rectangular shape, the long sides of the support plate 22 are parallel. They are also flat and are perpendicular to the mounting surface, so that several camera modules 20 can be lined up flush.

According to the invention, all assembly modules have an identical basic shape, so that they can in principle be exchanged for one another, although the width can vary. In the case of the spacer plates, the width can even be the same as or greater than their length, see FIG.

A lens 21 is arranged on the front side of the carrier plate 22 opposite the printed circuit board 25 and protrudes from this front side. The lens 21 is screwed into a threaded hole in the support plate 22 with a thread. the Threaded hole overlies image sensor so lens aligns with image sensor. The lens 21 is arranged centrally on the carrier plate 22 in relation to the longitudinal extent and the width. However, any eccentric arrangements are possible. Furthermore, in one embodiment variant, the support plate can have a height that increases towards one longitudinal end, so that the lens 21 is arranged tilted relative to the mounting surface. In a joint arrangement with an illumination module 41, an angle can be realized in this way between the optical axis of the camera module 20 and the light emission direction of the illumination module 40 in order to carry out laser triangulation.

FIG. 9 shows a carrier profile 31 according to the invention in cross section or in an uncovered side view with a camera module 20 mounted on the carrier profile 31 according to FIGS. 7 and 8. The cross section is square here, for example, but it can also be rectangular or any other. The carrier profile 31 is a modified hollow profile or construction profile made of metal, in particular aluminum, as is commonly used in industrial plant and special machine construction. It consists of a support structure 32 with numerous chambers 33 and a central cavity 34 which extend along the longitudinal axis 39 over the entire axial length of the profile 31. The central cavity 34 is used as a cable duct for the data lines 29 to the camera modules 20 and, if necessary, further electrical lines to other assembly modules, which are thus protected in the carrier profile 31 . The carrier profile is mirror-symmetrical in relation to a center plane, which also extends through the camera module 20 .

The carrier profile 31 has two parallel longitudinal grooves 35 on each of three of its sides for accommodating sliding blocks or for fastening further components to the carrier profile 31 or for fastening the carrier profile 31 itself. One of the sides of the carrier profile 31 has a longitudinal groove 36 for accommodating the assembly modules 20 , 40, or the camera or lighting modules. The housing body 22, 23 of a camera module extends partially into this longitudinal groove 36 in the manner of a tongue and groove connection. Thus, each assembly module 20, 41 can be placed on the carrier profile 31 without tilting and is only lengthwise in one direction the hollow profile axis 39 movable. To put it more precisely, the frame 23 of the housing body 22, 23 lies in the longitudinal groove 36, with the mounting surfaces of the mounting wings 24 resting on the carrier profile 31 on the outside.

The groove bottom 38 rises in a middle area to the camera module 20 so that it is deeper beyond this elevation in order to ensure sufficient space for the retaining screws 26 of the printed circuit board 25 . A thermal bridge 37 provides a thermally conductive connection between the camera module 20 and the carrier profile 31, in particular between the printed circuit board 25 and the raised groove base 38.

10 shows a multi-camera system 30 according to the invention with a carrier profile 31 according to FIG. 9, which is fully equipped in section A with twelve structurally identical camera modules 20 according to FIGS. A camera module 20 can be removed at any time in the event of repairs without changing the arrangement relative to one another. The camera modules 20 can also be identical with regard to their image sensors. Alternatively, some of the camera modules 20 can contain a line image sensor and the remaining part can contain a matrix image sensor. In another embodiment, it is possible for the image sensors to differ in terms of pixel resolution.

FIGS. 11, 12 and 13 show alternative assembly variants in which camera modules 20, 20a, 20b are arranged on the carrier profile (31). The carrier profile 31 itself can have any length, in particular form a camera bar, as was mentioned in the introductory part with regard to the prior art. FIGS. 11 and 12 show partially equipped carrier profiles 31, while FIGS. 13 and 14 show fully equipped carrier profiles 31. In FIG. 11, several camera modules 20 are arranged equidistantly from one another. In FIG. 12, only three camera modules 20 are flush next to one another at the longitudinal ends. Further camera modules 20 are not available. FIG. 13 shows a fully equipped carrier profile 31 on which a camera module 20 with a lower resolution and a camera module 20a with a higher resolution are arranged alternately. The higher resolution camera module 20a is, for example, a 5x5 (25) megapixel still camera. It has a width four times that of Base unit B and thus corresponds to twice the width of the camera module 20 with lower resolution.

Similar to FIG. 12, in FIG. 14 only camera modules 20 are arranged flush next to one another at the longitudinal ends, specifically four camera modules 20, 20b in each case. Furthermore, these camera modules 20, 20b differ in that a thermal imaging camera 20b is arranged next to a photographic camera 20. There are two spacer plates 40d between the four-part arrangements at the longitudinal ends. The width of the spacer plates 40d corresponds here to ten times the base unit B, which corresponds to five times the width of a camera module 20, 20b. The spacer plates 40d are used on the one hand to close the longitudinal groove 36 so that no foreign bodies can get to the side of or behind the camera modules 20. On the other hand, the spacer plates 40 are also used here for the precise positioning of the camera modules 20, 20b along and transversely to the carrier profile axis 39.

Although FIGS. 11, 12 and 14 each show a multi-camera system 30 with an assembly of the carrier profile 31 that is symmetrical to the center of the carrier profile, an asymmetrical assembly can also be possible and desired in other embodiment variants.

The spacer plates 40 are helpful, especially in the case of large distances between assembly modules or between an assembly module 20, 41 and a longitudinal end of the carrier profile 31, so that an assembly module is not accidentally placed in the wrong position. The spacer plates 40, like the other modules 20, 41, can be moved freely on the carrier profile 31. By means of one or more spacer plates 40 between the camera or lighting modules 20, 41, each of these modules 20, 41 can be arranged exactly on one of the module positions on the carrier profile 31.

The spacer plates 40 can have different widths. Purely as an example, four spacer plates 40 of different widths are shown in FIG. In relation to a camera module 20, which is shown to the left of the spacer plates 40 and here has twice the width of the base unit B, the spacer plate width corresponds a simple, integer or half-integer multiple of the camera module width. A first spacer plate 40a has half the width B of the camera module 20. A second spacer plate 40b has the width 2B of the camera module 20. A third spacer plate 40c has 2.5 times and a fourth spacer plate has 5 times the width of the camera module 20 For example, the camera module width is 2cm, so the width of the camera modules is 1, 2, 5 and 10cm. In Figure 14, two 10cm spacer plates 40d are installed.

FIGS. 16 and 17 show further configuration variants of multi-camera systems 30 according to the invention. These differ from the previous ones in that lighting modules 41 are arranged on the carrier profile 31 in addition to the camera modules 20 . An illumination module 41 has a light source in the form of a light-emitting diode (LED) or a laser, preferably a point or line laser. The light source is arranged here in the center in relation to the longitudinal extent of the carrier plate.

In both variants, the carrier profile 31 is fully equipped, i. H. There is an assembly module 20, 4041 at each module position, with additional spacer plates 40 being installed in variant 16. In the variant according to FIG. 15, three camera modules 20 are each followed by a lighting module 41, so that each lighting module 41 has an adjacent camera module 20 on both sides.

In the variant according to FIG. 16, a camera module 20 is arranged on the outermost longitudinal ends and a lighting module 41 is arranged adjacent to it. Groups of three assembly modules are arranged at a distance from one another between the longitudinal ends, with each group consisting of two camera modules 20 and a lighting module 41 lying between them. The spacer plates 40 bridge the distances between the groups and between a group and the lighting module arranged at the longitudinal end.

In the two variants according to FIGS. 16 and 17, position numbers 18 from 1 to 23 are assigned to the individual module positions. These are arranged here by way of example, for example printed or engraved, that they remain visible when the assembly module 20, 40, 41 is mounted, so that one can look at the position of the corresponding placement module can be assured at any time. The position numbers 18 can be used on the one hand for the target position-oriented assembly of the carrier profile 31 according to instructions, in that the target position of an assembly module 20, 40, 41 is addressed by the corresponding position number 18 (e.g. camera module with matrix sensor at position 18). Furthermore, specifying the position number 18 can be useful when setting up the multi-camera system 30 by software, since the software knows the position of an assembly module 20, 40, 41 in relation to the longitudinal extent 39 of the carrier profile 31 by specifying the position number 18.

In the embodiment variant according to FIG. 18, an assembly module 20, 40, 41 can engage in a latching connection with the carrier profile 31 at each module position in order to latch in at the defined module position. From this position, the module 20,

40, 41 can then only be displaced longitudinally to the carrier profile 31 by overcoming a corresponding force. Such a latching connection is formed here by a cavity 19 in the groove base 38 at each module position of the carrier profile 31 in the form of a recess or blind hole and a spring-loaded latching means, e.g. a ball, on the side of the respective assembly module 20, 40, 41. The cavities 19 are equidistantly spaced and together form a row. If the assembly module 20, 40, 41 is displaced longitudinally in the longitudinal groove 36, the latching means automatically engages in the corresponding cavity 19 at each module position. The cavities 19 thus ensure the discrete module position of a camera module 20 or lighting module 41 on the carrier profile 31 as the installation site.

As FIG. 18 also shows, openings 42 in the form of oblong holes are made equidistant from one another in the groove base 38 and provide a connection to the cavity 34 and serve as a cable bushing 42 for the respective data or coaxial line 29 . As can also be seen from FIG. 20, the carrier profile 31 has a further, inner cable bushing 42a, which is aligned with the outer cable bushing 42.

In the embodiment variant according to FIG. 18, the module positions for the assembly modules 20, 40, 41 are additionally identified visually by markings 17 on the carrier profile 31, which are present at regular intervals are where the distance between two marks 17 defines the base unit B. The width B of the assembly modules 20 used here corresponds to twice the base unit. The markings 17 are in the form of lines and are formed by slots or notches in the carrier profile 31 . Their distance is 1cm here, for example.

In addition, each camera module 20 has a marking 43 in the form of a slot or notch in the middle of its chamfered end face 46. Precise positioning is possible by arranging a camera module 20 in the middle between two markings on the carrier profile 31 and aligning them with them, or by marking 43 on the Camera module 20 is aligned in alignment with a marking 17 of the carrier profile 31.

Finally, the carrier profile carries 31 position numbers 18, which are each assigned to a module position and can be printed or engraved.

Figures 19 to 21 show the carrier profile 31 according to Figure 18 in the assembly variant according to Figure 11, in Figure 19 only the beginning section of the carrier profile 31, in Figure 20 the cross section in the middle of the first discrete module position 01 along the section line BB in Figure 19 and in Figure 21 shows an enlargement of the camera module 20 mounted at this first module position 01. As FIG. 20 shows, the cavity 19 is an indentation in the groove base 38. In addition, the outer cable bushing 42 and the inner cable bushing 42a aligned therewith to the inner cavity space 34 can be seen in FIG.

It can be seen in FIG. 19 that the markings 17 are on or introduced on the two outer longitudinal sides of the carrier profile 31 . Furthermore, the camera module 20 also has a central marking 43 on both end faces 46 . The distance between two adjacent markings 17 corresponds to the base unit B. And each marking 17 indicates a discrete module position.

FIG. 20 illustrates a fastening variant of the camera module 20 by clamping using eccentrics 44, 45. The camera module 20 has an eccentric pin 45 and an eccentric disk 44. The eccentric pin 45 has on the the support profile 31 facing away from the support plate 22 an accessible head. The eccentric disk 44 is firmly connected to the end of the eccentric pin 45 opposite the head and is arranged eccentrically to the axis of the eccentric pin 45 . A rotation of the eccentric pin 45 results in a pivoting of the eccentric disc 45 in such a way that the eccentric disc 44 protrudes increasingly from the housing body 22 , 23 as the rotation of the eccentric pin 45 progresses and thereby clamps it on the inside of the longitudinal groove 36 . To improve the clamping effect, the longitudinal inner side of the longitudinal groove 36 has a recess 47, the transition from the longitudinal inner side of the longitudinal groove 36 to this recess forming a chamfer. The two eccentric disks 44 rest against this bevel in a clamping manner when pivoted out.

The eccentric discs 44 and eccentric pins 45 also fulfill the task of the retaining screws 26 in Figure 9 and hold the circuit board 25 on the housing body 22, 23.

FIG. 20 also shows that the lens 21 extends through the carrier plate 22 and projects as far as the image sensor 6b. For this purpose, the lens 21 has an external thread and is screwed into the carrier plate 22 .

As can be seen from FIG. 21, the camera module 20 cut in FIG. 20 is located at the module position with the number 01. This position number 18 is arranged on a longitudinal side of the carrier profile 31 below the module position, in particular below the marking assigned to this module position. In addition, Figure 21 shows an enlarged representation of the exact positioning of the camera module 20 by aligning the marking 43 on the camera module 20 with the corresponding marking 17 on the carrier profile 31.

In the figures 22 and 23 an embodiment variant of a fully equipped carrier profile 31 is shown in which on every 1 + n-12th module position (n = 0, 1, 2, ...) a camera module 20 is arranged, with between two adjacent Camera modules 20 is a spacer plate 40d. Thus, the carrier profile 31 is equipped alternately with a camera module 20 and a spacer plate 40d. The Camera module is at the 1st, 13th, 25th, etc. module position. Analogous to FIG. 21, FIG. 23 shows an enlarged view of the camera module 20 at the module position 01. The only difference from FIG. In addition, the spacer plate 40d is aligned on the first camera module 20 without offset transversely to the longitudinal axis 39 of the carrier profile 31, so that the end face 46 of the spacer plate 40d and the end face 46 of the camera module are aligned with one another.

FIG. 24 shows a perspective view of a single spacer plate 40d, as arranged on the carrier profile 31 in FIGS. 22 and 23. Figure 25 shows its side view. FIG. 24 makes it clear that the spacer plate 40d also has a marking 43 on its end face 46, which must be aligned with a corresponding marking 17 on the carrier profile 31 for exact positioning along the profile axis 39. However, the spacer plate 40d in FIGS. 22 and 23 already has its exact positioning due to the flush contact with the first camera module 20, so that the markings 43, 17 are automatically aligned.

FIG. 25 makes it clear that the spacer plates 40 can also be clamped in an identical manner to the camera module 20 in FIG. 20 with the aid of eccentrics 44, 45. Reference is therefore made to the explanations for FIG. The lighting modules 41 can also have this type of attachment.

In summary, the invention is thus that due to the special design of the camera modules 20, image sensors 6a, 6b and lighting modules 41 can be mounted on a carrier profile 31 at a defined distance from one another and can be dismantled again. A carrier profile 31 equipped in this way thus forms a camera bar. A design that is comparable to the camera modules 20 is used for the lighting modules 41, so that the camera modules 20 and lighting modules 41 can be arranged at defined distances on the same carrier profile 31. Furthermore, only lighting modules 41 can be arranged on a second carrier profile 31 in order to form a pure light or laser bar in this way, which together with the camera bar in the multi-camera system 30 is used. Mixed operation of different image sensor principles in the camera modules 20, ie line and matrix sensors, is also possible.

The exact positioning of the camera and lighting modules 20, 41 on the carrier profile 31 is in addition to their design by graphic markings 17 such as lines, notches, dimensions or position numbers 18 along the carrier profile 31, by a snap-in option at each module position z. B. in the form of cavities 19 along the carrier profile 31, into which the modules 20, 41 can snap at the module positions, and/or through the use of spacer plates 40 of defined width (1, 2, 5, 10, 20, 50, 100 [cm]) supported.

The invention is intended to enable a user to arrange or join together a large number of image sensors or light sources (including lasers) in a precise and reproducible manner in order to solve measuring tasks in industrial image processing, in particular in the quality control of strip-shaped materials or transported piece goods .

The defined and predominantly equidistant arrangement of the imaging sensors is of exceptional importance in metrology, because only in this way can mathematical algorithms be used to evaluate the image data, which enable a position or geometric measurement of objects in 2D or 3D space (e.g Strip surface inspection, laser triangulation, triangulation, stereoscopic measurement, 3D metrology, etc.). However, the modular architecture of the components of the multi-camera system according to the invention also results in technical and economic advantages in the manufacture, assembly and commissioning of multi-camera systems, since the method can be used to quickly assemble almost any number of image sensors, possibly even with different operating principles, to form a system. This novel arrangement of camera modules and, if necessary, lighting modules creates a measuring system that is modularly scalable and can be calibrated quickly. Furthermore, the time for commissioning or service calls can be shortened and downtimes of production plants can be reduced. It should be understood that the foregoing description is given by way of example for purposes of illustration and does not limit the scope of the invention in any way. Features of the invention that are indicated as "may", "exemplary", "preferred", "optional", "ideal", "advantageous", "optional" or "suitable" are to be considered purely optional and also limit the does not include a scope of protection, which is defined solely by the claims. Insofar as elements, components, process steps, values or information are mentioned in the above description which have known, obvious or foreseeable equivalents, these equivalents are also included in the invention. The invention also includes any changes, alterations or modifications of exemplary embodiments which have the exchange, addition, alteration or omission of elements, components, method steps, values or information as their subject matter, as long as the basic idea according to the invention is retained, regardless of whether the change, alteration, or modifications improves or degrades an embodiment.

Although the above description of the invention mentions a large number of physical, non-physical or procedural features in relation to one or more specific exemplary embodiments, these features can also be used in isolation from the specific exemplary embodiment, at least insofar as they do not necessarily require the presence of further features. Conversely, these features mentioned in relation to one or more specific exemplary embodiment(s) can be combined as desired with one another and with other disclosed or undisclosed features of exemplary embodiments shown or not shown, at least insofar as the features are not mutually exclusive or lead to technical incompatibilities. Reference List

I Camera system for industrial image processing (IMP) 2a Object, gear wheel

2b object, band

3 camera

3a line camera 3b matrix camera

4 data line

5 evaluation computer 6a line image sensor 6b matrix image sensor

7 Optical axis of the camera

8 light source, laser

9 light beam

10 reference plane

I I image plane

12 camera bars

13 light bars, laser bars

14 defects, defect

15 Serial interface

16 laser line

17 tick mark

18 position number

19 cavity of a snap-in connection

20 camera module

20a photographic camera module 20b thermal camera module

21 lens

22 carrier plate

23 frames

24 mounting wings

25 circuit board

26 Circuit board retaining screw Fastening screw for camera module Data interface Data line, coaxial line Multi-camera system Carrier profile Support structure Chambers Central cavity Longitudinal groove for sliding blocks Longitudinal groove for assembly modules Thermal bridge Groove floor Longitudinal axis Dummy plate a Dummy plate, first width b Dummy plate, second width c Dummy plate, third width d Dummy plate, fourth width Lighting module, outer cable duct a Inner cable duct Marking, notch on the assembly module Eccentric disc Eccentric pin Chamfered front side of an assembly module Recess

Claims

Expectations

1. Modular multi-camera system (30) for industrial image processing with at least one beam-shaped carrier profile (31) and a plurality of assembly modules (20, 40, 41) attached thereto, at least some of which are camera modules (20) each with an image sensor (6a, 6b ) and a lens (21), characterized in that the assembly modules (20, 40, 41) are arranged individually on the outside of the carrier profile (31) in discrete module positions so that they can be removed and are flush and can be lined up next to one another and have a width in the direction of the longitudinal axis (39) of the carrier profile (31) which corresponds to a single or a multiple of a basic unit (B).

2. Multi-camera system (1) according to claim 1, characterized in that at least one assembly module (20, 40, 41) is a spacer plate (40) against which another assembly module (20, 40, 41) rests flush and in particular transversely to the longitudinal axis (39) of the carrier profile (31) is aligned to take the module position.

3. Multi-camera system (1) according to claim 1 or 2, characterized in that the carrier profile (31) and the assembly modules (20, 40, 41) are designed such that an assembly module (20, 40, 41) has a snap-in connection at each module position can enter with the carrier profile (31) to take the module position.

4. Multi-camera system (1) according to one of the preceding claims, characterized in that the carrier profile (31) has markings (17, 18, 19) specifying the discrete module positions at regular intervals, the distance between two markings (17, 18, 19 ) corresponds to the base unit (B).

5. Multi-camera system (1) according to one of the preceding claims, characterized in that at least some of the assembly modules (20, 40, 41) are lighting modules (41).

6. Multi-camera system (1) according to one of the preceding claims, characterized in that the carrier profile (31) has a longitudinal groove (36) in which the assembly modules (20, 40, 41) lie at least partially and in the direction of the longitudinal axis (39) of the carrier profile (31) are displaceable.

7. Multi-camera system (1) according to one of the preceding claims, characterized in that the carrier profile (31) is a hollow profile, in particular a construction profile.

8. Multi-camera system (1) according to one of the preceding claims, characterized in that individual data or control lines (29) are routed to the assembly modules (20, 40, 41) in a cavity (34) inside the carrier profile (31).

9. Multi-camera system (1) according to one of the preceding claims, characterized in that an assembly module (20, 40, 41) has a rectangular, in particular elongated, basic shape with flat, parallel longitudinal sides.

10. Multi-camera system (1) according to one of the preceding claims, characterized in that an assembly module (20, 40, 41) has a carrier plate (22) with which it is attached to the carrier profile (31), and that a printed circuit board (25 ) is held on the rear side of the carrier plate (22) facing the carrier profile (31).

11. Multi-camera system (1) according to claim 10, characterized in that the carrier plate (22) is part of a housing body (22, 23) within which electronics are arranged.

12. Multi-camera system (1) according to claim 11, characterized in that the housing body is open on its rear side facing the carrier profile (31) and the printed circuit board (25) closes the housing body.

13. Multi-camera system (1) according to one of the preceding claims, characterized in that at least one of the assembly modules (20, 41) is in thermally conductive connection with the carrier profile (31) via a thermal bridge (37).

14. Multi-camera system (1) according to one of the preceding claims, characterized in that all camera modules (20) have line image sensors (6a) or matrix image sensors (6b) or that some of the camera modules (20) have line image sensors (6a) and another part of the camera modules (20) have matrix image sensors (6b).

15. Multi-camera system (1) according to one of the preceding claims, characterized in that at least one of the camera modules (20) is a thermal imaging camera module (20b).

16. Method for positioning assembly modules (20, 40, 41) on a bar-shaped carrier profile (31) for producing a modular multi-camera system (30) for industrial image processing according to one of claims 1 to 15, characterized in that the assembly modules (20, 40, 41) can be arranged individually on the outside of the carrier profile (31) at discrete module positions so that they can be removed by placing them flush against one another, or by aligning them with markings on the carrier profile (31) along its longitudinal axis (39) or by snapping them into the module position.