JP2020024401A - Device and method for controlling illumination of industrial camera system - Google Patents

Abstract

To improve the operability of illumination control of an industrial image recording system.SOLUTION: An operation interface 212 is provided for setting a plurality of image photographing parameters of an industrial camera 231 and a plurality of illumination parameters for setting an illumination control device 220, a direct connection line 200 is connected to the illumination control device, and a communication interface is further provided for transmitting the illumination parameters to the illumination control device. The communication interface may preferably be set for bidirectional communication including feedback from the illumination control device to the industrial camera.SELECTED DRAWING: Figure 2

Description

Detailed description of the invention

  The present invention relates to an apparatus and a method for controlling illumination of an industrial camera system.

  The effect of industrial camera systems (so-called machine vision systems or MV systems) is based on the interaction of many of these factors, including the illumination of such systems. As an example, lighting control by light emitting diodes (LEDs) is increasingly being introduced into such systems. In each image processing system where illumination intensity needs to be optimized and the sequence between the image camera and the illumination device needs to be accurately triggered, LED illumination control is an essential element. This includes, for example, pulse control or flash control (the switch-on period of the lighting device is synchronized with the camera and the subject), overflash control (increase the light intensity from the lighting device for a predetermined short time), constant current Supply control (lighting is performed with a stable constant current supply), control of multiple lighting systems (single and multiple trigger intensity control and / or fast synchronization is performed), or remote control of lighting system parameters This applies to a case where the configuration of the system is changed by remote control when the setting is advantageous (for example, for effective setting at the time of system setting).

  While LED lighting devices are often configured as 12V or 24V lighting devices, such LEDs are semiconductor devices, and the current flowing therethrough, rather than the voltage, directly affects intensity. Most LED manufacturers point out that effective current control should be performed. Generally, according to the LED data sheet, a very small change in the LED voltage causes a large change in the LED current, and a large change in the LED current causes a large change in the output light intensity. Therefore, in LED control, not voltage but current is controlled in order to stabilize the output light intensity and enable accurate control. Therefore, the output of the LED light can be accurately controlled by the current control. For example, overflash control of the illumination device for increasing the output of the light can be performed, which is more advantageous for the user.

  LED technology and materials science have developed remarkably in recent years. Because of the higher brightness and light intensity of the new LEDs, they can also be used in applications where previously only incandescent bulbs and other lighting technologies were used. Accordingly, a correspondingly strong control is needed for new high power LEDs.

  Lighting control usually uses pulse operation and continuous operation as operation modes. In continuous operation, the lights are switched on continuously. This is the easiest mode of operation since the only parameter that needs to be set is the illumination intensity. Overflash is not allowed. In pulse operation, the lighting is switched on only on demand. When a light pulse is needed, the control receives a trigger signal that can be sent from the camera to the lighting control. Here, the delay between the trigger signal and the output pulse, the pulse length, and the pulse strength may be configurable.

  The required intensity parameters (such as the nominal value of the current of the LED lighting device used, etc.) are generally entered by the user. This may be performed by a hardware user interface, a web page-based Internet interface, or a lighting control device (lighting controller) configuration or application program. In addition, a customer-specific control function such as a firmware function may be provided. As an example, at each trigger event, a sequence of pulses having different intensities may be output on different illumination channels. In this case, the sequence length, various intensities, and the pulse width for each channel can be configured.

  Thus, conventional industrial camera systems with controllable lighting operate primarily with three separate system components: camera, lighting control, and lighting device. These components are from different companies and need to be adapted to each other by setting parameters via separate user interfaces. These components need to be configured and adapted on the user side, for example via a corresponding native web interface. This is rather cumbersome and requires considerable effort in setting up an industrial camera system for a particular application of the user.

  Accordingly, it is an object of the present invention to improve the operability of lighting control of an industrial image recording system.

  According to the invention, this object is achieved by a device according to claim 1, a method according to claim 11, and a computer program according to claim 13.

  Therefore, by using the direct communication interface with the lighting control device, the camera user interface can be used not only for setting the camera parameters but also for setting the lighting parameters. Thus, only one user interface needs to be directly arranged on the industrial camera. Therefore, since only one software interface needs to be used, the initial setting and operation of the entire industrial image photographing system (MV system) become extremely easy. Also, the direct communication interface can reduce the number of cables or network connections required between the industrial camera and the lighting control device. Further, in the case of bi-directional data transmission via a communication interface, feedback may be performed from the lighting control device to the industrial camera. As a result, the lighting status, that is, the operating state, the error state, the temperature, and the like can be fed back to the user on the camera user interface.

  According to a first advantageous aspect, the industrial camera may comprise a camera module for an embedded vision system and / or the user interface may comprise a GenICam compliant interface.

  According to a second advantageous aspect, the connection line may be adapted to transmit binary information.

  According to a third advantageous aspect, the communication interface comprises: signaling for automatic detection of the lighting control device, automatic parameter setting between the industrial camera and the lighting control device, simple pulsing, and / or It may be used for taking over the lighting control by a camera.

  According to a fourth advantageous aspect, the communication interface may be used for feeding back at least one of a light parameter, an error and a lighting state from a lighting device to the industrial camera.

  According to a fifth advantageous aspect, the brightness of the illumination may be controlled via the communication interface to control the brightness of image capture by the industrial camera.

  The components of the devices proposed to achieve the foregoing objectives may be implemented separately or in discrete circuits, integrated circuits (eg, application-specific integrated circuits (ASICs), or programmable circuits). It may be implemented together as a circuit (eg, a Field Programmable Gate Array (FPGA). Specifically, an industrial camera includes an FPGA as a core element with extended interface capabilities. Also, the steps of a method claim may be implemented as a software program or software routine that controls a processor of a microcontroller for its execution.

The present invention will be described in more detail based on preferred embodiments with reference to the drawings.
FIG. 1 is a schematic block diagram of lighting control with a corresponding autonomous control interface.
FIG. 2 is a schematic block diagram of an illumination system including the camera-side control interface according to the first embodiment.
FIG. 3 is an example of an industrial image capturing system provided with illumination control according to the second embodiment.

  In the following embodiments, an improved operation concept for lighting control of an industrial camera system is presented. First, an overview of the actual contents of the development by the applicant is given.

  The operability of industrial camera systems is enhanced by standardized network and communication architectures. As an example, the camera interface standard is defined by the “Gigabit-Ethernet for Machine Vision (GigE Vision)” standard. This standard uses reliable and affordable Ethernet network technology for communication between the camera and a personal computer (PC). In this regard, GigE Vision provides an open framework for transmitting images and control signals between a camera and a PC over a standard Gigabit Ethernet line. In addition to the advantages of cable length, GigE Vision also improves data security. A general-purpose interface for camera control for all cameras is created according to the “Generic Interface for Camera (GenICam)” standard. This interface is independent of the camera interface and characteristics. This interface can be used for various transmission media such as GigE, Camera Link, and USB. Its purpose is to inform the system of which functions are available to the camera itself, without the need for manufacturer specific software, to ensure unique access to configuration and image feeds. Therefore, the interface technology (GigE Vision, Camera Link, etc.) of the industrial camera can be separated from the user application programming interface (Application Programming Interface: API).

  Using the aforementioned standards, the usability of an industrial camera system can be improved by direct communication between a lighting control component (eg, a controller) and a control device (eg, a personal computer (PC)). .

  FIG. 1 is a schematic block diagram of the illumination control. Here, for example, a standard interface can be used. A control device 110 (e.g., PC, laptop, etc.) with an application interface 111 for integration with lighting control within one industrial camera system may be connected to any data connection link 100 (e.g., GigE Vision or Ethernet / It is connected to a lighting control device (eg, a lighting controller) 120 via a data communication network such as an IP. Accordingly, the user monitors the configuration and / or status of the light sources 121 to 12n (for example, LED lighting devices) connected to the lighting control device 120 using the control device 110 and, for example, the user interface of the application interface 111. You may. The current supply and data exchange between the lighting control device 120 and the light sources 121 to 12n may be performed by separate line connections.

  Further, the configuration of the industrial camera 131 and / or the control of the image capturing may be performed by a corresponding camera interface (for example, GenICam, GigE Vision) 112 of the control device 110. Here, the camera may, for example, issue a trigger signal to synchronize the illumination control with the image trigger to the illumination control device 120 via the trigger line T.

  In this way, the lighting control can be integrated into the industrial camera system, so that the user can configure the light sources 121-12n and monitor their status using the control device 110. As an example, the user may set the timing control of the entire industrial camera system including a plurality of cameras and the pulse operation of the lighting with the same control device 110.

  However, this has the disadvantage that the control and parameter setting of the lighting control device 120 must be performed via a unique application interface 111 and direct feedback from the lighting control device 120 to the industrial camera 131 is not possible. There is.

  According to the embodiment, a new digital communication option is provided between the industrial camera and the lighting control device, and the setting and parameter setting of the entire MV system can be performed through a single camera-side user interface. This allows the user to pre-set lighting parameters (brightness, flash duration, latency, etc.) via, for example, (web-based) camera settings, and optionally from a lighting control device in the case of two-way communication Feedback information may be received.

  FIG. 2 is a schematic block diagram of an MV system including the lighting control according to the first embodiment.

  Referring to FIG. 2, the MV system includes an industrial camera 231 (for example, a GenICam compliant wired MV camera). The industrial camera 231 can be controlled and parameterized by the control device 210 (eg, PC, laptop, etc.) via the camera operation interface 212 (eg, GenICam, GigE Vision). The industrial camera 231 may be, for example, a camera module for an embedded vision system that meets general MV standards and is compliant with GenICam. Various types of embedded vision systems can be used.

  Alternatively, is the industrial camera 231 connected via the camera operation interface 212 by a programming interface (Application Programming Interface: API) for configuring a camera and image capturing by a single board computer (Single Board Computer: SBC)? Or a system-on-chip (SoC) or a field-programmable gate array (FPGA) via data transmission based on low-voltage differential signaling (LVDS). May be connected directly. This allows the industrial camera 231 to be used in multiple embedded vision solutions, such as, for example, portable medical devices, automatic license plate detection systems, industrial inspection solutions, stereo cameras or code readers.

  The camera operation interface 212 may be an interface via a network (for example, a camera operation interface conforming to GenICam). The camera operation interface 212 may preferably be connected directly to the housing of the industrial camera 231 so that a connection cable can be connected via a suitable plug element. GigE Vision, USB3 Vision, CoaxPress, and Camera Link are state-of-the-art technologies that make the camera operation interface 212 compatible with standards-based components and equipment. Each of these techniques meets specific requirements, especially with respect to bandwidth, multi-camera configuration, or cable length. Further, a conventional technology such as FireWire or USB 2.0 may be adopted according to the field of use.

  The programming interface of the camera operation interface 212 may use existing program code without modifying any model of industrial camera and operating system. Here, the relevant software package generally includes a development program set (Software Development Kit (SDK)) and a computer system (for example, Windows (registered trademark) PC, Linux (registered trademark) PC, or Mac). And a driver and a tool that enable the operation of the industrial camera 231 by the PC. This software package is suitable for all operating systems (Windows, Linux x86, Linux ARM, OS X, etc.) and all interfaces and standards (GigE Vision, USB3 Vision, IEEE 1394, Camera Link, BCON for LVDS, etc.). And may include a number of programming examples for common camera applications in multiple supported programming languages (C, C ++, C #, VB.Net, etc.).

  In addition, the MV system according to FIG. 2 includes a lighting control device (for example, a lighting controller) 220 that controls and sets parameters of a plurality of lighting devices (for example, LED lighting devices) 221 to 22n. The lighting control device 220 may be connected to the industrial camera 231 via the direct connection line 200. The lighting control device 220 is responsible for controlling the lighting and may be separate or integrated with the lighting system.

  According to the first embodiment, a lighting control device 220 that is not part of a camera may be able to partially or fully parameterize or control via a camera operation interface 212. Therefore, there is no need to connect the lighting control device 220 to an image processing control device (such as the control device 210). The direct communication between the industrial camera 231 and the lighting control device 220 is performed by, for example, the binary information transmission line 200 (for example, the trigger line T shown in FIG. 1). Thus, the lighting can be operated via the camera operation interface 212. If the industrial camera 231 outputs the trigger signal to the lighting control device 220 in any way, the line used for that purpose may be used as the connection line 200, and the line between the industrial camera 231 and the lighting control device 220 may be used. Can exchange data and instructions. Thus, the operation of the lighting control device 220 (for example, setting of the current intensity, the flash period, and the like) may be performed via the camera operation interface 212. In that case, the corresponding operation element (for example, GenICam node) may be integrated into the camera operation interface 212.

  The lighting control device 220 is provided in a separate housing or in a lighting module. The lighting control device 220 may include a microcontroller that performs communication with the industrial camera 231 and drives the driver stages of the lighting devices 221 to 22n.

  According to the second embodiment, a bidirectional interface may be set between the industrial camera 231 and the external lighting control device 220. Via this interface, the user may control and / or adjust the lighting control device 220 and the lighting via the camera operation interface 212, for example receiving feedback information regarding the configuration of the lighting system comprising the lighting devices 221-22n. You may. Therefore, the two-way interface between the industrial camera 231 and the lighting control device is a single camera-side user interface, that is, the parameter setting and control of the lighting control device 220 and the industrial camera 231 via only the camera operation interface 212. enable. In this case, the camera-side user interface may support the GenICam standard. Thereby, the user may set, for example, lighting parameters (brightness, flash period, waiting time, etc.) via the camera operation interface 212, or inquire each of them.

  In addition, the direct connection line 200 to the bidirectional interface between the industrial camera 231 and the lighting control device 220 can automatically detect the connected lighting control device 220 by the industrial camera 231 and / or the industrial camera 231. May be used for data exchange for automatic parameter setting between the camera and the lighting control device 220, and optionally for taking over control by the industrial camera 231. Thereby, light parameters (for example, type designation, maximum current, etc.) may be transferred from the lighting control device 220 or each of the lighting devices 221 to 22n to the industrial camera 231. Automatic detection may be performed, for example, via a predefined signal (signal sequence, data pattern, data sequence, etc.). In this case, the industrial camera 231 monitors the connection line 200, requests a takeover of control when detecting a predefined signal, and takes over control when receiving a correct response from the lighting control device 220. The use of pulsed lighting can be greatly simplified for the user, since such automatic camera parameterization automatically and optimally adjusts the lighting time sequence and the light switch-on. Pulsed illumination increases light intensity by reducing heat generation in the light, and at the same time, extends life.

  Since the industrial camera 231 may detect the connection of the lighting control device 220 via the bidirectional interface, the industrial camera 231 may autonomously set parameters (for example, correctly configure a binary output). Since the characteristics of the industrial camera 231 and the lighting control device 220 are known, for example, the timing (eg, flash period, waiting time, etc.) may be automatically set in an appropriate manner.

  Further, the industrial camera 231 may not only adjust the illumination time and the gain to control the current brightness, but also adjust the brightness of the illumination. This control is particularly relevant for the industrial camera 231 because the industrial camera 231 has information about the brightness of the real image.

  Further, the lighting control device 220 may notify the industrial camera about the status of the lighting (readiness, temperature, error, etc.), and the industrial camera may indicate the status to the user via the camera operation interface 212. .

  In addition, a failure and / or status response from the lighting devices 221-22n to the industrial camera 231 may be provided by providing corresponding flag information. This has the effect that the industrial camera 231 is the only error feedback source.

  Lighting control device 220 may also have its own trigger input. With this trigger input, the light may be switched on / off without passing through the industrial camera 231. Also, an output may be provided to the lighting control device 220, which may indicate an error condition.

  The camera operation interface 212 may be used not only for the control of the illumination control device 220 but also for a further control device (not shown in FIG. 2) for controlling the lens.

  These extended operation and feedback options greatly simplify lighting integration and operation. Specifically, the user only needs to integrate or configure one programming interface.

  FIG. 3 shows an example of an industrial image capturing system according to the third embodiment. In this system, the lighting control according to the first or second embodiment may be used. This image photographing system is a camera-based measurement system including three illumination devices 321 to 323. This system measures the dimensions of the disk-shaped objects 310 and 312 supplied by the conveyor belt 300, and inspects the surface for defects and impurities. The three illumination devices 321 to 323 are controlled and parameter-set via a camera operation interface (not shown in FIG. 3) of the industrial camera 331 that captures four images of the disk-shaped object 310 to be inspected.

  The control of the image capturing process is performed by an image capturing control device (not shown in FIG. 3). The image capture control device is controlled by a direct interface to the industrial camera 331. In the first image, all three lighting devices 321 to 323 are switched on to measure the dimensions of the disc-shaped object 310 to be inspected, and the industrial camera 331 is triggered. In the second image, only the second lighting device 322 is driven at half power to identify surface defects, and the industrial camera 331 is triggered. In the third image, the first lighting device 321 is driven at low power to identify impurities and the industrial camera 331 is triggered. Finally, in the fourth image, the third illuminator 323 is driven at half power to identify subsurface properties, and the industrial camera 331 is triggered again.

  Lighting control programmed via the camera operation interface of the industrial camera 331 is activated for each image capture via the lighting control device. For each trigger, different selected lighting devices 321 to 323 are driven, and four images are captured with different lighting characteristics. When the next object 312 to be inspected appears, the image capturing sequence is repeated.

  In summary, an apparatus and method for controlling illumination in an industrial imaging system has been described. The apparatus includes an operation interface for setting a plurality of image capturing parameters of an industrial camera and a plurality of lighting parameters for setting a lighting control device. Also provided is a communication interface for connecting the direct connection line to the lighting control device and transmitting lighting parameters to the lighting control device. The communication interface may preferably be set up for two-way communication including feedback from the lighting control device to the industrial camera.

  Note that the invention is not limited to the embodiments described above. Rather, various modifications can be made within the scope of the following claims. In particular, the present invention is not limited to a particular data communication or a particular type of interface between the camera and the lighting control device, nor to a particular camera operation interface. Other serial and parallel interfaces may be used as well. The invention can be used for any data transmission between a camera and a controllable device suitable for lighting control.

It is a schematic block diagram of the lighting control provided with the corresponding autonomous control interface. FIG. 2 is a schematic block diagram of an illumination system including a camera-side control interface according to the first embodiment. It is an example of an industrial image capturing system provided with lighting control according to the second embodiment.

Claims (13)

An apparatus of an industrial camera (231) for controlling illumination in an industrial image capturing system,
An operation interface (212) arranged on the industrial camera and configured to set a plurality of image capturing parameters of the industrial camera (231) and a plurality of lighting parameters for setting a lighting control device (220); )When,
A communication interface disposed on the industrial camera, configured to connect a direct connection line (200) to the lighting control device (220), for transmitting the lighting parameters to the lighting control device (220); ,
An apparatus comprising:   The apparatus of claim 1, wherein the lighting parameters are used to set at least one of brightness, flash duration, and latency of the lighting.   The apparatus according to claim 1 or 2, wherein the communication interface is configured for two-way communication including feedback from the lighting control device (220) to the industrial camera (231).   The apparatus of claim 3, wherein the feedback from the lighting control device (220) comprises a configuration of the lighting system comprising a lighting device (221-22n).   The device according to any of the preceding claims, wherein the industrial camera (231) comprises a camera module for an embedded vision system.   The device according to any of the preceding claims, wherein the operating interface (212) comprises a GenICam compliant interface.   Apparatus according to any of the preceding claims, wherein the connection line (200) is adapted for the transmission of binary information.   The communication interface may include signaling for automatic detection of the lighting control device (220), automatic parameter settings between the industrial camera (231) and the lighting control device (220), simple pulsing, and / or 5. The device according to claim 3, wherein the device is used for a handover of the lighting control by a control camera.   9. The method of claim 3, wherein the communication interface is used to feed back at least one of light parameters, errors, and lighting conditions of a lighting device (221-22 n) to the industrial camera (231). 10. An apparatus according to any of the preceding claims.   Apparatus according to any of the preceding claims, wherein the control of the brightness of the image capture by the industrial camera (231) is also performed by controlling the brightness of the illumination via the communication interface. A method for controlling lighting in an industrial imaging system, comprising:
In the operation interface (212) of the camera device (231), a plurality of image capturing parameters of the camera device (231) and a plurality of settings for a lighting control device (220) arranged apart from the camera device (231). Setting the lighting parameters of
-Controlling the lighting parameters via the communication interface located on the camera device (231) and having a direct connection line (200) between the camera device (231) and the lighting control device (220); Transmitting to the device (220);
A method that includes   The method of claim 11, further comprising the step of bi-directionally transmitting data over the communication interface.   A computer program stored on a data carrier and, when executed by a computing device, causes the computing device to perform the method of claim 11.