JP6482266B2 - Lighting control power supply and lighting control method - Google Patents

Description

  The present invention relates to an illumination control power source and an illumination control method for controlling an illuminator based on the brightness of an image captured by a camera.

  Industrially used image-based visual inspection systems include, as lower-level devices, an illumination control power source for controlling an LED illuminator, a camera for imaging a work illuminated by the LED illuminator, and an image output from the camera. And an image processing device for making an image suitable for appearance inspection, and the sequence control is performed on the operation control timing of the illumination control power source, the camera, the image processing device, etc. as an upper layer device. It consists of PLC.

  In the system using the PLC, specifications such as protocols and connections are established so that communication for exchanging data and signals between the PLC, which is an upper layer device, and each lower layer device can be established relatively easily. A method and the like are defined, and the user does not have to spend much effort to establish communication between the upper layer and the lower layer.

  On the other hand, in such a system, for example, it is not basically assumed that data is directly exchanged between lower-layer devices. Therefore, when trying to control the LED illuminator so that the brightness of the image is kept constant based on the brightness of the image captured by the camera, first, the illumination control power source, the image processing device, The user performs communication settings and the like and installs a control program in the image processing apparatus so that data can be directly exchanged between them.

  More specifically, in the appearance inspection system 300A in which the illuminator 101A is controlled based on the brightness of the image shown in Patent Document 1 and FIG. 6, the target brightness of the image that is the brightness of the image that is desired to be kept constant. A function as a dimming value calculation unit 102C that calculates a dimming value input to the illumination control power supply 100A by feedback calculation with respect to a deviation between the value and an actually measured luminance value that is the brightness of an actually captured image is realized. Is installed separately from the program for the image processing unit 102B in the image processing apparatus 102A. Further, the illumination control power supply 100A and the image processing apparatus 102A are directly connected by wiring, and data indicating a dimming value is transmitted from the image processing apparatus 102A to the illumination control power supply 100A. Communication is established.

  However, the communication between the lighting control power source and the image processing device, which is communication between lower-layer devices, needs to be in line with the original data format and communication method used in the lighting control power source. Therefore, it takes much time and effort for the user to establish such communication. In addition, it is necessary to install a lighting control program unrelated to the original function of the image processing apparatus, which is a cause of complicated settings by the user.

JP 2010-8098 A

  The present invention has been made in view of the above-described problems, and it is not necessary to establish communication between devices belonging to a lower layer, so that it is possible to reduce the trouble of installing a lighting control program, and a camera with only simple settings. It is an object of the present invention to provide an illumination control power source and an illumination control method capable of controlling the brightness of an illuminator based on an image captured in (1).

  That is, the illumination control power source of the present invention is an illumination control power source that controls the illuminator based on the brightness of the image captured by the camera, and supplies the illuminator with power according to the received dimming value. A power supply unit to supply; an external shared storage unit; a shared storage unit access unit that acquires brightness of an image captured by the camera stored in the shared storage unit as an actual measurement value; A dimming value is calculated based on the target value set as the brightness of the image to be captured by the camera and the actual measurement value acquired by the shared storage unit access unit, and the calculated dimming value is And a dimming value control unit for inputting to the power supply unit.

  The illumination control method of the present invention further includes a power supply unit that supplies power corresponding to the received dimming value to the illuminator, and controls the illuminator based on the brightness of an image captured by the camera. An illumination control power source is used, and the brightness of an image captured by the camera stored in the shared storage unit is accessed by accessing a shared storage unit outside the illumination control power source. A shared storage unit access step to be acquired as a light source, and a dimming value is calculated based on a target value set as brightness of an image to be captured by the camera and an actual measurement value acquired by the shared storage unit access unit And a dimming value control step of inputting the calculated dimming value to the power supply unit.

  In such a case, the shared storage unit access unit is configured to acquire an actual measurement value related to the brightness of an actual captured image. As long as communication is established, it is possible to control the illuminator based on the brightness of the image.

  That is, the user does not need to establish communication between lower hierarchies such as between the illumination control power supply and the image processing apparatus.

  Further, the illumination control power supply includes the dimming value control unit that calculates a dimming value based on the actual measurement value and the target value of the brightness of the image and inputs the dimming value to the power supply unit. There is no need to install a brightness control program for devices other than the lighting control power supply.

  Therefore, it is possible to greatly reduce the labor and time that the user has spent on the conventional system construction when realizing the control of the illuminator based on the brightness of the image.

  Regardless of the characteristics and specifications of the camera and the image processing apparatus that performs image processing on the image of the camera, a correspondence relationship is created between the dimming value used in the illumination control power supply and the brightness of the image. In order to realize feedback control based on the brightness of the image, a dimming value input mechanism for inputting a desired dimming value to the power supply unit, and the power supply unit are input by the dimming value input mechanism. An initial setting unit that sets an actual measurement value acquired by the shared storage unit access unit as a target value in the dimming value control unit in a state in which power corresponding to the dimming value being supplied is supplied to the LED illuminator; As long as it is further provided.

  In order to reduce the effort related to establishment of communication in the system and to make it possible to realize the control of the illuminator in a short control cycle by reducing the amount of data transmitted and received as much as possible, the shared storage unit includes: A part of data after predetermined image processing is performed by an image processing device on an image captured by the camera is stored, and the shared storage unit performs sequence control on the camera and the image processing device. What is necessary is just to be provided in PLC to perform.

  When realizing control of the illuminator based on the brightness of the image, the shared storage unit access unit communicates only with the PLC so that the system can be constructed without requiring complicated settings from the user. It is only necessary to be configured to perform the above. In such a case, for example, wiring between the PLC and the illumination control power supply may be performed, and only the location of the memory area to be read out may be specified, so that it does not take time for setting compared to the conventional case.

  In the case where the illuminator is an LED illuminator, as a specific embodiment suitable for performing brightness control based on an image, the power supply unit may include a current command corresponding to the received dimming value. A current command output unit for outputting a value, and a constant current control unit for performing a constant current control so that a current value flowing through the LED illuminator becomes a current command value output by the current command output unit. If it is.

  As described above, according to the illumination control power source and the illumination control method of the present invention, the shared storage unit access unit determines the brightness of the image captured by the camera stored in the shared storage unit provided outside. Since it is configured to obtain and perform feedback calculation regarding the brightness of the image within the illumination control power source, the configuration relating to illumination control can be provided only in the illumination control power source. Therefore, it is possible to minimize the trouble of establishing communication and installing a program for lighting control in a device other than the lighting control power source, and it is possible to control an advanced illuminator only by preparing only the lighting control power source of the present invention. Can be realized.

The structural example of the external appearance inspection system using the control power supply for illumination which concerns on one Embodiment of this invention. The schematic diagram shown about the outline | summary of operation | movement of the external appearance inspection system in the embodiment. The typical control block diagram of the external appearance inspection system and the control power supply for illumination in the embodiment. The flowchart which shows operation | movement of the control power supply for illumination in the initial setting mode in the embodiment. The flowchart which shows operation | movement of the control power supply for illumination in the normal operation mode in the embodiment. The typical control block diagram which shows the structure of the conventional external appearance inspection system.

  An illumination control power supply 100 according to an embodiment of the present invention and an appearance inspection system 300 configured using the illumination control power supply 100 will be described with reference to the drawings.

  The appearance inspection system 300 according to the present embodiment is configured to automatically determine the presence or absence of a scratch, a printing error, a defect, or the like on the work W based on a captured image of the work W.

  As shown in FIG. 1, the appearance inspection system 300 images an LED illuminator 101 that irradiates light to the work W, a lighting control power source 100 that controls the LED illuminator 101, and the work W as a lower-level device. And a camera C that outputs a signal indicating the captured image, and an image processing apparatus 102 that receives the signal from the camera C and creates an inspection image by image processing suitable for the inspection. Further, the appearance inspection system 300 includes a PLC 200 that controls the operation timing of the illumination control power source 100, the camera C, and the image processing apparatus 102 as an upper layer apparatus. Basic communication has been established between the two. As can be seen from FIG. 1, in the appearance inspection system 300 of this embodiment, no wiring for direct communication is provided between the illumination control power supply 100 and the image processing apparatus 102. In this embodiment, the upper layer device and the lower layer device are defined from the viewpoint of sequence control, and the device that issues the sequence control command is the upper layer device, and the device that operates based on the command is the lower layer device. It is a hierarchical device. The definition of the upper hierarchy and the lower hierarchy may be defined from other viewpoints.

  In this appearance inspection system 300, the brightness of an image to be captured including the characteristics of the camera C and the image processing apparatus 102 as well as the LED illuminator 101 and the illumination control power supply 100 is controlled. It is configured. More specifically, as shown in FIGS. 2 and 3, the appearance inspection system 300 inputs a target luminance value that is a target value of the brightness of an image captured by the camera C, and the image processing apparatus 102. The feedback control system is configured to output an actually measured luminance value, which is an actually measured value of the brightness of the image after the image processing output from. That is, the LED illuminator 101 irradiates the workpiece W with light, and the camera C captures the reflected light of the workpiece W. Then, the image processing apparatus 102 receives the imaging data signal output from the camera C, and performs predetermined image processing to generate an image for inspection. At this time, the luminance of a background portion that is a part of the image for inspection and has a low possibility of causing scratches or defects, for example, is transmitted to the PLC 200 as an actually measured luminance value. The PLC 200 stores data indicating the actually measured luminance value in a predetermined area of the shared memory M (shared storage unit) designated by the image processing apparatus 102. Finally, the illumination control power supply 100 accesses the shared memory M to acquire the measured luminance value, and changes the power supplied to the LED illuminator 101 so that the measured luminance value matches the target luminance value. . The appearance inspection system 300 is configured so that one cycle of such control is repeatedly performed.

  Next, a specific configuration of the illumination control power supply 100 will be described with reference to FIG.

  The illumination control power supply 100 is constituted by a so-called computer or electric circuit provided with a CPU, a memory, an input / output means, a display device, etc., and an illumination control program stored in the memory is executed, and various devices Are configured to exhibit at least functions as the power supply unit 1, the mode switching unit 2, the dimming value input mechanism 3, the initial setting unit 4, the dimming value control unit 5, and the shared memory access unit 6. It is.

  The configuration and function of each part will be described in detail.

  The power supply unit 1 supplies power corresponding to the received dimming value to the LED illuminator 101. In this embodiment, the dimming value is a value indicating what percentage of the rated output of the illumination control power supply 100 is driven, and a desired value can be set between 0 and 100%, for example. The power supply unit 1 is configured to keep the current value of the current flowing through the LED illuminator 101 constant at a current value corresponding to the received dimming value.

  More specifically, the power supply unit 1 includes a current command output unit 11 that outputs a current command value according to the received dimming value, and a current value that flows through the LED illuminator 101 is the current command output. And a constant current control unit 12 that performs constant current control so that the current command value output by the unit 11 is obtained.

  The current command output unit 11 receives a dimming value input from either the dimming value input mechanism 3 or the dimming value control unit 5, and responds to the dimming value with respect to the rated current. The ratio current value is input to the constant current control unit 12 as a current command value.

  The mode switching unit 2 includes an initial setting mode in which the power supply unit 1 receives a dimming value from the dimming value input mechanism 3 and only current feedback control by the constant current control unit 12 is performed, and the power supply unit. 1 is a normal operation mode in which a dimming value is received from the dimming value control unit 5 and feedback control is performed based on image brightness including characteristics up to the camera C and the image processing apparatus 102. The control system is switched. The control block diagram shown in FIG. 3 shows the state in the normal operation mode, and in the initial setting mode, the ON / OFF of each switch is opposite to that shown in FIG.

  The dimming value input mechanism 3 is used by the user to manually set the dimming value to a desired value in the initial setting mode. It is realized by means.

  The initial setting unit 4 supplies the LED illuminator 101 with power corresponding to the dimming value input by the dimming value input mechanism 3 when the power supply unit 1 is operating in the initial setting mode. In this state, the measured brightness value acquired by the shared memory access unit 6 is set as the target brightness value in the dimming value control unit 5. That is, the measured luminance value when the dimming value is adjusted by the dimming value input mechanism 3 and the brightness of the image output from the image processing apparatus 102 is suitable for appearance inspection is the normal operation. It is set as the target brightness value for the mode.

  On the other hand, the dimming value control unit 5 automatically changes the dimming value input to the power supply unit 1 according to the brightness of the image captured by the camera C in the normal operation mode, and the brightness of the image. Is maintained at the target luminance value set in the initial setting mode. More specifically, the dimming value control unit 5 includes a target luminance value that is a target value set as the brightness of an image to be captured by the camera C, and the shared memory access unit 6 (shared storage). The dimming value is calculated by feedback calculation based on the actual luminance value which is the actual measurement value acquired by the unit access unit), and the calculated dimming value is input to the power supply unit 1. .

  Explaining the specific control operation, the dimming value control unit 5 has zero deviation between the target luminance value and the actually measured luminance value when the target luminance value is set by manual operation in the initial setting mode. The dimming value control unit 5 associates the dimming value received by the power supply unit 1 with a target luminance value as an initial dimming value. If there is a deviation between the target luminance value and the measured luminance value in the normal operation mode, the initial dimming value is changed to another dimming value according to the magnitude of the deviation. Input to the power supply unit 1. For example, when the actually measured luminance value is larger than the target luminance value, the dimming value is set to a value smaller than the initial dimming value so as to reduce the light amount of the LED illuminator 101. Conversely, when the measured luminance value is smaller than the target luminance value, the dimming value is set to a value larger than the initial dimming value so as to increase the light amount of the LED illuminator 101.

  The shared memory access unit 6 accesses an external shared memory M and acquires the brightness of an image captured by the camera C stored in the shared memory M as an actual measurement value. Here, the shared memory access unit 6 communicates only with the shared memory M of the PLC 200 which is an upper layer device, and acquires the luminance value stored in a predetermined area of the shared memory M as the actually measured luminance value. However, it is configured to output to the dimming value control unit 5. In other words, the shared memory access unit 6 is not configured to be communicable with the image processing apparatus 102 or the camera C, which are lower-layer apparatuses, and can directly acquire data from these apparatuses. Is not configured. That is, the shared memory access unit 6 is only indirectly established with the image processing apparatus 102 via the shared memory M through communication that can be easily established with the PLC 200.

  Further, the luminance value stored in the shared memory M is a luminance value in the background portion of the image after the binarization processing or the like is performed by the image processing apparatus 102. The brightness value is transmitted by the camera C to the predetermined area of the shared memory M of the PLC 200 from the image processing apparatus 102 and updated every time image processing in the image processing apparatus 102 is performed. It is set so that. Since the communication between the image processing apparatus 102 and the PLC 200 is also a communication between the upper layer apparatus and the lower layer apparatus, the communication can be easily established without any special setting. is there.

  The operation of the illumination control power supply 100 in the appearance inspection system 300 configured as described above will be mainly described with reference to the flowcharts of FIGS. 4 and 5.

  First, the operation in a state where the initial setting mode is set by the mode switching unit 2 will be described with reference to FIG. First, communication between the illumination control power source 100 and the image processing apparatus 102 is established with the PLC 200 (steps S1 and S2). Next, the user adjusts the dimming value by the dimming value input mechanism 3, and adjusts the illumination state of the LED illuminator 101 (step S3).

  On the other hand, the image processing apparatus 102 performs image processing such as binarization processing on the image captured by the camera C (step S4). In addition, in the image after image processing, for example, a background luminance value other than the inspection area is transmitted from the image processing apparatus 102 to the shared memory M of the PLC 200 (step S5).

  For example, when the user determines that the image output from the image processing apparatus 102 has a brightness suitable for visual inspection, a target luminance value provided in the illumination control power supply 100 is determined. Input to the decision button is performed (step S6). Thereafter, the shared memory access unit 6 of the illumination control power supply 100 accesses the shared memory M of the PLC 200, and acquires the actually measured luminance value stored at that time (step S7). Then, the initial setting unit 4 sets the acquired actual luminance value as a target luminance value in the dimming value control unit 5, and the dimming value control unit 5 sets the set target luminance value and the time point The dimming value input by the dimming value input mechanism 3 is stored as an initial dimming value corresponding to the target luminance value (step S8).

  When the initial setting mode is completed, the mode switching unit 2 switches the control system to the normal operation mode, and the LED illuminator 101 is controlled based on the brightness of the image. That is, as shown in the flowchart of FIG. 5, the image processing apparatus 102 performs image processing based on the captured image data of the workpiece W (step S9), and the image processing apparatus 102 performs back processing on the image after the image processing. The luminance value of the image of the ground portion is transmitted to the shared memory M of the PLC 200 as the actually measured luminance value (step S10).

  On the other hand, in the illumination control power supply 100, the shared memory access unit 6 acquires the measured luminance value from the shared memory M of the PLC 200 (step S11), and the dimming value control unit 5 and the acquired measured luminance value Based on the deviation of the target luminance value set by the initial setting unit 4, the degree to which the initial dimming value should be changed is calculated, and is output to the power supply unit 1 as a new dimming value (step S12). ). The power supply unit 1 performs constant current control so that the current flowing through the LED illuminator 101 is kept constant with a command current value corresponding to the dimming value input from the dimming value control unit 5. (Step S13). The cycle from step S9 to step S13 may be repeated each time a new image is captured by the camera C, for example, or when the camera C captures a predetermined number of times according to the processing speed of each calculation. The target luminance value may be updated. That is, it may be continuous control or batch control.

  As described above, according to the illumination control power supply 100 and the appearance inspection system 300 of the present embodiment, the actual illumination state in which the shared memory M of the PLC 200, which is a higher-level device, is accessed and the state of the entire control system can be considered And the feedback calculation based on the measured luminance value is also performed in the illumination control power supply 100. Therefore, the illumination control power supply 100, which is a subordinate device, and the There is no need to establish communication with the image processing apparatus 102 using a special protocol or the like.

  Therefore, it is possible to realize feedback control based on the brightness of the image simply by connecting the illumination control power supply 100 to the PLC 200, and to greatly reduce the effort required for the user to construct the appearance inspection system 300. it can. Further, since the configuration for controlling the brightness based on the image is substantially provided in the illumination control power supply 100, for example, it is not necessary to install a program other than image processing in the image processing apparatus 102. In addition, the appearance inspection system 300 is easily constructed.

  Furthermore, since the correspondence relationship between the dimming value and the luminance value can be set as appropriate in the initial setting mode, an illumination control system according to the inspection can be easily constructed according to the difference in the workpiece W or the inspection item.

  For these reasons, the user can realize the brightness control based on the image by preparing the illumination control power supply 100 of the present embodiment and connecting it to the PLC 200 and the LED illuminator 101 and performing the minimum setting. This makes it possible to construct a very simple system.

  Other embodiments will be described.

  In the embodiment, the shared memory of the PLC is used as an external shared storage unit of the illumination control power supply. However, for example, a shared register may be used, and the upper layer of the system is not limited to the PLC. The shared storage unit access unit may access the shared memory and the shared register of the computer. Further, the shared storage unit access unit may access a shared memory or a shared register of a computer constituting the image processing apparatus.

  Although the luminance value is used as the actual measurement value or the target value of the image brightness, for example, the illuminator may be controlled based on the image brightness using other values.

  In the above embodiment, the brightness control of the LED illuminator is performed. However, the illumination control power source of the present invention may be used to control the illuminator of other light emission principles.

  The power supply unit performs constant current control of the LED illumination, but may control the LED illuminator by various control methods according to the received dimming value. For example, what is necessary is just to perform control suitable for the purpose such as constant voltage control and PWM control. In this case as well, the command value may be appropriately generated according to the input dimming value.

  In the above embodiment, the illumination control power supply is used to construct an appearance inspection system, but may be used for other purposes. The appearance inspection system may detect not only the presence or absence of scratches but also the outline of the workpiece. In addition, the workpiece is not particularly limited and may be used for various purposes.

  In addition, various modifications and combinations of the embodiments may be made without departing from the spirit of the present invention.

300 ... Appearance inspection system 200 ... PLC
DESCRIPTION OF SYMBOLS 100 ... Illumination control power supply 101 ... LED illuminator 102 ... Image processing apparatus C ... Camera W ... Work 1 ... Power supply part 11 ... Current command output part 12 ... Constant current control unit 2 ... mode switching unit 3 ... dimming value input mechanism 4 ... initial setting unit 5 ... dimming value control unit 6 ... shared memory access unit

Claims (6)

Provided separately from an image processing device that processes an image of a workpiece imaged by a camera, an illumination control power source that controls an illuminator that irradiates the workpiece with light, and the image processing device and the illumination control power source A visual inspection system comprising a shared storage unit for storing the image data obtained by the image processing device,
The control power supply for lighting is
A power according to the received dimming value the illuminator to supply power supply unit,
A shared storage unit access unit that accesses the shared storage unit and acquires the brightness of the image stored in the shared storage unit as an actual measurement value;
The dimming value is calculated based on the target value set as the brightness of the image to be captured by the camera and the actual value acquired by the shared storage unit access unit, and the calculated dimming value A dimming value control unit that inputs the power to the power supply unit ,
An appearance inspection system configured so that the illumination control power source can control the illuminator without directly communicating with the image processing apparatus . A dimming value input mechanism for inputting a desired dimming value to the power supply unit;
In a state where the power supply unit supplies power to the illuminator according to the dimming value input by the dimming value input mechanism, the measured value acquired by the shared storage unit access unit is set as a target value. The visual inspection system according to claim 1, further comprising an initial setting unit that is set in the dimming value control unit. The shared storage unit stores a part of data after predetermined image processing is performed by an image processing apparatus on an image captured by the camera.
The visual inspection system according to claim 1, wherein the shared storage unit is provided in a PLC that performs sequence control of the camera and the image processing apparatus. The appearance inspection system according to claim 3, wherein the shared storage unit access unit is configured to communicate only with the PLC. The illuminator is an LED illuminator;
The power supply unit
A current command output unit that outputs a current command value according to the received dimming value;
The constant current control part which performs constant current control so that the electric current value which flows into the said LED illuminator may become the electric current command value which the said electric current command output part outputs comprises. The appearance inspection system described. Provided separately from an image processing device that processes an image of a workpiece imaged by a camera, an illumination control power source that controls an illuminator that irradiates the workpiece with light, and the image processing device and the illumination control power source A visual inspection method using a shared storage unit that stores the image data obtained by the image processing device,
The electric power corresponding to the received dimming value and the power supply step of supplying to said illuminator,
Accessing the shared storage unit, and the shared storage unit access acquiring a brightness of the image stored in the shared storage unit as the measured value,
A dimming value is calculated based on the target value set as the brightness of the image to be captured by the camera and the actual value acquired by the shared storage unit access unit, and the calculated dimming value is calculated. A dimming value control step for inputting to the power supply unit ,
An appearance inspection method, wherein the illumination control power source controls the illuminator without directly communicating with the image processing apparatus .