JP2017072522A - Photoelectric switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoelectric switch that can correctly detect even such a workpiece that changes color among manufacturing lots while suppressing wrong detection.SOLUTION: A photoelectric switch comprises: matching degree calculation means that compares acquired color information with color information on a reference color to calculate a matching degree; detection signal generation means that compares the calculated matching degree with a predetermined detection determination threshold to conduct a workpiece determination; and reference color specification means that specifies a start reference color, additional reference color and interpolation reference color on the basis of a take-in instruction. The reference color specification means is configured to: specify color information acquired on the basis of a first take-in instruction as color information on the start reference color; specify color information acquired on the basis of a second take-in instruction as color information on the additional color reference color; and specify the interpolation reference color based on the start reference color and additional reference color. The detection signal generation means compares the highest matching degree out of a matching degree relative to the start reference color, a matching degree relative to the interpolation reference color, and a matching degree relative to the additional reference color with the detection determination threshold to conduct a workpiece determination.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a photoelectric switch, and more particularly, to an improvement in a photoelectric switch that receives reflected light from a detection region, acquires color information, and performs work determination.

  A photoelectric switch is a detection device that detects light using light, projects detection light, receives reflected light or transmitted light from the work, etc., makes a work determination, and detects a signal based on the result of the work determination. Is generated. The photoelectric switch includes a received light amount type photoelectric switch that performs workpiece determination based on the amount of reflected or transmitted light received from a detection area including the workpiece, and a distance measurement type photoelectric switch that measures the distance to the workpiece and performs workpiece determination. There are a switch and a color discrimination type photoelectric switch that discriminates the color of the workpiece surface and discriminates the workpiece.

  Light-receiving-type photoelectric switches use the fact that the amount of received light varies due to differences in the reflectance or color of the workpiece surface, differences in the distance to the workpiece, differences in the tilt (tilt angle) of the workpiece surface, etc. This is a general-purpose photoelectric switch that can be applied to many purposes. On the other hand, the distance measurement type photoelectric switch measures a feature by measuring the feature depending on the shape of the workpiece as the distance to the workpiece, and changes the reflectance and color of the workpiece surface, and the tilt (tilt angle) of the workpiece surface. It is hard to be affected by fluctuations. In addition, the color discrimination type photoelectric switch determines the workpiece based on the color of the workpiece surface, and is affected by variations in the reflectance of the workpiece surface, variations in the distance to the workpiece, and variations in the workpiece surface tilt (tilt angle). It is difficult to receive.

A conventional photoelectric switch of a color discrimination system includes three light emitting elements that respectively generate red, green, and blue detection lights, and one light receiving element that receives reflected light and generates a light reception signal (for example, a patent). Literatures 1-4). In this type of photoelectric switch, for example, the ratio r _k of the light reception amount levels of the three colors based on the light reception amount levels R _k , G _k , and B _k of the three colors obtained by sequentially lighting the light emitting elements in time division. _{= R k / M k, g} k = G k / M k, represents a color by bk ₌ B _k / _M k (OR _{M k = R k + G k} + B k of the light-receiving amount), corresponding to the work color light It is determined whether or not the quantity level ratios r ₁ , g ₁ , b ₁ match the received light quantity level ratios r ₀ , g ₀ , b ₀ corresponding to the reference color registered in advance. Specifically, by comparing the ratio of the received light amount level of each color with the ratio of the received light amount level of the reference color, the degree of coincidence of the two color information is obtained, and by comparing this degree of coincidence with the determination threshold value, the work determination is performed. Done.

  The received light level of the reference color is determined based on the received light level of each color acquired at the timing designated by the user. For example, a maximum value and a minimum value are obtained for each color component based on a plurality of received light amount levels or a ratio of received light amount levels acquired within a predetermined period, and an intermediate value between the maximum value and the minimum value is the received light of the reference color It is specified as the ratio of the light level or the light receiving level.

JP 2000-112440 A Japanese Patent Laid-Open No. 2000-121441 JP 2005-127869 A JP 2005-291748 A

  The conventional photoelectric switch described above uses color matching to determine color information, which is usually represented by three parameters, using a single parameter called matching, and therefore discriminates based on the amount of received light and a threshold value. It can be handled in the same way as a light receiving type photoelectric switch, and is easy to set. On the other hand, in order to correctly detect a work whose color changes within the same work in the conventional photoelectric switch, even if the reference color determined from the maximum value and the minimum value obtained for each color component is used, The judgment threshold value of the conventional photoelectric switch must be set sufficiently low according to the amount of change. That is, in the conventional photoelectric switch, even if the optimum reference color is obtained, depending on the amount of change in the color, even if the work color is a work having a low degree of coincidence with the reference color, it is determined as a work. Thus, there is a problem that the detection accuracy is lowered. For example, there has been a problem that a desired workpiece cannot be detected correctly due to the influence of the color of the workpiece between manufacturing lots, the contamination of the workpiece surface, the blur of the print mark, and the color deterioration.

  The present invention has been made in view of the above circumstances, and provides a photoelectric switch that can correctly detect even a workpiece whose color changes between manufacturing lots while suppressing erroneous detection. Objective.

  The photoelectric switch according to the first aspect of the present invention includes: a light projecting unit that projects detection light toward a detection region; a light receiving unit that receives reflected light from the detection region and generates a light reception signal; Color information acquisition means for acquiring color information based on two or more of the received light signals respectively corresponding to the specific wavelengths of the color, and the degree of coincidence between the two color information by comparing the acquired color information with the color information of the reference color A degree-of-matching calculating means for calculating a workpiece, comparing the calculated degree of matching with a predetermined detection determination threshold value to determine a workpiece, and generating a detection signal based on the result of the workpiece determination And a reference instruction specifying means for specifying a start reference color, an additional reference color, and an interpolation reference color based on the input instruction. The reference color designation means designates the color information acquired based on the first take-in instruction as color information of a start reference color, and the second take-in instruction after the first take-in instruction The color information acquired based on the reference color is designated as color information of the additional reference color, and color information between the start reference color and the additional reference color based on the color information of the start reference color and the color information of the additional reference color Designation of one or more interpolation reference colors for interpolation is performed. The degree-of-match calculation means compares the color information with the color information of the start reference color, the color information of the interpolation reference color, and the color information of the additional reference color when the color information is newly acquired. The degree of coincidence is calculated. The detection signal generation means performs work determination by comparing the degree of coincidence with the start reference color, the degree of coincidence with the interpolation reference color, and the degree of coincidence with the additional reference color with the detection determination threshold. .

  This photoelectric switch is a color discrimination type photoelectric switch, and workpiece determination is performed using two or more reference colors. For this reason, since the detection determination threshold can be set higher than in the case where workpiece determination is performed using one reference color, the workpiece has a color change between production lots while suppressing erroneous detection. Can be detected correctly.

  In addition, since one or more interpolation reference colors for interpolating color information between the start reference color and the additional reference color are automatically specified, it is possible to save the trouble of instructing the capture of the interpolation reference color. In particular, only by designating two points of the start reference color and the additional reference color, the color between them can be added as the interpolation reference color. As a result, when colors vary between individuals (such as lot-to-lot variations), it is only necessary to prepare both ends of the color variation without preparing all color variation work and setting a reference color. It can be set so that color eyes can also be detected.

  Furthermore, the interpolation reference color is designated based on the color information of the start reference color and the color information of the additional reference color. For this reason, the number of interpolation reference colors is suppressed compared to the case where the interpolation reference colors are set regardless of the degree of coincidence between the start reference color and the additional reference color, so that the work determination processing load during actual operation is reduced. Can be reduced.

  In the photoelectric switch according to the second aspect of the present invention, in addition to the above configuration, the reference color designating unit has a degree of coincidence calculated in advance by comparing the color information of the additional reference color with the color information of the start reference color. While the interpolation reference color is designated when it is equal to or less than the predetermined interpolation judgment threshold, the interpolation reference color is not designated when the degree of coincidence exceeds the interpolation judgment threshold.

  According to such a configuration, since the interpolation reference color is designated according to the degree of coincidence between the start reference color and the additional reference color, the interpolation reference color is determined regardless of the degree of coincidence between the start reference color and the additional reference color. Compared with the case of setting, the processing load for workpiece determination during actual operation can be reduced.

  In the photoelectric switch according to the third aspect of the present invention, in addition to the above configuration, when the coincidence calculation unit newly designates the additional reference color, the color information of the additional reference color is stored in the start reference color. The degree of coincidence is calculated by comparing with the color information, and the degree of coincidence is calculated by comparing with the color information of all the additional reference colors specified before the additional reference color and the color information of the interpolation reference color. The reference color designating means compares the degree of coincidence with the start reference color, the degree of coincidence with the interpolation reference color and the degree of coincidence with the additional reference color with the interpolation determination threshold value to compare the interpolation reference color Is configured to specify.

  According to such a configuration, the interpolation reference color is designated by narrowing down to the reference color having the highest degree of coincidence. Therefore, it is possible to reduce the processing load of the interpolation determination as to whether or not to interpolate the reference color, as compared with the case where the degree of coincidence is compared with the interpolation determination threshold for all the reference colors.

  In addition to the above configuration, the photoelectric switch according to the fourth aspect of the present invention displays the highest degree of coincidence among the degree of coincidence with the start reference color, the degree of coincidence with the interpolation reference color, and the degree of coincidence with the additional reference color. It comprises a display means. According to such a configuration, the workpiece can be moved or the posture of the workpiece can be changed while checking the degree of coincidence used for the interpolation determination as to whether or not to interpolate the reference color. For this reason, the workability at the time of setting the reference color can be improved.

  A photoelectric switch according to a fifth aspect of the present invention includes a determination threshold value specifying unit that specifies the detection determination threshold value and the interpolation determination threshold value based on a pressing operation on an operation key in addition to the above configuration, and the display unit includes: The detection determination threshold value and the interpolation determination threshold value are configured to be displayed. According to such a configuration, the detection determination threshold value and the interpolation determination threshold value can be arbitrarily designated by operating the operation keys.

  In the photoelectric switch according to the present invention, since workpiece determination is performed using two or more reference colors, it is possible to correctly detect even a workpiece whose color changes between manufacturing lots while suppressing erroneous detection.

It is the top view which showed one structural example of the photoelectric switch 1 by embodiment of this invention. FIG. 2 is a plan view showing an upper surface and a rear surface of the housing 10. FIG. 2 is a block diagram illustrating an example of a functional configuration in the photoelectric switch 1 of FIG. 1. FIG. 4 is a block diagram illustrating a configuration example of a main control unit 100 in FIG. 3. It is explanatory drawing which showed operation | movement of the photoelectric switch 1 of FIG. 3 compared with the comparative example. It is explanatory drawing which showed typically an example of the operation | movement at the time of the setting of the interpolation reference color in the photoelectric switch 1 of FIG. 4 is a flowchart illustrating an example of an operation when setting a reference color in the photoelectric switch 1 of FIG. 3. 4 is a flowchart showing an example of an operation when setting an interpolation reference color in the photoelectric switch 1 of FIG. 3. It is the flowchart which showed an example of the operation | movement at the time of the operation mode in the photoelectric switch 1 of FIG.

  Embodiments of the present invention will be described below with reference to the drawings. In this specification, for the sake of convenience, the direction of the optical axis (principal axis) of the light projecting lens is described as the front-rear direction. However, the posture of the photoelectric switch according to the present invention is not limited.

<Photoelectric switch 1>
FIG. 1 is a plan view showing a configuration example of a photoelectric switch 1 according to an embodiment of the present invention, in which a color discrimination type photoelectric switch 1 is shown. (A) in the drawing shows the front surface of the housing 10 and (b) shows the right side surface of the housing 10. FIG. 2 is a plan view showing the upper surface and the rear surface of the housing 10, and (a) in the drawing shows the indicator lamp 3, the operation key 6 and the adjustment screw 7 provided on the upper surface. ) Shows the operation keys 5 and the display panel 8 provided on the back surface.

  The photoelectric switch 1 is a detection device that projects detection light, receives reflected light from a detection region, performs workpiece determination, and outputs a detection signal based on the result of workpiece determination. The workpiece determination is performed by determining the color of the workpiece surface, and a detection signal indicating whether the workpiece is acceptable or not is output.

  The housing 10 of the photoelectric switch 1 is a casing for housing circuit elements and optical components. The housing 10 is provided with a light projecting / receiving window cover 2, an indicator lamp 3, a wiring cable 4, operation keys 5 and 6, an adjusting screw 7 and a display panel 8. The detection light is emitted from the front surface of the housing 10 and the reflected light from the detection region is incident on the front surface. The light projecting / receiving window cover 2 is a protective transparent plate that closes the light projecting / receiving opening formed on the front surface of the housing 10, and is attached to the housing 10.

  The indicator lamp 3 is an LED (light emitting diode) indicator that is turned on according to the result of the workpiece determination, and is disposed at the front end of the upper surface of the housing. The operation key 6 is a push-type set key used when specifying a reference color for workpiece determination, and is disposed on the upper surface of the housing 10. The adjustment screw 7 is an operator for changing the distance to the detection region and adjusting the size of the projection spot, and is arranged on the upper surface of the housing 10.

  The operation key 5 is a push-down direction key used when a threshold value for workpiece determination is designated, and includes an up key 5a and a down key 5b. The numerical value can be incremented by operating the up key 5a, and the numerical value can be decremented by operating the down key 5b. The operation keys 5 a and 5 b are disposed on the back surface of the housing 10.

  The wiring cable 4 includes a power cable for supplying power to the circuit elements in the housing 10 and a signal cable for transmitting a control signal and a detection signal. The lead-out portion of the wiring cable 4 is disposed at the lower end on the rear surface of the housing.

  The display panel 8 is a display device that displays a threshold value and a degree of coincidence for workpiece determination, and is disposed on the back surface of the housing 10. For example, the display panel 8 is a 7 segment display. The display panel 8 may be an active matrix driving display device such as an LCD (Liquid Crystal Display).

  FIG. 3 is a block diagram showing an example of a functional configuration in the photoelectric switch 1 of FIG. The photoelectric switch 1 includes a main control unit 100, a light projecting drive unit 101, a color filter 102, a light receiving element unit 103, an amplifier unit 104, a memory 105, a power supply unit 106, an input / output unit 107, a display unit 108, and an operation unit 109. Composed.

  The main control unit 100 controls light projection and reception, and performs workpiece determination based on the light reception signal. The light projecting drive unit 101 drives the light emitting diode 21 based on an instruction from the main control unit 100. For example, the light projecting drive unit 101 is driven by a high-frequency pulse adjusted so that the average current is constant.

  The light emitting diode 21 is a light emitting element that generates detection light including two or more color components having different hues. The light emitting diode 21 is formed of a semiconductor chip that generates white light as detection light, and is surface-mounted on a circuit board. For example, the light emitting diode 21 is a white LED (Light Emitting Diode) that generates white light by mixing light of two colors having complementary colors.

  The detection light is emitted through a projection lens (not shown). The light projection lens forms an image of the detection light on the detection area. As the projection lens, a chromatic aberration correction lens that suppresses chromatic aberration, for example, an achromatic lens composed of two or more optical lenses having different dispersion rates is used. On the other hand, the reflected light from the detection region is incident through a light receiving lens (not shown). The light receiving lens forms an image of the reflected light on the light receiving surface of the light receiving element unit 103.

  The light receiving element unit 103 selectively receives reflected light from the detection region corresponding to two or more specific wavelengths, and generates two or more received light signals respectively corresponding to the received light amounts for the specific wavelengths. The light receiving element unit 103 is a multi-division PD unit in which two or more PDs (Photo Diodes) 22 are two-dimensionally arranged on a circuit board. For example, the PDs 22 are arranged in a 12 × 24 matrix.

  The color filter 102 is an optical element that selectively transmits light of a color component having a specific wavelength according to a two-dimensional position, and is disposed on the light receiving surface of the light receiving element unit 103. In the color filter 102, an R filter region, a G filter region, and a B filter region that selectively transmit any of red light, green light, and blue light are arranged in a matrix. Each of the R filter region, the G filter region, and the B filter region is formed of a minute rectangular region, and is formed in association with the PD 22.

  The amplifier unit 104 is an amplifier unit that amplifies the light reception signal input from each PD 22 and outputs the amplified signal to the main control unit 100. The amplifier unit 104 can switch the gain. The light reception signal is amplified for each color component of a specific wavelength and output to the main control unit 100.

  The memory 105 holds a workpiece determination threshold value, reference color information, and the like. The power supply unit 106 is connected to an external device such as a controller via the wiring cable 4 and supplies DC power to the main control unit 100 and the light projecting drive unit 101 based on the control of the main control unit 100. The input / output unit 107 is connected to an external device such as a controller via the wiring cable 4, receives a control signal, outputs the control signal to the main control unit 100, and outputs the detection signal input from the main control unit 100 to the external device. Send.

  The display unit 108 displays the workpiece determination threshold and the degree of coincidence on the display panel 8 based on the control of the main control unit 100. The operation unit 109 generates an operation signal based on the pressing operation of the operation keys 5 a, 5 b, and 6 and outputs the operation signal to the main control unit 100. The operation unit 109 is a take-in instruction receiving unit that receives a take-in instruction for taking in the color information of the reference color, and inputs a take-in instruction to the main control unit 100 based on a pressing operation on the operation key 6.

  The main control unit 100 identifies a long press operation and a short press operation on the operation key 6 and selects a reference color designation method. The long press operation is a press operation in which the operation continues for a certain length of time, and the operation start and operation end are detected. The short press operation is a press operation whose duration is less than the above time length.

  For example, one point tuning, color unevenness tuning or interpolation tuning is selected as the reference color designation method. One-point tuning is a method in which only one color information is designated as the color information of the reference color, and color information is taken in by detecting a long press operation of the operation key 6 and designated as the reference color.

  Color unevenness tuning is a method of sequentially specifying two or more reference colors, and a short press operation of the operation key 6 and a subsequent long press operation are detected. In color unevenness tuning, the color information captured based on the short press operation of the operation key 6 is designated as the color information of the start reference color, and 1 color is selected from the color information captured based on the long press operation after the short press operation. Alternatively, color information of two or more additional reference colors is specified.

  Interpolation tuning is a method of designating an interpolation reference color for interpolating color information between two reference colors. Color information is taken in by detecting a simultaneous long press operation of the operation key 6 and the operation key 5a. In the interpolation tuning, the color information acquired based on the first short press operation of the operation key 6 is designated as the color information of the start reference color, and the color information acquired based on the subsequent short press operation is the color information of the additional reference color. Specified. When an additional reference color is newly specified, one or more interpolation reference colors for interpolating color information are automatically inserted between the additional reference color and the reference color specified before the additional reference color. Specified.

  For example, the interpolation tuning may be tuning performed when a reference color is added after setting a reference color by one-point tuning or color unevenness tuning. When the reference color is set by one-point tuning, that is, when interpolation tuning is performed after long-pressing the operation key 6 for the workpiece to be detected and setting the reference color, the reference color for the one-point tuning becomes the start reference color, An additional reference color is specified by interpolation tuning, and one or more interpolation reference colors are automatically specified as necessary so that the color between the start reference color and the additional reference color can be detected without interruption. .

  In addition, when interpolation tuning is performed after setting a reference color by color unevenness tuning, an additional reference color is specified by interpolation tuning for multiple reference colors set by color unevenness tuning, and the specified additional The degree of coincidence is obtained between the reference color and a plurality of reference colors, and one or more as necessary, so that the color between the reference color having the largest degree of coincidence and the additional reference color can be detected without interruption. An interpolation reference color is automatically specified.

<Main control unit 100>
FIG. 4 is a block diagram showing a configuration example of the main control unit 100 of FIG. The main control unit 100 includes a light projection amount control unit 110, a color information acquisition unit 111, a reference color designation unit 112, a reference color storage unit 113, a coincidence degree calculation unit 114, a detection signal generation unit 115, a capture period designation unit 116, The determination threshold value specifying unit 117, the determination threshold value storage unit 118, and the notification unit 119 are configured.

  The light projection amount control unit 110 controls the light projection drive unit 101 based on the light reception signal input from the amplifier unit 104 and adjusts the light projection amount by the light emitting diode 21. For example, when the amount of reflected light received exceeds a certain level, the amount of emitted light is reduced. On the other hand, when the amount of received light falls below the certain level, control is performed to increase the amount of emitted light and return to the original state.

  In the light emission amount control unit 110, the amplifier unit 104 is controlled based on the light reception signal input from the amplifier unit 104, and the gain is switched. For example, when the amount of reflected light received exceeds a certain level, the gain of the amplifier unit 104 is reduced. On the other hand, when the amount of received reflected light falls below the certain level, the gain of the amplifier unit 104 is increased to increase the original gain. Control to return to the state is performed. These light emission control is performed based on the received light amount of RGB. Alternatively, it is performed based on parameters obtained by combining the received light amounts of RGB.

The color information acquisition unit 111 acquires color information based on two or more received light signals respectively corresponding to two or more specific wavelengths and outputs the color information to the coincidence calculation unit 114 and the reference color designation unit 112. The acquired color information is determined based on the received light amount levels of the three colors. For example, if the received light amount level of red light is R ₁ , the received light amount level of green light is G ₁ , the received light amount level of blue light is B _1, and the sum of received light amounts is M _k = R _k + G _k + B _k. According to the set (r ₁ , g ₁ , b ₁ ) using the ratios r _k = R _k / M _k , g _k = G _k / M _k , and b _k = B _k / M _k of the three light reception levels. Color is expressed. The color information (r ₁ , g ₁ , b ₁ ) is periodically and repeatedly acquired.

The reference color designating unit 112 designates the color information (r ₀ , g ₀ , b ₀ ) acquired by the color information acquiring unit 111 as the color information of the reference color based on the capture instruction from the operation unit 109. The reference color storage unit 113 holds the color information (r ₀ , g ₀ , b ₀ ) of the reference color registered by the reference color specifying unit 112.

The coincidence calculation unit 114 uses the color information (r ₁ , g ₁ , b ₁ ) acquired by the color information acquisition unit 111 as the reference color information (r ₀ , g ₀ , b ₀ ), the degree of coincidence C between the two color information is calculated and output to the detection signal generation unit 115. The degree of coincidence C is a parameter indicating the degree of color coincidence, and it is quantitatively evaluated how much the color to be compared is similar to the color registered as a reference for work determination.

For example, the degree of coincidence C is expressed using an integer in the range of 0 to 999. If the color to be compared completely matches the reference color, the matching degree C is 999. The display unit 108 displays the matching degree C calculated by the matching degree calculation unit 114 on the display panel 8. In addition, as the color information, a set of r _k , g _k , and b _k (r _k , g _k , b _k ), which is the ratio of the received light amount level of each color, has been illustrated. Not limited to. For example, a combination (R _k , G _k , B _k ) of a received light level of red light, a received light level of green light, and a received light level of blue light may be used as color information. Further, the color information is not limited to the RGB color system, and a set of color component values based on the color system such as Lab may be used as the color information.

  The detection signal generation unit 115 compares the degree of coincidence C calculated by the degree of coincidence calculation unit 114 with a predetermined detection determination threshold Cd, performs work determination, generates a detection signal, and outputs the detection signal to the input / output unit 107. . The detection signal is generated based on the result of the work determination. In the operation mode, every time color information is newly acquired, the degree of coincidence C is calculated, and the work determination is performed.

  The capture period designation unit 116 designates a reference color capture period based on a capture instruction from the operation unit 109. The reference color capture period is a parameter adjustment period in color unevenness tuning, and is specified by identifying a short press operation and a long press operation on the operation key 6. For example, the reference color capture period is a time from the start of operation of the long press operation after the short press operation to the end of the operation after the short press operation of the operation key 6.

  The reference color designating unit 112 designates two or more reference colors based on the capture instruction from the operation unit 109. That is, the reference color designating unit 112 uses the color information acquired within the reference color capture period as the color information of the candidate color, and compares the matching degree C between the candidate colors with a predetermined additional determination threshold value Ct. Specify the reference color.

  Specifically, the reference color designation method in the color unevenness tuning will be described. The reference color designation unit 112 designates the candidate color acquired at the beginning of the reference color capture period as the start reference color, and the color of the start reference color. Information is stored in the reference color storage unit 113. The color information of the start reference color is acquired based on a short press operation of the operation key 6.

  Next, when a candidate color is newly acquired, the reference color designating unit 112 designates the candidate color as an additional reference color if the degree of matching C of the candidate color with the start reference color is less than the additional determination threshold value Ct. The color information of the color is stored in the reference color storage unit 113. On the other hand, the reference color specifying unit 112 does not specify an additional reference color if the degree of matching C is equal to or greater than the additional determination threshold Ct. The reference color storage unit 113 holds color information of the start reference color and color information of the additional reference color.

  When a candidate color is newly acquired, the matching degree calculation unit 114 compares the color information of the candidate color with the color information of the start reference color to calculate the matching degree C, and the candidate color is acquired. The degree of coincidence C is calculated by comparing with the color information of all the additional reference colors specified before. The reference color specifying unit 112 specifies the additional reference color by comparing the highest match C between the match C for the start reference color and the match C for the additional reference color with the additional determination threshold Ct.

  When the reference color specifying unit 112 newly designates the additional reference color, the notification unit 119 notifies the user that the reference color has been added. Specifically, the user is notified of the addition of the reference color by turning on the indicator lamp 3. For example, when the reference color is added, the indicator lamp 3 is turned on with a display color different from that used when the workpiece is determined. The indicator lamp 3 is turned on for a certain period of time each time a new reference color is designated.

  The display unit 108 displays on the display panel 8 the highest degree of coincidence C between the degree of coincidence C for the start reference color and the degree of coincidence C for the additional reference color. With such a configuration, the workpiece can be moved or the posture of the workpiece can be changed while confirming the degree of coincidence C used for addition determination as to whether or not to add the candidate color to the reference color.

  The determination threshold value specification unit 117 specifies the detection determination threshold value Cd and the additional determination threshold value Ct based on the operation signal from the operation unit 109 and stores them in the determination threshold value storage unit 118. The determination threshold storage unit 118 holds the detection determination threshold Cd and the additional determination threshold Ct registered by the determination threshold specifying unit 117. The detection determination threshold value Cd and the additional determination threshold value Ct can be arbitrarily designated or changed by operating the operation keys 5a or 5b. The detection determination threshold Cd and the additional determination threshold Ct may be the same value.

  The display unit 108 displays either the detection determination threshold value Cd or the additional determination threshold value Ct specified by the determination threshold value specification unit 117 on the display panel 8 according to the operation state. That is, in the operation mode, the detection determination threshold value Cd is displayed. On the other hand, during color unevenness tuning, an additional determination threshold value Ct is displayed.

  When the color information is newly acquired in the operation mode, the coincidence calculation unit 114 compares the color information with the color information of the start reference color to calculate the coincidence C, and the color information of the additional reference color The degree of coincidence C is calculated by comparison. When the color information is newly acquired, the detection signal generation unit 115 obtains the highest matching degree C among the matching degrees C calculated by comparing the color information with the color information of two or more reference colors. Work determination is performed in comparison with the detection determination threshold Cd.

  Next, a reference color designation method in interpolation tuning will be described. The reference color designating unit 112 designates an additional reference color and an interpolation reference color based on the simultaneous long pressing operation of the operation key 6 and the operation key 5a after setting the reference color by one-point tuning or color unevenness tuning. Stored in the color storage unit 113. In other words, the reference color specifying unit 112 sets the reference color by one-point tuning, and when a simultaneous long press operation on the operation key 6 and the operation key 5a is detected, the reference color for one-point tuning is set as the start reference color. In addition to designating the newly acquired color information as the color information of the additional reference color, one or more interpolation standards are necessary so that the color between the start reference color and the additional reference color can be detected without interruption. Specify the color.

  The reference color designating unit 112 sets a plurality of reference colors set in the color unevenness tuning when a simultaneous long press operation on the operation key 6 and the operation key 5a is detected after setting the reference color by color unevenness tuning. On the other hand, the newly acquired color information is designated as the color information of the additional reference color, and the degree of coincidence C is obtained between the designated additional reference color and the plurality of reference colors, and the largest degree of coincidence C among them is obtained. One or more interpolation reference colors are designated as necessary so that the color between the reference color and the additional reference color can be detected without interruption.

  Specifically, the interpolation reference color is designated when the degree of coincidence C calculated by comparing the color information of the additional reference color with the color information of the start reference color is equal to or less than a predetermined interpolation determination threshold Ch. Is called. On the other hand, when the degree of coincidence C exceeds the interpolation determination threshold Ch, the interpolation reference color is not designated.

  When the additional reference color is newly designated, the coincidence calculation unit 114 compares the color information of the additional reference color with the color information of the start reference color to calculate the coincidence C, and from the additional reference color Also, the degree of coincidence C is calculated by comparing with the color information of all the additional reference colors specified previously and the color information of the interpolation reference colors.

  The reference color designating unit 112 compares the matching degree C with respect to the start reference color, the matching degree C with respect to the interpolation reference color, and the matching degree C with respect to the additional reference color with the interpolation determination threshold value Ch to compare the interpolation reference color. Specify. When an interpolation reference color is designated, one or more interpolation reference colors are automatically set between the newly designated additional reference color and the reference color having the highest matching degree C. For example, the color information of the interpolation reference color is calculated by linear interpolation.

  When the color information is newly acquired in the operation mode, the degree of coincidence calculation unit 114 compares the color information with the color information of the start reference color, the color information of the interpolation reference color, and the color information of the additional reference color to make a match Each degree C is calculated. The detection signal generation unit 115 compares the degree of coincidence C with respect to the start reference color, the degree of coincidence C with respect to the interpolation reference color, and the degree of coincidence C with respect to the additional reference color with the detection determination threshold Cd to perform work determination. Do.

  The display unit 108 displays on the display panel 8 the highest match C among the match C for the start reference color, the match C for the interpolation reference color, and the match C for the additional reference color. With such a configuration, the workpiece can be moved or the posture of the workpiece can be changed while confirming the degree of coincidence C used for interpolation determination as to whether or not to interpolate the reference color.

  The determination threshold value specifying unit 117 specifies the interpolation determination threshold value Ch based on the operation signal from the operation unit 109 and stores it in the determination threshold value storage unit 118. The interpolation determination threshold Ch can be arbitrarily designated or changed by operating the operation keys 5a or 5b. The detection determination threshold value Cd and the interpolation determination threshold value Ch may be the same value. The display unit 108 displays the interpolation determination threshold value Ch specified by the determination threshold value specification unit 117 on the display panel 8.

  FIG. 5 is an explanatory diagram showing the operation of the photoelectric switch 1 of FIG. 3 in comparison with a comparative example, and schematically shows the operation when setting a reference color for work determination. (A) in the figure shows the case of the photoelectric switch 1 according to the present invention, and (b) shows a comparative example. In this figure, when the candidate color measurement points are plotted on a two-dimensional plane in the color space, the horizontal axis represents the color component a and the vertical axis represents the color component b.

  In the photoelectric switch 1 according to the present invention, the color information acquired within the reference color capture period is used as the color information of the candidate color, and the degree of coincidence C between candidate colors is compared with the additional determination threshold value Ct to designate the additional reference color 32. Is done. A region 31 is a color distribution range of the target work. If the color unevenness is large, the region 31 is widened.

  The start reference color 30 is a candidate color acquired at the beginning of the reference color capture period. The additional reference color is a candidate color having a matching degree C with the start reference color 30 that is less than the additional determination threshold Ct. The measurement points of the start reference color 30 and the additional reference color 32 are in the region 31. The radius of the circle 33 added to the measurement point of the start reference color 30 and the additional reference color 32 corresponds to the addition determination threshold value Ct. As the additional determination threshold Ct is higher, the radius of the circle 33 is smaller.

  If there is dirt or gradation on the work surface, the saturation and brightness will change greatly even if the hue is the same. In the case of such a workpiece, the change in color within the same workpiece is represented as an elongated region 31. By filling the region 31 with a circle 33, it is possible to correctly detect a workpiece whose color changes.

  According to the present invention, since the work determination is performed using the reference color having the highest degree of coincidence C among the two or more reference colors, even if the detection determination threshold Cd is set high, the color changes within the same work. It is possible to correctly detect the workpiece as described above.

  On the other hand, in the comparative example, one reference color 43 is designated based on the two measurement points 41 and 42 instructed to take in color information by the user. The measurement point of the reference color 43 is a midpoint between the two measurement points 41 and 42, and each color component of the reference color 43 is an average value of the color components of the measurement points 41 and 42. The radius of the circle 44 added to the measurement point of the reference color 43 corresponds to the determination threshold value. In order to correctly detect a workpiece whose color corresponds to the measurement point 41 or 42, the determination threshold must be set sufficiently low. That is, in order to correctly detect a workpiece whose color changes within the same workpiece, the radius of the circle 44 must be sufficiently large. For this reason, there is a problem that NG workpieces having completely different colors are erroneously detected.

  FIG. 6 is an explanatory diagram schematically showing an example of the operation when setting the interpolation reference color in the photoelectric switch 1 of FIG. (A) in the drawing shows a case where four interpolation reference colors 35 are designated between the start reference color 30 and the additional reference color 32. When the matching degree C between the start reference color 30 and the additional reference color 32 is equal to or less than the interpolation determination threshold Ch, the interpolation reference color 35 is designated.

  Further, the division number n when designating the interpolation reference color 35 is designated based on the degree of coincidence between the start reference color 30 and the additional reference color 32 and the interpolation determination threshold Ch. (N-1) interpolation reference colors 35 are equally arranged on a line segment connecting two reference colors. The radius of the circle 34 added to the measurement point of the start reference color 30 corresponds to the interpolation determination threshold value Ch. The higher the interpolation determination threshold Ch is, the smaller the radius of the circle 34 is.

  (B) in the drawing shows a case where two interpolation reference colors 35 are designated between two additional reference colors 32. When the degree of coincidence C between the additional reference color 32 and the newly specified additional reference color 32 is equal to or less than the interpolation determination threshold Ch, the interpolation reference color 35 is specified.

  (C) in the figure shows a case where two interpolation reference colors 35 are designated between the interpolation reference color 35 and the additional reference color 32. When the additional reference color 32 is newly designated, the color information of the additional reference color 32 is compared with the color information of the start reference color 30, and the degree of coincidence C is calculated. The degree of coincidence C is calculated by comparing the color information of all the specified additional reference colors 32 and the color information of the interpolation reference color 35. If the highest matching degree C among the matching degree C with respect to the start reference color 30, the matching degree C with respect to the interpolation reference color 35, and the matching degree C with respect to the additional reference color 32 is equal to or less than the interpolation determination threshold Ch, the interpolation reference color 35 is obtained. Is specified.

Steps S101 to S109 in FIG. 7 are flowcharts showing an example of the operation when setting the reference color in the photoelectric switch 1 in FIG. In the figure, a processing procedure after detecting a short press operation on the operation key 6 is shown. First, the main control unit 100 reads the current amount of received light, calculates color information including the ratios r _k , g _k , and b _{k of the} amount of received light for each color component, and registers them as start reference colors (steps S101 to S103). ).

Next, if the main control unit 100 detects a long press operation on the operation key 6 (step S104), the main control unit 100 acquires color information and calculates a matching degree C. That is, the main control unit 100 reads the current received light amount, calculates the color information composed of the received light amount ratios r _k , g _k , and b _k for each color component, and sets it as a candidate color (step S105). Then, the main control unit 100 compares the color information of the candidate color with the color information of the start reference color and obtains a matching degree C (Step S106).

  The main control unit 100 compares the calculated degree of coincidence C with the additional determination threshold Ct. If the degree of coincidence C is less than the additional determination threshold Ct, the main control unit 100 designates the candidate color as an additional reference color and proceeds to the next processing procedure. (Steps S107 and S108). If the degree of coincidence C is equal to or greater than the additional determination threshold Ct, the main control unit 100 does not designate a candidate color as an additional reference color and proceeds to the next processing procedure.

  The processing procedure after step S105 is repeated until the operation key 6 is released, and if the end of the long press operation is detected, this processing ends (step S109). Further, in step S106, the degree of coincidence C is calculated by comparing the color information of the candidate color with the color information of the start reference color and the color information of the additional reference color specified before the candidate color. In step S107, the highest matching degree C between the matching degree C with respect to the start reference color and the matching degree C with respect to the additional reference color is compared with the additional determination threshold value Ct to designate the additional reference color.

Steps S201 to S208 in FIG. 8 are flowcharts showing an example of the operation when setting the interpolation reference color in the photoelectric switch 1 in FIG. In the figure, a processing procedure after detecting a simultaneous long press operation on the operation key 6 and the operation key 5a is shown. First, the main control unit 100 reads the current received light amount, calculates color information including the received light amount ratios r _k , g _k , and b _k for each color component, and registers them as additional reference colors (steps S201 to S203). ).

  Next, the main control unit 100 calculates the degree of coincidence C by comparing with the reference colors registered so far, and compares it with the interpolation determination threshold Ch (steps S204 and S205). At this time, if the highest matching degree C is equal to or less than the interpolation determination threshold Ch, the main control unit 100 determines the division number n from the matching degree between the reference color and the additional reference color having the highest matching degree C and the interpolation determination threshold Ch. Is determined (step S206). Then, the main control unit 100 calculates the interpolation color information from the color information of the reference color and the additional reference color having the highest degree of matching C and the division number n, and registers it as the interpolation reference color (steps S207 and SS208). On the other hand, if the highest matching degree C exceeds the interpolation determination threshold Ch, the main control unit 100 ends this process without specifying the interpolation reference color.

Steps S301 to S307 in FIG. 9 are flowcharts showing an example of the operation in the operation mode in the photoelectric switch 1 in FIG. First, the main control unit 100 reads the current received light amount and calculates color information including the ratios r _k , g _k , and b _k of the received light amount for each color component (steps S301 and S302). Next, the main control unit 100 compares the acquired color information with the color information of the reference color and calculates the degree of coincidence C (step S303). The main control unit 100 repeats the processing procedure of step S303 if other reference colors are registered, and proceeds to the next processing procedure if the degree of coincidence C is calculated for all reference colors (step S304). . That is, the degree of coincidence C is calculated for all reference colors registered as the start reference color and the additional reference color.

  Next, the main control unit 100 selects the highest matching degree Cmax among the matching degrees C for each reference color (step S305), and performs work determination by comparing with the detection determination threshold Cd (steps S306 and S307). . That is, if the matching degree Cmax is equal to or greater than the detection determination threshold Cd, it is determined that the workpiece is a desired workpiece, and if the matching degree Cmax is less than the detection determination threshold Cd, it is determined that the workpiece is a defective workpiece.

  According to the present embodiment, since workpiece determination is performed using two or more reference colors, the detection determination threshold Cd can be set higher than in the case where workpiece determination is performed using one reference color. Thus, it is possible to correctly detect even a workpiece whose color changes between production lots while suppressing erroneous detection.

  In addition, since one or more interpolation reference colors for interpolating color information between the start reference color and the additional reference color are automatically specified, it is possible to save the trouble of instructing the capture of the interpolation reference color. Furthermore, the interpolation reference color is designated based on the color information of the start reference color and the color information of the additional reference color. For this reason, the number of interpolation reference colors is suppressed compared to the case where the interpolation reference colors are set regardless of the degree of coincidence between the start reference color and the additional reference color, so that the work determination processing load during actual operation is reduced. Can be reduced.

  In addition, since the interpolation reference color is designated according to the matching degree C between the start reference color and the additional reference color, the interpolation reference color is set regardless of the matching degree C between the start reference color and the additional reference color. In comparison, it is possible to reduce the processing load for workpiece determination during actual operation.

  Further, the interpolation reference color is designated by narrowing down to the reference color having the highest matching degree C. Therefore, it is possible to reduce the processing load for the interpolation determination as to whether or not to interpolate the reference color, as compared with the case where the degree of coincidence C is compared with the interpolation determination threshold Ch for all the reference colors.

In the present embodiment, an example has been described in which the degree of coincidence C is calculated based on the ratios r _k , g _k , and b _k of the light reception amount levels of the three colors. The calculation method is not limited to this. The configuration may be such that the degree of coincidence C is obtained based on the ratios r _k , g _k , b _k of the received light amount levels of the three colors and the sum M _{k of the} received light amounts. By using such a degree of coincidence C, not only chromatic work, but also work in which the hue and saturation are similar and only lightness changes greatly, especially achromatic colors having black and white shades. Can be detected correctly.

  Further, in the present embodiment, an example has been described in which notification is performed by turning on the indicator lamp 3 when a reference color is added, but the present invention limits the notification method when a reference color is added. is not. For example, the configuration may be such that the user is notified of the addition of the reference color by audio output.

  In this embodiment, an example in which a reference color capture instruction is input based on a pressing operation of the operation key 6 has been described. However, the present invention provides a method for instructing capture of a reference color. However, the present invention is not limited to this. For example, based on a trigger signal input from an external device such as a controller, the configuration may be such that color information is captured and specified as color information for a reference color.

  In the present embodiment, an example has been described in which the reference color capture period is defined by a short press operation of the operation key 6 and a subsequent long press operation. However, the present invention is not limited to the reference color capture period. The specification method is not limited to this. For example, the period from the first short press operation to the operation key 6 to the second short press operation may be used as the reference color capture period. Alternatively, the period from the first short pressing operation on the operation key 6 until a predetermined time elapses may be set as the reference color capturing period. Alternatively, the period from the first short pressing operation on the operation key 6 until the number of color information acquisitions exceeds a certain number may be used as the reference color capturing period.

  In this embodiment, an example in which white light including two or more color components having different hues is used as detection light has been described. However, the present invention is not limited to this. For example, a configuration in which three light emitting elements that respectively generate red, green, and blue detection lights are provided as light sources for light projection, and the respective light emitting elements are sequentially turned on in a time-sharing manner.

  In the present embodiment, an example in which reflected light is received using the light receiving element unit 103 formed of a multi-division PD unit has been described. However, the present invention limits the configuration of the light receiving element unit 103 to this. is not. For example, the light receiving element unit 103 may include a spectroscope that splits reflected light into three color components and three light receiving elements that receive each color component. Alternatively, when red, green, and blue detection lights are sequentially projected in a time division manner, a configuration in which one light receiving element is provided as the light receiving element unit 103 may be used.

DESCRIPTION OF SYMBOLS 1 Photoelectric switch 2 Light emitting / receiving window cover 3 Indicator lamp 4 Wiring cables 5, 6 Operation key 7 Adjustment screw 8 Display panel 10 Case 21 Light emitting diode 22 PD (photodiode)
30 Start reference color 31 Region 32 indicating color distribution range Additional reference colors 33 and 34 Circle 35 indicating allowable color difference Interpolation reference color 100 Main control unit 101 Light projecting drive unit 102 Color filter 103 Light receiving element unit 104 Amplifier unit 105 Memory 106 Power supply Unit 107 input / output unit 108 display unit 109 operation unit 110 light intensity control unit 111 color information acquisition unit 112 reference color designation unit 113 reference color storage unit 114 coincidence calculation unit 115 detection signal generation unit 116 capture period designation unit 117 determination threshold Specification unit 118 Determination threshold value storage unit 119 Notification unit

Claims (5)

Light projecting means for projecting detection light toward the detection area;
A light receiving means for receiving reflected light from the detection region and generating a light reception signal;
Color information acquisition means for acquiring color information based on two or more received light signals respectively corresponding to two or more specific wavelengths;
A degree of coincidence calculation means for comparing the acquired color information with the color information of the reference color and calculating the degree of coincidence of both color information;
Detection signal generation means for comparing the calculated degree of coincidence with a predetermined detection determination threshold value to perform work determination, and generating a detection signal based on the result of the work determination;
An import instruction accepting means for accepting an instruction for taking in the reference color;
A reference color specifying means for specifying a start reference color, an additional reference color, and an interpolation reference color based on the capture instruction;
The reference color designation means designates the color information acquired based on the first take-in instruction as color information of a start reference color, and the second take-in instruction after the first take-in instruction The color information acquired based on the reference color is designated as color information of the additional reference color, and color information between the start reference color and the additional reference color based on the color information of the start reference color and the color information of the additional reference color Specify one or more interpolation reference colors to interpolate
The degree-of-match calculation means compares the color information with the color information of the start reference color, the color information of the interpolation reference color, and the color information of the additional reference color when the color information is newly acquired. Calculate the degree of match,
The detection signal generation means performs work determination by comparing the degree of coincidence with the start reference color, the degree of coincidence with the interpolation reference color, and the degree of coincidence with the additional reference color with the detection determination threshold. A photoelectric switch characterized by that.   The reference color specifying means specifies the interpolation reference color when the degree of coincidence calculated by comparing the color information of the additional reference color with the color information of the start reference color is equal to or less than a predetermined interpolation determination threshold value. On the other hand, if the degree of coincidence exceeds the interpolation determination threshold value, the interpolation reference color is not designated. When the additional reference color is newly specified, the coincidence degree calculation means calculates the degree of coincidence by comparing the color information of the additional reference color with the color information of the start reference color, and the additional reference color The degree of coincidence is calculated by comparing the color information of all the additional reference colors specified before and the color information of the interpolation reference colors,
The reference color designating means compares the degree of coincidence with the start reference color, the degree of coincidence with the interpolation reference color, and the degree of coincidence with the additional reference color with the interpolation determination threshold value to determine the interpolation reference color. 3. The photoelectric switch according to claim 2, wherein designation is performed.   4. The photoelectric device according to claim 3, further comprising display means for displaying a matching degree with respect to the start reference color, a matching degree with respect to the interpolation reference color, and a matching degree with respect to the additional reference color. switch. A determination threshold value specifying means for specifying the detection determination threshold value and the interpolation determination threshold value based on a pressing operation on the operation key;
The photoelectric switch according to claim 4, wherein the display unit displays the detection determination threshold value and the interpolation determination threshold value.

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