JP4447441B2 - Displacement sensor and displacement measurement method - Google Patents

Description

  The present invention relates to a displacement sensor and a displacement measuring method for measuring a displacement such as a dimension of an article based on a light cut image, for example.

  Displacement sensors that measure displacement such as the dimensions of an article based on a light section image (an image obtained by a light section method) are known. In this type of displacement sensor, the measurement point coordinates are automatically extracted from the image acquired from the image sensor incorporated in the sensor head by using a predetermined measurement point extraction algorithm, and the purpose is determined from the automatically extracted measurement point coordinates. The amount of displacement to be calculated is calculated.

  In the sensor head, a laser diode that outputs a spot beam (cross-sectional minute circular beam) and a line beam (cross-sectional linear beam) to be cutting light, and a region including those beam irradiation points are photographed from different angles, An image pickup device (one-dimensional CCD, two-dimensional CCD, etc.) that generates and outputs an image including a variation corresponding to the detection target displacement is incorporated.

  On the main device side, the measurement point coordinates are automatically extracted from the images acquired from each of one or two or more sensor heads using a user-specified measurement algorithm. Thereafter, the actual displacement is calculated from the automatically extracted measurement point coordinates by, for example, triangulation calculation.

  In the case where an allowable variation value (threshold value) of the displacement amount is set, an allowable value determination process is further performed, and a binary signal that is a quality determination result of the target product is output.

  In such a conventional displacement sensor, if a measurement point extraction algorithm or the like is specified in advance, a measurement point is automatically extracted from the acquired image, and finally a corresponding displacement amount is calculated. It does not take much time for the user.

  However, all data used in the process from image acquisition to displacement calculation (raw image from the image sensor, automatically extracted measurement point coordinates, various automatically set threshold values, etc.) should be checked at all. Absent.

  Therefore, if the measured displacement value shows an abnormal value or the judgment value is bad, it is determined whether the measurement object is truly abnormal or whether the sensor malfunctioned due to ambient light, etc. Can not do it.

  In addition, in the conventional displacement sensor, it is not possible to extract the measurement points by arbitrarily limiting the field of view of the image sensor. This problem is particularly noticeable in a displacement sensor using a two-dimensional image sensor (such as a two-dimensional CCD). That is, in a displacement sensor using a two-dimensional image sensor, there are usually a large number of pixel columns extending in the displacement direction in parallel (several tens of columns). If the points and bottom points have to be extracted, the product becomes extremely inconvenient.

  The present invention has been made paying attention to the above-mentioned conventional problems, and its object is to improve the usability of this type of displacement sensor.

  A more specific object of the present invention is to provide a displacement sensor capable of easily confirming data used in the process from image acquisition to displacement amount calculation.

  Other objects and effects of the present invention should be easily understood by those skilled in the art by referring to the following description of the specification.

The displacement sensor according to the present invention is based on the received light intensity distribution acquired from the image sensor, and a predetermined measurement point extraction algorithm is used to change the height of the measurement target article on the received light intensity distribution. Displacement sensor based on the optical cutting method that automatically extracts the measurement point coordinates in the direction in which the position of the reflected light image changes , and calculates the displacement amount in the height direction of the surface of the article to be measured based on the automatically extracted measurement point coordinates It is.

  Here, the “imaging element” is intended to be an imaging element that can identify the address of the light receiving position corresponding to the displacement by arranging a plurality of pixels in the displacement measuring direction. Therefore, an image sensor that cannot specify the address of the light receiving position such as PSD is excluded. The imaging element referred to here includes at least a one-dimensional CCD and a two-dimensional CCD.

  The “measurement point extraction algorithm” includes various conventionally known algorithms. For example, a peak value search algorithm, a bottom value search algorithm, an average value search algorithm, a closest approach value search algorithm from a sensor, and the like will be included in at least this.

  “Measurement point coordinates” is coordinate data that is the basis for calculating the displacement. The accuracy of this coordinate data can be defined in pixel units or sub-pixel units. If a two-dimensional image sensor is used as the image sensor, the measurement point coordinates could have a two-dimensional value. However, in general, the basis for the displacement calculation will be the coordinate value in the displacement direction.

  “Automatic extraction” means meaning without human intervention. However, it is not intended to exclude even interactive processing such as inquiring the user to select a mode in the process of extracting measurement point coordinates.

  The “calculation formula from the measurement point coordinates” will vary depending on the optical arrangement of the sensor head. In general, the corresponding displacement amount can be obtained from the measurement point coordinates by the principle of triangulation.

  Needless to say, the data output from the displacement sensor is not limited to the calculated displacement amount data. For example, the displacement amount data can be applied to an allowable range threshold specified by the user, and a determination result corresponding to a non-defective product or a defective product can be output.

In addition to the above configuration, in the displacement sensor of the present invention, on the line bright waveform indicating the received light intensity distribution in the direction is changed the position of the reflected light image on the imaging device, the position of the reflected light image Display data editing means for editing display data for an image monitor for displaying an image in which a graphic showing the allowable range of measurement values in the changing direction is displayed.

  According to such a configuration, the product quality determination process can be verified by comparing the peak portion of the line bright waveform with a figure such as a boundary line indicating the allowable range of measurement values.

Here, since it is “display data editing means”, the image monitor in the displacement sensor of the present invention is not an essential requirement. That is, in the displacement sensor of the present invention, it is sufficient that at least the display data editing means is provided, and the image monitor may be provided integrally from the beginning, and if necessary, a commercially available image monitor is provided. May be.

In a preferred embodiment, the display data for the image monitor, on a line bright waveform, in addition to the figure indicating the measurement value tolerance range in the direction of position changes of the reflected light image on the imaging device, the measuring point You may make it correspond to the image which overlays and displays the figure which shows a coordinate, and the figure which shows the measured value tolerance | permissible_range in a displacement measurement direction.

  According to such a configuration, by comparing the line bright waveform with a figure such as a mark indicating the automatically extracted measurement point, a figure such as a boundary line indicating the allowable measurement value range, and the line bright waveform, the peak of the line bright waveform is obtained. The relationship between the part, the automatically extracted measurement point coordinates, and the measurement value allowable range can be easily confirmed.

In another preferred embodiment, the display data for the image monitor, on a line bright waveform, in addition to the figure indicating the measurement value tolerance range in the direction of position changes of the reflected light image on the imaging device, wherein You may make it correspond to the image which overlaps and displays the symbol which shows the determination result obtained by the comparison with a measurement point coordinate and the said measurement value tolerance | permissible_range.

As is clear from the above description, according to the present invention, it is possible to check the data used in the process of image acquisition, displacement amount calculation, and determination through the display on the image monitor, and thereby the measured displacement When the quantity shows an abnormal value or when the determination result is abnormal, it is easy to determine whether the measurement object is truly abnormal or whether the sensor malfunctioned due to ambient light or the like .

  A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

  As described above, the displacement sensor of the present invention automatically extracts the measurement point coordinates from the received light luminance distribution acquired from the image sensor using a predetermined measurement algorithm, and uses the automatically extracted measurement point coordinates. A displacement sensor for calculating a displacement amount to be displayed has display data editing means for editing data used in the process from image acquisition to displacement amount calculation into display data for an image monitor.

  A block diagram showing an example of a system configuration of a displacement sensor to which the present invention is applied is shown in FIG.

  As shown in the figure, the displacement sensor 1 includes a main body device 10, two sensor heads 20A and 20B, an image monitor 30, and an operating device 40. Reference numeral 50 indicates an external device such as a PLC. The main unit 10 forms the center of the present displacement sensor and is mainly composed of a microprocessor. As will be described later with reference to FIG. 3, various processing functions are implemented in software in the main body device 10.

  The sensor heads 20A and 20B are devices that detect a displacement amount to be converted into position information on the light receiving screen. An example of the sensor heads 20A and 20B is shown in FIG. As shown in the figure, the sensor heads 20A and 20B include a laser diode 201 that emits laser light, a slit plate 202 disposed on the front side of the laser diode 201, and laser light that has passed through the slit plate 202 as an object to be detected. A lens system 203 for focusing and irradiating on the lens 60; a lens system 204 for focusing the light from the detection object 60; and an image sensor arranged so that a light image obtained via the lens system 204 is connected to the light receiving surface. 205.

  Since the slit of the slit plate 202 has a linear shape, the light beam irradiated on the detection object 60 is a line beam (a beam having a linear cross section). In this example, the axial direction of the line beam (the longitudinal direction of the cross section of the line beam) is a direction orthogonal to the paper surface.

  On the other hand, the image sensor 205 is a two-dimensional CCD element in this example. In particular, this two-dimensional CCD element has an elongated rectangular field of view. As an example, 1077 pixels in the long side direction and 68 pixels in the short side direction orthogonal thereto are arranged on the light receiving surface of the CCD element. The direction of the line beam formed on the light receiving surface is a direction orthogonal to the longitudinal direction of the light receiving surface of the CCD element.

  Returning to FIG. 1, the operating device 40 is of a handy type, and on the surface thereof, an up key and a down key (not shown) for moving a cursor are arranged in addition to a numeric keypad and various function keys. The operation device 40 is connected to the main body device 10 via a predetermined electric cord.

  The image monitor 30 receives the monitor output (display data) output from the main device 10 and displays a corresponding image on the screen. As this image monitor 30, any commercially available display such as a CRT display or a liquid crystal display can be adopted.

  The external device 50 receives the displacement amount data output D1 and the determination output D2 output from the main device 10, and for example, a programmable controller (PLC) corresponds to this. The main device 10 is a main part of the present invention, and automatically extracts measurement point coordinates from the images acquired from the two sensor heads 20A and 20B using a user-specified measurement point extraction algorithm. Then, from the automatically extracted measurement point coordinates, the actual displacement amount is calculated by, for example, triangulation calculation, and when the displacement variation allowable value (threshold value) is set, An allowable value determination process is performed to generate a binary signal that is a quality determination result of the target product. Then, the generated displacement amount data output D1 and the determination output D2 which is a binary signal are sent to the external device 50.

  A block diagram showing the internal functional configuration of the main unit is shown in FIG. As shown in the figure, the main body apparatus is roughly composed of a measurement unit 110 and a control unit 120. The measurement unit 110 includes an interface unit 111 for the sensor head and an image calculation unit 112 that processes image data captured from the sensor heads 20A and 20B via the interface unit 111.

  On the other hand, in the control unit 120, a GUI unit 121 that functions as an interface with the image monitor 30 and the operation unit 40, and an appropriate process is applied to the image data sent from the measurement unit 110 to the GUI unit 121. An image processing unit 122 for sending out, an external output interface unit 124 for sending out the displacement data output D1 and the determination output D2 described above to an external device, and a control processing unit 123 for overall control of the entire apparatus. It is out.

  Next, a data flow in the apparatus will be described. The sensor head control unit 111B included in the interface unit 111 controls the light amount of the laser diode 201 (see FIG. 2) so that the received light amount of the CCD built in the sensor heads 20A and 20B is appropriate. In this state, the image data D3 captured by the CCDs in the sensor heads 20A and 20B is captured into the measuring unit 110 by the action of the image capturing unit 111A.

  The image data thus captured by the measurement unit 110 is sent to the image transfer unit 112A and the measurement processing unit 112B in the image calculation unit 112. The image transfer unit 112A sends the image data D3 coming from the image capture unit 111A to the image processing unit 122 in the control unit 120. Further, the measurement processing unit 112B performs measurement processing based on the image data D3, obtains the displacement amount data D1 and the determination output D2, and sends these data D7 to the control processing unit 123 in the control unit 120.

  The measurement point coordinate automatic extraction processing and displacement amount measurement processing, which are the main parts of the present invention, are mainly realized by the measurement processing unit 112B.

  The control processing unit 123 in the control unit 120 obtains line beam direction measurement point coordinate data D8 based on the data D7 sent from the measurement processing unit 112B, and sends this to the image processing unit 122. The image processing unit 122 sends image data and data D4 including line bright to the GUI unit 121. The GUI unit 121 receives various commands from the operation device 40, edits the display data, and sends this to the image monitor 30 as the monitor output D5.

  The display data editing process, which is a main part of the present invention, is mainly realized by the image processing unit 122 and the GUI (graphic user interface) unit 121.

  Next, the displacement amount measuring operation of the displacement sensor described above will be described in detail with reference to the flowchart of FIG. In the figure, in the first step, an image photographed by the CCD in the sensor head is taken into the apparatus main body (step 401).

  FIG. 5 shows an explanatory diagram of an image captured by the CCD in the sensor head. As shown in the figure, the CCD built in the sensor head has an elongated rectangular visual field 71. The X direction along the long side of the field of view is the displacement direction, and the Y direction along the short side is the line beam direction (hereinafter also simply referred to as the line direction). In the field of view 71 of the sensor, a line beam image (irradiation light image) 72 is drawn as a zigzag straight line in this example. In the displacement direction, the left side in the figure is the direction closer to the sensor head, and the right side is the direction farther from the sensor head.

  Returning to FIG. 4, as a next step, a feature point extraction process within the measurement range is executed (step 402). An explanatory diagram of the measurement point extraction process within the measurement range is shown in FIG. As shown in the figure, in the field of view 71 of the sensor, a measurement range 73 is indicated by two parallel dotted lines 74 and 75 extending in the left-right direction in the figure. In this measurement point extraction process, the peak position (Px, Py) and the bottom position (Bx, By) are extracted by using a predetermined feature point extraction algorithm within the measurement range (measurement point extraction range) 73. Is done. As will be described later, the start point straight line 74 and the end point straight line 75 that specify the measurement range (measurement point extraction range) 73 are set in advance by the user.

  Returning to FIG. 4, in the next step, the line bright of the line including the feature point is extracted (step 403). An explanatory diagram showing the relationship between the image captured by the CCD and the line bright waveform is shown in FIG. As shown in the figure, in this line bright extraction process, the received light intensity of each pixel is extracted on the line including the peak position indicated by the alternate long and short dash line in the figure, and this is arranged in the displacement direction. The line bright waveform 76 shown in FIG. As shown in FIG. 7, the line bright waveform 76 is drawn on orthogonal coordinates with the horizontal axis as the displacement direction and the vertical axis as the gradation.

  Returning to FIG. 4, in the next step, the measurement point coordinates on the line bright are extracted according to a predetermined extraction algorithm (step 404). The extraction of the measurement point coordinates is performed through a threshold value determination process and a measurement point coordinate extraction process. An explanatory diagram showing an example of the threshold value determining method is shown in FIG. As shown in the figure, the threshold value TH is determined as a% with respect to the luminance Vp of the pixel PP indicating the peak value. That is, it is automatically determined as TH = Vp × a%. An explanatory diagram of the measurement point coordinate extraction process is shown in FIG. In this example, three types of measurement point coordinate extraction methods are prepared: a centroid mode, an edge center mode, and a one-side edge mode. In the center-of-gravity mode, as shown in FIG. 9A, the measurement point is obtained as the density center of gravity of the portion exceeding the threshold value TH indicated by hatching in the figure. In the edge center mode, a measurement point is obtained as the center of two edges that are the intersections of the line bright waveform and the threshold value TH. Further, in the one-side edge mode, a measurement point is obtained as one-side edge between the line bright waveform and the threshold value TH.

  Returning to FIG. 4, in the next step, the displacement amount is calculated from the measurement point coordinates (step 405). This displacement amount calculation processing is obtained as displacement amount Z = A × B / (C × X), for example, when the optical system is triangulation. Here, X is a displacement direction coordinate, and A, B, and C are constants determined by the optical system.

  Returning to FIG. 4, in the next step, the obtained displacement amount (determination output if necessary) is output to the image monitor 30 and the external device 50 (step 406). The calculation of the determination result based on the determination value designated by the user is performed as follows, for example.

Judgment result HIGH: When the displacement is larger than the HIGH judgment value Judgment result PASS: LOW judgment value? Displacement amount? HIGH judgment value (good product)
Judgment result LOW: When displacement is smaller than LOW judgment Judgment result ERROR: When sensor becomes incapable of measurement An explanatory diagram of a method of generating an image on the monitor screen is shown in FIG. As shown in the figure, in this embodiment, four (layer) image memories (0) to (3) are used. Among them, the image memory (0) is the raw image captured from the sensor head, the image memory (1) is the screen frame judgment value, the fixed drawing component, etc., and the image memory (2) is the line bright and measurement. In the image memory (3), the amount of displacement and the criterion are stored. The data on the screen memories (0) to (3) are read out by being overlapped with each other by the actions of the GUI unit 121 and the image processing unit 122, and are output to the image monitor 30 as monitor output (display data) D5. Sent.

  Next, some specific display examples on the image monitor 30 will be described with reference to FIGS.

  FIG. 11 shows an example of a monitor screen in a state where normal measurement values are obtained. As shown in FIG. 4B, in this example, the reference distance between the sensor head and the measurement object is set to 100 mm, and the displacement is measured within a range of 20 mm before and after that. Suppose. As shown in FIG. 5A, the screen of the image monitor is divided into four stages in the vertical direction. These areas are an image display area 77, a graph display area 78, a numerical value display area 79, and a guide display area 80 in order from the top.

  In the image display area 77, a raw image (gradation image) acquired from a two-dimensional CCD as an image sensor is displayed. In the figure, reference numeral 81 indicates a line beam image, and reference numeral 82 indicates a cross symbol indicating the measurement point coordinates on the raw image.

  In the graph display area 78, the line bright waveform is displayed together with vertical and horizontal ruled lines. Reference numeral 83 indicates a line bright waveform, and reference numeral 84 indicates vertical and horizontal ruled lines. Reference numeral 85 represents a cross symbol indicating the measurement point coordinates on the line bright waveform. Further, two dotted lines 86 and 87 extending in the vertical direction in the figure are determination reference values for LOW and HIGH.

  The numerical value display area 79 displays a numerical value indicating the displacement amount and a symbol indicating the determination result. In the figure, numeral 88 indicates a numerical value (+101.5345) indicating a measured value, and numeral 89 indicates a symbol (PASS) indicating a determination result.

  FIG. 12 illustrates an example of a monitor screen in a state where the image and the line bright waveform are enlarged in the displacement axis direction. In the figure, the same components as those in FIG. As shown in the figure, in this example, both the raw image on the image display area 77 and the line bright waveform 83 on the graph display area 78 are greatly enlarged in the displacement measurement direction. For this reason, the line beam image indicated by reference numeral 81 is drawn thick in a circular shape instead of a linear shape. By enlarging and displaying the raw image and the line bright waveform in this way, the relationship between the measurement point coordinates and the raw image and the line bright waveform can be made clearer, and the relationship between the two must be confirmed precisely. Can do.

  An explanatory diagram showing an example of a monitor screen in a state where erroneous measurement due to disturbance has occurred is shown in FIG. In the figure, the same components as those in FIG. In this example, although the optical image 81 based on the normal line beam is within the allowable range, as shown by reference numeral 89, the determination result is LOW, which is a defective product. On the other hand, when the raw image in the image display area 77 is viewed, a light image based on the disturbance light appears at a position deviated below the lower limit value as indicated by reference numeral 90, and the measurement point as indicated by reference numeral 82. It can be seen that the cross symbol 82 indicating the coordinates is located in the erroneous light image 90. Similarly, when the graph display region 78 is viewed, the true peak on the line bright curve 83 is within the allowable range, but the peak based on the disturbance is located below the lower limit value. It can be seen that the cross symbol indicating the measurement point coordinates indicated by reference numeral 85 is located at the peak value due to the disturbance light. From these displays, the user understands that the actual product displacement amount is not abnormal, but malfunctioned due to an erroneous light image 90 caused by ambient light.

  FIG. 14 is an explanatory diagram showing an example of a monitor screen in a state where a step difference measurement is performed using two sensor heads simultaneously. In the figure, the same components as those in FIG. As shown in FIG. 14 (b), in this example, two sensor heads (0) and (1) are arranged opposite to the measurement object, respectively, and the distance from each is measured. The distance deviation (step) is automatically calculated and output. That is, as shown in FIG. 9A, in this example, a numerical value (+4.5345) indicating a step is displayed in the numerical value display area 79 as indicated by reference numeral 88. In addition, the image display area 77 is divided into two upper and lower rows, in which a raw image relating to the sensor head (0) is displayed in the upper part, and a raw image relating to the sensor head (1) is displayed in the lower part. In addition, optical images 81a and 82a corresponding to line beams and cross symbols 81b and 82b indicating measurement point coordinates are displayed on each raw image. In the graph display area 78, line bright waveforms 83a and 83b corresponding to the sensor heads (0) and (1) and cross symbols 85a and 85b indicating measurement point coordinates are displayed. Therefore, according to the above image display, when any abnormality occurs, it can be confirmed which of the sensor heads (0) and (1) has occurred. In this case, the symbol (PASS) indicating the determination result indicated by reference numeral 89 corresponds to the allowable width for the step.

  FIG. 15 shows an example of a monitor screen in a state in which the displacement amount data is displayed in time series. In addition, about the same component as FIG. 11, the same code | symbol is attached | subjected and description is abbreviate | omitted. As shown in FIG. 15 (a), in this example, the distance between the parts A and B sequentially conveyed on the belt conveyor and the sensor head is sequentially measured, and the result is shown in FIG. 15 (a). As shown in FIG. 4, the time-series waveform (trend graph) 91 is displayed on the graph display area 78. At this time, in the image display area 77, a light image 81 of the line beam at that time and a cross symbol 82 indicating the measurement point are displayed. According to such display contents, it is possible to smoothly perform the measurement process while clearly grasping the tolerance or variation of the parts A and B sent sequentially.

  Next, the setting process of the measurement range 73 described in the previous measurement will be described. As described above, in the displacement sensor of this embodiment, two sensor heads 20A and 20B can be connected. Further, as shown in FIG. 14, it is possible to measure a step while simultaneously operating these sensor heads. Naturally, it is possible to select and set these two sensor heads separately.

  An explanatory view showing a monitor screen at the time of the sensor head selection operation is shown in FIG. In the figure, the same components as those in FIG. A dialog box 92 is opened by performing a predetermined operation with the operating device 40 connected to the apparatus main body, and one of the sensor heads 20A and 20B can be designated by a predetermined selection operation in that state.

  FIG. 17 is an explanatory diagram showing a monitor screen during the operation of determining the start point of the measurement area in the beam line direction. Note that the same components as those in FIG. While the measurement area is being selected, a start point line 92 and an end point line 93 are drawn in the image display area 77 as indicated by dotted lines extending in the horizontal direction in the figure. These lines 92 and 93 can be translated in the vertical direction on the screen by a predetermined operation. When determining the start point line 92, the cursor 94 is set to the start point line (A) 92 side by a predetermined operation. In this state, the start point line 92 can be adjusted to a desired position by adjusting the start point line 92 to a desired pixel position (pixel) and performing a predetermined determination operation. In the figure, the start point line 92 is aligned at the 16th pixel.

  An explanatory diagram showing a monitor screen during the end point determination operation of the measurement region in the beam line direction is shown in FIG. Note that the same components as those in FIG. When setting the end point line 93 to a desired position, first, the cursor 94 is moved to the end point line (B) 93 side, and in this state, the end point line 93 is moved up and down to move to a desired position. The determination of the end point line 93 is completed by performing the confirmation operation. In this example, the end point line 93 is set at the 40th pixel. During the above setting operation, the movement positions of the start point line 92 and the end point line 93 are displayed in the numerical value display area 79. Thereby, the measurement region (measurement point extraction range) 95 can be specified between 16 pixels and 40 pixels.

  Next, a process of extracting a feature point (measurement point) in three modes (normal mode, peak mode, and bottom mode) in the measurement region after determining the measurement region will be described.

  FIG. 19 shows an explanatory diagram (normal mode) showing a monitor screen during the line direction measurement point extraction operation in the measurement region. Note that the same components as those in FIG. As shown in the figure, a line beam image 96 having a flat peak and a bottom is displayed in the image display area 77. In the normal mode, the measurement point is automatically set between the peak position and the bottom position. A cross symbol (cursor) indicated by reference numeral 97 indicates the position of the measurement point. As described above, in the normal mode, the measurement point is automatically set between the peak position and the bottom position within the measurement range sandwiched between 16 pixels and 40 pixels.

  FIG. 20 shows an explanatory diagram (peak mode) showing a monitor screen during the line direction measurement point extraction operation in the measurement region. Note that the same components as those in FIG. As shown in the figure, a line beam image 96 having a flat peak and a bottom is displayed in the image display area 77. In the peak mode, the measurement points are set at these peak positions. A cross symbol (cursor) indicated by reference numeral 97 indicates the position of the measurement point. As described above, in the peak mode, the measurement point is automatically set at the peak position within the measurement range between 16 pixels and 40 pixels.

  FIG. 21 shows an explanatory diagram (bottom mode) showing the monitor screen during the line direction measurement point extraction operation in the measurement region. Note that the same components as those in FIG. As shown in the figure, a line beam image 96 having a flat peak and a bottom is displayed in the image display area 77. In the bottom mode, the measurement points are set at these peak positions. A cross symbol (cursor) indicated by reference numeral 97 indicates the position of the measurement point. As described above, in the bottom mode, the measurement point is automatically set at the bottom position within the measurement range between 16 pixels and 40 pixels.

  An explanatory diagram showing a monitor screen during the measurement point extraction operation on the line bright is shown in FIG. Note that the same components as those in FIG. As shown in the figure, a line bright waveform is drawn in the graph display area 78, and a cursor 98 indicating measurement point coordinates is displayed in the vicinity of the peak position. The cursor 97 and the cursor 98 may be aligned in a straight line extending in the vertical direction. Then, the measurement point coordinates can be confirmed more precisely by comparing the image display area 77 and the graph display area 78.

  An explanatory diagram showing a monitor screen during extraction of measurement points on the line bright is shown in FIG. Note that the same components as those in FIG. As is clear from a comparison between the graph display area (normal size) 78 and the graph display area (enlarged size) 78 ′, in this example, the line bright waveform is expanded in the displacement measurement direction. As a result, according to the line bright waveform shown in the graph display area (enlarged size) 78 ′, the relationship between the measurement point coordinates and the line bright waveform can be confirmed with higher accuracy. This operation can be performed, for example, by confirming the measurement point coordinates in the graph display area (normal size) 78 and then selecting the enlargement mode by a predetermined operation.

  As described above, as is apparent from the description of each embodiment, according to this displacement sensor, not only the displacement measurement result is confirmed, but also various data (raw data) used in the process from the acquisition of the raw image to the measurement of the displacement amount. Images, line bright waveforms, and various threshold values) can be displayed on the monitor screen, so if an abnormality appears in the measurement result, whether the cause is an abnormality in the measurement object itself or a malfunction due to ambient light For example, when it is applied to a production line, it is possible to quickly take measures when a trouble occurs.

  In particular, since the raw image and the line bright waveform are displayed side by side in parallel on the monitor screen, if there is an abnormality in the measurement result or the cause is disturbance light, the raw image and the line bright waveform are displayed. It is possible to accurately grasp the cause of the situation.

  In addition, since the measurement range can be set not only in the displacement measurement direction but also in the direction orthogonal to this, the line beam image is offset in the field of view of the two-dimensional CCD, or on the measurement object. If the measurement points are similarly offset in the field of view of the CCD, more precise measurement is possible by narrowing down the measurement points in consideration of the deviation.

  Furthermore, since information from two sensor heads that operate simultaneously can be displayed in parallel or superimposed on the monitor screen, there is some error when performing step measurement using two sensor heads. When this occurs, it is possible to quickly and accurately grasp which sensor head has the cause.

  In addition, when articles are conveyed one after another on the conveyor, the amount of displacement detected sequentially can be displayed on the monitor screen in chronological order, making it easier to use in the inspection process on the production line. Will be good.

It is a block diagram which shows an example of the system configuration | structure of the displacement sensor to which this invention was applied. It is explanatory drawing which shows the internal structure of a sensor head roughly. It is a block diagram which shows the internal function structure of a main body apparatus. It is a general flowchart which shows roughly the displacement amount measurement operation | movement of a displacement sensor. It is explanatory drawing of the image imaged with CCD in a sensor head. It is explanatory drawing of the measurement point extraction process in a measurement range. It is explanatory drawing which shows the relationship between the picked-up image by CCD, and a line bright waveform. It is explanatory drawing of the threshold value determination method. It is explanatory drawing of a measurement point coordinate extraction process. It is explanatory drawing of the monitor screen production | generation method. It is a figure which shows an example of the monitor screen in the state in which the normal measurement value was obtained. It is explanatory drawing which shows an example of the monitor screen in the state which expanded the image and the line bright waveform to the displacement axis direction. It is explanatory drawing which shows an example of the monitor screen in the state in which the erroneous measurement by disturbance generate | occur | produced. It is explanatory drawing which shows an example of the monitor screen in the state which uses two sensor heads simultaneously, and performs a level | step difference measurement. It is a figure which shows an example of the monitor screen in the state which displays displacement amount data in time series. It is explanatory drawing which shows the monitor screen at the time of sensor head selection operation. It is explanatory drawing which shows the monitor screen in operation in the starting point determination operation of the measurement area | region of a beam line direction. It is explanatory drawing which shows the monitor screen during the end point determination operation of the measurement area | region of a beam line direction. It is explanatory drawing (normal mode) which shows the monitor screen in line direction measurement point extraction operation in a measurement area | region. It is explanatory drawing (peak mode) which shows the monitor screen in line direction measurement point extraction operation in a measurement area | region. It is explanatory drawing (bottom mode) which shows the monitor screen in line direction measurement point extraction operation in a measurement area | region. It is explanatory drawing which shows the monitor screen during measurement point extraction operation on a line bright. It is explanatory drawing which shows the monitor screen during measurement point extraction operation on a line bright.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Main body apparatus 20A, 20B Sensor head 30 Image monitor 40 Controller 50 External apparatus 60 Object to be detected 71 Sensor field of view 72 Line beam image 73 Measurement range 74 Measurement range start point 75 Measurement range end point 76 Line bright waveform 77 Image display Area 78 Graph display area 79 Numerical display area 80 Guide display area 81 Optical image of line beam 82 Cross symbol indicating measurement point coordinate 83 Line bright waveform 84 Ruled line 85 Cross symbol indicating measurement point coordinate 86 Lower limit of allowable range 87 Allowable range 88 A numerical value indicating the measurement result 89 A symbol indicating the determination result 90 A light image based on disturbance 92 A starting point line 93 An end point line 94 A cursor indicating a selected line 96 A line beam image 97 A cursor indicating a measuring point coordinate 98 A measuring point coordinate Cursor shown 110 Measuring unit 1 DESCRIPTION OF SYMBOLS 1 Sensor head interface 111A Image acquisition part 111B Sensor head control part 112 Image arithmetic processing part 112A Image transfer part 112B Measurement processing part 120 Control part 121 GUI part 122 Image processing part 123 Control processing part 124 External output interface part 201 Laser diode 202 Slit plate 203 Projecting lens system 204 Receiving lens system 205 Imaging device (two-dimensional CCD)
D1 Displacement data output D2 Judgment output

Claims (6)

From receiving the luminance distribution obtained from the image sensor, on the light receiving intensity distribution by using a predetermined measuring point extraction algorithm, with the height change of the measurement target object, the position change of the reflection light image on the imaging device A displacement sensor based on a light cutting method that automatically extracts measurement point coordinates in a direction to be calculated and calculates a displacement amount in the height direction of the surface of the measurement target article based on the automatically extracted measurement point coordinates,
An image is displayed in which a line bright waveform indicating a light-receiving luminance distribution in a direction in which the position of the reflected light image on the image sensor changes is superimposed with a figure indicating a measurement value allowable range in the direction in which the position of the reflected light image changes. A displacement sensor having display data editing means for editing display data for image monitoring. The display data editing means indicates a measurement value allowable range in a direction in which the position of the reflected light image changes on a line bright waveform indicating a light reception luminance distribution in a direction in which the position of the reflected light image on the image sensor changes. displacement sensor according to claim 1 in addition to the graphics, for displaying an image of extensive figure indicating the measuring point coordinate, to edit the display data for an image monitor, characterized in that. The display data editing means indicates a measurement value allowable range in a direction in which the position of the reflected light image changes on a line bright waveform indicating a light reception luminance distribution in a direction in which the position of the reflected light image on the image sensor changes. in addition to graphics, the claims wherein the editing measurement point coordinates and for displaying the symbol indicating the determination result obtained by comparison of the measured value tolerance range, the display data for an image monitor, characterized in that The displacement sensor according to 1. A displacement measurement method based on a light cutting method,
Obtaining a received light intensity distribution from the image sensor;
Measurement in the direction in which the position of the reflected light image on the image sensor changes in accordance with the change in the height of the article to be measured on the received light brightness distribution using the predetermined measurement point extraction algorithm from the received received light brightness distribution Automatically extracting point coordinates and calculating the amount of displacement in the height direction of the surface of the measurement target article based on the automatically extracted measurement point coordinates;
An image is displayed in which a graphic indicating a measurement value allowable range in the direction in which the position of the reflected light image changes is superimposed on a line bright waveform indicating a light reception luminance distribution in the direction in which the position of the reflected light image on the image sensor changes. Editing the display data for
Providing the display data to an image monitor, and displaying an image of a line bright waveform on a screen of the image monitor. In the editing step, a figure indicating a measurement value allowable range in a direction in which the position of the reflected light image changes on a line bright waveform indicating a light reception luminance distribution in a direction in which the position of the reflected light image on the image sensor changes. The displacement measurement method according to claim 4, wherein display data for displaying an image in which a graphic indicating the measurement point coordinates is superimposed is edited. In the editing step, a figure indicating a measurement value allowable range in a direction in which the position of the reflected light image changes on a line bright waveform indicating a light reception luminance distribution in a direction in which the position of the reflected light image on the image sensor changes. in addition, editing the display data for displaying an image of extensive symbol indicating a determination result obtained by the comparison of the measured value tolerance range and the measuring point coordinate, it in claim 4, wherein the The displacement measuring method described.

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