JP2006349416A - Surface texture measuring machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface texture measuring machine capable of improving the repeatability of surface texture measurement. <P>SOLUTION: The surface texture measuring machine 10 comprises an illumination device 12 irradiating a work 22 to be an object of surface texture analysis with illumination light 24, a light quantity detector 14 detecting the light 26 obtained by irradiating the work 22 with the illumination light 24 from the illumination device 12 to output the light quantity data 28, an external light detector 16 detecting the luminance of the surrounding light 30 of the measuring environment and outputting the surrounding light data 32, a comparison means 18 monitoring the variation from a predetermined reference value of the surrounding light data 32 from the external detector 16 and an automatic correction means 20 for correcting the light quantity data 28 of the light quantity detector 14 according to the variation value when the variation value monitored with the comparison means 18 exceeds a specific value. It performs surface texture analysis of the work 22 based on the light quantity data 28 from the light quantity detector 14. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a surface texture measuring machine, and more particularly to a mechanism for improving the repeatability of surface texture measurement.

In order to measure surface properties such as dimensions and shapes of workpieces, surface property measuring machines such as projectors and image measuring machines are used.
By the way, as the accuracy of the workpiece increases, the surface texture measuring machine is required to have high surface texture measurement repeatability (repeatability).

In order to meet such a demand, conventionally, improvement of mechanical accuracy such as assembly accuracy of the surface texture measuring device can be considered. Conventionally, it is possible to reduce the movement error of each axis of the measuring machine in order to improve the repeatability of the measurement, and to measure the movement error of each axis in order to reduce the movement error of each axis of the measuring machine ( For example, Patent Document 1).
JP 2003-302202 A

  However, the improvement in repeatability of measurement by the conventional method has reached the technical limit, and further improvement in repeatability is required for the surface texture measuring machine as the workpiece becomes more accurate. Nevertheless, conventionally, there has been no suitable technique that can solve this problem.

In the past, the critical cause that hinders the improvement of the repeatability of the surface texture measurement in the surface texture measuring machine was also unknown.
The present invention has been made in view of the problems of the prior art, and an object thereof is to provide a surface texture measuring machine capable of improving the repeatability of further surface texture measurement.

<Clarification of the cause>
As a result of intensive investigations on the improvement of the repeatability of measurement in the surface texture measuring machine, the main causes that hinder the improvement of the repeatability of measurement are more than the influence of good or bad mechanical accuracy, Clarified that changes in ambient conditions (eg brightness and color) in the environment where the surface texture measuring machine is installed are greatly affected by changes in the work surface condition (eg brightness and color). .
In addition, in order to suppress the influence due to the state change of the workpiece surface, the present inventors detect the amount of light according to the change in the ambient light condition of the environment where the surface texture measuring machine is installed. I realized that it was very important to correct the light quantity data in the instrument.
And the present inventors came to comprise the following points based on elucidation of the above causes.

That is, in order to achieve the object, a surface texture measuring instrument according to the present invention includes an illumination device, a light amount detector, an external light detector, a monitor unit, and an automatic correction unit, and the light amount detector. The surface property analysis of the workpiece is performed based on the light amount data from
Here, the illuminating device irradiates a workpiece to be subjected to surface texture analysis with illumination light under a predetermined illumination condition.
The light amount detector detects detection light obtained by irradiating the work with illumination light from the illumination device, and outputs light amount data.
The external light detector detects ambient light conditions in the measurement environment and outputs ambient light data.
The monitoring means monitors the change value of the ambient light data from the external light detector from a predetermined reference value.
The automatic correction unit corrects the light amount data in the light amount detector based on the change value monitored by the monitor unit.

Ambient light (outside light) here is not just outdoor light, but outdoor light (light whose color changes due to daylight or sunset) or indoor light (incandescent bulbs or fluorescent light). This includes light that changes the brightness and color of the light.
The ambient light conditions here refer to ambient light conditions such as brightness and color of the ambient light.
Specifically, the correction of the light amount data in the light amount detector here means, for example, the light amount data in the light amount detector by one or more operations selected from the group consisting of the following (1) to (3). Is preferably corrected.
(1) Change the gain of the light quantity detector amplifier (2) Change the offset of the light quantity detector amplifier (3) Change the threshold value of the light quantity detector of the light quantity detector

Here, it is particularly preferable to select the operations (1) to (3) based on the following points.
(1) When the light reflectance of the workpiece is low and dark, the gain change of (1) is particularly effective.
(2) When it is desired to cancel the influence of external light, the offset change of (2) is particularly effective.
(3) When it is desired to correct an edge detection error due to a difference in light quantity, the threshold value change in (3) is particularly effective.

Examples of the timing for obtaining the reference value of the ambient light data (illumination) on the monitor means include the following timings.
(1) The brightness that can reduce the eye fatigue of the measurer is used as a reference, and the ambient light data that is the output of the ambient light detector at that time is used as the reference value of the ambient light data (illumination).
(2) The actual workpiece measurement is performed under a plurality of different illumination conditions, and the ambient light data, which is the output of the external light detector, when the measured value closest to the true value is obtained is the ambient light data (illumination ) Standard value.

Examples of the surface texture measuring instrument of the present invention include a projector, an image measuring instrument and the like.
An example of the projector of the present invention is one that performs surface property analysis of a workpiece based on an image projected on a screen.
An example of the image measuring machine according to the present invention is one that performs image processing on image data picked up by a camera and analyzes the surface property of a workpiece.
Examples of the light amount detector of the present invention include a spot light amount detector and an image sensor. Examples of the spot light amount detector of the present invention include, for example, a phototransistor, a photodiode, and a photo IC that are excellent in detecting changes in ambient brightness in a surface texture measuring instrument. Examples of the image sensor of the present invention include a CCD camera and a CMOS camera.

<Edge automatic detection device>
In the present invention, the light amount detector includes an automatic edge detection device for detecting edge information of the workpiece from the light amount data using a predetermined edge detection threshold. The automatic correction unit corrects a threshold for edge detection in the automatic edge detection device based on the change value monitored by the monitoring unit. The surface texture measuring machine preferably performs surface texture analysis of the workpiece based on edge information detected by the edge automatic detection device.

<Image measuring machine>
In the present invention, the light amount detector includes a camera of an image measuring machine for performing surface property analysis of the workpiece based on the light amount data obtained by imaging the detection light from the workpiece.
The automatic correction unit corrects light amount data at the camera of the image measuring machine based on the change value monitored by the monitor unit. The surface texture measuring machine preferably performs surface texture analysis of the workpiece based on light quantity data from the camera of the image measuring machine.
The monitor means outputs a change value from the reference value of the ambient light data as an analog amount (continuous value) that is difference data from the reference value, or a digital amount (discrete value) that is a comparison result with the reference value. (Value: ON / OFF value). An output with an analog amount allows continuous correction of the light amount data and edge detection threshold, and an output with a digital amount makes a discrete correction of the light amount data and edge detection threshold (eg, from A value to B Switching to a value) is possible.

<Light intensity correction>
In the present invention, it is preferable that the lighting device corrects the lighting condition based on a change value monitored by the monitoring unit.
The illumination conditions here refer to illumination conditions including the brightness or light quantity of illumination light, the color of illumination light, the illumination angle of the illumination light with respect to the workpiece, the illumination form (so-called epi-illumination, transmitted illumination, etc.) and the like.

<External command>
In the present invention, it is preferable to include external command means and external correction means.
Here, the external command means is configured to detect light amount data in the light amount detector or an edge in the automatic edge detection device based on at least one condition selected from the group consisting of the shape, material and finish of the workpiece. Assume that an external command for instructing correction of the detection threshold is input.
The external correction means further corrects the light quantity data at the light quantity detector or the edge detection threshold value at the edge automatic detection device based on an external command from the external command means.

Furthermore, in the present invention, an external command for inputting an external command for instructing correction of the illumination condition of the illumination device based on at least one condition selected from the group consisting of the shape, material and finish of the workpiece. Command means are provided. It is preferable that the illumination device further corrects the illumination condition based on an external command from the external command unit.
Here, the external command input from the external command means may be a command with an analog amount (continuous value) or a command with a digital amount (discrete value: ON / OFF value). In the case where the command is an analog amount (continuous value), the correction is performed continuously. In the case where the command is a digital amount, the correction is performed discretely.

<Characteristics of the present invention>
The combination of the problem solving means as described above can be reached only by elucidating the cause that hinders the improvement of the repeatability of the surface property measurement by the present inventors.
On the other hand, after obtaining the knowledge described in the elucidation of the cause by the inventors as described above and then analyzing it after the fact, it may seem that the present invention can be easily configured based on the following prior literature. .
However, it is not related to the technical level at the time of filing of the present invention, for example, surface texture measurement, and even if the following prior art description items belonging to other fields are taken into account, the cause or trigger of the elucidation of the cause by the present inventors ( There is nothing that can be motivated.
Therefore, the present invention cannot be easily configured only by the following points described in the following prior art documents, and the effect of the present invention, that is, the improvement in repeatability of the surface property measurement can be reliably obtained. It is also difficult.

(1) Although it is a technique related to a projection display device, not related to surface property measurement, the brightness of the image on the screen is corrected according to the brightness in the vicinity of the screen in order to improve the lamp life and the screen image quality. (For example, Japanese Patent No. 3610931 and Japanese Patent Application Laid-Open No. 2004-354882).
(2) Although this technique is not related to surface property measurement but is related to a microscope system, the brightness of the display is corrected in accordance with the brightness of the surroundings of the display (for example, JP-A-8-21957).
(3) Although it is not related to surface texture measurement, it is a technology related to paper sheets handling processors, but in order to prevent erroneous detection of paper sheets, it is detected whether or not the paper sheets are inserted according to external light. The detection level of the sensor to be corrected is corrected (for example, Japanese Utility Model Laid-Open No. 5-2279).
(4) Although it is not related to surface property measurement but is related to a color image processing apparatus with a brightness correction function, it is based on the brightness of a specific pixel in the received image data in order to determine the quality of an object having a color difference. Then, the point which correct | amends the brightness | luminance of each other pixel (for example, Unexamined-Japanese-Patent No. 2004-220552).

<Light intensity data correction>
According to the surface texture measuring instrument according to the present invention, the external light detector, the monitoring device, and the automatic correcting device are combined based on the elucidation of the cause that hinders the improvement of the repeatability of the surface texture measurement as described above. As a result, the repeatability of the surface texture measurement can be improved.
<Projector>
In the present invention, the automatic correction means corrects the edge detection threshold in the edge automatic detection device in accordance with the change in ambient brightness, so that repeatability of edge detection based on the edge detection threshold is achieved. Therefore, the repeatability of further surface property measurement can be improved.
<Image measuring machine>
In the present invention, the automatic correction means may improve the repeatability of the surface property measurement by the image measuring machine by correcting the light amount data with the camera of the image measuring machine according to the change of the ambient light condition. it can.
<Light intensity correction>
In the present invention, the illumination device corrects illumination conditions according to changes in ambient light conditions, so that the change in the state of the workpiece surface can be kept to a minimum. Can be improved.

<External command>
In the present invention, the external correction means improves the repeatability of the further surface property measurement by correcting the light quantity data and the edge detection threshold value in the light quantity detector based on the external command from the external command means. be able to.
In the present invention, the illuminating device corrects the illumination condition based on the external command from the external command means, whereby the repeatability of further surface property measurement can be improved.

Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a schematic configuration of a surface texture measuring instrument according to an embodiment of the present invention.
A surface texture measuring machine 10 shown in FIG. 1 includes an illumination device 12, a light amount detector 14, an illuminance sensor element 16 (external light detector), a comparison means (monitor means) 18, and an automatic correction circuit (automatic correction means). 20).
Here, the illuminating device 12 irradiates the workpiece 22 to be subjected to surface texture analysis with illumination light 24.
The light amount detector 14 detects detection light 26 obtained by irradiating the work 22 with illumination light 24 under a predetermined illumination condition from the illumination device 12, and outputs light amount data 28.
The external light detector 16 detects the ambient brightness of the environment where the surface texture measuring instrument 10 is installed (condition of ambient light 30 in the measurement environment: ambient light condition) and outputs ambient light data 32.
The comparison means 18 monitors the change value of the ambient light data 32 from the external light detector 16 from a predetermined reference value.
When the change value monitored by the comparison means 18 exceeds an allowable range (predetermined value) in which the repeatability of the surface texture measurement can be maintained, the automatic correction means 20 determines the light amount detector according to the change value. 14 is corrected. That is, when the ambient light data 32 is larger than the reference value and the illumination is too bright, the light amount detector 14 reduces the light amount data 28 by decreasing the gain or offset, and the ambient light data 32 is smaller than the reference value. If the illumination is too dark, the light amount data 28 is corrected by increasing the gain or offset of the light amount detector 14 to increase the light amount data 28.
In the present embodiment, the surface property analysis of the workpiece 22 is performed based on the light amount data 28 from the light amount detector 14.

In the present embodiment, the illumination device 12 includes a light source 34 including a lamp or the like, and illumination correction means 36.
When the change value monitored by the comparison unit 18 exceeds a predetermined value, the illumination correction unit 36 corrects the light amount (predetermined illumination condition) of the illumination light 24 from the light source 34 according to the change value.

The external light detector 16 detects the brightness (ambient light condition) of the ambient light 30 in the detection area 40 that is optimal for detecting the ambient brightness of the environment where the surface texture measuring instrument 10 is installed. .
Accordingly, when the ambient brightness is too bright, the illumination light amount of the illumination device 12 is decreased, and when the ambient brightness is too dark, the illumination light amount of the illumination device 12 is increased.

The present embodiment further includes external correction means (external correction circuit) 42.
The external correction circuit 42 is connected to the external command unit 44 and can correct the light amount data 28 in the light amount detector 14 in accordance with the instruction amount from the external command unit 44.
Here, in correcting the light amount data 28 in the light amount detector 14, whether the correction by the automatic correction circuit 20 is prioritized, the correction by the external correction circuit 42 is prioritized, or whether both corrections are used together is external. Selection is possible in the command means 44.
Here, the instruction in the external command means 44 is determined by the measurer operating an operation panel (not shown) provided with a setting device. When the surface texture measuring instrument 10 is controlled by the measurement part program, the external command means 44 decodes the command in the measurement part program and determines the instruction amount.

  In the present embodiment, the surface texture analyzing means 46 is provided. The surface property analysis means 46 performs surface property analysis of the workpiece 22 based on the light amount data 28 from the light amount detector 14.

Thus, by configuring the surface texture measuring instrument 10 according to the present embodiment, the repeatability of the surface texture measurement can be improved.
In other words, in a surface texture measuring machine, the cause that hinders the improvement of the repeatability of surface texture measurement is not expected to be the effect of changes in the brightness of the workpiece surface, etc. Under the circumstances considered, the present invention was clarified for the first time in the change of the brightness of the workpiece surface.
Based on the elucidation of such a cause, the present invention has reached the point that it is important to perform the following points in order to reduce the influence of changes in the brightness of the workpiece surface.

(1) Initial setting First, the ambient light data 32 from the illuminance sensor element 16 when optimum illumination is obtained is stored in the comparison means 18 as a reference value for illumination.
Further, the setting information of the light quantity detector 14 at this time, for example, gain information in the light quantity detector 14, offset information in the light quantity detector 14, or threshold information in the light quantity detector 14 to be described later, etc. 14 is stored in the comparison means 18 as an initial setting.

(2) Measurement under ambient brightness monitoring During measurement of the workpiece 22, the comparison means 18 monitors the change value of the ambient light data 32 of the external light detector 16 from a predetermined reference value. It is monitored whether or not the change value is within an allowable range (size, time) in which the repeatability of the surface property measurement of the workpiece 22 can be maintained.

(3) Correction During the measurement, when the comparison unit 18 determines that the monitored change value exceeds the predetermined value, the light amount data in the light amount detector 14 corresponding to the change value is sent to the automatic correction circuit 20. 28 correction is instructed. The automatic correction circuit 20 corrects the setting of the light amount detector 14 in accordance with the change value monitored by the comparison means 18.

As described above, according to the surface texture measuring instrument 10 according to the present embodiment, the light amount data in the light amount detector 14 is corrected according to the change in ambient brightness, and the surface property analysis of the workpiece 22 is performed. Even if the ambient brightness changes during the measurement of the workpiece 22, the influence can be greatly reduced, so that it is possible to ensure a stable surface property measurement repeatability.
Hereinafter, the surface texture measuring instrument according to the present embodiment will be described more specifically.

Projector Conventionally, when performing dimensional measurement of the workpiece in the projector, then cleared to zero count of scale combined visually crosshairs on the screen to one side of the workpiece, by moving the measuring table, cross to the other edge A general method is to know the workpiece size from the scale count when the lines are aligned. Recently, an automatic edge detection device that automatically detects an edge has been developed in place of the operation of aligning the crosshair on the screen with one side of the workpiece or the operation of aligning with the other edge of the workpiece.

A general automatic edge detection device is effective in reducing variations in measured values caused by differences in measurers, but it is difficult to further improve repeatability.
That is, in the projector, the cause of hindering improvement in the repeatability of the measurement is greatly affected by the change in brightness around the environment where the projector is placed and the brightness of the workpiece surface. For example, the amount of light entering through the window changes between daytime and night. Also, the brightness of the room changes depending on whether the room lighting is on or off.
In this way, the brightness around the environment in which the projector is installed changes, which affects the brightness of the workpiece surface.
If the surroundings of the environment where the projector is installed are darkened with the illumination kept constant, the contrast ratio of the light and darkness of the work becomes small. For this reason, the repeatability of edge detection may deteriorate, or edge detection itself may be impossible.
For this reason, in projectors equipped with an automatic edge detection device, it is very important to suppress the effect of changes in the brightness of the workpiece surface. It is very important to correct the edge detection threshold value of the automatic edge detection device in accordance with the change in the brightness around the environment in which it is installed.

In the present embodiment, it is also important to easily correct the edge detection threshold.
That is, it is troublesome to reset the edge detection threshold value every time the brightness of the workpiece surface changes. Also, since the edge detection threshold differs depending on the workpiece material and surface properties, the measurer will be able to measure the repeatability of the measurement results while maintaining the brightness around the environment where the projector is installed. It has to be calibrated all the time before and is cumbersome.

Therefore, in the present embodiment, the edge detection threshold is automatically corrected according to the change in the brightness around the environment where the projector is installed.
FIG. 2 shows a schematic configuration when a projector is used as the surface texture measuring machine shown in FIG. Parts corresponding to those in FIG. 1 are denoted by reference numeral 100 and description thereof is omitted.

In the projector (surface texture measuring machine) 110 shown in the figure, an automatic edge detection device is used as the light amount detector 114 (hereinafter referred to as an automatic edge detection device 114).
The edge automatic detection device 114 includes a light receiving element 152, an amplifier 154, and a light amount comparator 156.
Here, the light receiving element 152 includes, for example, a spot light amount detector and the like, receives the detection light 126 of the workpiece 122 obtained by the illumination 124 of the illumination device 112, and outputs this as light amount data.
The detection light 126 from the work 122 is split by a beam splitter 158, and the first split light 126 a is enlarged and projected onto the light receiving element 152 and the second split light 126 b is projected onto the screen 160.
The amplifier 154 amplifies the light amount data from the light receiving element 152.
The light quantity comparator 156 monitors the light quantity data from the amplifier 154 and detects edge information of the workpiece 122 from the light quantity data using a predetermined threshold for edge detection.

In the present embodiment, the automatic correction circuit 120 outputs correction information for correcting the light amount comparator 156 and the amplifier 154 based on the output of the comparison unit 118.
When the change value monitored by the comparison unit 118 exceeds a predetermined value (the allowable range in which the edge detection repeatability of the edge automatic detection device 114 can be maintained), the automatic correction circuit 120 responds to the change value. The threshold for edge detection in the light amount comparator 156 of the automatic edge detection device 114 and the gain and offset of the amplifier 154 are corrected.

In the present embodiment, the external correction circuit 142 is connected to the amplifier 154 and the light amount comparator 156.
The external correction circuit 142 corrects the gain or offset of the light amount data in the amplifier 154 or the edge detection threshold value in the light amount comparator 156 in accordance with an instruction from the external command means 144.

In the present embodiment, the control information storage unit 162 is provided.
The control information storage unit 162 stores detector control information representing a relationship between a change value of ambient brightness and an optimum light amount data correction value corresponding to the change value, which is obtained in advance in the projector 110. is doing.
During the measurement, when the change value monitored by the comparison unit 118 exceeds a predetermined value, the comparison unit 118 corrects the light amount data in the light amount detector 156 with an optimum correction value corresponding to the change value. From the detector control information in the control information storage means 162, an optimum correction value corresponding to the ambient brightness change value is selected, and the light amount data in the light amount detector 156 is selected with the selected correction value. The automatic correction circuit 120 is instructed to correct (a threshold value for edge detection in the light quantity comparator 156, a gain and an offset in the amplifier 154, etc.).

  When measuring the size of the workpiece 122 with the projector 110, the projector 110 moves the measurement table 168 via the stage control means 164 and the stage driving means 166 to detect the first edge of the workpiece 122, and this first edge. The count amount of the scale 170 at the detection position is acquired. The projector 110 detects the second edge of the workpiece 122 by moving the measurement table 168, and acquires the count amount of the scale 170 at the second edge detection position.

The projector 110 includes a surface texture analysis unit 146 in the subsequent stage of the automatic edge detection device 114.
The surface texture analyzing unit 146 is configured to determine the first of the workpiece 122 based on the count amount at the first edge of the workpiece 122 and the count amount at the second edge, which is the edge information obtained by the automatic edge detection device 114. The surface property information such as the dimension between the edge and the second edge is obtained.

Thus, by configuring the projector 110 according to the present embodiment, the repeatability of the surface property measurement can be improved.
That is, the present inventors have found that the cause of the improvement in the repeatability of the surface texture measurement in the projector is the change in the brightness of the workpiece surface due to the change in the brightness around the environment where the projector is installed. We first elucidated the point of this change in the brightness of the surface of the workpiece, which was not expected to be an effect, and was mainly thought to be due to the mechanical accuracy.
In addition, the present inventors have reached a point where it is important to perform the following points in the projector in order to suppress the influence of the change in brightness of the workpiece surface.

(1) Initial setting First, the ambient light data 132 from the illuminance sensor element 116 when desired illumination is obtained is stored in the comparison unit 118 as a reference value of illumination.
At this time, setting information of the light amount detector 114, for example, gain information in the amplifier 154 of the automatic edge detection device 114, offset information in the amplifier 154 of the automatic edge detection device 114, and a light amount comparator 156 of the automatic edge detection device 114. The threshold value information for edge detection and so on is stored in the comparison means 118 as the initial setting of the automatic edge detection device 114.

(2) Measurement under ambient brightness monitoring During measurement of the workpiece 122, the comparison unit 118 monitors the change value of the ambient light data 132 of the external light detector 116 from a predetermined reference value. Thereby, during the measurement of the workpiece 122, the comparison unit 118 monitors whether or not the change in ambient brightness is within an allowable range (size, time) in which the repeatability of edge detection can be maintained.

(3) Light amount data correction When the automatic correction circuit 120 determines that the change value monitored by the comparison unit 118 exceeds a predetermined value (allowable range in which the repeatability of the surface texture measurement can be maintained), the change value Accordingly, the edge detection threshold value in the edge automatic detection device 114, the gain or offset in the amplifier 154, etc. are corrected.

As a result, the projector 110 according to the present embodiment can ensure stable edge detection repeatability even when the ambient brightness changes during measurement of the workpiece 122, so that stable surface property measurement can be performed. Repeatability can be ensured.
In addition, in this embodiment, the automatic correction circuit 120 automatically corrects the edge detection threshold value, gain, or offset, thereby eliminating the troublesome calibration work of the edge detection threshold value, gain, or offset. Therefore, the repeatability of surface property measurement can be easily improved.

<Light intensity correction>
By the way, in the projector 110, in order to further improve the repeatability of the surface texture measurement, it is also very important to correct the amount of illumination by the illumination device 112 according to the change value of the surrounding brightness.

  For this reason, the present embodiment includes an illumination correction unit 136 that corrects the illumination light amount of the light source 134 according to the change value when the change value monitored by the comparison unit 118 exceeds a predetermined value during measurement. Is also suitable.

Note that the control information storage unit 162 stores illumination control information representing a relationship between a change value of ambient brightness and an optimum illumination light amount correction value corresponding to the change value obtained in advance in the projector 110. I remember it.
When the monitored change value exceeds a predetermined value, the comparison unit 118 corrects the illumination light amount of the light source 134 according to the change value. The optimal illumination light quantity correction value corresponding to the brightness change value is selected. The comparison unit 118 instructs the illumination correction unit 136 to correct the illumination light amount of the light source 134 with the selected correction value.

  In the present embodiment, during the measurement of the workpiece 122 as described above, the illumination light amount by the illumination device 112 is automatically corrected according to the change in ambient brightness. It is automatically corrected. As a result, the following effects are obtained.

(1) Even if the ambient brightness changes, the stable repeatability of the screen 160 brightness can be ensured. Therefore, based on the image projected on the screen 160, the surface property measurement of the stable workpiece can be performed. Repeatability can be ensured.

(2) Since the lamp light amount of the light source 134 that illuminates the workpiece 122 is automatically switched according to the ambient brightness, even if the ambient brightness changes, the screen 160 light amount that is easy on the eyes of the measurer can be obtained. Can be maintained.
As a result, the burden on the measurer is reduced by reducing the degree of fatigue of the measurer's eyes. Therefore, when the measurer performs the surface property analysis of the workpiece based on the image projected on the screen 160, Repeatability can be ensured.
In addition, the lighting conditions at the time when the work is most easily performed for each measurer are stored in the control information storage unit 162 and linked to the lighting control information for the lighting device 112, so that the repeatability of the preferred lighting conditions can be set for each measurer. It can also be ensured.

(3) Further, by optimizing the lighting conditions of the lighting device 112, the work 122 can be illuminated without unnecessarily maintaining the lamp illuminance in a bright state, so that the lamp illuminance is unnecessarily kept bright. Thus, power consumption can be reduced or lamp life can be extended.

Image Measuring Machine FIG. 3 shows a schematic configuration when an image measuring machine is used as the surface texture measuring machine shown in FIG. Parts corresponding to those in FIG. 1 are indicated by reference numeral 200, and parts corresponding to those in FIG. 2 are indicated by reference numeral 100, and description thereof is omitted.

The image measuring machine (surface texture measuring machine) 210 shown in the figure uses a camera that images the detection light 226 of the work 222 by illumination of the lighting device 212 as the light quantity detector 214 (hereinafter referred to as the CCD camera 214). .
Further, when the change value monitored by the comparison unit 218 exceeds a predetermined value, the automatic correction circuit 220 determines the light amount data 228 (hereinafter referred to as image data 228) from the CCD camera 214 of the image measuring device 210 according to the change value. ) Is corrected.
The image measuring device 210 includes a surface property analyzing means 246. The surface texture analysis unit 246 performs image processing on the image data 228 from the CCD camera 214 and performs surface texture analysis of the workpiece 222.

  In the present embodiment, the light source 234 includes a plurality of lamps, and the plurality of lamps are provided along the outer periphery of the light receiving element 252 of the CCD camera 214.

By configuring the image measuring device 210 according to the present embodiment as described above, the repeatability of the surface property measurement by the image measuring device 210 can be improved.
That is, the present inventors have clarified that in the image measuring machine, the cause of hindering the improvement of the repeatability of the surface property measurement is the change in the brightness of the workpiece surface.
In addition, the present invention has reached the point that it is very important to perform the following points in the image measuring machine in order to suppress the adverse effect on the repeatability of measurement due to the change in brightness of the workpiece surface.

(1) Initial setting First, the ambient light data 232 from the illuminance sensor element 216 when desired illumination is obtained is stored in the comparison means 218 as a reference value of illumination.
Also, the setting information of the CCD camera 214 at this time, for example, gain information in the amplifier 254, offset information in the amplifier 254, threshold information in the light amount comparator 256, and the like are sent to the comparison means 218 as initial settings of the CCD camera 214. Remember.

(2) Measurement under ambient brightness monitoring During measurement of the workpiece 222, the comparison means 218 monitors the change value of the ambient light data 232 of the external light detector 216 from a predetermined reference value. . Thereby, the comparison means 218 determines whether or not the change in ambient brightness is within an allowable range (size, time) in which the repeatability of the surface property measurement by the image measuring device 210 can be maintained during measurement of the workpiece 222. Is monitoring.

(3) Light amount data correction When the automatic correction circuit 220 determines that the change value monitored by the comparison unit 218 exceeds a predetermined value, the automatic correction circuit 220 corrects the image data 228 in the CCD camera 214 according to the change value. .

  As described above, in this embodiment, by correcting the image data 228 in the CCD camera 214 in accordance with the change in the brightness of the work 222, the CCD camera 214 can be used even when the brightness of the work 222 changes during measurement. Therefore, the repeatability of the surface property measurement by the image measuring instrument 210 can be ensured.

  Further, in the present embodiment, as in the first embodiment, the repeatability of the surface property measurement by the image measuring device 210 is further improved by correcting the light amount of the illumination device 212 according to the change in ambient brightness. can do.

Modification <Measurement mode>
The measurement mode of the present invention is not limited to each of the above-described configurations, and any surface texture measuring machine uses transmitted illumination by the illumination device or reflected illumination by the illumination device, for example, on the work material, properties, measurement items, etc. It can be suitably selected depending on the case.

<External command>
In the present embodiment, it is also preferable to correct the light amount data by the following external command in order to ensure the repeatability of the surface texture measurement more reliably in the surface texture measuring machine.

That is, according to the present inventors, when measuring a plurality of parts of a work, it has been found that the light quantity data from the light quantity detector may vary depending on the shape, material, and finish of the work.
For example, the reflectance of light changes and the light amount data changes in a part having a different surface roughness even in the same workpiece. In such a case, it is also very important to be able to add light amount data correction from the outside depending on which part of the workpiece is measured.

<Light intensity data correction>
To this end, in the present invention, an external command for inputting an external command for instructing correction of light quantity data in the light quantity detector based on at least one condition selected from the group consisting of the shape, material and finish of the workpiece. Command means are provided.
In the present invention, it is preferable that the external correction circuit corrects the light amount data in the light amount detector based on an external command from the external command means.

  For example, in FIG. 2, the external correction circuit 142 can correct the gain or offset in the amplifier 154 of the light quantity detector 114 or the edge detection threshold value in the light quantity comparator 156 based on an instruction from the external command means 144. Thus, it is also preferable that the light quantity data 128 in the light quantity detector 114 can be further corrected.

  In FIG. 3, it is also preferable that the external correction circuit 242 can further correct the image data 228 in the CCD camera 214 of the image measuring device 214 based on an instruction from the external command means 244.

In this way, regarding the light amount data correction in the light amount detector, by providing the automatic correction circuit and the external correction circuit, the light amount data correction in the light amount detector is compared with the case where only the automatic correction circuit is provided. It can be done more appropriately.
Further, in the embodiment shown in FIGS. 1 to 3, an example is shown in which the gain and offset in the amplifiers 154 and 254 and the edge detection threshold value in the light amount comparators 156 and 256 are corrected in order to perform light amount data correction. However, the present invention is not limited to this, and other parameters that can correct the light amount data may be corrected. For example, sensitivity correction of the light receiving elements 152 and 252 may be performed. In the case of a color light receiving element, color balance correction may be performed.
In addition to correcting all of gain, offset, edge detection threshold, sensitivity, etc., only one or more highly effective parameters may be corrected.
Further, in the embodiment of FIG. 3, the CCD camera 214 includes the light amount comparator 256 and outputs binarized data. However, the present invention is not limited to this, and the output of the amplifier 254 is not provided. May be used as the light amount data 228 as it is. Further, the amplifier and the light quantity comparator do not need to be integrated with the light quantity detector, and may be separated as a preamplifier, or may be incorporated in the surface property analyzing means. In short, it is only necessary to correct the light amount data.

<Light intensity correction>
Further, for example, in a portion having the same workpiece but different surface roughness, the light reflectance changes and the light amount data changes. For this reason, since the illumination may be too bright or too dark as the light amount data correction limit is exceeded, in the present invention, it is also very important to enable correction of the illumination light amount from the outside.

Therefore, in the present invention, external command means for inputting an external command for instructing correction of the illumination light quantity of the lighting device based on at least one condition selected from the group consisting of the shape, material and finish of the workpiece It is also suitable to provide.
In the present invention, it is preferable that the illumination correction unit corrects the illumination light quantity of the illumination device based on an external command from the external command unit.

For example, in FIG. 2, it is preferable that the illumination correction unit 136 further corrects the amount of illumination light from the light source 134 based on an external command from the external command unit 144.
In FIG. 3, it is also preferable that the illumination correction unit 236 further corrects the amount of illumination light from the light source 234 based on an external command from the external command unit 244.

In this way, by providing an automatic correction method and an external correction method for the light amount correction in the lighting device, the light amount correction of the lighting device can be performed more appropriately than in the case where only the automatic correction method is adopted. Can do.
Furthermore, although the case where the light amount correction of the illumination device and the light amount data correction of the light amount detector are used together has been shown, the correction may be performed by selecting only one of them.
Further, in each embodiment, the external light detector has been shown to detect brightness as the ambient light condition of the measurement environment. However, the present invention is not limited to this, and may detect a color, or may detect both. good.
Moreover, although the illumination condition correction of the illumination device has shown the case where the illumination light quantity is corrected, the color of the illumination light, the irradiation angle of the illumination light with respect to the workpiece, and the illumination form (epi-illumination illumination, transmitted illumination, etc.) are not limited thereto. It may be corrected (including switching). Here, when correcting or switching the irradiation angle of the illumination light with respect to the workpiece, it is preferable that the external light detector can calculate and output the irradiation angle of the illumination light from the shadow of the illumination light on the workpiece.
Further, FIG. 2 shows a configuration in which the detection light 126 from the workpiece 122 is divided by the beam splitter 158, the first divided light 126a is projected onto the light receiving element 152, and the second divided light 126b is enlarged and projected onto the screen 160. However, as a modification, the detection light 126 is enlarged and projected on the screen 160 without using a beam splitter, and the light receiving element 152 is arranged on the screen 160 (left side in FIG. 2). A configuration for performing detection may be used.

It is explanatory drawing of schematic structure of the surface texture measuring device concerning one Embodiment of this invention. It is explanatory drawing of schematic structure at the time of using a projector as the surface texture measuring machine shown in FIG. It is explanatory drawing of schematic structure at the time of using an image measuring machine as a surface texture measuring machine shown in FIG.

Explanation of symbols

10, 110, 210 Surface texture measuring machine (projector, image measuring machine)
12, 112, 212 Illumination device 14, 114, 214 Light amount detector (automatic edge detection device, camera of image measuring machine)
16, 116, 216 Illuminance sensor element (external light detector)
18, 118, 218 Comparison means (monitoring means)
20, 120, 220 Automatic correction circuit (automatic correction means)

Claims (7)

An illuminating device that irradiates a workpiece to be subjected to surface texture analysis with illumination light under a predetermined illumination condition;
A light amount detector that detects detection light obtained by irradiating the work with illumination light from the illumination device, and outputs light amount data;
An ambient light detector that detects ambient light conditions in the measurement environment and outputs ambient light data;
Monitoring means for monitoring a change value from a predetermined reference value of ambient light data from the external light detector;
Automatic correction means for correcting light quantity data in the light quantity detector based on the change value monitored by the monitoring means;
A surface texture measuring machine that performs surface texture analysis of the workpiece based on light intensity data from the light intensity detector. In the surface texture measuring machine according to claim 1,
The light amount detector includes an edge automatic detection device for detecting edge information of the workpiece from the light amount data using a predetermined threshold for edge detection,
The automatic correction means corrects the threshold for edge detection in the automatic edge detection device based on the change value monitored by the monitoring means,
A surface texture measuring machine that performs surface texture analysis of the workpiece based on edge information detected by the edge automatic detection device. In the surface texture measuring machine according to claim 1,
The light amount detector includes a camera of an image measuring machine for performing surface property analysis of the workpiece based on light amount data obtained by imaging the detection light from the workpiece,
The automatic correction means corrects the light amount data at the camera of the image measuring machine based on the change value monitored by the monitor means,
A surface texture measuring machine that performs surface texture analysis of the workpiece based on light quantity data from a camera of the image measuring machine. In the surface texture measuring instrument according to any one of claims 1 to 3,
The illumination apparatus corrects the illumination condition based on a change value monitored by the monitor means. The surface texture measuring machine according to claim 2,
External command means for inputting an external command for instructing correction of the threshold for edge detection in the automatic edge detection device based on at least one condition selected from the group consisting of the shape, material and finish of the workpiece When,
An external correction means for correcting an edge detection threshold in the automatic edge detection device based on an external command from the external command means;
A surface texture measuring machine characterized by comprising: In the surface texture measuring instrument according to any one of claims 1 to 4,
Based on at least one condition selected from the group consisting of the shape, material and finish of the workpiece, external command means for inputting an external command for instructing correction of light amount data in the light amount detector;
External correction means for correcting the light quantity data in the light quantity detector based on an external command from the external command means;
A surface texture measuring machine characterized by comprising: In the surface texture measuring instrument according to any one of claims 1 to 4,
Based on at least one or more conditions selected from the group consisting of the shape, material and finish of the workpiece, comprising external command means for inputting an external command for instructing correction of the lighting conditions of the lighting device,
The illuminating device further corrects the illumination condition based on an external command from the external command means.

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