JP6358040B2 - Method for detecting optimum measurement position of inner diameter measuring device - Google Patents

Description

  The present invention relates to a method for detecting an optimum measurement position of an inner diameter measuring device that measures the inner diameter of a hole to be measured.

  The non-contact type inner diameter measuring device inserts the sensor body into the hole to be measured, irradiates the inner peripheral surface of the hole to be measured from the sensor body, receives the reflected light reflected from the inner peripheral surface, and reflects it. The inner diameter of the hole to be measured is obtained based on the size of light. In order to increase the measurement accuracy of the inner diameter of the hole to be measured, it is necessary that the center of the hole to be measured and the center of the sensor body match as much as possible. For this reason, the center of the hole to be measured is aligned with the center of the sensor body while the sensor body is moved by a minute amount by the moving mechanism.

  For example, in the optical inspection apparatus for the inner wall of a tubular product disclosed in Patent Document 1, the inner wall of the tubular product is inspected by irradiating the inner wall of the tubular product with a laser beam and taking an image reflecting the inner wall with a video camera. It is disclosed. In this optical inspection apparatus, a pattern generating means for irradiating the inner wall of the tubular product with laser light in a probe housing inserted into the tubular product, and an electronic camera for photographing the laser light reflected on the inner wall of the tubular product are provided. Is provided.

JP-A-10-197215

  However, in the inner diameter measuring device or the like, no special device for aligning the center of the sensor body with the center of the hole to be measured has been made. The optimum measuring position of the inner diameter measuring device, where the center of the sensor body is aligned with the center of the hole to be measured, is a moving mechanism based on the sensation of the operator so that the reflected light is projected almost uniformly on the entire circumference of the circle. Is operating. Therefore, whether or not the inner diameter measuring device is at the optimum measurement position depends on the operator's sense, and further improvement is required to increase the measurement accuracy of the inner diameter of the hole to be measured.

  The present invention has been made in view of such a background, can improve the measurement accuracy of the inner diameter of the hole to be measured by the inner diameter measuring device, and can greatly reduce the time for measuring the inner diameter of the hole to be measured. It was obtained in an attempt to provide a method for detecting the optimum measurement position of a measuring device.

One aspect of the present invention is a method for detecting an optimum measurement position of an inner diameter measuring device that measures the inner diameter of a hole to be measured provided in an object to be measured.
The inner diameter measuring device includes a light emitting unit that irradiates light on the entire inner peripheral surface of the hole to be measured, and reflected light that is irradiated from the light emitting unit and reflected from the entire inner peripheral surface of the hole to be measured. A sensor body having a light receiving portion for receiving light; and
A calculation unit for obtaining an inner diameter of the hole to be measured based on the size of the reflected light received by the light receiving unit;
A moving mechanism for moving a position at which the sensor body is disposed in the measurement hole in a vertical direction and a horizontal direction in a measurement plane of the measurement hole ;
In detecting the optimum measurement position where the center of the sensor body matches the center of the hole to be measured with a predetermined accuracy,
The sensor body is sequentially moved to a plurality of measurement positions by the moving mechanism, and light is emitted from the light emitting unit to the entire circumference of the inner peripheral surface of the hole to be measured at the plurality of measurement positions. The reflected light reflected from the entire circumference of the inner peripheral surface of the hole to be measured is received by the light receiving unit, and a luminance evaluation value based on the luminance of the reflected light received by the light receiving unit is obtained,
In the method for detecting the optimum measurement position of the inner diameter measuring apparatus, the optimum measurement position is obtained based on the luminance evaluation values at the plurality of measurement positions.

The method for detecting the optimum measurement position of the above inner diameter measuring device can objectively and rationally detect the optimum measurement position where the center of the sensor body is aligned with the center of the hole to be measured with a predetermined accuracy using a computer. It is.
Specifically, in detecting the optimum measurement position, a luminance evaluation value when measuring the hole diameter of the hole to be measured is obtained for a plurality of measurement positions. The luminance evaluation value is a value based on the luminance level of the reflected light received by the light receiving unit. The larger the luminance evaluation value, the closer the center of the sensor body is to the center of the hole to be measured. Moreover, the brightness | luminance of reflected light means the brightness of reflected light. Then, the optimum measurement position is obtained based on the luminance evaluation values at the plurality of measurement positions.

Therefore, in the method for detecting the optimum measurement position of the inner diameter measuring device, the optimum measurement position where the center of the sensor body is aligned with the center of the hole to be measured with a predetermined accuracy is not dependent on the operator's sense but is objective and rational. Can be detected automatically. Then, the measurement accuracy can be improved by measuring the inner diameter of the hole to be measured by the inner diameter measuring device at the optimum measurement position.
Further, the luminance evaluation value can be calculated using the operation of the sensor main body and the moving mechanism by the computer. Thereby, the time which measures the internal diameter of a to-be-measured hole with an internal diameter measuring apparatus can be shortened very much.

  Therefore, according to the method for detecting the optimum measurement position of the inner diameter measuring device, the measurement accuracy of the inner diameter of the hole to be measured by the inner diameter measuring device can be improved, and the time for measuring the inner diameter of the hole to be measured is extremely shortened. be able to.

Explanatory drawing which shows the structure of the internal diameter measuring apparatus concerning an Example. Explanatory drawing which shows the measurement area | region which becomes small gradually according to an Example. Explanatory drawing which shows the center at the time of a measurement area | region setting concerning an Example. Explanatory drawing which shows the virtual line set to several circumferential direction position, and typically shows the state which selects a selection pixel about the reflected light projected on the light-receiving part concerning an Example. The flowchart which shows the detection method of the optimal measurement position of the internal diameter measuring apparatus concerning an Example. FIG. 6 is an explanatory graph showing another method for selecting a selected pixel according to an embodiment. (A) Explanatory drawing which shows each measurement position in a 1st measurement area | region concerning an Example, (b) The graph which shows the result of having calculated | required the luminance evaluation value of each measurement position in a 1st measurement area | region. (A) Explanatory drawing which shows each measurement position in a 2nd measurement area | region concerning an Example, (b) The graph which shows the result of having calculated | required the luminance evaluation value of each measurement position in a 2nd measurement area | region. (A) Explanatory drawing which shows each measurement position in a 3rd measurement area | region concerning an Example, (b) The graph which shows the result of having calculated | required the luminance evaluation value of each measurement position in a 3rd measurement area | region. (A) Explanatory drawing which shows each measurement position in a 4th measurement area | region concerning an Example, (b) The graph which shows the result of having calculated | required the luminance evaluation value of each measurement position in a 4th measurement area | region. The graph which put together the calculation result of the brightness | luminance evaluation value in the 1st-4th measurement area | region concerning an Example. The graph which shows the result of having measured the radius of the to-be-measured hole in each measurement position in the 1st-4th measurement area | region concerning an Example.

A preferred embodiment of the above-described method for detecting the optimum measurement position of the inner diameter measuring apparatus will be described.
In the method for detecting the optimum measurement position of the inner diameter measuring apparatus, the sensor body is sequentially moved to the plurality of measurement positions set at a predetermined pitch in the vertical direction and the horizontal direction in a predetermined area by the moving mechanism. An evaluation step for obtaining the luminance evaluation value, and a selection step for selecting a measurement position having the maximum luminance evaluation value among the plurality of measurement positions as the luminance maximum measurement position, and the luminance maximum measurement position. The measurement area is narrowed sequentially around the center, the pitch for setting the plurality of measurement positions in the vertical direction and the horizontal direction in the measurement area is sequentially reduced, and the evaluation step and the selection step are repeated. Thereafter, the luminance evaluation value at the maximum luminance measurement position and the luminance at the measurement position where the luminance evaluation value is the second largest. When the difference between the value becomes within a predetermined value, the luminance maximum measurement position it is preferable to perform the detection step of the above optimum measurement position.

  In this case, in detecting the optimum measurement position, the evaluation step and the detection step are repeated. In the evaluation step, a luminance evaluation value when measuring the hole diameter of the hole to be measured is obtained for a plurality of measurement positions obtained by dividing the predetermined measurement region in the vertical and horizontal directions at a predetermined pitch. In the selection step, the luminance maximum measurement position that maximizes the luminance evaluation value is selected from among the plurality of measurement positions. Then, the measurement area is narrowed around the maximum luminance measurement position, and the pitch for setting a plurality of measurement positions in the measurement area is reduced, and the evaluation step and the selection step are performed.

Further, the evaluation step and the selection step are repeatedly performed with the measurement area and the pitch being sequentially reduced until the condition for performing the detection step is satisfied. In the detection step, when the difference between the luminance evaluation value at the maximum luminance measurement position and the luminance evaluation value at the measurement position having the second highest luminance evaluation value is within a predetermined value, the maximum luminance measurement position is determined. The optimum measurement position.
Thereby, the precision which calculates | requires an optimal measurement position can be improved, and the measurement precision of the internal diameter of the to-be-measured hole by an internal diameter measuring apparatus can further be improved.

  The light receiving unit includes a plurality of pixels that receive light, and each of the plurality of pixels includes a digital camera configured to detect the magnitude of the luminance stepwise. In the plurality of pixels in the light receiving unit, from the center of the reflected light at a plurality of circumferential positions arranged at predetermined angular intervals around the center of the reflected light having a substantially circular shape along the hole shape of the hole to be measured. The pixel with the highest luminance among the plurality of pixels located on the virtual line extending in the radial direction, or the pixel located at the center of gravity of the figure obtained by integrating the luminance of the plurality of pixels located on the virtual line is selected as the selected pixel. And a luminance difference value obtained by subtracting the minimum luminance value of the plurality of selected pixels from the maximum luminance value of the plurality of selected pixels. It may be.

By selecting a selected pixel from a plurality of pixels located on a virtual line extending in the radial direction from the center of the reflected light, the luminance evaluation value can be easily calculated. Moreover, the calculation accuracy of the luminance evaluation value can be improved by using the average value of the luminance in the plurality of selected pixels and the difference value of the luminance in the plurality of selected pixels. Note that the luminance evaluation value is calculated to be larger as the average value of luminance is larger, and larger as the difference value of luminance is smaller.
In addition, the maximum luminance value in the plurality of selected pixels refers to the luminance of the selected pixel having the maximum luminance among the plurality of selected pixels, and the minimum luminance value in the plurality of selected pixels refers to the plurality of selected pixels. This means the luminance of the selected pixel having the minimum luminance among the pixels.

  Further, the luminance evaluation value X is obtained when the average luminance value of the plurality of selected pixels is La, the maximum luminance value of the plurality of selected pixels is L1, and the minimum luminance value of the plurality of selected pixels is L2. X = La / (L1-L2).

  When the luminance evaluation value X is obtained based only on the average value La of the luminance, even if the center of the sensor body is decentered with respect to the center of the hole to be measured, the luminance evaluation is performed by the selected pixel having a partially high luminance. The value X can be large. On the other hand, when the luminance evaluation value X is obtained based only on the luminance difference value (L1-L2), the luminance evaluation value X may increase even when the luminance of the plurality of selected pixels is generally low. is there.

  Therefore, by setting the luminance evaluation value X to a value obtained by dividing the luminance average value La by the luminance difference value (L1-L2), if there is a selected pixel having a partially high luminance, the luminance average value While La increases, the luminance difference value (L1-L2) also increases, and the luminance evaluation value X decreases. Further, when the luminance evaluation value X is a value obtained by dividing the luminance average value La by the luminance difference value (L1-L2), the luminance difference is obtained when the luminance of the plurality of selected pixels is small as a whole. While the value (L1-L2) decreases, the average luminance value La also decreases, and the luminance evaluation value X decreases.

  When the center of the sensor body is almost aligned with the center of the hole to be measured, the luminance average value La increases and the luminance difference value (L1-L2) decreases, synergistically. The brightness evaluation value X increases. Therefore, the calculation accuracy of the luminance evaluation value can be further improved by obtaining the luminance evaluation value based on the above X = La / (L1-L2).

Embodiments according to the method for detecting the optimum measurement position of the inner diameter measuring device will be described below with reference to the drawings.
As shown in FIG. 1, the inner diameter measuring apparatus 1 of this example is an apparatus that measures the inner diameter of a measurement hole 51 provided in the measurement object 5. The inner diameter measuring device 1 includes a sensor main body 2, a calculation unit 41, and a moving mechanism 3. The sensor body 2 has a light emitting unit 21 that irradiates the entire circumference of the inner peripheral surface of the hole 51 to be measured with the light C <b> 1, and reflected light that is irradiated from the light emitting unit 21 and reflects the entire circumference of the inner peripheral surface of the hole 51 to be measured And a light receiving unit 22 for receiving C2. The calculation unit 41 is configured to obtain the inner diameter of the hole 51 to be measured based on the magnitude of the reflected light C2 received by the light receiving unit 22. The moving mechanism 3 is configured to move the position where the sensor body 2 is disposed in the hole 51 to be measured in the vertical direction L and the horizontal direction W.

In the method of detecting the optimum measurement position Y, an evaluation step, a selection step, and a detection step are performed when detecting the optimum measurement position Y where the center of the sensor body 2 is aligned with the center of the hole 51 to be measured with a predetermined accuracy.
In the evaluation step, as shown in FIGS. 2 and 3, the sensor body 2 is moved by the moving mechanism 3 to a plurality of measurement positions 71 set at a predetermined pitch P in the vertical direction L and the horizontal direction W in a predetermined measurement region 7. To move sequentially. In addition, at a plurality of measurement positions 71, the light C <b> 1 is irradiated from the light emitting unit 21 to the entire inner peripheral surface of the hole 51 to be measured, and the reflected light C <b> 2 that reflects the entire inner peripheral surface of the hole 51 to be measured While receiving light by the light receiving unit 22, the luminance evaluation value X of the reflected light C2 received by the light receiving unit 22 is obtained. In the selection step, the measurement position 71 having the maximum luminance evaluation value X among the plurality of measurement positions 71 is selected as the maximum luminance measurement position 71A.

  As shown in the figure, the measurement area 7 is sequentially narrowed around the maximum luminance measurement position 71A, and a pitch P for setting a plurality of measurement positions 71 in the vertical direction L and the horizontal direction W in the measurement area 7 is set. The evaluation step and the selection step are repeated by decreasing the size sequentially. Thereafter, in the detection step, when the difference between the luminance evaluation value X at the maximum luminance measurement position 71A and the luminance evaluation value X at the measurement position 71B at which the luminance evaluation value X is the second largest is within a predetermined value, the luminance The maximum measurement position 71A is the optimum measurement position Y.

First, the configuration of the inner diameter measuring device 1 will be described in detail.
As shown in FIG. 1, the inner diameter measuring apparatus 1 of this example measures the inner diameter of a measured hole 51 in a measured object 5 that has been machined or the like without contacting the inner peripheral surface of the measured hole 51. It is a non-contact type measuring device.
The light emitting unit 21 in the sensor body 2 is disposed inside the glass tube 20. The light emitting unit 21 includes a light source 211 disposed at an intermediate position of the glass tube 20 and a conical mirror 212 disposed at the tip position of the glass tube 20. The conical mirror 212 is configured to refract light emitted from the light source 211 along the central axis of the glass tube 20 at a right angle and irradiate the inner peripheral surface of the hole 51 to be measured.

  The light receiving unit 22 in the sensor main body 2 is configured by a digital camera disposed at the base end position of the glass tube 20. The digital camera has a plurality of pixels 6 that receive the reflected light C2, and each of the plurality of pixels 6 is configured to detect the magnitude of luminance as a digital value step by step. Further, the hole 51 to be measured is a perfect circle, and the reflected light C2 received by the light receiving unit 22 has a substantially perfect circle as shown in FIG.

  As shown in FIG. 1, the calculation unit 41 of the inner diameter measuring device 1 is constructed by a computer 4, and operations of the sensor main body 2 and the moving mechanism 3 of the inner diameter measuring device 1 are controlled by the computer 4. Further, the computer 4 has a detection calculation unit 42 for executing the method for detecting the optimum measurement position Y. Calculations in the calculation unit 41 and the detection calculation unit 42 and operations of the sensor body 2 and the moving mechanism 3 can be performed using the same computer 4. In addition, a monitor 43 is connected to the computer 4, and the monitor 43 is configured to project a substantially circular reflected light C <b> 2 captured by the light receiving unit 22. The reflected light C2 photographed by the light receiving unit 22 can be visually captured.

The calculation unit 41 detects the size of the substantially circular reflected light C2 received by the light receiving unit 22 from the difference in luminance in the plurality of pixels 6, and based on the size of the reflected light C2, the calculation unit 41 It is configured to determine the inner diameter.
As shown in FIG. 1, the moving mechanism 3 includes a moving head 31 to which the sensor body 2 is attached, and a vertical sliding portion 32 for sliding the moving head 31 in the vertical direction (vertical direction in the measurement plane) L. A horizontal slide portion 33 for sliding the movable head 31 in a horizontal direction (horizontal direction in the measurement plane) W orthogonal to the vertical direction L, and a vertical direction orthogonal to the vertical direction L and the horizontal direction W. It has a vertical slide part 34 for sliding to H, and a drive source (not shown) for driving the vertical slide part 32, the horizontal slide part 33, and the vertical slide part 34, respectively. Further, the moving mechanism 3 is disposed with respect to a table 35 on which the object to be measured 5 is placed.

Next, a method for detecting the optimum measurement position Y of the inner diameter measuring device 1 and the function and effect will be described in detail with reference to the flowchart of FIG.
In detecting the optimum measurement position Y, the evaluation step and the detection step are repeated. As shown in FIG. 2, in the evaluation step, the holes 51 to be measured are measured at a plurality of measurement positions 71 set at predetermined equal intervals P in the vertical direction L and the horizontal direction W in the predetermined first measurement region 7A. A luminance evaluation value X when the hole diameter is measured is obtained.

  Specifically, as shown in FIG. 1, the moving mechanism 3 is operated so that the tip 201 of the sensor main body 2 attached to the moving head 31 is measured on the object 5 to be measured placed on the table 35. It inserts in the hole 51 (step S1 of FIG. 5). At this time, the center of the sensor body 2 is made to match the center of the hole 51 to be measured as much as possible. Further, a predetermined first for moving the sensor body 2 in the longitudinal direction L and the lateral direction W within a range in which the sensor body 2 can be moved in the longitudinal direction L and the lateral direction W in the hole 51 to be measured. The measurement area 7A is set.

  As shown in FIG. 2, the first measurement region 7 </ b> A is set around the center of the sensor body 2 that matches the center of the hole 51 to be measured as much as possible. In the first measurement region 7A, a plurality of measurement positions 71 are set at predetermined equal intervals P in the vertical direction L and the horizontal direction W. In this example, the pitch P in the vertical direction L and the pitch P in the horizontal direction W are the same. Further, in the first measurement region 7A of this example, a total of 25 measurement positions 71 are set, with 5 in the vertical direction L and 5 in the horizontal direction W. In the figure, each measurement position 71 is numbered 1-25. The measurement position 71 in this example is a position where the center of the sensor body 2 is aligned. In addition, the predetermined pitch P is a distance for sequentially moving the sensor body 2 in the vertical direction L and the horizontal direction W by the moving mechanism 3.

  Then, the sensor body 2 is moved to the first measurement position 71 among the plurality of measurement positions 71 by the moving mechanism 3 (S2 in FIG. 5), and the entire circumference of the inner peripheral surface of the hole 51 to be measured from the light emitting unit 21. The reflected light C2 that reflects the entire circumference of the inner peripheral surface of the hole 51 to be measured is received by the light receiving unit 22 (S3 in FIG. 5). At this time, the luminance evaluation value X of the reflected light C2 received by the light receiving unit 22 is obtained.

  In calculating the luminance evaluation value X, as shown in FIG. 4, in the digital image (a plurality of pixels 6) displayed on the light receiving unit 22, substantially circular reflected light along the hole shape of the hole 51 to be measured. A plurality of circumferential positions D around the center O of C2 are set at predetermined angular intervals. Then, at each circumferential position D, the pixel 6 having the highest luminance among the plurality of pixels 6 located on the virtual line E extending in the radial direction from the center O of the reflected light C2 is selected as the selected pixel 6A. As a result, a selected pixel 6A corresponding to the number of circumferential positions D is selected (S4 in FIG. 5).

  Next, in the evaluation step, an average value La of the luminance in the plurality of selected pixels 6A is obtained. Further, the maximum luminance value L1 (the luminance of the selected pixel 6A having the highest luminance among the plurality of selected pixels 6A) and the minimum luminance value L2 (the plurality of selected pixels 6A) of the plurality of selected pixels 6A. The luminance of the selected pixel 6A having the minimum luminance among the pixels 6A) is detected.

  Also, a luminance difference value (L1-L2) obtained by subtracting the minimum luminance value L2 from the maximum luminance value L1 is obtained. Then, the luminance evaluation value X at the first measurement position 71 is obtained from X = La / (L1-L2) (S5 in FIG. 5). Here, the luminance evaluation value X is a value based on the luminance level of the reflected light C2 received by the light receiving unit 22, and the center of the sensor body 2 is the center of the hole 51 to be measured as the luminance evaluation value X increases. Means close to. Further, the brightness of the reflected light C2 means the brightness of the reflected light C2.

  By the way, when the luminance evaluation value X is obtained based only on the average value La of luminance, even if the center of the sensor body 2 is decentered with respect to the center of the hole 51 to be measured, a selected pixel having a partially high luminance. The luminance evaluation value X may increase by 6A. On the other hand, when the luminance evaluation value X is obtained based only on the luminance difference value (L1-L2), the luminance evaluation value X is large even when the luminance of the plurality of selected pixels 6A is small as a whole. There is.

  Therefore, by setting the luminance evaluation value X to a value obtained by dividing the luminance average value La by the luminance difference value (L1-L2), if there is a selected pixel 6A having a partially high luminance, the luminance average While the value La increases, the luminance difference value (L1-L2) also increases, and the luminance evaluation value X decreases. Further, by setting the luminance evaluation value X to a value obtained by dividing the average luminance value La by the luminance difference value (L1-L2), when the luminance in the plurality of selected pixels 6A is small as a whole, the luminance value While the difference value (L1-L2) decreases, the average luminance value La also decreases, and the luminance evaluation value X decreases.

  When the center of the sensor body 2 is almost aligned with the center of the hole 51 to be measured, the luminance average value La becomes large and the luminance difference value (L1-L2) becomes small, and synergistically. In particular, the luminance evaluation value X increases. Therefore, by calculating the luminance evaluation value X based on the equation X = La / (L1-L2), the calculation accuracy of the luminance evaluation value X can be greatly improved.

  Next, the sensor body 2 is moved to the second measurement position 71 among the plurality of measurement positions 71 by the moving mechanism 3 (S2 in FIG. 5), and the entire circumference of the inner peripheral surface of the hole 51 to be measured from the light emitting portion 21. The reflected light C2 that reflects the entire circumference of the inner peripheral surface of the hole 51 to be measured is received by the light receiving unit 22 (S3 in FIG. 5). At this time, the luminance evaluation value X of the reflected light C2 received by the light receiving unit 22 is obtained. Further, the luminance evaluation value X is similarly obtained for the third to twenty-fifth measurement positions 71 (S2 to S6 in FIG. 5).

Next, in the selection step, among the first to 25th measurement positions 71 for the first measurement region 7A, the maximum brightness measurement position 71A where the brightness evaluation value X is maximum and the brightness evaluation value X are the second largest. The second measurement position 71B is selected (S7 in FIG. 5). As shown in FIGS. 2 and 3, the maximum luminance measurement position 71A is set as the center of the second measurement region 7B set next to the first measurement region 7A.
Moreover, after performing the selection step, for the first measurement region 7A, whether or not the difference between the luminance evaluation value X at the maximum luminance measurement position 71A and the luminance evaluation value X at the second measurement position 71B is within a predetermined value. Is determined (S8 in FIG. 5).

  Next, in the evaluation step executed again, as shown in FIGS. 2 and 3, the second measurement region 7B having a narrower range than the first measurement region 7A is set around the maximum luminance measurement position 71A ( S9 in FIG. In the second measurement region 7B, a plurality (25 in this example) of measurement positions 71 are set at predetermined equal intervals P in the vertical direction L and the horizontal direction W (S9 in FIG. 5). The pitch P set in the second measurement area 7B is smaller than the pitch P set in the first setting area.

And about the 2nd measurement area | region 7B, the brightness | luminance evaluation value X in the 1st-25th measurement position 71 is calculated | required similarly to the case of the 1st measurement area | region 7A (S2-S6 of FIG. 5).
Next, in the selection step executed again, for the second measurement region 7B, among the first to 25th measurement positions 71, the luminance maximum measurement position 71A where the luminance evaluation value X is maximum and the luminance evaluation value X are The second largest measurement position 71B is selected (S7 in FIG. 5). Then, as shown in FIGS. 2 and 3, the luminance maximum measurement position 71A is set as the center of the third measurement region 7C set next to the second measurement region 7B (S9 in FIG. 5).
Further, for the second measurement region 7B, it is determined whether or not the difference between the luminance evaluation value X at the maximum luminance measurement position 71A and the luminance evaluation value X at the second measurement position 71B is within a predetermined value (FIG. 5). S8).

Thereafter, the measurement areas 7 after the third measurement area 7C are similarly set until the difference between the luminance evaluation value X at the maximum luminance measurement position 71A and the luminance evaluation value X at the second measurement position 71B is within a predetermined value. Then, the evaluation step and the selection step are repeated (S2 to S9 in FIG. 5).
For a specific measurement area 7 after the third measurement area 7C, when the difference between the luminance evaluation value X at the maximum luminance measurement position 71A and the luminance evaluation value X at the second measurement position 71B falls within a predetermined value ( As a detection step, the luminance maximum measurement position 71A is detected as the optimum measurement position Y (S10 in FIG. 5).

Thus, in the method for detecting the optimum measurement position Y of the inner diameter measuring device 1, the optimum measurement position Y where the center of the sensor body 2 is aligned with the center of the hole 51 to be measured with a predetermined accuracy does not depend on the operator's senses. It can be detected objectively and rationally.
In addition, the sensor body 2 can be moved to the optimum measurement position Y, and the inner diameter measuring device 1 can measure the hole diameter of the hole 51 to be measured in the object 5 to be measured. And the measurement precision can be improved by measuring the internal diameter of the to-be-measured hole 51 by the internal diameter measuring apparatus 1 in the optimal measurement position Y.

This measurement can be omitted. That is, when the brightness evaluation value X of the reflected light C2 is obtained for the maximum brightness measurement position 71A detected as the optimum measurement position Y, the diameter of the reflected light C2 is obtained, and this is the diameter of the hole 51 to be measured. It can be.
Further, the evaluation step and the selection step are performed using the operations of the sensor main body 2 and the moving mechanism 3 by the computer 4. Thereby, the time which measures the internal diameter of the to-be-measured hole 51 by the internal diameter measuring apparatus 1 can be shortened very much.

  Therefore, according to the method for detecting the optimum measurement position Y of the inner diameter measuring apparatus 1 of this example, the measurement accuracy of the inner diameter of the measured hole 51 by the inner diameter measuring apparatus 1 can be improved, and the inner diameter of the measured hole 51 can be reduced. Measurement time can be greatly reduced.

  In the calculation of the luminance evaluation value X, the selected pixel 6A selected from the plurality of pixels 6 located on the virtual line E at the plurality of circumferential positions D is not limited to the pixel 6 having the highest luminance. As shown, the pixel 6 located at the center G of the figure F obtained by integrating the luminance of the plurality of pixels 6 located on the virtual line E can be obtained.

(Confirmation test)
In this confirmation test, the optimum measurement position Y was actually detected by repeating the evaluation step and the selection step.
In this confirmation test, the first measurement area 7A to the fourth measurement area 7D were set, and the optimum measurement position Y was detected.
FIG. 7A shows a state in which the maximum brightness measurement position 71A is obtained for the first measurement region 7A, and FIG. 7B shows the brightness evaluation value X of each measurement position 71 in the first measurement region 7A. The results are shown. In the figure, in the first measurement region 7A, the twelfth measurement position 71 is the maximum luminance measurement position 71A, and the nineteenth measurement position 71 is the second measurement position 71B.

  FIG. 8A shows a state in which the maximum luminance measurement position 71A is obtained for the second measurement region 7B, and FIG. 8B shows the luminance evaluation value X of each measurement position 71 in the second measurement region 7B. The results are shown. The second measurement region 7B is set around the twelfth measurement position 71 as the maximum luminance measurement position 71A in the first measurement region 7A. In the figure, in the second measurement region 7B, the sixteenth measurement position 71 is the maximum luminance measurement position 71A, and the twenty-third measurement position 71 is the second measurement position 71B.

  FIG. 9A shows a state in which the maximum luminance measurement position 71A is obtained for the third measurement region 7C, and FIG. 9B shows the luminance evaluation value X of each measurement position 71 in the second measurement region 7C. The results are shown. The third measurement region 7C is set around the sixteenth measurement position 71 as the maximum luminance measurement position 71A in the second measurement region 7B. In the figure, in the third measurement region 7C, the eighth measurement position 71 is the maximum luminance measurement position 71A, and the thirteenth measurement position 71 is the second measurement position 71B.

  FIG. 10A shows a state in which the maximum luminance measurement position 71A is obtained for the fourth measurement region 7D, and FIG. 10B shows the luminance evaluation value X of each measurement position 71 in the fourth measurement region 7D. The results are shown. The fourth measurement region 7D is set around the eighth measurement position 71 as the maximum luminance measurement position 71A in the third measurement region 7C. In the figure, in the fourth measurement region 7D, the eighth measurement position 71 is the maximum luminance measurement position 71A, and the third measurement position 71 is the second measurement position 71B. In this confirmation test, when the luminance evaluation value X at each measurement position 71 is obtained for the fourth measurement region 7D, the luminance evaluation value X at the maximum luminance measurement position 71A, the luminance evaluation value X at the second measurement position 71B, and Is within the predetermined value, and the luminance maximum measurement position 71A in the fourth measurement region 7D is detected as the optimum measurement position Y.

  FIG. 11 summarizes the calculation results of the luminance evaluation values X in the first to fourth measurement regions 7A to 7D of FIGS. 7B to 10B. It can be seen that the luminance evaluation value becomes higher from the first first measurement region 7A toward the last fourth measurement region 7D. It can be seen that the luminance evaluation value X changes in a wave shape and increases at the measurement position 71 where the center of the sensor body 2 is close to the center of the hole 51 to be measured.

FIG. 12 shows the result of measuring the radius of the hole 51 to be measured at each measurement position 71 when obtaining the luminance evaluation value X at each measurement position 71 in each measurement region 7A to 7D. As shown in the figure, especially in the first measurement region 7A, when the center of the sensor body 2 deviates from the center of the hole 51 to be measured, it can be seen that the variation in the measured value of the radius of the hole 51 to be measured is large. . And it turns out that the dispersion | variation in the measured value of the radius of the to-be-measured hole 51 becomes small toward the 2nd measurement area | region 7B, the 3rd measurement area | region 7C, and the 4th measurement area | region 7D. In the fourth measurement region 7D, it can be seen that even if the measurement position 71 is different, the difference in the radius of the measured hole 51 to be measured is small.
From the above results, it can be seen that according to the method for detecting the optimum measurement position Y of the inner diameter measuring apparatus 1 of the above embodiment, the measurement accuracy of the inner diameter of the hole 51 to be measured by the inner diameter measuring apparatus 1 can be improved.

DESCRIPTION OF SYMBOLS 1 Inner diameter measuring apparatus 2 Sensor main body 21 Light emission part 22 Light receiving part 3 Movement mechanism 4 Computer 41 Calculation part 5 Measured object 51 Measured hole 6 Pixel 6A Selected pixel 7, 7A, 7B, 7C, 7D Measurement area 71 Measurement position 71A Brightness Maximum measurement position C2 Reflected light D Circumferential position E Virtual line P Pitch X Luminance evaluation value Y Optimal measurement position

Claims (4)

A method for detecting an optimum measurement position of an inner diameter measuring device for measuring an inner diameter of a hole to be measured provided in an object to be measured,
The inner diameter measuring device includes a light emitting unit that irradiates light on the entire inner peripheral surface of the hole to be measured, and reflected light that is irradiated from the light emitting unit and reflected from the entire inner peripheral surface of the hole to be measured. A sensor body having a light receiving portion for receiving light; and
A calculation unit for obtaining an inner diameter of the hole to be measured based on the size of the reflected light received by the light receiving unit;
A moving mechanism for moving a position at which the sensor body is disposed in the measurement hole in a vertical direction and a horizontal direction in a measurement plane of the measurement hole ;
In detecting the optimum measurement position where the center of the sensor body matches the center of the hole to be measured with a predetermined accuracy,
The sensor body is sequentially moved to a plurality of measurement positions by the moving mechanism, and light is emitted from the light emitting unit to the entire circumference of the inner peripheral surface of the hole to be measured at the plurality of measurement positions. The reflected light reflected from the entire circumference of the inner peripheral surface of the hole to be measured is received by the light receiving unit, and a luminance evaluation value based on the luminance of the reflected light received by the light receiving unit is obtained,
A method for detecting an optimum measurement position of an inner diameter measuring device, wherein the optimum measurement position is obtained based on the luminance evaluation values at the plurality of measurement positions. An evaluation step of sequentially moving the sensor body to the plurality of measurement positions set at a predetermined pitch in the vertical direction and the horizontal direction in a predetermined area by the moving mechanism, and obtaining the luminance evaluation value;
Performing a selection step of selecting, as the luminance maximum measurement position, the measurement position at which the luminance evaluation value is maximum among the plurality of measurement positions;
In addition, the measurement area is sequentially narrowed around the maximum brightness measurement position, and the pitch for setting the plurality of measurement positions in the vertical direction and the horizontal direction is sequentially reduced in the measurement area, and the evaluation step and the above Repeat the selection step,
After that, when the difference between the luminance evaluation value at the maximum luminance measurement position and the luminance evaluation value at the measurement position where the luminance evaluation value is the second largest is within a predetermined value, the maximum luminance measurement position is The method for detecting the optimum measurement position of the inner diameter measuring apparatus according to claim 1, wherein a detection step for setting the measurement position is performed. The light receiving unit includes a plurality of pixels that receive light, and each of the plurality of pixels includes a digital camera configured to be able to detect the magnitude of luminance in stages,
In the plurality of pixels in the light receiving unit, the luminance evaluation values are obtained at a plurality of circumferential positions arranged at predetermined angular intervals around the center of the reflected light having a substantially circular shape along the hole shape of the hole to be measured. A pixel having the highest luminance among a plurality of pixels located on a virtual line extending in the radial direction from the center of the reflected light, or a pixel located at the center of gravity of a figure obtained by integrating the luminances of the plurality of pixels located on the virtual line. , Select each as the selected pixel,
It is obtained based on an average value of luminance in the plurality of selected pixels and a difference value of luminance obtained by subtracting a minimum value of luminance in the plurality of selected pixels from a maximum value of luminance in the plurality of selected pixels. A method for detecting an optimum measurement position of the inner diameter measuring device according to claim 1.   The luminance evaluation value X is expressed as follows: La is the average luminance value of the plurality of selected pixels, L1 is the maximum luminance value of the plurality of selected pixels, and L2 is the minimum luminance value of the plurality of selected pixels. It calculates | requires based on = La / (L1-L2), The detection method of the optimal measurement position of the internal-diameter measuring apparatus of Claim 3 characterized by the above-mentioned.

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