WO2010095551A1

WO2010095551A1 - Method for measuring external shape of rectangular plate-like object, and method for calibrating relative position of image-capturing means

Info

Publication number: WO2010095551A1
Application number: PCT/JP2010/051975
Authority: WO
Inventors: 秀人谷; 静則金子
Original assignee: 旭硝子株式会社
Priority date: 2009-02-18
Filing date: 2010-02-10
Publication date: 2010-08-26
Also published as: CN102301201A; JPWO2010095551A1; TW201100744A; KR101442895B1; CN102301201B; KR20110126601A

Abstract

Provided is a method for measuring the external shape of a rectangular plate-like object being conveyed by use of a shape measurement device which is provided with four image-capturing means previously arranged corresponding to the four corners of the rectangular plate-like object and a storage means for storing the relative coordinates of the respective four image-capturing means. The method is provided with a step of determining whether or not the rectangular plate-like object has reached a measurement section, a step of causing the four image-capturing means to capture the images including the corner portions at the respective four corners of the rectangular plate-like object having reached the measurement section, a step of computing corner post coordinates which are coordinate values from image original point of the four corners of the rectangular plate-like object on the basis of the captured images, and a step of computing the lengths of the four sides and the squareness of the four corners of the rectangular plate-like objects on the basis of the computed corner post coordinates and the relative coordinates stored in the storage means.

Description

Method for measuring outer shape of rectangular plate-shaped object, and method for calibrating relative position of imaging means

The present invention relates to a measuring method for measuring the outer shape (dimensions, squareness of four corners, etc.) of a rectangular plate-like material such as a glass plate, and in particular, the outer shape of a rectangular plate-like material such as a glass plate conveyed on a line ( The present invention relates to a measurement method capable of measuring dimensions, squareness of four corners, etc.) non-stop.

Conventionally, in the field of glass plates such as glass plates for liquid crystal displays, glass plates for plasma displays, glass plates for field emission displays, glass plates for flat display panels such as organic EL, etc., the outer shape of the rectangular glass plate (dimensions and dimensions) It is required to measure the squareness of the four corners in a non-contact manner in a short time with high precision and efficiency. As a device that meets this requirement, the glass plate is imaged, and the captured image, etc. Based on this, a shape measuring device that automatically measures the outer shape (such as dimensions and squareness of four corners) of a glass plate has been proposed (see, for example, Patent Document 1).

FIG. 10 is a front view of the shape measuring apparatus described in Patent Document 1. FIG. FIG. 11 is a side view of the shape measuring apparatus described in Patent Document 1.

As shown in FIGS. 10 and 11, the shape measuring apparatus 100 described in Patent Document 1 includes an X-axis guide 102 extending in the X-axis direction, a Y-axis guide 104 extending in the Y-axis direction, an imaging unit 106, and an imaging unit 106. A motor (not shown) that moves in the X and Y directions along the X and

Y axis guides

102 and 104 is provided.

In this shape measuring apparatus 100, as shown in FIG. 11, the edges of the glass plate 110 carried in an inclined posture and supported on the inspection table 108 are imaged while moving the imaging means 106 in the XY directions, Based on the captured image or the like, the external shape (size, squareness of four corners, etc.) of the glass plate 110 is automatically measured.

Japanese Unexamined Patent Publication No. 2007-205724

However, since the shape measuring apparatus 100 is configured to image the edge or the like of the glass plate 110 using the imaging means 106 moving in the XY directions, the glass plate 110 must be fixed on the inspection table 108 for a certain period of time. In other words, it is not possible to measure the shape of each of the plurality of glass plates 110 conveyed on the line in a non-stop manner, and the measurement takes time, and feedback to manufacturing conditions is delayed when a defect occurs. For this reason, there is a problem that the yield cannot be improved.

This invention is made in view of such a situation, and measures the external shape (dimensions, squareness of four corners, etc.) of a rectangular plate such as a glass plate conveyed on a line in a non-stop manner. An object is to provide a measurement method capable of performing

In order to achieve the above object, the present invention has a shape including four image pickup means arranged in advance corresponding to the four corners of a rectangular plate-like object, and a storage means for storing the relative coordinates of each of the four image pickup means. In the measuring method for measuring the outer shape of the rectangular plate conveyed so as to pass through the shape measuring section using the measuring device, the step of determining whether or not the rectangular plate has reached the measuring section And, when it is determined that the rectangular plate-like object has reached the measurement section, the four imaging means captures images including the corners of the four corners of the rectangular plate-like object that has reached the measurement section. Calculating corner post coordinates, which are coordinate values from the image origin of each of the four corners of the rectangular plate based on the captured image, and the calculation Calculating the length dimension of each of the four sides of the rectangular plate based on the corner post coordinates of the rectangular plate and the relative coordinates stored in the storage means; and the calculated corner post Calculating a squareness of each of the four corners of the rectangular plate based on the coordinates, the relative coordinates stored in the storage means, and the calculated length dimension. A method for measuring the outer shape of a plate-like object is provided.

According to the above configuration, a rectangular plate shape is formed simultaneously (or almost simultaneously) with four image pickup units arranged in advance corresponding to the four corners of the rectangular plate-like object without moving the image pickup unit in the XY directions as in the prior art. Taking an image including the corners of each of the four corners of the object, and based on the captured image, etc., the outer shape of the rectangular plate (the length dimension of each of the four sides of the rectangular plate and the four corners of the rectangular plate (Each squareness) is calculated. For this reason, it becomes possible to measure the shape in a non-stop manner for each of the plurality of rectangular plates conveyed on the line, and it is possible to improve the yield.

Furthermore, in the outer shape measuring method of the present invention, the step of comparing the calculated length dimension and squareness with a predetermined standard value, and the quality of the outer shape of the rectangular plate-like object based on the comparison result. And a step of making a determination.

According to the above configuration, it is possible to determine the quality of the outer shape of the rectangular plate-like object.

Further, the external shape measuring method of the present invention includes a pre-measured length dimension of each of the four sides of the calibration standard rectangular plate, and a pre-measured squareness of each of the four corners of the calibration standard rectangular plate. Based on the above, the step of correcting the squareness measured in advance at each of the four corners of the rectangular plate-like object, and the four imaging means capture images including the corner portions of the four corners of the standard rectangular plate for calibration Calculating the corner post coordinates of each of the four corners of the standard rectangular plate for calibration based on the captured image, and the corner post coordinates of the calculated standard rectangular plate for calibration, Based on the corrected squareness and the length dimension measured in advance on each of the four sides of the standard rectangular plate for calibration, the relative coordinates of the four imaging units are calculated. And storing in the storage means may further comprise a.

According to the above configuration, by using the (known) standard rectangular plate for calibration in which the length dimension of each of the four sides and the squareness of each of the four corners are measured in advance, the outer shape of the rectangular plate (rectangular plate shape) It is possible to calculate the relative coordinates of each of the four imaging units that are the basis for calculating the length dimension of each of the four sides of the object and the squareness of each of the four corners of the rectangular plate-like object.

Moreover, since it includes a step of correcting the squareness measured in advance at each of the four corners of the rectangular plate, the length dimension of each of the four sides of the standard rectangular plate for calibration and the squareness of each of the four corners are measured. Even if a measurement error is included in, the measurement error is canceled out. For this reason, it becomes possible to calculate the relative coordinates of each of the four imaging units with higher accuracy.

Furthermore, the present invention provides a calibration standard rectangular plate-like shape in a method for calibrating the relative coordinates of the four imaging means in a shape measuring apparatus provided with four imaging means previously arranged corresponding to the four corners of the rectangular plate-like object. Based on the pre-measured length dimension of each of the four sides of the object and the pre-measured squareness of each of the four corners of the standard rectangular plate for calibration, the four corners of the rectangular plate were measured in advance. A step of correcting the squareness, a step of capturing an image including each of the four corners of the standard rectangular plate for calibration by the four imaging means, and the calibration standard based on the captured image. Calculating the corner post coordinates of each of the four corners of the rectangular plate, the calculated corner post coordinates of the standard rectangular plate for calibration, the corrected squareness, and Calculating the relative coordinates of each of the four imaging means based on the pre-measured length dimension of each of the four sides of the calibration standard rectangular plate-like object, the relative position of the imaging means Provide a calibration method.

As described above, according to the present invention, a measuring method capable of measuring the outer shape (dimensions, squareness of four corners, etc.) of a rectangular plate such as a glass plate conveyed on a line in a non-stop manner. Can be provided.

It is a system configuration figure of a shape measuring device applied to a shape measuring method of a rectangular plate object of this embodiment. It is a figure for demonstrating the general manufacturing process of a glass plate. FIG. 4 is a plan view of the vicinity of a shape measurement section 32 on a measurement line 30. It is a figure for demonstrating the positional relationship of four sides and a corner part of the calibration standard glass plate 36, and the imaging means 18C0-18C3. This is an example of images P1 to P4 picked up by the image pickup means 18C0 to 18C3. 10 is a flowchart for explaining a process of calculating relative coordinates of four imaging units 18C0 to 18C3. FIG. 6 is a diagram for explaining the relationship between the lengths E1, E2, ER, EL of each of the four sides of the calibration standard glass plate 36 and the squareness ∠1 to ∠4 of each of the four corners of the calibration standard glass plate 36. FIG. 6 is a diagram for explaining the relationship between relative coordinates S0 to S3, approximate correction angles R1 *, R2 *, etc. of four imaging means 18C0 to 18C3. It is a flowchart for demonstrating the method to measure the external shape of the work glass plate. It is a front view of the shape measuring apparatus of patent document 1. It is a side view of the shape measuring apparatus of patent document 1.

Hereinafter, a preferred embodiment of a method for measuring the outer shape of a rectangular plate according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a system configuration diagram of a shape measuring apparatus applied to the method for measuring the outer shape of a rectangular plate according to the present embodiment. FIG. 2 is a diagram for explaining a general manufacturing process of a glass plate. FIG. 3 is a plan view of the vicinity of the shape measurement section 32 on the measurement line 30.

[Outline of shape measuring device]
As shown in FIG. 2, the glass plate is generally a cutting step for cutting a plate glass manufactured to a predetermined thickness into a predetermined size, a chamfering step for chamfering the cut glass plate, and after chamfering processing. The glass plate is manufactured through a washing / drying step for washing / drying and a measurement step (measurement line) for measuring the outer shape of the glass plate after washing / drying.

The shape measuring apparatus 10 of this embodiment is an apparatus for measuring the outer shape of a glass plate, and is installed in a shape measuring section 32 on a measurement line 30 as shown in FIG. The cleaned and dried glass plate 34 (for example, a rectangular glass plate of length L (several m) × width W (several m) shown in FIG. 3; hereinafter referred to as a work glass plate) is a known conveying means (not shown). ) On the measurement line 30 and pass through the shape measurement section 32. The shape measuring apparatus 10 automatically measures the outer shape of the workpiece glass plate 34 passing through the shape measuring section 32 (the length dimension of each of the four sides of the workpiece glass plate 34 and the squareness of each of the four corners, etc.) in a non-stop manner.

[Configuration of shape measuring device]
As shown in FIG. 1, the shape measuring apparatus 10 includes an image processing apparatus 12, four illumination units 16 connected to the image processing apparatus 12 via an LED power source 14 and a predetermined interface (not shown), and the image processing apparatus 12. Are provided with four imaging means 18C0 to 18C3 connected via a predetermined interface (not shown), a sensor 20 connected to the image processing device 12 via a predetermined interface (not shown), and the like.

The image processing apparatus 12 includes a calculation / control unit 12a such as an MPU or CPU, a storage unit 12b such as a RAM or ROM, and the like. The image processing apparatus 12 includes a control unit that controls each illumination unit 16 and each imaging unit 18C0 to 18C3 by the calculation / control unit 12a executing a predetermined program read into the storage unit 12b, and the outer shape of the work glass plate 34. It functions as a calculation means for calculating the shape.

The illumination means 16 is for illuminating the four corners of the work glass plate 34, and is, for example, an illumination device including a plurality of LED light sources (not shown) arranged in a ring shape. The illumination means 16 is arrange | positioned at four places corresponding to each of the four corners of the workpiece | work glass plate 34, as shown in FIG. The illumination unit 16 is turned on according to control from the image processing apparatus 12 and illuminates the four corners of the work glass plate 34.

The imaging means 18C0 to 18C3 are for imaging the four corners of the work glass plate 34, and are, for example, an imaging device including a CCD type or CMOS type imaging device (for example, resolution: several tens of μm / pic). In the imaging means 18C0 to 18C3, the corner portions C1 to C4 (see FIGS. 1, 3, and 4) of the four corners of the work glass plate 34 are in the visual field range (for example, visual field range: several tens mm × several tens mm). It is arranged at four locations corresponding to each of the four corners of the work glass plate 34 so as to be accommodated. The imaging means 18C0 to 18C3 capture images P1 to P4 including the corner portions C1 to C4 at the four corners of the work glass plate 34 in accordance with control from the image processing device 12. FIG. 5 is an example of images P1 to P4 picked up by the image pickup means 18C0 to 18C3. The captured images P1 to P4 are taken into the image processing device 12.

The sensor 20 is for detecting whether or not the workpiece glass plate 34 to be measured has reached the measurement section 32 (a predetermined imaging position in the measurement section 32), and is, for example, a photo interrupter. When the sensor 20 detects the edge 34a (edge) in the transport direction of the workpiece glass plate 34, the sensor 20 notifies the image processing apparatus 12 of a detection signal to that effect. Upon receiving the notification, the image processing apparatus 12 controls each illumination unit 16 so as to illuminate the four corners of the work glass plate 34 that has reached the measurement section 32. At the same time, the imaging means 18C0 to 18C3 are controlled so as to capture images including the corner portions C1 to C4 at the four corners of the work glass plate 34, respectively.

[Relative coordinate calculation using calibration standard glass plate (calibration method)]
Next, processing for calculating the relative coordinates of each of the four imaging units 18C0 to 18C3 using the calibration standard glass plate will be described with reference to FIG. FIG. 6 is a flowchart for explaining processing for calculating the relative coordinates of the four imaging units 18C0 to 18C3. The following processing is realized by the image processing apparatus 12 (calculation / control means) executing a predetermined program read into the storage means 12b or the like.

As shown in FIGS. 4 and 7, the lengths E1, E2, EF, ER of the four sides of the calibration standard glass plate 36 and the squares ∠1 to ∠4 of the four corners of the calibration standard glass plate 36 are as follows. Measured in advance using a calibration gauge such as a linear gauge and stored in the storage means 12b as shown in Table 1.

The perpendicularity is the magnitude of the deviation from the right angle of each of the four corners of the calibration standard glass plate 36 that should be a right angle. In this embodiment, it is assumed that a point on the calibration standard glass plate 36 that is 1000 mm away from the corner portions C1 to C4 of each of the four corners of the calibration standard glass plate 36 and an inner angle of each of the four corners are perpendicular. The distance (mm) to a point on the calibration standard glass plate 36 that is 1000 mm away from each of the corners C1 to C4 of the four corners of the calibration standard glass plate 36 was adopted as a squareness. Note that the difference (rad) between the inner angles of the four corners of the calibration standard glass plate 36 and the inner angles (right angles) of the four corners of the calibration standard glass plate 36 when the inner angles of the four corners are right angles is directly calculated. You may employ | adopt as an angle.

However, these measurement values themselves (especially squares ∠1 to ∠4) already contain measurement errors (calibration gauge offset errors). The square errors ∠1 to ∠4 are corrected so that this measurement error is canceled and the sum of the inner angles of the four corners of the calibration standard glass plate 36 becomes four right angles (step S10).

Specifically, the squares ∠1 to ∠4 are corrected as shown in the following Table 2, Equation 1, and Table 3.

In Table 2, DWSn ← ∠n / 1000 is obtained by dividing the squares ∠1 to ∠4 by 1000 mm, which is the distance between the squareness measurement points and the corners C1 to C4 at the four corners, to the variables DWS1 to DWS4. ∠1 / 1000 to ∠4 / 1000 are respectively substituted. In Table 2, for Rn # ← ATAN (DWSn), the radians (RAD) of the corner portions C1 to C4 are assigned to the variables R1 # to R4 #, respectively. Represents.

In Table 2, aR ← (R1 # + R2 # + R3 # + R4 #) / 4.0 substitutes the average value of the radians (RAD) of the internal angles Atan (DWS1 to DWS4) for the variable aR. It represents that. In Table 2, Rn ← Rn # -aR indicates that the values obtained by subtracting the variable aR from the variables R1 # to R4 # are assigned to the variables R1 to R4, respectively.

Thereby, an error is included in the measured value of the inner angle of the calibration standard glass plate 36, and the sum R1 # + R2 # + R3 # + R4 # of the measured value of the inner angle of the calibration standard glass plate 36 is not zero. Even so, R1 + R2 + R3 + R4 is zero as described below.
R1 + R2 + R3 + R4 = (R1 # -aR) + (R2 # -aR) + (R3 # -aR) + (R4 # -aR)
= R1 # + R2 # + R3 # + R4 # -4xaR
= 0

In the above processing, if at least one of | R3 + R4 |> 0.000001 or | AR12 |> 0.000001 is not satisfied, both R3 ^* and R4 ^* are set to zero. If at least one of | R1 + R2 |> 0.000001 or | AR12 |> 0.000001 is not satisfied, both R1 ^* and R2 ^* are set to zero.

The above processing is based on the assumption that the calibration standard glass plate 36 is a substantially parallelogram, and the sum of the angles of both ends of the sides with which the difference in length between opposite sides is compared (in the case of a true parallelogram) The difference in length between the long sides, so that this difference is proportionally distributed to the original angle value and the difference in side length is reflected in the squareness, The difference in length between the short sides is corrected.

Through this process, the approximate correction angles R1 * to R4 * are calculated and stored in the storage means 12b.

Next, the image processing apparatus 12 controls each illumination means 16 so as to illuminate the four corners of the calibration standard glass plate 36. At the same time, the imaging means 18C0 to 18C3 are controlled so as to capture images including the corner portions C1 to C4 at the four corners of the calibration standard glass plate 36, respectively.

Each illumination means 16 is turned on according to the control from the image processing device 12 and illuminates the four corners of the calibration standard glass plate 36. Further, each of the imaging means 18C0 to 18C3 captures images P1 to P4 including the corner portions C1 to C4 at the four corners of the calibration standard glass plate 36 according to the control from the image processing apparatus 12 (step S12). FIG. 5 is an example of images P1 to P4 picked up by the image pickup means 18C0 to 18C3. The captured images P1 to P4 are taken into the image processing device 12.

Next, the image processing device 12 uses the corner post coordinates (hereinafter referred to as CP coordinates) which are mm-converted coordinate values from the image origins at the four corners of the calibration standard glass plate 36 based on the captured images P1 to P4. C1PX to C4PX, C1PY to C4PY and corner cut dimensions (hereinafter referred to as CC dimensions) C1LX to C4LX, C1LY to C4LY are calculated (steps S14 and S16).

For example, by performing predetermined image processing on each of the images P1 to P4, as shown in FIG. 5, each edge (horizontal edge EH, vertical edge EV, oblique edge EB) is detected and the horizontal / vertical edge EH is detected. The intersection of EV and the oblique edge EB is obtained (step S14). Based on these intersections and the like, CP coordinates C1PX to C4PX, C1PY to C4PY and CC dimensions C1LX to C4LX, C1LY to C4LY are calculated (step S16).

Next, the image processing apparatus 12 measures in advance the calculated CP coordinates C1PX to C4PX, C1PY to C4PY of the calibration standard glass plate 36, and each of the four sides of the calibration standard glass plate 36 stored in the storage means 12b. Relative coordinates of the four imaging means 18C0 to 18C3 based on the length dimensions E1, E2, ER, EL and the approximate correction angles R1 *, R2 *, R3 *, R4 * stored in the storage means 12b S0 to S3 are calculated and stored in the storage means 12b (step S18).

Specifically, the relative coordinates S0 to S3 of each of the four imaging units 18C0 to 18C3 are calculated using the formulas shown in Table 4 below.

Through the above processing, the relative coordinates S0 to S3 of the four imaging units 18C0 to 18C3 are calculated and stored in the storage unit 12b. FIG. 8 shows the relationship between the relative coordinates S0 to S3, approximate correction angles R1 * and R2 *, etc. of the four imaging means 18C0 to 18C3.

[Measurement method of outer shape of workpiece glass plate]
Next, a method for measuring the outer shape of the work glass plate 34 conveyed so as to pass through the shape measuring section 32 using the shape measuring apparatus 10 having the above configuration will be described with reference to FIG. FIG. 9 is a flowchart for explaining a method of measuring the outer shape of the work glass plate 34. The following processing is realized by the image processing apparatus 12 (calculation / control means) executing a predetermined program read into the storage means 12b or the like. It is assumed that the storage unit 12b stores the relative coordinates S0 to S3 of the four imaging units 18C0 to 18C3 in advance. Note that the stored relative coordinates S0 to S3 are read out from the storage means 12b and used as long as the arrangement of the imaging means 18C0 to 18C3 is the same as before. It is possible. That is, as long as the arrangement of the imaging units 18C0 to 18C3 is the same as the previous arrangement, the previously stored relative coordinates S0 to S3 can be reused, and it is not necessary to perform steps S10 to S18 each time.

First, the image processing apparatus 12 determines whether or not the work glass plate 34 has reached the measurement section 32 (step S20). When the image processing apparatus 12 determines that the workpiece glass plate 34 to be measured has reached the measurement section 32 (in the predetermined imaging position) (step S20: YES), that is, the conveyance direction of the workpiece glass plate 34 from the sensor 20 Each of the illumination means 16 is controlled so as to illuminate the four corners of the work glass plate 34 that has reached the measurement section 32. At the same time, the imaging means 18C0 to 18C3 are controlled so as to capture images including the corner portions C1 to C4 at the four corners of the work glass plate 34, respectively.

Each illumination means 16 lights up according to the control from the image processing apparatus 12 and illuminates the four corners of the work glass plate 34. Further, each of the imaging units 18C0 to 18C3 controls the images p1 to p4 including the corner portions C1 to C4 at the four corners of the work glass plate 34 according to the control from the image processing device 12 (similar to the images P1 to P4 shown in FIG. 5). Image) is captured (step S22). The captured images p1 to p4 are taken into the image processing device 12.

Next, the image processing device 12 calculates the CP coordinates c1Px to c4Px, c1Py to c4Py and the CC dimensions c1Lx to c4Lx, c1Ly to c4Ly of the four corners of the work glass plate 34 based on the captured images p1 to p4. (Steps S24 and S26).

For example, by performing predetermined image processing on each of the images p1 to p4, each edge (horizontal edge EH, vertical edge EV, oblique edge EB) is detected in the same manner as shown in FIG. The intersection of the vertical edges EH and EV and the oblique edge EB is obtained (step S24). Based on these intersections and the like, CP coordinates c1Px to c4Px, c1Py to c4Py and CC dimensions c1Lx to c4Lx, c1Ly to c4Ly are calculated (step S26).

Next, the image processing apparatus 12 uses the calculated CP coordinates c1Px to c4Px and c1Py to c4Py of the work glass plate 34 and the relative coordinates S0 to S3 stored in the storage unit 12b to perform the work glass plate 34. Are calculated and stored in the storage means 12b (step S28).

Specifically, the length dimensions E1, E2, ER, and EL of each of the four sides of the work glass plate 34 are calculated using the following formula.

Through the above processing, the length dimensions E1, E2, ER, EL of each of the four sides of the work glass plate 34 are calculated and stored in the storage means 12b.

Next, the image processing apparatus 12 calculates the calculated CP coordinates c1Px to c4Px, c1Py to c4Py, the relative coordinates S0 to S3 stored in the storage unit 12b, and the calculated length dimensions E1, E2, ER. , EL, the squares ∠1 to ∠4 at the four corners of the work glass plate 34 are calculated (step S28).

Specifically, the internal angles r1 to r4 converted to radians (RAD) of each corner portion of the work glass plate 34 are calculated using the following formula, and the work glass is further calculated based on the internal angles r1 to r4. The squares ∠1 to ∠4 at the four corners of the plate 34 are calculated.

Through the above processing, the squares ∠1 to ∠4 at the four corners of the work glass plate 34 are calculated and stored in the storage means 12b.

Next, the image processing apparatus 12 calculates predetermined lengths (settings) such as the calculated length dimensions E1, E2, ER, EL and squareness ∠1 to ワーク 4 of the four sides of the workpiece glass plate 34. Range), and based on the comparison result, whether the calculated length dimensions E1, E2, ER, EL and squareness 直 1 to ∠4 are within the standard value (setting range), that is, The quality of the outer shape of the work glass plate 34 is determined (step S30). Then, if the calculated length dimensions E1, E2, ER, EL and the perpendicular angles ∠1 to ∠4 are within the standard value (setting range) (step S30: YES), the image processing device 12 performs step S20. Returning to step S20, steps S20 to S30 are repeated for the workpiece glass plate 34 that has reached the measurement section 32. That is, the shape is measured in a non-stop manner for each of the plurality of work glass plates 34 (see FIG. 3) conveyed on the measurement line 30. On the other hand, if the calculated length dimensions E1, E2, ER, EL and the perpendicular angles ∠1 to ∠4 are not within the set range (step S30: NO), the image processing device 12 displays an alarm or the like on the display 22. To that effect.

As described above, according to the method for measuring the external shape of the work glass plate of the present embodiment, it is possible to correspond to the four corners of the work glass plate 34 in advance without moving the imaging means 18C0 to 18C3 in the XY directions as in the prior art. The four image pickup means 18C0 to 18C3 arranged in this manner simultaneously (or substantially simultaneously) pick up images including the corner portions C1 to C4 of the four corners of the work glass plate 34, and based on the picked up images p1 to p4, etc. Then, the outer shape of the work glass plate 34 (the length dimension of each of the four sides of the work glass plate 34 and the perpendicularity of each of the four corners of the rectangular plate-like object) is calculated (steps S20 to S28). For this reason, it becomes possible to measure the shape in a non-stop manner for each of the plurality of work glass plates 34 (see FIG. 3) conveyed on the measurement line 30 and to improve the yield.

Moreover, according to the external shape measuring method of the work glass plate of the present embodiment, by using the (standard) calibration standard glass plate 36 in which the length dimension of each of the four sides and the squareness of each of the four corners are measured in advance, It is possible to calculate the relative coordinates of each of the four imaging units 18C0 to 18C3 which are the basis for calculating the outer shape of the work glass plate 34 (the length dimension of each of the four sides of the work glass plate 34 and the perpendicularity of each of the four corners). Become.

Moreover, according to the method for measuring the external shape of the work glass plate of the present embodiment, since the calibration includes the step S10 for correcting the squareness measured in advance at each of the four corners of the calibration standard glass plate 36, the calibration measured in advance. Even if a measurement error is included in the length dimension of each of the four sides of the standard glass plate 36 and the squareness of each of the four corners, the measurement error is offset. Therefore, it is possible to calculate the relative coordinates of each of the four imaging units 18C0 to 18C3 with higher accuracy.

Next, a modified example will be described.

In the above embodiment, the example in which the measurement object is the standard glass plate 36 for calibration and the work glass plate 34 with the four corners cut as shown in FIG. 5 has been described, but the present invention is not limited to this. For example, even if a calibration standard glass plate 36 or a work glass plate 34 whose four corners are not cut as shown in FIG. The relative coordinates S0 to S3 are calculated, and the lengths E1, E2, ER and EL of the four sides of the workpiece glass plate 34, and the squares ∠1 to ∠4 at the four corners of the workpiece glass plate 34 are calculated. It is possible.

In the above embodiment, the example in which the measurement target is a glass plate that has undergone a cutting process, a chamfering process, and a cleaning / drying process has been described, but the present invention is not limited to this. For example, a glass plate before the cutting step, a glass plate before the chamfering step after the cutting step, and a glass plate before the cleaning / drying step after the chamfering step can be measured.

In the above embodiment, an example has been described in which the relative coordinates S0 to S3 of the four imaging units 18C0 to 18C3 are calculated by the processing of steps S10 to S18, but the present invention is not limited to this. For example, if the relative coordinates S0 to S3 of each of the four imaging units 18C0 to 18C3 are measured in advance, the external shape of the workpiece glass plate 34 is measured using the relative coordinates S0 to S3 measured in advance. (Steps S20 to S32) can be performed.

In the above embodiment, an example in which the rectangular plate-like object to be measured is a glass plate has been described, but the present invention is not limited to this. The present invention can be similarly applied to other rectangular plates such as a wooden plate, a metal plate, and a resin plate.

The above embodiments are merely examples in all respects. The present invention is not construed as being limited to these descriptions. The present invention can be implemented in various other forms without departing from the spirit or main features thereof.

Although this application has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on Feb. 18, 2009 (Japanese Patent Application No. 2009-035732), the contents of which are incorporated herein by reference.

DESCRIPTION OF SYMBOLS 10 ... Shape measuring apparatus 12 ... Image processing apparatus 12a ... Calculation / control means 12b ... Memory | storage means 14 ... LED power supply 16 ... Illuminating means 20 ... Sensor 30 ... Measurement line 32 ... Measurement section 34a ... Edge 36 ... Standard glass plate for calibration C1-C4 ... Corner

Claims

Passing through the shape measurement section using a shape measuring device comprising four image pickup means arranged in advance corresponding to the four corners of the rectangular plate-like object, and storage means for storing relative coordinates of each of the four image pickup means In the measuring method of measuring the outer shape of the rectangular plate that is conveyed as
Determining whether the rectangular plate has reached the measurement section;
When it is determined that the rectangular plate-like object has reached the measurement section, the four imaging means captures images including the corners of the four corners of the rectangular plate-like object that has reached the measurement section;
Based on the captured image, calculating corner post coordinates that are coordinate values from the image origin of each of the four corners of the rectangular plate,
Calculating the length dimension of each of the four sides of the rectangular plate based on the calculated corner post coordinates of the rectangular plate and the relative coordinates stored in the storage means;
Calculating the squareness of each of the four corners of the rectangular plate based on the calculated corner post coordinates, the relative coordinates stored in the storage means, and the calculated length dimension;
A method for measuring the outer shape of a rectangular plate-shaped object.
Comparing the calculated length dimension and squareness with a predetermined standard value;
Based on the comparison result, performing a pass / fail judgment of the outer shape of the rectangular plate-like object;
The external shape measuring method of the rectangular plate-shaped object according to claim 1, further comprising:
Based on the pre-measured length dimension of each of the four sides of the standard rectangular plate for calibration and the squareness measured in advance of each of the four corners of the standard rectangular plate for calibration, the four corners of the rectangular plate Correcting each pre-measured squareness;
Capturing images including corner portions of the four corners of the standard rectangular plate for calibration by the four imaging means;
Calculating the corner post coordinates of each of the four corners of the standard rectangular plate for calibration based on the captured image;
Based on the calculated corner post coordinates of the calibration standard rectangular plate, the corrected squareness, and the length dimension measured in advance on each of the four sides of the calibration standard rectangular plate, the 4 The method for measuring the external shape of a rectangular plate-like object according to claim 1, further comprising: calculating a relative coordinate of each of the two imaging units and storing the calculated coordinate in the storage unit.
In the method of calibrating the relative coordinates of the four image pickup means in the shape measuring apparatus including the four image pickup means previously arranged corresponding to the four corners of the rectangular plate-shaped object,
Based on the pre-measured length dimension of each of the four sides of the standard rectangular plate for calibration and the squareness measured in advance of each of the four corners of the standard rectangular plate for calibration, the four corners of the rectangular plate Correcting each pre-measured squareness;
Capturing images including corner portions of the four corners of the standard rectangular plate for calibration by the four imaging means;
Calculating the corner post coordinates of each of the four corners of the standard rectangular plate for calibration based on the captured image;
Based on the calculated corner post coordinates of the calibration standard rectangular plate, the corrected squareness, and the length dimension measured in advance on each of the four sides of the calibration standard rectangular plate, the 4 Calculating the relative coordinates of each of the two imaging means;
A method for calibrating the relative position of the image pickup means.