JPH03148002A - Measuring method of size of object - Google Patents

Abstract

PURPOSE:To measure with high accuracy by using an assisting luminous flux which connects a light emitting element with a confronting light receiving element slantwise in addition to main luminous fluxes connecting the both elements. CONSTITUTION:A light emitting unit 1 and a light receiving unit 2 are provided perpen dicular to a reference surface 3, with a distance R therebetween. A body A to be measured butts against a guide 4 in a manner that a distance S between an upper left corner B of the body A and the unit 2 in a direction of a luminous flux is 4/1 the distance R. Basically, every pair of a light emitting element L and a photodetecting element P is sequentially scanned in the order of L1P1, L2P2,.... At this time, since main luminous fluxes l1 - l5 are interrupted by the body A, all the outputs of elements P1 - P5 are OFF. On the other hand, a main luminous flux l6 is not hindered, and therefore an output of an element P6 becomes ON. Then, an element L7 of a main luminous flux l7 next to the main luminous flux l6 is connected with the element P5 of the main luminous flux l5 by an assisting luminous flux l75 and scanned. Since the luminous flux l75 is shielded by the body A at this time thereby to turn the element P5 OFF, a larger one of the two values temporarily detected by the main luminous flux l is used as a measuring value of the scanning result of the luminous flux l75.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides an object dimension measuring method for photoelectrically measuring the height, width, and depth of a rectangular object to be measured without contact and with high resolution. It is related to.

[Prior Art] A large number of light-emitting elements such as light-emitting diodes and light-receiving elements such as photodiodes are arranged at equal intervals on two parallel rows of light-emitting units and light-receiving units, and the light-emitting elements and light-receiving elements face each other. A photoelectric device is conventionally known that measures the dimensions of the object to be measured, such as its height, by counting the number of beams of light that are blocked by the object to be measured, among the parallel beams of light connecting the objects.

FIG. 6 shows such a conventional method for measuring object dimensions, where ■ is a light-emitting unit in which light-emitting elements L, ~L are arranged;
2 is a light receiving unit in which light receiving elements P1 to Pl+ are arranged, both of which are parallel to each other, and a reference plane 3 that connects them.
It is arranged perpendicularly to the Light emitting unit 1,
In the light receiving unit 2, when the object A to be measured is placed on the reference surface 3, the light beams emitted from the light emitting elements L1 to L5 are blocked by the object A and reach the light receiving elements P1 to P. On the other hand, the luminous fluxes from the light emitting elements L6 to Ll+ are received by the light receiving elements P6 to pH, respectively, so that the upper surface of the object A is illuminated by the luminous flux i! It is determined that it is between s and β6.

The specific measurement sequence is L, P, , L2P2, Ls
When scanning is performed so that the light emitting elements are connected in the order of P-1... and the light receiving elements P are connected one pair at a time and are sequentially in operation,
The outputs of the light receiving elements P1 to P, which are shielded by the object A, remain off, but the principal beams 26 to β1. is not shielded from light, so the outputs from the light receiving element L6 onwards are turned on. Therefore, between the adjacent shaded light flux β6 and unblocked light flux β6,
It is determined that the upper surface of the object to be measured A is present, and the height H can be measured from the number of blocked light beams β1 to β5.

Figure 7 is an example of how the measured value changes when the height H of the object A changes continuously in the conventional device shown in Figure 6, making it easier to understand. Therefore, the element spacing, that is, the mutual spacing of parallel principal beams β, is set to 1 cm.
The values are entered assuming that. In this case, the resolution is 1 cm between the elements, and the measured value is given as a digital quantity whose display changes in units of 1 cm.

[Problem to be solved by the invention] However, in measurement using such a conventional method,
In principle and in practice, it is not possible to obtain a resolution finer than the element spacing. In order to obtain high resolution, it is necessary to narrow the element spacing, use a large number of light emitting elements, and use a large number of light receiving elements P, which not only makes the device expensive, but also requires the use of light emitting elements.
0.5 due to restrictions on the size of the photodetector P and mounting dimensions.
There is a problem in that it is difficult to obtain element spacing and resolution narrower than cm.

As a means for solving the above-mentioned problems, it is an object of the present invention to reduce the dimensions of a rectangular parallelepiped-shaped object to be measured in the direction parallel to one light-emitting unit and one light-receiving unit to a resolution finer than the arrangement spacing between the light-emitting element and the light-receiving element. The object of the present invention is to provide a method for measuring the dimensions of an object.

[Means for Solving the Problem] In order to achieve the above object, in the object dimension measuring method according to the present invention, a light-emitting unit in which light-emitting elements are arranged in a straight line at equal intervals, and a light-receiving element are arranged in a straight line at equal intervals. and the light receiving units arranged in a straight line are arranged in parallel with a distance R apart,
Of the parallel principal beams connecting the light-emitting element and the light-receiving element facing each other as a pair, the number of principal beams that are blocked or unblocked by the rectangular parallelepiped-shaped object placed between the light-emitting unit and the light-receiving unit is counted. In the method of determining the dimensions of the object to be measured, the object to be measured is arranged so that the distance S between the light receiving unit or the light emitting unit and the side surface of the object to be measured is an integral fraction of the distance R, and the object is light-shielded or unshaded. Near the two adjacent principal beams that are separated, the light emitting element and the light receiving element that do not face each other are connected diagonally to the principal beam to form at least one auxiliary beam, part or all of which passes between the two principal beams. use,
A method characterized in that the dimensions of the object to be measured in a direction parallel to the light emitting unit and the light receiving unit are measured by determining the output of the light receiving element depending on whether the main light beam and the auxiliary light beam are blocked or not. It is.

[Operation] The object dimension measurement method having the above configuration performs measurement by using, in addition to the main beam that connects the light emitting element and the light receiving element facing each other, an auxiliary beam that connects the light emitting element and the light receiving element diagonally. .

[Example] The present invention will be described in detail based on the example illustrated in FIGS. 1 to 5.

FIG. 1 shows, as an example, a method of measuring the element interval, that is, the interval of the principal beam β, by dividing it into two substantially by using one auxiliary beam in combination. This method is partially similar to the conventional method shown in FIG. 6, and the same reference numerals as in FIG. 6 indicate the same components. The light emitting unit 1 and the light receiving unit 2 are arranged parallel to each other with a distance R apart from each other and perpendicular to the reference plane 3. A guide 4 is installed on the reference plane 3 so that the distance S in the direction of the light beam between the left side surface of the object A, more precisely, the upper left corner point B, and the light receiving unit 2 is one quarter of the distance R. Place the object to be measured A in contact with the however,
There is no problem even if the guide 4 is provided at the entrance of the object A to be measured outside the measuring device, or if the guide 4 is omitted and a guideline is displayed on the reference surface 3 instead.

The distance α2 between the lowest luminous flux and the reference surface 3 can be selected as appropriate depending on the measurement purpose and display means, but for ease of understanding, 0.75 times the element spacing is adopted and the following value is used. Explain. Similar to the conventional device shown in Fig. 6, the basic sequence is l+P+, L, β2, L3P, . . . so that the light-emitting element L and the light-receiving element P are coupled one pair at a time to become operational. Scan sequentially. At that time, the main luminous flux 2. ~f2
8 is shielded from light by the object to be measured A, so the light receiving elements P, ~P,
The outputs of the light-receiving element P6 remain off, but the output of the light-receiving element P6 is turned on because the principal beam β6 is not blocked. Then, it is learned that the upper surface of the object A is located between the principal beams I2s and 16, and the sequential scanning of the principal beams I2s and 16 is completed. For simplicity, taking as an example the case where the element spacing is 1 cm, the principal luminous flux β
As a result of scanning only, the height H of the object A is 5.0 cm.
or 5.5 cm.

Next, the light emitting element L7 for the principal beam β□ next to the principal beam β6 which was turned on for the first time during the sequential scanning of the principal beam, and the light receiving element P for the principal beam β□ whose output was turned off last. are connected by the auxiliary light beam β7s and scanned. Auxiliary light flux f2? , is slightly inclined with respect to the principal ray β, and a part thereof is divided into two adjacent principal rays ρ6. It passes between β6. In the illustrated state, the auxiliary light beam β7s is blocked by the object A and the light receiving element P5 is off, so the auxiliary light beam β7s. As a result of the scanning, the larger value of 5.5 cm of the two values tentatively determined based on the principal beam β is adopted as the measured value. If the output of the light receiving element P is turned on without the auxiliary light beam β76 being blocked by the object A, the measured value is determined to be 5.0 cm.

Similar to the characteristic example of the conventional method shown in Fig. 7, Fig. 2 shows how the measured value using the method shown in Fig. 1 changes when the height H of the object to be measured A changes. It is. As shown in the figure, the resolution, that is, the minimum measurement unit, has been improved to 0.5 cm, which is obtained by dividing the element spacing of 1 cm into two, and the difference between the measured value and the true value, that is, the measurement error due to rounding, is all within ±0.25 cm. . If the true value is 0.75 cm or less, it will be displayed as 0, but if you want to include the area around 0 in the effective measurement range, set the interval α2 between the principal luminous flux I21 and the reference surface 3 to 0.
25 cm, and an increase in height H of 0.25 cm or more can be handled by displaying the measured value in increments of 0.5 cm from 0.

Regarding the measurement sequence and scanning of the light flux, other methods can be adopted without necessarily using the above-mentioned basic method. For example, the order in which the light emitting element and the light receiving element P are successively connected and operated is L+P+, L, IP,, L2P2,
L4P, , LaPs, LsPs, L4P4, L, β4,
L, Ps, L, β6, L, P,... (in terms of luminous flux, β1, I231, 122, β42, I2s, β53 ships! 4, β64, J21+, flood?++, Q6,...) In this way, the main light beam and the auxiliary light beam may be scanned alternately, and a measurement value may be added in the minimum measurement unit for each blocked light beam.

Apart from the theoretical characteristics mentioned above, there are also dimensional errors of the device, operational errors in the position of the measurement object A, and actual errors that occur when the corners of the rectangular parallelepiped measurement object A are rounded. Consider the measurement error above. First, let us assume that the actual value of the distance S between the left side surface of the object to be measured A and the light receiving unit 2 changes by ±10%, that is, ±1 cm with respect to the design value, for example, 10 cm. The phenomenon that occurs in this case is that, for example, the true value of the boundary point that switches the measured value between 5.0 cm and 5.5 cm is originally 5.25 cm, but
．． It varies within the range of 2 cm to 5.3 cm, that is, the boundary point deviates by ±0.050 m from the theoretical value,
When the true value is 5.17 cm or 5.32 cm, the measured values remain 5.0 cm and 5.5 cm, respectively, and do not change regardless of changes in the distance S.

Next, if point B in the upper left corner of object A in FIG. Assuming a ratio of 40 to 1, if the radius of the roundness is 1 cm, the boundary point at which the measured value is switched is, for example, 5.25 cm, as in the previous example.
m to 5.20 cm. This reduction amount is 0.05c
m is directly proportional to the element spacing and the radius of the roundness, and the light emitting unit 1
and is inversely proportional to the distance R between the light receiving unit 2.

In this way, for example, with respect to the method shown in FIG. 1 in which digital display is performed using 0.5 cm as the minimum display unit, in the example using practical numerical values such as those mentioned above, the increasing measurement error will be For example, ±0.
0.5cm, which is a minute amount, so the maximum theoretical rounding error is ±0.2
5 cm increases only to about ±0.3 cm, which causes almost no problem in practice. Although the measurement has been described so far assuming that the object A is stationary, the same measurement is possible even when the object A is moving in the horizontal direction orthogonal to the principal beam 2.

Next, an example in which the element spacing is divided into four and measured will be described with reference to FIG. The configuration of the apparatus used is almost the same as in the two-part measurement shown in FIG. 1, except that the number of light emitting elements is one more, that is, two more than in the conventional method shown in FIG. 6. As in the two-split measurement, as a result of principal beam scanning, the principal beam I26 is shaded and the principal beam I26 is not shaded, so first, the reference value is determined to be 5-Ocm. Using the same expression as in the case of two-part measurement, 5.0 cm, 5.
．． It is tentatively determined that the length is 25 cm, 5.5 cm, or 5.75 cm. Next, by scanning the auxiliary light beam, the first auxiliary light beam I266 is blocked, and the other light beam I27 is blocked.
5. Since I285 is not light-shielded, the measurement value is the minimum measurement unit of 0.2 which is the element spacing divided into four.
5cm is added to the standard value of 5.0cm, resulting in 5.25cm.

In this embodiment, which measures the element spacing by dividing it into 5 parts, as shown in Fig. 4, the number of light emitting elements is further increased by one. The difference is that the distance S between the side surface of the object to be measured A and the light receiving unit 2 facing it is set to 115 of the distance R. The reference value is 5.0 cm because the principal beam β6 is blocked and the principal beam I26 is not blocked due to scanning by principal beam flooding. Next, as a result of scanning the auxiliary light beam, as shown in the figure, the first auxiliary light beam 126B is blocked, and the other auxiliary light beams I276 and I281.12s* are not blocked, so the measured value is set to the reference value of 5.0 cm in the minimum measurement unit. 0
．． Add 2cm to 5.2cm. In addition, the auxiliary light flux β
If γ6 is not shaded, then the auxiliary beams j2as and I2i+s are also naturally not shaded, so if the scanning of the auxiliary beams is stopped immediately after detecting that the first auxiliary beams β and S are not shaded, and the measured value is immediately displayed. good.

The distance between the lowermost principal beam 12r and the reference surface 3 is 7/8 times the element spacing for α4 in the case of 4-part measurement in FIG. 3, and 7/8 times the element distance for α5 in the case of 5-part measurement in FIG. If it is 9/10 times the spacing, the effective measurement range will be 1 cm or more, which is one unit of the element spacing, which is 1 cm in the example.

In the method of the present invention shown in FIGS. 1, 3, and 4, the basic measurement method using the main beam and the auxiliary beam in combination is summarized as follows.

(The product of the number of principal beams blocked by the scanning of the al principal beam and the element spacing is determined as the reference value of the dimension of the object to be measured.

(b) During subsequent scanning of the auxiliary light beams, the product of the number of blocked auxiliary light beams multiplied by the minimum measurement unit is added to the reference value to obtain the measured value.

Alternatively, as described above, the main beam and the auxiliary beam can be sequentially scanned alternately, and the measured value can be obtained from the total number of blocked beams, but this method requires more assistance than the basic method described above. The number of scanning beams increases.

In the method according to the present invention, the number of divisions of the element spacing to obtain a predetermined minimum measurement unit is not limited to 2 or 4.5 as already described, but other numbers are also possible. The main ones are listed in Table 1 along with the distance S conditions attached to the number of divisions.

The size of each distance S is an integer fraction of the distance 11flR between the light emitting unit 1 and the light receiving unit 2.

Table 1 Number of divisions Distance between light receiving unit and object to be measured S2 R/2
, R/4, R/6,...3 R/3, R/6,...
・ 4 R/4, R/8,... 5 R15, R/10,... 6 R/6,... 8 R/8,... 10 R/10,... In this method For example, if four auxiliary light beams are used together, it is possible to perform high-precision measurement with five divisions, that is, a five-fold improvement in resolution. Considering this effect from the opposite perspective, for a device having the same measurement range and resolution, the number of light-emitting elements and light-receiving elements necessary for the present invention is, for example, 5 times the number of light-emitting elements and light-receiving elements of the conventional device in the case of 5-division measurement. It only needs to be slightly more than 1/2.

Furthermore, in addition to the height H of the object to be measured A, the method according to the present invention can also be put to practical use in measuring planar dimensions, that is, the width W and depth. However, when measuring the depth, for example, a guide in the direction parallel to the principal beam is added along the back side of the object A so that the measurement can be performed only by detecting the side position in the same way as when measuring the height H. If the number of units is increased, it becomes difficult to carry in/out and install the object to be measured A. Therefore, we decided to limit the number of actually installed guides 4 to only one as shown in Fig. 5, and then detect the positions of both sides in the depth direction to measure the depth of the rectangular parallelepiped-shaped object to be measured. This will be explained next.

In FIG. 5, the light emitting unit 1 has light emitting elements L1 to Lll and L1° to L8' arranged symmetrically on both sides of the center line CL, and the light receiving unit 2 has light emitting elements PI to Lll symmetrically arranged.
P7 and P1'' to P7'' are arranged symmetrically on both sides of the center line CL. Dimensions D1 and D2 in the depth direction of the object A to be measured with respect to the center line CL are individually measured at a resolution of 1/2 of the element interval, and the determined depth dimension is given by +D*. The four divisions in Figure 3,
2 according to the 5 divisions in Figure 4 and other division numbers shown in Table 1
A set of single-sided measuring devices are similarly arranged symmetrically, and D=D++
It goes without saying that the dimensions of Da can be similarly measured by double-sided measurement.

Various methods according to the present invention can be considered for measuring the width or length of a board or sheet, but for example, if FIG. 5 is rotated 90 degrees counterclockwise and considered to be a side view rather than a plan view, If we understand that the width W of the measurement object A is extremely small and that the width W corresponds to the thickness of the plate material, then the length D of the plate material placed on the guide 4 is 0, +0. It turns out that it can be measured as .

In that case, even if the distance S between the lower end of the plate and the light receiving unit 2 changes slightly due to a warp of the plate that is difficult to correct,
As already mentioned, the errors that occur are extremely small.

In addition, in the embodiment, the explanation has been made with reference numeral 1 as a light emitting unit and 2 as a light receiving unit, but even if the two are interchanged and the reference numeral 1 is a light receiving unit and 2 is a light emitting unit, the basic function of the present invention remains the same. .

The auxiliary beam used for split measurement is slightly inclined with respect to the main beam, but there is no need to specially design the optical system for this purpose. Only a part of the emitted luminous flux is used as an auxiliary luminous flux. Moreover, since the angular difference between the main beam and the auxiliary beam, that is, the angle of inclination, is practically only a few degrees at most, the difference in light intensity of irradiation is small, and the present invention can be applied to simply detect whether the beam is unblocked or blocked. There is no problem.

[Effects of the Invention] As explained above, the method for measuring object dimensions according to the present invention has the following effects:
Although there are some restrictions regarding the location of the object to be measured,
By improving the measurement sequence, for example, when one auxiliary light beam is used in combination, the effect is equivalent to doubling the number of light-emitting elements and light-receiving elements, and dimensions can be measured with a resolution that divides the element spacing into multiple parts. , it becomes possible to perform extremely inexpensive, practical, and highly accurate measurements.

[Brief explanation of the drawing]

Drawings 1 to 5 show an embodiment of an apparatus for realizing the object dimension measuring method according to the present invention, and FIG. 1 is a configuration diagram;
Figure 2 is a diagram of its characteristics; Figures 3, 4, and 5 are diagrams of other embodiments; Figure 6 is a diagram of a conventional method for measuring object dimensions; and Figure 7 is its characteristics. It is a diagram. 1 is a light emitting unit, 2 is a light receiving unit, 3 is a reference plane, 4 is a guide, A is a measured object, L1 to L, , L, °
~L8゛ is a light emitting element, p, -p, , p,'~P7°
is a light receiving element.

Claims (1)

[Claims] 1. A light-emitting unit in which light-emitting elements are arranged in a straight line at equal intervals, and a light-receiving unit in which light-receiving elements are arranged in a straight line at equal intervals are arranged in parallel with a distance R between them, and the light-emitting elements facing each other and Of the parallel principal beams connecting the light-receiving elements as a pair, count the number of principal beams that are blocked or unblocked by the rectangular parallelepiped-shaped object placed between the light-emitting unit and the light-receiving unit, and determine the dimensions of the object to be measured. In the method, the object to be measured is arranged such that the distance S between the light receiving unit or the light emitting unit and the side surface of the object to be measured is an integer fraction of the distance R, and two adjacent lines divided into light shielding and non-light shielding are arranged. The light emitting element and the light receiving element, which do not face each other, are connected diagonally to the main beam in the vicinity of the main beam, and at least one auxiliary beam is used, a part or all of which passes between the two main beams. and an object dimension measuring method, characterized in that the dimensions of the object to be measured in a direction parallel to the light emitting unit and the light receiving unit are measured by determining the output of the light receiving element depending on whether the auxiliary light beam is blocked or not. .