JP7315920B2 - Size measuring device and size measuring method - Google Patents

Description

The present invention relates to a size measuring device and a size measuring method for measuring the size of luggage without contact.

In general, in parcel delivery services such as postal mail and courier services, charges are determined by the size and weight of parcels. For this reason, the person in charge usually measures the size (width, length, height) of the package using a tape measure or the like when accepting the package.

Conventionally, there has been proposed a device for automatically measuring the size of a package in order to improve work efficiency (see Patent Documents 1 to 4). For example, Patent Literature 1 discloses a package size measuring device that scans and irradiates a package with a laser beam, virtually recognizes the outline of the package from the portion where the light is blocked by the package, and calculates the size of the package. .

Further, Patent Document 2 describes a size measuring device that captures images of the entire package (box) at different angles (from different positions) using two cameras, and calculates the distance between feature points (the length of each side) from the image. is disclosed. Patent Literature 3 discloses a size measuring device that acquires an image of an object (box) to be measured, displays virtual measurement markers superimposed on the image, and calculates the length of each side by calculation.

On the other hand, Patent Document 4 discloses a handy device that projects a light pattern onto the corners of a package (box), simultaneously captures images of the entire package at different angles with two cameras, and calculates the length of each side of the package from the images. A terminal type size measuring device is disclosed.

Japanese Patent Application Laid-Open No. 2003-232621 WO2014/006832 WO2014/157340 JP 2013-253799 A

However, the size measuring devices described in Patent Documents 1 to 3 have poor portability because it is necessary to fix the laser irradiation device and the camera at predetermined positions, and installation locations are limited to business offices and delivery bases. There is a problem of being

On the other hand, a handy terminal type size measuring device has also been developed, such as the device described in Patent Document 4. However, in the conventional handy terminal type size measuring device, it is difficult to align the reference point, and the height of the package cannot be determined. There is a problem that the measurement cannot be performed with high accuracy. In addition, the device described in Patent Document 4 detects feature points (common vertices), faces and sides (edges) that affect the measurement value by image processing based on the captured image. There is a problem that the measurement results are greatly different depending on the imaging conditions such as the focus, the orientation of the package, and the measurement accuracy and measurement stability are inferior.

Specifically, the size measuring device described in Patent Document 4 projects a pattern onto three sides converging at the vertex. A pattern is projected onto two sides, and the length of the side is calculated from two bending points (characteristic points). However, at least three points are required to precisely determine the size of the face of a cube or rectangular parallelepiped.

In the device described in Patent Document 4, a common vertex is obtained from another inflection point (characteristic point), and three points forming a surface are obtained using this point. Since one of the points is not a characteristic point obtained from a bending point by pattern projection, an error is likely to occur in identifying the surface. In addition, the device described in Patent Document 4 detects edges from an image when specifying sides, but it is extremely difficult to precisely detect edges in objects with rounded corners, such as cardboard. .

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a compact size measuring device and a size measuring method that can easily measure the width, length and height of a load and that is portable.

The size measuring apparatus according to the present invention includes a laser light source and a diffractive optical element having a non-periodically formed fine concave-convex structure on its surface, and a pattern projection unit that projects a measurement pattern for each surface onto a package to be measured. and an image capturing unit for capturing an image of the package on which the measurement pattern is projected, and an arithmetic processing unit for calculating the width, length, and height of the item from the image captured by the image capturing unit.
The fine concavo-convex structure of the diffractive optical element can be, for example, a computer-generated hologram.
In the size measuring apparatus of the present invention, for example, light from the laser light source is applied to the entire region of the diffractive optical element in which the fine concave-convex structure is formed.
In the size measuring apparatus of the present invention, the light from the laser light source is diffracted by the fine unevenness of the diffractive optical element to form the measurement patterns projected on at least three mutually adjacent surfaces of the baggage, for example. .
Further, the measurement pattern may be provided with a marker indicating the position of the corner common to the three surfaces.
On the other hand, the arithmetic processing unit may detect bending points of the measurement pattern projected on the baggage, and obtain a three-dimensional straight line indicating each side of the baggage from the three-dimensional positions of the bending points.

The size measuring method according to the present invention uses a laser light source and a pattern projection device having a diffractive optical element on the surface of which a fine concave-convex structure is formed aperiodically. an imaging step of capturing an image of the package on which the measurement pattern is projected; and an arithmetic processing step of calculating the width, length and height of the package from the image captured in the imaging step. I do.
In the pattern projection step, the light from the laser light source can be irradiated to the entire region of the diffractive optical element where the fine uneven structure is formed.
In the pattern projection step, the measurement pattern may be projected onto each of at least three mutually adjacent surfaces of the baggage.
In the arithmetic processing step, bending points of the measurement pattern projected onto the baggage may be detected, and a three-dimensional straight line indicating each side of the baggage may be obtained from the three-dimensional positions of the bending points.

According to the present invention, since the measurement pattern is formed using the diffractive optical element in which the fine concave-convex structure is formed aperiodically on the surface, it is possible to reduce the weight and size of the device, and it is simple. can measure the width, length and height of the package.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the structure of the size measuring device of embodiment of this invention. 2 is a diagram showing the configuration of a pattern projection unit 2; FIG. 1. It is a conceptual diagram which shows the usage method of the size measuring device 10 shown in FIG. FIG. 10 is a diagram showing a measurement pattern; 10A and 10B are diagrams showing a state when a measurement pattern is projected; FIG. FIG. 10 is a diagram showing an example of a measurement pattern with marks (marks) indicating corners; 4 is a flowchart showing processing steps in an arithmetic processing unit 4; It is a figure which shows each point used for calculation.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited to embodiment described below.

(composition)
FIG. 1 is a diagram schematically showing the configuration of a size measuring device according to an embodiment of the present invention. The size measuring device 10 of the present embodiment measures the size of a rectangular parallelepiped (including a substantially rectangular parallelepiped) or a cubic (including a substantially cubic) package in a non-contact manner. , a measurement unit 1 a including a pattern projection unit 2 and an imaging unit 3 , a grasping unit 1 b , and an arithmetic processing unit 4 .

[Pattern Projector 2]
FIG. 2 is a diagram showing the configuration of the pattern projection section 2. As shown in FIG. The pattern projection unit 2 projects a measurement pattern for each surface onto the package to be measured. As shown in FIG. A diffractive optical element 22 and the like are provided. The type of laser light source 21 used in the size measuring device 10 of this embodiment is not particularly limited, and for example, semiconductor lasers, fiber lasers, solid-state lasers, gas lasers, and the like can be used.

A diffractive optical element generally has a fine concave-convex structure formed on its optical surface, and the fine concave-convex structure diffracts incident light, thereby realizing control of the irradiation position of light and irradiation of light in an arbitrary pattern. . In particular, since the size measuring apparatus 10 of the present embodiment uses the diffractive optical element 22 having a fine uneven structure formed aperiodically on the surface, the diffractive optical element 22 is not a normal two-dimensional pattern, but a three-dimensional pattern. can be formed. As a result, it is possible to project the measurement pattern for each surface onto a plurality of surfaces of the baggage with a single irradiation.

The non-periodic fine concave-convex structure of the diffractive optical element 22 used in the size measuring apparatus 10 of the present embodiment can be formed, for example, using a computer generated hologram (CGH) technique (Masahiro Yamaji et al. , APPLIED PHYSICS LETTERS, No. 93, 041116, 2008).

Further, in the size measuring apparatus 10 of the present embodiment, the light from the laser light source 21 is applied to the entire region of the diffractive optical element 22 where the fine uneven structure is formed. As a result, the light from the laser light source 21 is diffracted by the fine unevenness of the diffractive optical element 22, and a pattern for measurement projected onto at least three mutually adjacent surfaces of the package to be measured can be formed.

The measurement pattern projected from the pattern projection unit 2 may be, for example, a lattice-like grid pattern, an elliptical pattern, a hyperbola pattern, or the like, but the grid pattern is preferable from the viewpoint of arithmetic processing. In addition, the measurement pattern may be projected onto at least three mutually adjacent surfaces of the package. The pattern for measurement may not be formed on the entire surface of the substrate. Furthermore, the measurement pattern may be provided with a marker that indicates the position of the corner common to the three projected surfaces.

In a conventional size measuring device, even if a measurement pattern such as a grid pattern is projected onto a package to be measured, the pattern is distorted or disturbed on some or all of the surfaces, resulting in the same pattern on different surfaces. At intervals, it was not possible to project a uniform measurement pattern. On the other hand, the size measuring device 10 of the present embodiment uses the diffractive optical element 22 having a non-periodically formed fine concavo-convex structure on the surface. A uniform measurement pattern can be projected on the surface of the substrate without distortion.

When projecting a measurement pattern onto a package using the above-described conventional method, adopting a method of laser scanning with a mirror device as described in Patent Document 1, for example, makes the system complicated and poor in portability. Become. In addition, the method described in Patent Document 1 cannot simultaneously project the measurement pattern onto the baggage (batch projection), so the quality of the image acquired from the imaging device is degraded and an extra load is imposed on the image processing. On the other hand, in the method of using an LED light source and a mask, for example, as described in Patent Document 4, a large amount of light is blocked by the mask, so the energy utilization efficiency is low. , it is difficult to project a pattern over a wide area with high accuracy.

In addition to the diffractive optical element described above, there is a diffraction grating as an optical component that can generate a light pattern using a laser light source, but the pattern that can be projected on a diffraction grating is limited to simple repeating patterns. There is a problem. In addition, general projectors that use liquid crystals or MEMS (Micro Electro Mechanical Systems) that can project arbitrary patterns draw figures by blocking light, and have problems such as low energy efficiency and poor portability. be.

On the other hand, the size measuring apparatus of this embodiment uses the laser light source 21 and the diffractive optical element 22 having a fine concave-convex structure formed aperiodically on the surface, so that an arbitrary measurement pattern can be applied over a wide range. It is possible to perform simultaneous projection with high accuracy, and the size of the apparatus itself can be reduced. In addition to the laser light source 21 and the diffractive optical element 22 described above, the pattern projection unit 2 is provided with a projection lens 23 that collects the light emitted from the diffractive optical element 22 and emits the light toward the package. good too.

[Imaging unit 3]
The image pickup unit 3 picks up an image of the package on which the measurement pattern is projected, and acquires the image. , and a lens system for forming an image of a subject on an image sensor. Examples of the lens system used in the size measuring device of this embodiment include a short focal length lens, a zoom lens, and a fisheye lens.

Further, analog communication, digital serial communication, or parallel communication by CSI (Camera Serial Interface) can be applied to the connection between the imaging unit 3 and the arithmetic processing unit 4 . Further, it is preferable that the imaging unit 3 performs imaging in synchronization with projection of the measurement pattern by the pattern projection unit 2 . Thereby, power consumption can be reduced.

Furthermore, the size measuring apparatus of the present embodiment may be provided with a mechanism for transmitting a trigger signal from the imaging section 3 and causing the laser light source 21 to emit strong light during imaging. By providing such a mechanism, it is possible to reduce power consumption, prevent or suppress emission of unnecessary light from the laser light source 21, improve the working environment, and furthermore, allow the user ( operator).

[Arithmetic processing unit 4]
The arithmetic processing unit 4 uses the image acquired by the imaging unit 3 to calculate the width, length and height of the package to be measured. The method for calculating the size of the package from the image is not particularly limited. A method of calculating the three-dimensional coordinates of the package based on the above can be applied.

This arithmetic processing unit 4 may be provided in the apparatus, but is connected to the size measuring apparatus 10 of the present embodiment via a wire, wireless or the Internet, and is used to transmit image data and data regarding the calculated luggage size. If it can receive and transmit, it can be provided outside the device.

The size measuring device 10 of this embodiment may be provided with a display unit (not shown), an input unit (not shown), a label output unit (not shown), etc. in addition to the above units. It may also serve as a handy terminal for In addition, the pattern projection unit 2 can be attached to a mobile terminal equipped with a camera function such as a smartphone, and the mobile terminal can be used as a size measuring device by operating the application mobile terminal that functions as the arithmetic processing unit 4. is.

(motion)
Next, the operation of the size measuring device 10 of this embodiment, that is, the method of measuring the size of a package using the size measuring device 10 will be described. FIG. 3 is a conceptual diagram showing the size measuring method of this embodiment. As shown in FIG. 3, in the size measurement method of the present embodiment, for example, a size measurement device 10 is held by hand, and a laser beam 12 is emitted from a pattern projection unit 2 to project a measurement pattern for each surface onto a baggage 11. . At that time, for example, the light from the laser light source 21 is irradiated to the entire region of the diffractive optical element 22 where the fine concave-convex structure is formed.

FIG. 4 is a diagram showing a measurement pattern, and FIGS. 5A and 5B are diagrams showing a state when the measurement pattern shown in FIG. The measurement pattern 12a used in the size measurement method of the present embodiment is, for example, a lattice-like grid pattern shown in FIG. 4, and as shown in FIGS. projected.

At that time, the irradiation position of the laser beam 12 is visually adjusted so that the measurement pattern 12a formed on each surface is not distorted or disturbed. However, since the outer shape of the package 11 is not uniform, as shown in FIG. There may be a portion 12c where the line and the side of the package are not parallel.

Further, in the size measuring method of the present embodiment, a mark indicating the position of a corner common to three adjacent surfaces may be provided in the measurement pattern 12a. FIG. 6 is a diagram showing an example of a measurement pattern provided with markers (marks) indicating corners. As shown in FIG. 6, by providing the marker 12b in the measurement pattern 12a, adjustment of the irradiation position of the laser beam 12 is facilitated.

The shape of the marker 12b is not particularly limited, and various shapes other than the triangle shown in FIG. can do. In the size measuring apparatus of this embodiment, since the measurement pattern 12a is formed using the diffractive optical element 22, it is possible to incorporate the marker 12b into the measurement pattern 12a and project them simultaneously.

Next, the imaging unit 3 images the package 11 with the measurement patterns 12a projected on three surfaces adjacent to each other. At that time, the marker 12b can also be used for focusing and distance adjustment.

Subsequently, the arithmetic processing unit 4 calculates the width, length and height of the luggage 11 from the image acquired by the imaging unit 3 . FIG. 7 is a flow chart showing the processing steps in the arithmetic processing unit 4, and FIG. 8 is a diagram showing detection points, sides and planes used for arithmetic. As shown in FIG. 7, the arithmetic processing unit 4 first detects the bending point of the laser from the image captured by the imaging unit 3 . For example, in the case of the surface S1 shown in FIG. 8, points P _A1 , P _A2 , P _B1 , P _B2 , P _C1 , P _C2 are detected as bending points of the laser beam 12 .

Next, using the principle of triangulation, the three-dimensional positions of the detected bending points (hereinafter referred to as detection points) P _A1 , P _A2 , P _B1 , P _B2 , P _C1 and P _C2 are determined. A three-dimensional straight line indicating the sides LA, LB, LC, and LD is obtained from the three-dimensional position of each detection point. Specifically, a three-dimensional straight line indicating the side LA is obtained from the detection points P _A1 and P _A2 , a three-dimensional straight line indicating the side LB is obtained from the detection points P _B1 and P _B2 , and a side LB is obtained from the detection points P _C1 and P _C2 . A three-dimensional straight line indicating LC is obtained, and a three-dimensional straight line indicating side LD is obtained from detection points P _D1 and P _D2 . Here, in the case of the luggage shown in FIG. 8, since the distance between the two opposing sides corresponds to the length of the side orthogonal to those sides, the three-dimensional straight line of the side LA and the side LC and the side LB and the side LD From the three-dimensional straight line of , the length of two mutually orthogonal sides on the surface S1 is obtained.

Even if there is a bending point that cannot be seen (detected) in the image captured by the imaging unit 3, since each surface of the package 11 is rectangular or square, three-dimensional straight lines indicating each side can be obtained from other information. is possible. For example, when the point D1 shown in FIG. 8 is not visible in the image, the side LA and the side LD are orthogonal. It is possible to obtain a three-dimensional straight line that indicates the side LD.

From the viewpoint of measurement accuracy, it is desirable that there are two detection points (inflection points) on each side, and a total of eight detection points (bending points) on one surface. Therefore, even if there are 2 detection points on one of the 4 sides that make up one surface and 1 point on each of the remaining 3 sides, a total of 5 points of information can be obtained. , the size of the luggage 11 can be calculated. Further, since the side LA shown in FIG. 8 is common to the surface S2 and the side LD is common to the surface S3, it is possible to measure the size of the package 11 as a whole with fewer detection points.

Each of the steps described above is also performed for surfaces S2 and S3, and the lengths of the three sides of the package 11, that is, the size (width, length, and height) of the package 11 are calculated. The size of the parcel calculated by the arithmetic processing unit 4 in this way is displayed, for example, on the display unit of the size measuring device 10, and the person in charge performs the acceptance process based on the value.

As described in detail above, the size measuring apparatus of the present embodiment uses a diffractive optical element having a non-periodically formed fine concave-convex structure on its surface to project a measurement pattern for each surface onto a package to be measured. Therefore, a single irradiation can form a pattern with uniform light intensity without distortion or disturbance on multiple surfaces of the package. As a result, the size measuring apparatus of the present embodiment can measure the width, length, and height of an item simply by photographing the measurement pattern and the item with a camera.

Furthermore, the size measuring apparatus of this embodiment can generate a measurement pattern using 90% or more of the energy radiated from the light source, and can reduce the amount of power supplied to the light source as compared with the conventional one. As a result, it is possible to realize a size measuring device that is small, lightweight, can be held by hand, and is portable.

1a measuring unit 1b gripping unit 2 pattern projection unit 3 imaging unit 10 size measuring device 11 baggage 12 laser light 12a measurement pattern 12b marker 21 laser light source 22 diffraction optical element 23 projection lens

Claims (10)

a pattern projection unit that includes a laser light source and a diffractive optical element having a surface on which a fine uneven structure is formed aperiodically, and that projects a measurement pattern for each surface onto a package to be measured;
an imaging unit that captures an image of the package on which the measurement pattern is projected;
A size measuring device, comprising: an arithmetic processing unit that calculates the width, length, and height of the baggage from the image captured by the imaging unit. 2. The size measuring apparatus according to claim 1, wherein the fine concave-convex structure of said diffractive optical element is a computer-generated hologram. 3. The size measuring apparatus according to claim 1, wherein the light from the laser light source is applied to the entire area of the diffractive optical element where the fine uneven structure is formed. 4. Any one of claims 1 to 3, wherein the light from the laser light source is diffracted by the fine unevenness of the diffractive optical element to form the measurement pattern projected onto each of at least three mutually adjacent surfaces of the luggage. The size measuring device according to the paragraph. 5. The size measuring device according to claim 4, wherein the measurement pattern is provided with a marker indicating the position of the corner common to the three surfaces. 6. The processing unit according to any one of claims 1 to 5, wherein the arithmetic processing unit detects bending points of the measurement pattern projected onto the baggage, and obtains a three-dimensional straight line indicating each side of the baggage from the three-dimensional positions of the bending points. The size measuring device according to item 1. a pattern projection step of projecting a measurement pattern for each surface onto a package to be measured using a pattern projection device having a laser light source and a diffractive optical element having a non-periodically formed fine concavo-convex structure;
an image capturing step of capturing an image of the package on which the measurement pattern is projected;
and an arithmetic processing step of calculating the width, length, and height of the package from the image captured in the imaging step. 8. The size measuring apparatus according to claim 7, wherein in the pattern projection step, the light from the laser light source is applied to the entire region of the diffractive optical element where the fine uneven structure is formed. 9. The size measuring method according to claim 7, wherein in said pattern projecting step, said pattern for measurement is projected onto each of at least three mutually adjacent surfaces of said baggage. 10. The arithmetic processing step detects bending points of the measurement pattern projected onto the baggage, and obtains a three-dimensional straight line indicating each side of the baggage from the three-dimensional positions of the bending points. The size measurement method according to item 1.

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