JP6682809B2 - Inspection system and inspection method - Google Patents

Description

  The present invention relates to an inspection system and an inspection method for inspecting Braille or the like.

  In media such as cards, labels and packages, necessary information may be recorded in Braille. Incorrect Braille will convey incorrect information, so a Braille inspection is performed after the media is manufactured to see if the Braille was recorded correctly.

  As a Braille inspection, there is a method in which a transparent ink that emits UV light is used for the Braille portion, and the Braille portion is extracted by irradiating light having a UV wavelength (Patent Documents 1 and 2). In addition, there is also a method in which light having a plurality of wavelengths is applied to the Braille portion, and the Braille portion is extracted from the difference in how the images appear (Patent Document 3).

JP 2009-282271 JP JP 2010-181388 JP Japanese Patent Laid-Open No. 2007-66198

  However, in the methods of Patent Documents 1 and 2, it is necessary to use a special ink for the Braille portion, and using such an ink only for the Braille inspection has problems in terms of labor and cost. Also, the method of Patent Document 3 cannot grasp the detailed shape of Braille.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an inspection system and the like that can perform simple and detailed inspection of Braille or the like.

A first aspect of the present invention for solving the above-mentioned problems includes an illumination that irradiates a projection with inspection light from a plurality of positions, an imaging device that receives the inspection light reflected by the projection to perform imaging, and an illumination at each position. From the brightness information of a plurality of images obtained by shooting the projection by itself, using the photometric stereo method to create shape data indicating the three-dimensional shape of the projection, based on the shape data the projection And an inspection device for performing the inspection , wherein the protrusion is in Braille, and the inspection device performs the inspection of the planar shape of the protrusion as the inspection .

  In the present invention, shape data is created by creating shape data indicating the three-dimensional shape of a protrusion from the brightness information of a plurality of images obtained by photographing inspection of protrusions such as Braille by irradiating inspection light from each of a plurality of positions. Based on this, detailed inspection of protrusions such as Braille becomes possible. In addition, there is no need to use a special ink for inspection, and there is no labor or cost.

The inspection device, since creates the shape data by using a photometric stereo method, for the projections located on the pattern of media, to remove the influence of the reflectance of a picture can be created suitably a three-dimensional shape of the projections.

The projections Ri braille der, by using the technique of the present invention, braille can do detailed testing was correctly formed.

The test devices, as the test can be performed inspection of planar shape and height of the protrusions. For example, as the examination, the actual height of the actual area of the planar shape of the protrusion projections, with the resolution of the image is calculated from the shape data is compared with a reference value. Further, the inspection device can inspect the planar shape of the protrusion by extracting the contour of the protrusion from the inclination in the height direction of the protrusion based on the shape data.
In the present invention, detailed inspection of the planar shape and height of the protrusion can be performed using the shape data. Further, a more useful inspection can be performed by calculating the actual height and the actual area of the protrusion using the resolution and making a comparison determination.

It is desirable that the inspection device inspects a reading result of the protrusion as the inspection.
In the present invention, the reading result can be inspected from the shape data of the protrusion, and more detailed inspection is possible.

A second aspect of the present invention is an illumination for irradiating the projection with the inspection light from a plurality of positions. The illumination of each position is used alone to irradiate the projection with the inspection light, and the inspection light reflected by the projection is received by an imaging device. And the step of performing the image capturing, the inspection apparatus determines the three-dimensional shape of the protrusion using the photometric stereo method from the brightness information of the plurality of images obtained by performing the image capturing of the protrusion using illumination at each position independently. Creating the shape data shown, and inspecting the protrusion based on the shape data, the protrusion is Braille, the inspection device, as the inspection, the inspection of the planar shape of the protrusion. The inspection method is characterized by being performed.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an inspection system and the like that can perform simple and detailed inspection of Braille or the like.

Diagram showing inspection system 1 Diagram showing the hardware configuration of the inspection device 3 Diagram showing flow chart of inspection method Braille 11 image example Diagram explaining the photometric stereo method Example of Braille 11 shape data The figure explaining reading of Braille 11

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

(1. Inspection system 1)
FIG. 1A is a diagram showing an inspection system 1 according to an embodiment of the present invention. The inspection system 1 inspects Braille 11 formed on the medium 10, and includes an inspection device 3, a photographing device 5, an illumination 7, and the like.

  FIG. 1A shows the arrangement of the photographing device 5 and the illumination 7 when viewed from the side of the medium 10. Further, FIG. 1B is a diagram showing the arrangement of the photographing device 5 and the illumination 7 when viewed from above the medium 10.

  In this embodiment, it is assumed that the medium 10 is a resin card and has a rectangular flat surface. However, the medium 10 is not particularly limited, and may be, for example, various labels, packages, or the like. In addition, the material and shape are not particularly limited.

  Braille 11 is a smooth semi-spherical protrusion having a smooth surface formed on the medium 10. The braille 11 is formed, for example, by embossing the medium 10, but the forming method, material, etc. are not particularly limited. For example, it is possible to form the Braille 11 with resin or the like by a method such as printing.

  The inspection device 3 controls the image capturing device 5, the illumination 7, and the like to capture an image of the braille 11 on the medium 10, and performs the braille inspection from the image. In the present embodiment, as the Braille inspection, the planar shape and height of the Braille 11 and the reading result are inspected.

  FIG. 2 is a diagram showing a hardware configuration of the inspection device 3. As shown in FIG. 2, the inspection device 3 can be realized by, for example, a computer configured by connecting a control unit 31, a storage unit 32, an input unit 33, a display unit 34, a communication unit 35, and the like via a bus 36. However, the present invention is not limited to this, and various configurations can be appropriately adopted.

  The control unit 31 includes a CPU, ROM, RAM, and the like. The CPU calls a program related to the processing of the inspection device 3 stored in the storage unit 32, a recording medium such as a ROM, into the work memory area on the RAM and executes the program. ROM is a non-volatile memory that permanently holds computer boot programs, programs such as BIOS, and data. The RAM is a volatile memory, which temporarily holds programs and data loaded from the storage unit 32, ROM, and the like, and includes a work area used by the control unit 31 to perform various processes.

  The storage unit 32 is a recording medium such as a flash memory or a hard disk drive, and stores a program executed by the control unit 31, data necessary for executing the program, an OS, and the like. These programs and data are read by the control unit 31 as needed, transferred to the RAM and executed.

The input unit 33 inputs data, and has, for example, a keyboard, a pointing device such as a mouse, and an input device such as a numeric keypad.
The display unit 34 includes a display device such as a liquid crystal panel.
The communication unit 35 is a communication interface that mediates communication via a network or the like, and communicates with other devices.
The bus 36 is a path that mediates exchange of control signals, data signals, etc. between the respective units.

  The image capturing device 5 captures the Braille 11 of the medium 10 under the control of the inspection device 3, and is arranged above the medium 10 at a position corresponding to the central portion of the medium 10. The imaging device 5 is composed of, for example, an area camera and a lens, and receives the inspection light emitted from the illumination 7 and reflected from the Braille 11 to perform imaging. However, the photographing device 5 is not limited to this, and it is also possible to perform photographing while conveying the medium 10 using, for example, a line camera.

  The illumination 7 irradiates the Braille 11 with inspection light, and is provided at a plurality of different positions in this embodiment. That is, in this embodiment, the four illuminations 7 a to 7 d are provided above the medium 10 at positions corresponding to the four sides of the medium 10. The light source of the illumination 7 is not particularly limited, but for example, an LED (Light Emitting Diode) that emits inspection light of the same wavelength can be used as the light source of each of the illuminations 7a to 7d.

  Although not particularly shown, the image capturing device 5, the illumination 7, and the like are arranged in a dark room, and the Braille image is captured with the outside light blocked.

(2. Inspection method)
Next, a method for inspecting Braille by the inspection system 1 will be described with reference to FIG. FIG. 3 is a flowchart showing the inspection method.

  In the present embodiment, under the control of the inspection device 3, the Braille 11 is irradiated with the inspection light by using the illuminations 7a to 7d at each position independently, and the inspection light reflected by the Braille 11 is received by the imaging device 5. Then, the Braille 11 of the medium 10 is photographed under each of the illuminations 7a to 7d (S1).

  In S1, for example, only the illumination 7a is turned on to photograph the braille 11, and then the illumination 7a is turned off and only the illumination 7b is turned on to photograph the braille 11. This is repeated for the illuminations 7a to 7d, and four images obtained by photographing the braille 11 under each illumination 7a to 7d are obtained. 4A to 4D are examples showing a part of an image obtained by photographing Braille 11 using the illuminations 7a to 7d alone. As shown in the drawing, when the Braille 11 is photographed under each of the illuminations 7a to 7d that emit the inspection light from different directions, the shadow of the Braille 11 becomes different.

  The control unit 31 of the inspection device 3 acquires the images of the Braille 11 captured under the respective illuminations 7a to 7d from the image capturing device 5, and determines the three-dimensional shape of the Braille 11 from the brightness information (the gradation value of the image) of these images. The shape data that indicates is created (S2). At this time, if necessary, each image may be corrected to remove the influence of the illuminance unevenness of the illuminations 7a to 7d.

  There are various known methods for creating shape data, but in the present embodiment, based on the brightness information of a plurality of images as shown in FIG. 4, a three-dimensional shape of Braille 11 is formed by using the photometric stereo method. Shape data is created. Photometric stereo method is known (for example, Yusuke Mizunaga, Atlantic Ocean, Hisao Tokushima, Shigeomi Hara, Osamu Dozono, Yoshio Noguchi: Reconstruction of object shape by photometric stereo method, Saga University, 2004). A brief description will be given with reference to FIG.

  That is, when the imaging device 5 receives the inspection light emitted from the illumination 7 and reflected from the point P on the object, the amount of light received by the imaging device 5 is the amount of the inspection light emitted from the illumination 7, that is, the illumination 7. It is represented by the position of the imaging device 5, the reflectance ρ of the object at the point P and the surface inclination (α, β) (= (dz / dx, dz / dy)). If the light amount of the inspection light and the positions of the illumination 7 and the photographing device 5 are known, the above light receiving amount can be expressed by an equation in which ρ, α, and β are unknowns.

  Therefore, by using the at least three illuminations 7 at different positions individually and performing imaging with the imaging device 5, at least three equations indicating the amount of light received by the imaging device 5 can be obtained from the brightness of the point P on each captured image. Can stand. By solving these equations, ρ, α and β can be calculated, and the surface shape of the point P can be known from α and β. By similarly calculating the surface shape for each point on the image, a three-dimensional shape of the object can be created without being affected by the reflectance ρ of the object. If necessary, interpolation for smoothing the shape may be performed. Also, although a separate calculation is required, it is also possible to calculate the solid shape of the point P from two images obtained under two illuminations at different positions (for example, Yangjun, Onishi Noboru, Sugie). Noboru: Photometric stereo using two images, Information Processing Society of Japan, Vol.34 No.10, Oct.1993).

  FIG. 6 is a diagram showing the shape data of Braille 11 thus obtained, and FIG. 6A is an image in which the three-dimensional shape of Braille 11 is visualized. Further, FIG. 6B is an image showing the inclination of the Braille 11 in the height direction, and a portion having a large inclination is represented by high brightness (white).

  The control unit 31 of the inspection device 3 inspects the planar shape, height, and reading result of the braille 11 based on the shape data of the braille 11 created in S2 (S3).

  In S3, as an inspection of the planar shape of the braille 11, for example, the contour of the braille 11 is extracted from the image of FIG. 6B, and the area of the image of the braille 11 in the planar shape is used as an actual space in the real space. It is converted into an area and compared with a predetermined reference value to judge whether it is good or bad. The resolution can be obtained from the relationship between the actual size of the shooting range of Braille 11 calculated from the height and orientation of the shooting device 5 and the number of pixels of the image. For the planar shape of Braille 11, convert the size of the contour such as the length of the diameter to an actual value and compare it with a reference value as described above, or calculate the degree of approximation to a circle such as roundness and ellipticity to obtain a reference value. It is also possible to judge the quality by comparing with the value. Further, the height of the braille 11 in the shape data visualized in FIG. 6A is converted into the actual height in the real space by using the resolution and compared with a predetermined reference value, and the same good / bad judgment is made. It can be carried out. For example, since the ratio of the diameter of the braille 11 in the plane shape to the height of the braille 11 can be known from the shape data, the diameter of the braille 11 is converted to the actual length by using the resolution, and the actual ratio of the braille 11 to The height of can be calculated. Each of the above-mentioned reference values can be adapted to the Braille standard defined by JIS (Japanese Industrial Standard), for example.

  In the inspection of the reading result of the braille 11, for example, the braille 11 can be read from the image of FIG. 6B to determine whether the result is correct. FIG. 7 is an example of performing reading (decoding) of Braille from FIG. 6B, and by determining the presence or absence of Braille 11 in each predetermined area on the image as shown by the solid line, the Braille 11 is determined from the determination result. Can be read. In the example shown in the figure, it is possible to read "hi", "ta", "no", "to", "chi", "a", and "e" from the position of Braille 11. By comparing this with a positive value, An inspection can be done.

  As described above, in the present embodiment, the shape data indicating the three-dimensional shape of the Braille 11 is created from the brightness information of the plurality of images obtained by photographing the Braille 11 by irradiating the inspection light from each of the plurality of positions. By doing so, it is possible to perform a detailed inspection on whether the braille 11 is correctly formed based on the shape data. In addition, there is no need to use special ink for Braille for inspection, and it does not take time and cost.

  In addition, by creating shape data using the photometric stereo method, the effect of the reflectance ρ of the design is removed even for the Braille 11 on the design of the medium 10 such as characters and figures, and the three-dimensional shape of the Braille 11 is created. It can be created appropriately.

  Further, in the present embodiment, the shape data can be used to inspect the planar shape and height of the braille 11 and the reading result of the braille 11, and the detailed inspection of the braille 11 is possible. Further, a more useful inspection can be performed by calculating the actual height and the actual area of the Braille 11 using the resolution and making a comparison / judgment. It should be noted that it is possible to perform only the necessary one of these inspections.

  However, the present invention is not limited to the one described in the above embodiment. For example, in the present embodiment, the braille 11 is inspected, but if it is a protrusion on the medium similar to the braille 11, such as a protrusion used as identification information other than the braille or a protrusion for slip prevention, the same as in the present embodiment. Inspection is possible and the same effect can be obtained.

  Further, although the illumination 7 is provided at the position corresponding to the four sides of the medium 10, the present invention is not limited to this, and it may be provided at the position corresponding to the four corners, for example. Further, although the four illuminations 7 are provided, this is to prevent a shadowy portion from occurring in any image. If such a condition is satisfied, it is possible to use three or less illuminations. .

  Further, although the plurality of lights 7a to 7d are provided in the present embodiment, the present invention is not limited to this, and for example, one movable light can be moved to each position corresponding to the lights 7a to 7d and used.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and naturally, these also belong to the technical scope of the present invention. Understood.

1; inspection system 3; inspection device 5; photographing devices 7, 7a to 7d; illumination 10; medium 11; Braille

Claims (7)

Illumination that irradiates projections with inspection light from multiple positions,
An image capturing device that receives the inspection light reflected by the protrusions to capture an image,
From the brightness information of a plurality of images obtained by shooting the projection using the illumination of each position independently, create shape data showing the three-dimensional shape of the projection using the photometric stereo method, and in the shape data An inspection device that inspects the protrusions based on
Equipped with,
The protrusion is Braille,
The inspection apparatus is an inspection system characterized by performing an inspection of a planar shape of the protrusion as the inspection. The inspection system of claim 1 wherein the inspection system, which as the inspection, and performs inspection of the height of the protrusion. The test devices, as the inspection, the actual surface product of the planar shape of the projection, with the resolution of the image is calculated from the shape data, according to claim 1 or claim, characterized in that compared with a reference value Inspection system described in 2 . The inspecting device extracts the contour of the protrusion from the inclination of the protrusion in the height direction based on the shape data, and inspects the planar shape of the protrusion. Inspection system according to any one of. The test devices, as the inspection, the inspection system of claim 2 wherein the actual height of the front Symbol projections, with the resolution of the image is calculated from the shape data, and comparing the reference value.   The inspection system according to any one of claims 1 to 5, wherein the inspection device inspects a reading result of the protrusion as the inspection. Regarding illumination for irradiating the projection light to the projections from a plurality of positions, a step of irradiating the projection light with the projection light by using the illumination at each position independently, and receiving the test light reflected by the projections by the imaging device to perform imaging ,
The inspection device, from the brightness information of a plurality of images obtained by photographing the projection using the illumination of each position independently, to create shape data showing the three-dimensional shape of the projection using the photometric stereo method , A step of inspecting the protrusion based on the shape data,
Equipped with,
The protrusion is Braille,
The said inspection apparatus performs the inspection of the planar shape of the said protrusion as said inspection, The inspection method characterized by the above-mentioned .