JP2006277590A - Ovd image inspection method, image inspection device, and inspection viewer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an OVD image inspection method and image inspection device allowing for stable OVD defect inspection unaffected by instability of an OVD by fluttering and undulation, or some positional instability of the OVD, in a conveyance system, and also provide an OVD inspection viewer thereof. <P>SOLUTION: The image inspection device for OVD inspection comprises: at least one light source designed for a specific observation angle so as to develop at least one specific image among images formed as OVDs; an imaging part 6 for imaging at least one specific image developed by exposure to light from the light source; and an information analysis part 8 for performing image processing for at least one imaged specific image according to the content of inspection. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an OVD image inspection method, an image inspection apparatus, and an inspection viewer. In particular, the OVD master, the OVD, and the OVD formed on the base material are inspected.

  OVD (Optically Variable Device) is a foil in which a metal is deposited on a relief diffraction grating, and has a unique optical change function such as the appearance of a three-dimensional image and color shift. In order to enhance the anti-counterfeit effect, it is used, for example, in cash cards, credit cards, bankbooks, cash vouchers, banknotes and the like. In addition, among these products, as a more advanced anti-counterfeiting technology, there are a plurality of OVDs in which a plurality of fine diffraction gratings called multiple diffraction gratings are configured in a complicated manner, and a plurality of light wavelengths diffracted depending on an incident angle are different The ones with the symbols are also used. Since OVD is an element that guarantees authenticity in these products, thorough quality control is required for the total number of OVDs.

  Manufacture of a product provided with OVD is performed by applying a sheet-type, patch-type, or thread-type OVD foil or OVD sheet to a substrate such as a card or paper by transfer or pressure bonding.

  At the time of manufacturing these OVD-added products, defects such as pinholes, chips, wrinkles, creases, lifts, dirt, and scratches may occur in the OVD due to poor transfer to the substrate, poor machine adjustment, and the like. These inspections are important items for quality control. Such defective products must be removed as defective products, but OVD diffraction gratings depend on the wavelength of light and the angle of incidence. Quality inspection was difficult because the pattern and color observed with a slight change in incident angle changed.

  In addition, if the OVD foil or OVD sheet used in the manufacture of these products has defects such as pattern embossing defects, material defects, vapor deposition defects, pinholes, etc. Rather than performing quality inspection after applying OVD to the substrate and removing it as a defective product, it is possible to reduce the cost by performing quality inspection of the OVD foil or OVD sheet before applying OVD. It is required from the aspect.

  Conventionally, hologram inspection is generally performed by reading an image obtained by irradiating the entire hologram pattern with a specific light source using a CCD camera or the like, and inspecting the image by image recognition or the like. In order to inspect whether or not an inspection object such as a hologram has a defect, an optical pattern inspection apparatus that reflects and interferes with light incident at a predetermined incident angle (for example, displays an image) There has been proposed a method of inspecting using a patent document 1).

JP 2002-221696 A

However, in the inspection using the inspection apparatus described above, since the reproduced image presented in the rainbow color that appears from being irradiated with light is captured as image data of the entire hologram, it is suitable for inspection of the entire hologram.
When this is used for OVD inspection, the entire OVD is irradiated with a light source at a predetermined angle, and the light diffracted by the OVD is read by a CCD camera or the like, so that the read image data is the wavelength of the light of the OVD diffraction grating. Due to the dependency of the incident angle, multiple patterns appear, multiple colors appear due to the diffraction of each of the diffraction gratings, and the image is a whitish specular state that captures the OVD diffusely reflected light. However, there was a problem that stable image data suitable for inspection could not be captured.

  OVD foil, OVD sheet, OVD-attached card, sheet, wound paper, and other objects to be inspected are slightly fluctuated and swelled during transportation, and slightly misaligned OVD. Regardless of the OVD imaged, the color of the image data captured by a CCD camera or the like, for example, the changing color density of each color of red, blue, and green is different, and is obtained as image data suitable for inspection. It was difficult.

  The above example will be described in detail. For example, it is assumed that an image A and an image B are incorporated in the same OVD. In the color density (0 to 255 levels) expressed by the A and B images constituting the OVD, when the color density of the A image is red and changes in 10 levels, the color density of the B image is blue. Suppose that this is a trumpet that produces 20 steps of change. For example, when the first OVD is imaged with a CCD camera or the like, the image of A appears in red (20 steps), the image of B appears in blue (30 steps), and when the second OVD is imaged, A If the image of red is developed in red (30 steps) and the image of B is green (10 steps), the color density of the entire captured image changes greatly even if there is a slight variation, making it suitable for inspection. It was difficult to capture as an image. Therefore, when the above-described image expressed in a plurality of colors is used as an inspection image, the color density change differs for each of the plurality of colors, so that the accuracy of the threshold setting value after binarization processing of the image is increased. In other words, the inspection accuracy of OVD defects (dirt, hole, flaw, chipping, wrinkle, crease, embossing failure of the pattern, material failure, vapor deposition failure, etc.) was reduced.

  In addition, a method of installing a plurality of light sources in order to make an image appear stably has been proposed, but has a drawback that the apparatus becomes complicated.

  The present invention has been made in order to solve the above-described conventional problems, and is affected by slight fluctuations and undulations caused by slight flutter and undulation of the inspection object in the conveyance system at the time of inspection and slight fluctuations of the OVD. OVD image inspection method and image inspection apparatus capable of inspecting stable OVD defects (pinholes, chips, wrinkles, creases, lifts, dirt, scratches, defective pattern embossing, material defects, vapor deposition defects, etc.) The purpose is to provide an inspection viewer.

  The present invention provides at least one specific image of the OVD from at least one light source designed to correspond to a specific viewing angle designed to express at least one specific image among images formed as an OVD. It is characterized by extracting at least one specific image obtained by irradiating.

  The OVD image inspection method of the present invention is an inspection method for inspecting OVD, corresponding to a specific observation angle designed to express at least one specific image among images formed as OVD. The at least one specific image of the OVD is irradiated from the designed at least one light source, the at least one specific image expressed by the irradiation is captured by an imaging unit, and the captured at least one specific image is The information analysis unit performs image processing according to the inspection content and inspects.

  In the OVD image inspection method of the present invention, the OVD may be inspected by being wound or conveyed by a single sheet.

  The light source can be set at a predetermined angle depending on the expression angle of the specific image.

  According to a fifth aspect of the present invention, there is provided an extraction device for extracting an image formed as an OVD, at a specific observation angle designed to express at least one specific image among the images formed as an OVD. It comprises at least one light source designed correspondingly.

  The OVD image inspection apparatus of the present invention is an inspection apparatus for inspecting OVD, and is designed in correspondence with a specific observation angle designed to express at least one specific image among images formed as OVD. In addition, at least one light source, an imaging unit that captures the at least one specific image that is expressed by irradiation from the light source, and information that performs image processing on the captured at least one specific image according to inspection contents And an analysis unit.

  In the OVD image inspection apparatus of the present invention, when the OVD is inspected while being wound or conveyed by a single sheet, a sensor for timing may be further provided.

  The light source can be set at a predetermined angle depending on the expression angle of the specific image.

  The OVD inspection viewer of the present invention is an extraction device for extracting an image formed as an OVD, and observes a cylindrical support member formed so as to surround the periphery of the OVD and an OVD attached to the upper portion of the support member. At least one lens designed to correspond to a specific viewing angle designed to develop at least one specific image in an image formed as an OVD on the side surface of the support member and one or more lenses One illumination part is provided, It is characterized by the above-mentioned.

  When OVD is observed or inspected using the OVD image inspection apparatus of the present invention, only an image that appears at a specific angle with respect to at least one specific image among images formed as OVD is targeted. In order to perform observation or inspection, the influence of image changes and color changes caused by slight fluttering and waviness of the inspection object in the transport system and slight fluctuations in the position of the OVD is minimized. In this case, the image change and the color change, which were unstable elements at the time, are eliminated or very small, so that the OVD defect can be inspected stably and accurately.

  Further, according to the OVD image inspection method of the present invention, unlike the conventional OVD inspection, the entire OVD pattern and the pattern / color change state by the diffraction grating are not extracted and inspected, but in the OVD. For a specific image included, an image as a single color so that a light source is installed at an angle that produces only a specific color of the specific image at the observation angle at the time of OVD design, and other images and colors are not included Since the image is captured by a CCD camera or the like, an effect can be obtained as a partial inspection of an image with high OVD accuracy.

  Furthermore, if the inspection viewer of the present invention is used, the quality state can be confirmed even when inspecting in a stationary state by OVD sampling or the like.

  Embodiments of the present invention will be described. Defects in the present invention are OVD pinholes and chips, wrinkles, creases, floats, dirt, scratches, embossing defects, material defects, Deposition failure.

  Examples of the inspection light source of the present invention include fluorescent lamps, halogen lamps, and LED spot illumination.

  Examples of the imaging means include a CCD line sensor camera or a CCD area sensor camera.

  In carrying out the present invention, it is possible to inspect sheet-type, patch-type, and thread-type OVD foils and OVD sheets, and these OVDs and these OVDs are used as base materials such as cards and papers. If it is given, it becomes an inspection object. These objects to be inspected may be any form, such as a winding, a single wafer or the like. The OVD original plate is also an object to be inspected.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.
A feature of the OVD image inspection apparatus of the present invention is that a light source is installed with respect to a specific image that reflects and interferes with light incident at a predetermined incident angle, and displays the image. The specific image incorporated in the OVD Are installed with respect to an incident angle at which an image appears by using one light source or a plurality of light sources. The light source is adjusted by the position adjusting unit and fixed at a predetermined angle in order to irradiate the measurement area of the OVD to be inspected with a light source having an incident angle (θ).

  FIG. 1 shows an expression image of OVD1 described in the present embodiment. It is incorporated so that three images of the image 1a when the angle θ1 formed by the normal line and the incident light is −30 degrees, the image 1b when the angle is 0 degrees, and the image 1c when the angle is 45 degrees are developed.

  FIG. 2 shows a state in which an OVD expression image is observed. In order to observe the expression image of OVD, in the case of visual observation 2, it is set in a position perpendicular to OVD1, and in the case of CCD camera 3 attached to the image inspection apparatus, it is installed perpendicular to OVD1. Observed.

When the grating interval d of the diffraction grating constituting the image of the OVD 1 according to the present embodiment is observed with the visual observation 2 or the CCD camera 3 attached to the image inspection apparatus 3, the incident light from the irradiation apparatus 4 and the observation are observed. When the angle formed with the angle to be measured is θ, the observed color wavelength is λ, and Equation 1 is an equation showing this relationship.
(Formula) nλ = 2dsinθ (1)
θ: angle between incident light and diffracted light d: spatial frequency n: order of diffracted light ± 1, ± 2...
λ: Color wavelength

Since the observed color wavelength λ depends on the incident light angle θ and the grating interval d, the observation 2 or the CCD camera 3 of the image inspection apparatus 3 and the irradiation can be performed while observing the incident angle θ. The device 4 may not be installed perpendicular to the OVD 1.
For example, when this OVD1 is observed at an angle θ of 15 degrees, it can be seen from the formula 1 that the visible region of 400 to 700 nm can be observed if the lattice spacing d, that is, the number of lattices per millimeter is about 400 to 600. .

  Further, the observation distance by visual observation or the imaging distance by the CCD camera of the image inspection apparatus may be set at such a distance that the OVD 1 can be observed.

  The image data obtained by imaging is a printed image including the OVD imaged by pattern matching using OVD reference image data stored in advance in a memory, a comparison determination method represented by image processing, a special extraction method, or the like. The quality state is confirmed from the data, and the determination is made. As a desirable image processing method, binarization processing is used. Binarization is to cut out an object from an image in order to analyze the characteristics of the image and separate a background and a figure. An image represented by two values of 0 and 1 from a grayscale image having density values. Is to convert to By this binarization processing, the bright part is set to white and the dark part is set to black. When binarization processing is performed as image processing of captured image data, if there is an abnormality such as a pinhole or chipping in the OVD, it becomes different from the light of the reference intensity and is binarized so that it becomes white. When processed, the area of the white portion obtained by measurement becomes larger than the reference area stored in advance. By comparing this image data with the reference image data, the defect is immediately identified, so that the OVD defect can be easily determined and is found to be very useful.

  According to the above determination, if it is within the threshold range, it is determined to be normal, and if it is out of the threshold range, it is determined to be a defect and disposed of as an abnormal product. About disposal, what is necessary is just to utilize a well-known various technique suitably and to exclude a defective article.

  As described above, the present invention does not capture an image of the entire OVD, but irradiates light at a predetermined irradiation angle in order to express a specific image so that the specific image is displayed in a single color. Since it can be expressed, even if the object to be inspected is fluttered or swelled, the color density change amount is stable because the color to be expressed is a single color (for example, red), and binarization processing is performed. Since the subsequent threshold can be set with high accuracy, the inspection accuracy is improved.

  Example 1 FIG. 3 shows Example 1 of an OVD image inspection apparatus according to the present invention. The OVD image inspection apparatus 5 includes an imaging unit 6, a light source 7, an information analysis unit 8, a position adjustment unit 9, and a sensor 10. In this embodiment, the inspection is performed while sequentially inspecting the object 11 in the transport direction 12.

  The imaging unit 6 of the OVD image inspection apparatus 5 uses a CCD imaging device, the imaging distance is about 80 to 90 mm away from the inspection object 11, and the imaging angle is 0 degree in the horizontal direction and 0 degree in the vertical direction with respect to the surface of the inspection object 11. Set to. The light source 7 is LED spot illumination, and can be set to an arbitrary angle by the position adjusting unit 9 so that it can be used at an arbitrary angle with respect to the design of the image to be developed, and always irradiates the inspection object. .

  The OVD used in the first embodiment is an OVD 13 in which three symbols as shown in FIG. 4 are incorporated. A specific image that reflects and interferes with light incident at a predetermined incident angle and displays an image is displayed. When the irradiation angle θ is -30 degrees incident light with respect to the normal line, the design is 14a, and when the incident light is 0 degrees. It is incorporated so that the 14b symbol and the 14c symbol appear when the incident light is 45 degrees.

  While moving the inspection object 11 to which the OVD 13 is attached in the transport direction 12, light is irradiated from the light source 7 onto the surface of the OVD 13 of the inspection object 11, and the light diffracted by the irradiation light is imaged by the imaging unit 6. This embodiment is an example using one light source, and the angle of the light source 7 is adjusted by the position adjusting unit 9 in accordance with the angle of incident light of one of the three symbols incorporated in the OVD 13. To do. Since the light source 7 is known to be able to observe a visible region of 400 to 700 nm when the OVD 13 is observed at an angle θ of 15 degrees as described above, it is used in accordance with an arbitrary angle by incorporating a specific image to be expressed. be able to.

  For the inspection object 11 in the transport state, when the inspection object 11 reaches the imaging range of the imaging unit 6 by the sensor 10 that measures timing, an imaging signal is output and imaging is performed.

  Next, the captured image is inspected by performing image processing in the information analysis unit 8 according to the inspection content. In this embodiment, the image 2 recognized in advance by the information analysis unit 8 is set. A valuation process is performed to inspect the inspection object 11 for defects. The method of image processing varies depending on the contents of the inspection. For example, in the case of area management, a binarization process is performed, and in the case of directionality confirmation, a Fourier transform process is performed.

  If there is no problem in the inspection result, the normal operation state is obtained as it is. However, if any defect is found, the information analysis unit 8 outputs a defect signal to the machine or warning device, stops the machine, Notification. The inspection is performed even during the output of the defect signal, and all the inspection objects 11 to be conveyed are dealt with.

  (Example 2) FIG. 5: shows Example 2 of the OVD image inspection apparatus which installed multiple light sources. When inspecting an OVD in which a plurality of symbols are incorporated, if a plurality of light sources are added to the plurality of inspection symbols and inspected, the inspection accuracy is further improved. In the first embodiment, an example in which the inspection object 11 to which the OVD 13 including the three symbols illustrated in FIG. 4 is attached is inspected with one light source is described. In the second embodiment, the OVD 13 including the three symbols is embedded. An example in which the two are inspected using two light sources will be described.

  FIG. 5 is for inspecting, for example, two symbols 14a and 14b at the same time among the three symbols of the inspected object 11 to which the OVD 13 incorporating the three symbols is attached. The operation is performed in the same manner as in the first embodiment. . The diffracted light of each of the two symbols is picked up by the image pickup unit 6, and the picked-up image is recognized by the information analysis unit 8 as a composite image 15 of two symbols 14 a and 14 b, and binary for the composite image. Inspect and inspect.

  In the above embodiment, the inspection by the transport system has been described. However, the present invention is not limited to this, and the OVD original plate or the inspection object having the OVD or OVD attached to the sample stage or the like replacing the transport system. May be placed one by one and inspected in a stationary state.

  (Example 3) FIG. 6 shows Example 3 of the OVD inspection viewer according to the present invention. The OVD inspection viewer 16 includes a support member 17, one or more lenses 18 for observation, one or more illumination units 19 a, 19 b..., And changeover switches 20 a, 20 b.・ ・ Consists of The illumination unit is attached at an angle corresponding to a specific observation angle designed to express at least one specific image among images formed as OVD.

  An OVD inspection viewer 16 is installed on the object to be inspected OVD1, and the OVD1 is observed from the lens 18. At this time, for example, the illuminating unit 19a and the illuminating unit 19b are installed at positions corresponding to the incident light designed in FIG. 1 with the irradiation angles θ2a and θ2b with respect to the normal. If necessary, the irradiation switch 19a and the illumination unit 19b are switched by the changeover switches 20a and 20b attached to the respective illumination units, or simultaneous irradiation is performed.

  As described above, various modifications and changes are possible without being limited to the embodiments described above, and these are also within the scope of the present invention.

It is a figure which shows the expression image of OVD demonstrated in this Embodiment. It is a figure which shows the state which observes the expression image of OVD demonstrated in this Embodiment. It is a figure which shows the schematic of the OVD image inspection apparatus of Example 1. FIG. It is a figure which shows OVD in which the three symbols of a present Example were integrated. It is a figure which shows the schematic of the OVD image inspection apparatus of Example 2. FIG. It is a figure which shows the OVD inspection viewer of Example 3.

Explanation of symbols

1 OVD
2 Visual position 3 CCD camera 4 Irradiation device 5 OVD image inspection device 6 Imaging unit 7 Light source 8 Information analysis unit 9 Position adjustment unit 10 Sensor 11 Inspected object 12 Transport direction 13 OVD in which three patterns are incorporated
14a, 14b, 14c Image of OVD with design incorporated 15 Composite image 16 OVD inspection viewer 17 Support member 18 Lens 19a, 19b Illumination unit 20a, 20b Changeover switch

Claims (9)

Irradiating at least one specific image of the OVD from at least one light source designed to correspond to a specific viewing angle designed to develop at least one specific image in an image formed as an OVD An OVD image extraction method, wherein at least one specific image obtained by the method is extracted. An inspection method for inspecting OVD,
Illuminating at least one specific image of the OVD from at least one light source designed to correspond to a specific viewing angle designed to develop at least one specific image in an image formed as an OVD;
The at least one specific image expressed by the irradiation is imaged by an imaging unit,
An OVD image inspection method characterized by inspecting at least one captured specific image by performing image processing in an information analysis unit according to inspection contents. The OVD image inspection method according to claim 1, wherein the OVD is wound or conveyed by a single sheet. The OVD image inspection method according to claim 1, wherein the light source can be set to a predetermined angle according to an expression angle of the specific image. An extraction device for extracting an image formed as an OVD,
An OVD image extraction apparatus comprising: at least one light source designed to correspond to a specific observation angle designed to express at least one specific image in an image formed as an OVD. An inspection device for inspecting OVD,
At least one light source designed for a specific viewing angle designed to develop at least one specific image in an image formed as an OVD;
An imaging unit for imaging the at least one specific image expressed by irradiation from the light source;
An OVD image inspection apparatus, comprising: an information analysis unit that performs image processing on the captured at least one specific image according to inspection contents. The OVD image inspection apparatus according to claim 5, further comprising a sensor for timing when the OVD is inspected while being wound up or conveyed by a sheet. The OVD image inspection apparatus according to claim 5, wherein the light source can be set to a predetermined angle according to an expression angle of the specific image. In the OVD image extraction device according to claim 5,
A cylindrical support member formed so as to surround the periphery of the OVD;
One or more lenses for observing the OVD mounted on top of the support member;
At least one illumination unit designed to correspond to a specific observation angle designed to express at least one specific image among images formed as OVDs on a side surface of the support member. An OVD inspection viewer.

Images