CN202748301U - Multiband polarization imaging anti-counterfeiting element identification system - Google Patents

Abstract

The utility model relates to a multiband polarization imaging anti-counterfeiting element identification system, which is characterized by comprising an optical filter rotating wheel, three charge coupled device (CCD) cameras, a motor system, a halogen lamp and a computer, wherein the halogen lamp and the optical filter rotating wheel are arranged at the front and rear of an anti-counterfeiting sample to be tested; a plurality of polarizing films are arranged on the optical filter rotating wheel; the three CCD cameras are arranged behind the optical filter rotating wheel; the optical filter rotating wheel is controlled by the motor system; and the three CCD cameras output the photographed images to the computer for processing. According to the system, a polarization light source, a wave plate, the polarizing films, the CCD cameras and a stepping motor are integrated to the system, and optical electromechanical integration is realized; and by adoption of multiband 1/4lambda wave plate and the polarizing camera, the filtering band is self-defined and selected for anti-counterfeiting identification according to the detection aim, the three CCD cameras simultaneously work, the motor is accurately controlled to rotate through a digital signal processor (DSP) for rapidly acquiring the image, and the system has the functions of image filtering, fusing and storing and the like, and therefore, the aims of stably and reliably operating and saving manpower and financial resources can be fulfilled.

Description

Multi-band Polarization imaging Security element identification system

Technical field

The present invention relates to a kind of Multi-band Polarization imaging Security element identification system, for the polarization measurement sheet that uses the polarization anti-counterfeiting technology to make, stealthy labeling etc., can effectively detect the information of wherein hiding, and the detection method of native system is easy to use, testing result is intuitive and reliable, is with a wide range of applications in false proof discriminating field.

Background technology

In order to protect article; for example value document and paper; and the spare part of consumer product area, medicine, textile or other registered trademark products avoid imitated and forge and distort, and in order to detect the true and false of these article, for they have configured specific Security element.Making Security element needs some special material and pigment, because they have specific optical characteristics, therefore be not easy to be imitated.Known Security element has watermark, be combined in anti-counterfeiting line in the paper, luminous or magnetic-particle etc.; Security element can be added in printing-ink or the relief hologram, then be applied on the packing with shielded article surface or article as the paper tinsel element.

At present, the method of the Security element that the identification polarized material is made, mainly be to rely on that the color that manifests under the polarized light is different from the color that manifests under natural light or light to be realized, although more directly perceived, but it does not take full advantage of spectrum and the polarization characteristic of implicit pattern, can not accurately find out subtly the information of hiding in the Security element.

Summary of the invention

The technical matters that solves

For fear of the deficiencies in the prior art part, the present invention proposes a kind of Multi-band Polarization imaging Security element identification system, a plurality of hardware modules such as integrated data collection and processing, motor rotation control, have multiband, automatically space-time registration and the characteristics such as real-time, satisfy the performance requirement of polarization Security element identification.

Technical scheme

A kind of Multi-band Polarization imaging Security element identification system is characterized in that comprising optical filter runner, three CCD cameras, electric system, Halogen lamp LED and computing machines; Be provided with Halogen lamp LED and optical filter runner in the front and back of false proof print to be measured, the optical filter runner is provided with a plurality of polaroids; The postposition of optical filter runner is three CCD cameras, and the optical filter runner is controlled by electric system; Three CCD cameras export the image that absorbs to computing machine and process; After the optical filter runner circled, computing machine calculated polarization parameter and carries out image registration image rectification, and then sends a signal to the rotation that electric system is controlled double-deck optical filter runner; Described double-deck optical filter runner is provided with a plurality of circular holes, and a double-deck optical filter is set in each circular hole, and each double-deck optical filter only allows the light of the specific band in the white light to pass through; The polarization angle of the preposition polaroid of described three CCD cameras is 0 °, 45 ° and 90 °; Shuttling movement between three CCD cameras, electric system and the Computer Processing closes: when electric system is controlled double-deck optical filter runner and turned for 1/6 week, trigger the CCD camera imaging, when double-deck optical filter runner finished for 1 week, computing machine carried out image rectification and calculates polarization parameter; Image rectification finishes storage to be finished, and the motor of computer control electric system turned for 1/6 week so that turn double-deck optical filter runner again, started next cycle.

Described double-deck optical filter runner is provided with six circular holes that are used for installing optical filter, each diameter is about 25mm, wherein, a circular hole is empty, the fast axle that four circular holes are installed respectively the wavelength that differs from one another becomes 0 ° 1/4 λ wave plate with reference direction, another circular hole is installed fast axle becomes 90 ° with reference direction 1/4 λ wave plate, and its bandwidth must cover the wavelength of four the single wave plates in front.

Beneficial effect

A kind of Multi-band Polarization imaging Security element identification system that the present invention proposes, with polarized light source, wave plate, polaroid, CCD camera and stepper motor are integrated in the system, realized optical, mechanical and electronic integration, and adopt multiband 1/4 λ wave plate and polarization camera, can carry out anti-counterfeiting identification according to surveying the self-defined selection optical filtering of purpose wave band, three CCD cameras are worked simultaneously, has compact conformation, volume is little, the advantage such as fast, accurately control electric machine rotation by DSP and obtain fast image, and system also has image filtering, therefore the functions such as fusion and storage can reach reliable and stable work, save the purpose of manpower and financial resources.

Description of drawings

Fig. 1: Multi-band Polarization imaging anti-counterfeiting identification system hardware structure figure;

Fig. 2: Multi-band Polarization imaging anti-counterfeiting identification working-flow figure;

Fig. 3: runner quarter wave plate scheme of installation

Fig. 4: light path travel path and polarization multi-wavelength data cube schematic diagram in the imaging device;

Fig. 5: polarization parallel light-source structure figure;

Fig. 6: embodiment image registration process flow diagram;

Fig. 7: required scaling board schematic diagram during embodiment image registration is processed.

Embodiment

Now in conjunction with the embodiments, the invention will be further described for accompanying drawing:

In the technical scheme of the present invention, mainly comprise polarized light source module, multiband runner control module (being motor control module), the ingredients such as polarization camera set image capture module, image processing module.

The light source that this embodiment adopts is four Halogen lamp LEDs, forms polarized light source with four groups of sources of parallel light and polaroid, uses Halogen lamp LED as light source, places linear polarizer before light source, adds lens behind the polaroid, as shown in Figure 5.Each linear polarizer light transmission shaft equates with the angle of reference direction, and light is after the target area overlaps, and area coverage is not less than 50 * 75mm, is used for realizing the polarizing light irradiation to Security element to be measured.

The computing machine that this embodiment adopts comprises collected by camera software, and computer model is Lenovo Qitian M7300, and in addition, the multiway images transmitting device is made of the PCI1394 video frequency collection card usually, loads in the host computer system.

The CCD camera of this embodiment adopts dimension to look MV-1300, and it is covering visible light wave band and other 5 wave bands that the drive motor leadshine-1.8/4.0A stepper motor of runner, 1/4 λ wave plate adopt wavelength.The control module of runner is the polarization multi-spectral imaging instrument control system of seminar's exploitation.

Multiband runner control module mainly realizes the setting of runner self optical filter and the accurate control that motor rotates coaxial runner.Six circular holes that are used for installing optical filter on runner, have been designed altogether, each diameter is about 25mm, wherein, a circular hole is empty, a circular hole is installed fast axle becomes 90 ° with reference direction 1/4 λ wave plate, and its bandwidth must cover the wavelength of four the single wave plates in front, and the Stokes calculation of parameter is convenient in design like this, the fast axle that all the other four circular holes are installed respectively the wavelength that differs from one another becomes 0 ° 1/4 λ wave plate with reference direction, as shown in Figure 3.

Be right after the polarization camera behind the multiband runner, polarization camera set image capture module is mainly realized collection and the storage of three road polarization images.This module relates to three CCD cameras and three hardware such as linear polarizer, and three linear polarizer become 0 °, 45 °, 90 ° angle to be fixed on three CCD camera lens fronts with the axis of homology respectively with reference direction, and the image of collection is by Computer display.

Software flow of the present invention is:

Image acquisition, image registration, polarization parameter calculate

Referring to Fig. 2, introduce runner control and image acquisition

Circuit control unit is integrated on the DSP disposable plates, is the core component of native system, and its concrete control procedure is as follows:

1. the motor control module in the circuit control unit carries out initialization operation to motor, accurately controls runner to the tram by coaxial manner, i.e. the complete combination of runner hole and camera lens;

2. sent by approach switch and feed back signal to polarization camera image acquisition module, control simultaneously three road CCD cameras, imaging is carried out in automatic exposure, the complete rear storage of automatically carrying out image of imaging;

3. send and feed back signal to motor control module, control driven by motor runner rotates 60 °;

4. rotate complete after, repeat 2., 3. until the number of turns that sets in advance is done zero correction by approach switch, send and to feed back signal to circuit control unit, suppressed zero position;

5. during 4., if amount of images satisfies the requirement of calculating the Stokes parameter, can read memory image, the operations such as calculating of geometry correction and polarization parameter.

According to the impact of in calculating the degree of polarization process, whether ignoring circularly polarized light intensity V, the collection of polarization image is divided into two kinds of situations:

(1) ignores the impact of V: only need to consider the calculating of polarization parameter under natural light incident condition this moment.Namely only need obtain three images under the polarization angle by the circular hole of sky and just can calculate polarization parameter;

(2) impact of consideration V: consider the calculating of polarization parameter under monochromatic light incident condition this moment.The circular hole that namely needs single 0 ° of 1/4 λ wave plate successively imaging under three polarization angles and 90 ° of 1/4 λ wave plate under 45 ° of linear polarizer imaging totally four width of cloth images just can calculate polarization parameter.

Referring to accompanying drawing 6,7, the process of article image registration.At first scaling board is positioned over the target location, and keeps same plane with target as far as possible, obtain the scaling board image by three CCD cameras.Then extract the SIFT unique point of three width of cloth images, then calculate the associating descriptor of each unique point, next take the image of one of them camera as benchmark, use the bi-directional matching method that all the other two width of cloth images and benchmark image are mated, adopt at last based on the method for parameter estimation of RANSAC algorithm and least square method and find the solution the transformation model parameter, realize the registration between three width of cloth images.

Introducing polarization parameter calculates:

In the polarization imaging technical applications, generally adopt the polarization state of the accurate monochromatic plane wave of Stokes vector analysis, the Stokes vector can be described as: S=[IQUV] ^TWherein, I represents the total intensity of light wave, and Q represents the intensity of linearly polarized light on the horizontal direction, and U represents the intensity of linearly polarized light on 45 ° of directions.V represents the circular polarization light intensity.In application, V is generally very little, in native system, when using panchromatic photometry to calculate the polarization parameter image, ignores the size of V, and when using a certain single band photometry to calculate the polarization parameter image, V can not ignore.

Axis of homology direction and the reference direction angle of supposing linear polarizer are θ, and wave plate quick shaft direction and reference direction angle are φ, and then the strength formula of Stokes is

$I(\mathrm{\θ},\mathrm{\φ})=\frac{1}{2}[I+Q\cos 2\mathrm{\θ}+U\cos \mathrm{\φ}\sin 2\mathrm{\θ}+V\sin \mathrm{\φ}\sin 2\mathrm{\θ}]$

Thereby deriving as can be known, Stokes parameter and polarization parameter (degree of polarization DoLP, polarization azimuth AoP) are:

I＝I(0°,0°)+I(90°,0°)

Q＝I(0°,0°)-I(90°,0°)

U＝2I(45°,0°)-I(0°,0°)-I(90°,0°)

V＝2I(45°,90°)-I(0°,0°)-I(90°,0°)

$\mathrm{DoLP}=\frac{\sqrt{Q^2+U^2+V^2}}{I}$

$\mathrm{AoP}=\frac{1}{2}{\tan }^{-1}\frac{U}{Q}.$

Claims (2)

1. a Multi-band Polarization imaging Security element identification system is characterized in that comprising optical filter runner, three CCD cameras, electric system, Halogen lamp LED and computing machines; Be provided with Halogen lamp LED and optical filter runner in the front and back of false proof print to be measured, the optical filter runner is provided with a plurality of polaroids; The postposition of optical filter runner is three CCD cameras, and the optical filter runner is controlled by electric system; Three CCD cameras export the image that absorbs to computing machine and process; After the optical filter runner circled, computing machine calculated polarization parameter and carries out image registration image rectification, and then sends a signal to the rotation that electric system is controlled double-deck optical filter runner; Described double-deck optical filter runner is provided with a plurality of circular holes, and a double-deck optical filter is set in each circular hole, and each double-deck optical filter only allows the light of the specific band in the white light to pass through; The polarization angle of the preposition polaroid of described three CCD cameras is 0 °, 45 ° and 90 °; Shuttling movement between three CCD cameras, electric system and the Computer Processing closes: when electric system is controlled double-deck optical filter runner and turned for 1/6 week, trigger the CCD camera imaging, when double-deck optical filter runner finished for 1 week, computing machine carried out image rectification and calculates polarization parameter; Image rectification finishes storage to be finished, and the motor of computer control electric system turned for 1/6 week so that turn double-deck optical filter runner again, started next cycle.

2. Multi-band Polarization imaging Security element identification system according to claim 1, it is characterized in that: described double-deck optical filter runner is provided with six circular holes that are used for installing optical filter, each diameter is about 25mm, wherein, a circular hole is empty, the fast axle that four circular holes are installed respectively the wavelength that differs from one another becomes 0 ° 1/4 λ wave plate with reference direction, another circular hole is installed fast axle becomes 90 ° with reference direction 1/4 λ wave plate, and its bandwidth must cover the wavelength of four the single wave plates in front.

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