CN102183357A - Method and device for detecting contrast ratio of bright and dark regions of hidden image in anti-counterfeiting element - Google Patents
Method and device for detecting contrast ratio of bright and dark regions of hidden image in anti-counterfeiting element Download PDFInfo
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- CN102183357A CN102183357A CN 201010514531 CN201010514531A CN102183357A CN 102183357 A CN102183357 A CN 102183357A CN 201010514531 CN201010514531 CN 201010514531 CN 201010514531 A CN201010514531 A CN 201010514531A CN 102183357 A CN102183357 A CN 102183357A
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Abstract
The invention discloses a method and device for detecting a contrast ratio of bright and dark regions of a hidden image in an anti-counterfeiting element. The method comprises the following steps of: enabling incident light to enter a measurement region on the anti-counterfeiting element through a polaroid; adjusting the polaroid to ensure that the hidden image in the anti-counterfeiting element respectively forms a positive polaroid and a negative polaroid and measuring a reflectance spectrum of the measured region when in the positive polaroid and the negative polaroid, wherein the reflectance spectrum indicates the reflectivity of each wavelength in the incident optical band; and acquiring a difference value or a ratio value of the reflectivity when in the positive polaroid and the negative polaroid by respectively aiming at each wavelength in the reflectance spectrum according to the reflection spectrum when in the positive polaroid and the negative polaroid so that the contrast ratio of the bright and dark regions of the hidden image in the anti-counterfeiting element can be determined according to the difference value or the ratio value. The method and device disclosed by the embodiment of the invention realize the quantitive detection of the contrast ratio of the bright and dark regions of the hidden positive and negative polaroid image of the anti-counterfeiting element, thereby realizing the precise and accurate control over the quality of the anti-counterfeiting element.
Description
Technical field
The present invention relates to anti-counterfeiting technology, especially a kind of detection method and device of Security element hidden image light and shade region contrast.
Background technology
At present,, adopt the liquid crystal optically variable anti-counterfeiting element of hiding positive negative film information that has that liquid crystal technology makes, owing to have hiding meticulous picture and text, can realize that two wires anti-counterfeiting characteristic such as positive negative film conversion enjoys favor in field of anti-counterfeit technology.This Security element is placed on polaroid following time, can observes the positive negative image that it is hidden, also promptly: meticulous picture and text.Adjust the angle of polaroid and this Security element, when the hiding positive negative image of Security element presented brightest area with dark areas, its all dark area that present had been formed image, and all bright areas that present have been formed background, thereby formed positive.If the polaroid that adopts is a linear polarizer, when linear polarizer was horizontally rotated certain angle, the bright areas of the positive negative image that Security element is hidden and dark area were exchanged, thereby formed negative film.If the polaroid that adopts is a circular polarizing disk, when changing the rotation direction of circular polarizing disk, the bright areas of the positive negative image that Security element is hidden and dark area are exchanged, thereby form negative film.
The bright areas that the positive negative image that Security element is hidden presents and the contrast of dark area, be designated hereinafter simply as: the contrast in light and shade zone directly affects the readability of this positive negative image, thereby has determined the quality of Security element.Contrast is big more, and positive negative image is just clear more, and expression Security element quality is good more; Otherwise contrast is more little, and positive negative image is just unintelligible more, and the quality of expression Security element is poor more.Therefore, detection, the control of the contrast in the light and shade zone that the positive negative image of hiding is presented are particularly important.
Yet in realizing process of the present invention, the inventor finds that there is following problem at least in prior art:
At present, can only be by manually the contrast in the hiding positive negative image light and shade zone of Security element being carried out qualitative detection, during detection, the observer adopts polaroid to observe the positive negative image that Security element is hidden, and by polaroid rotation 90 degree being realized the switching between the positive negative film, the readability of image during by comparison positive and negative film, judge the contrast in the positive negative image light and shade zone that Security element is hidden, because different observers has nothing in common with each other to the perceptibility of color and light and shade, influenced by artificial vision's subjectivity, can't quantitatively judge the quality of Security element, therefore, can't realize to the Security element quality accurately, accurately control.
Summary of the invention
Embodiment of the invention technical matters to be solved is: detection method and device that a kind of Security element hidden image light and shade region contrast is provided, realize the detection by quantitative of the contrast in the positive negative image light and shade zone that Security element is hidden, thereby realize accurate, accurately control the Security element quality.
For solving the problems of the technologies described above, the detection method of a kind of Security element hidden image light and shade region contrast that the embodiment of the invention provides comprises:
Incident light is by the measured zone on the polaroid incident Security element;
Adjust polaroid, make the hidden image of Security element form positive and negative film respectively, and the reflectance spectrum of measured zone when measuring positive with negative film, described reflectance spectrum is represented the reflectivity of interior each wavelength of incident light wave band;
According to the reflectance spectrum of positive and negative film, obtain the difference or the ratio of positive and negative film reflectivity, so that determine the contrast in described Security element hidden image light and shade zone by described difference or ratio.
The pick-up unit of a kind of Security element hidden image light and shade region contrast that the embodiment of the invention provides comprises:
Chopper is used for the light beam of light emitted is divided into identical reference light of wave band and incident light;
Polaroid is used for changing the described incident light of incident into polarized light, by adjusting described polaroid, can make the hidden image of Security element form positive and negative film respectively;
The thing photodetector is used to receive the reflected light of described polarized light after described measured zone reflection, detects the intensity of reflected light of each wavelength in the incident light wave band, and described intensity of reflected light is converted to second electric signal;
The reference light detecting device is used to receive described reference light, detects the reference light intensity of each wavelength in the described incident light wave band, and this reference light intensity is converted to first electric signal;
Counter, be used for when the hidden image of Security element forms positive or negative film, respectively at each wavelength in the described incident light wave band, calculate the ratio of second electric signal and first electric signal, reflectance spectrum when obtaining positive or negative film, so that the reflectance spectrum during according to positive and negative film, obtain the difference or the ratio of positive and negative film, thereby determine that by described difference or ratio the contrast in described Security element hidden image light and shade zone, described reflectance spectrum represent the reflectivity of each wavelength in the described incident light wave band.
The detection method and the device of the Security element hidden image light and shade region contrast that the above embodiment of the present invention provides, make incident light be incident to measured zone on the Security element by polaroid, make the hidden image of Security element form positive or negative film respectively by adjusting polaroid, and the reflectance spectrum of measured zone when measuring positive or negative film, obtain the difference of each wavelength reflectivity when positive and negative film in the incident light wave band, thereby determine the contrast in Security element hidden image light and shade zone according to this difference, realized detection by quantitative to the contrast in the hiding positive negative image light and shade zone of Security element, compared with prior art, make that the evaluation criterion of contrast in positive negative image light and shade zone that Security element is hidden is more objective, unanimity, thus realized to the Security element quality accurately, accurately control.
Below by drawings and Examples, technical scheme of the present invention is described in further detail.
Description of drawings
In order to be illustrated more clearly in the embodiment of the invention or technical scheme of the prior art, to do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below, apparently, accompanying drawing in describing below only is some embodiments of the present invention, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the process flow diagram of an embodiment of detection method of Security element hidden image light and shade region contrast of the present invention;
Fig. 2 is the process flow diagram of another embodiment of detection method of Security element hidden image light and shade region contrast of the present invention;
Fig. 3 is the structural representation of an embodiment of pick-up unit of Security element hidden image light and shade region contrast of the present invention;
Fig. 4 is the structural representation of another embodiment of pick-up unit of Security element hidden image light and shade region contrast of the present invention;
Fig. 5 is the process flow diagram of an Application Example of detection method of Security element hidden image light and shade region contrast of the present invention;
Fig. 6 is by a reflected light spectrogram that obtains embodiment illustrated in fig. 5;
Fig. 7 is by another reflected light spectrogram that obtains embodiment illustrated in fig. 5;
Fig. 8 is the process flow diagram of the detection method Another application embodiment of Security element hidden image light and shade region contrast of the present invention;
Fig. 9 is by a reflected light spectrogram that obtains embodiment illustrated in fig. 8.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the invention, the technical scheme in the embodiment of the invention is clearly and completely described, obviously, described embodiment only is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills belong to the scope of protection of the invention not making the every other embodiment that is obtained under the creative work prerequisite.
Fig. 1 is the process flow diagram of an embodiment of detection method of Security element hidden image light and shade region contrast of the present invention.As shown in Figure 1, the detection method of this embodiment comprises following flow process:
Particularly, the measured zone on the Security element can be selected and demarcate on Security element in advance.
The detection method of the Security element hidden image light and shade region contrast that provides according to the above embodiment of the present invention, make incident light be incident to measured zone on the Security element by polaroid, make the hidden image of Security element form positive and negative film respectively by adjusting polaroid, and the reflectance spectrum of measured zone when measuring positive and negative film respectively, the difference of reflectivity or ratio when obtaining positive and negative film, thereby determine the contrast in Security element hidden image light and shade zone according to this difference or ratio, realized detection by quantitative to the contrast in the hiding positive negative image light and shade zone of Security element, make that the evaluation criterion of contrast in positive negative image light and shade zone that Security element is hidden is more objective, unanimity, thus realized to the Security element quality accurately, accurately control.
Reflectivity is meant the ratio of reflected light and incident intensity.It has reflected the reflection of light degree of object to a certain wavelength.Reflectivity is high more, and observed object is bright more, and reflectivity is low more, and object is dark more.Reflectance spectrum has embodied the size of object to the reflection of light rate of different wave length intuitively.The reflectivity of identical wavelength subtracts each other in the reflectance spectrum in the zone that object or image bright-dark degree is different, and the difference that obtains can be used as the means of estimating the zones of different light and shade contrast.By reflection peak height in the reflectance spectrum that compares bright-dark degree's zones of different, can learn the size of light and shade region contrast intuitively.The difference of reflectivity is big more under the identical wavelength, and the light and shade region contrast is high more, illustrates that the quality with Security element of hiding positive negative image is good more.
Among the detection method embodiment of the present invention, when incident light passes through polaroid, change polarized light into by natural light, because the liquid crystal molecule orientation direction difference of zones of different, also just different as the catoptrical intensity that obtains after the surface reflection of polarization of incident light light through the Security element measured zone, the strong and weak difference of light intensity is just sketched the contours of hidden image.When hidden image was the best in quality, the bright areas reflected light was the strongest, and the dark area reflected light is the most weak, almost was black, thereby made the light and shade contrast reach maximum, and pattern is the most clear.When the bright-dark degree of pattern area and background area to timing, also just realized the conversion between the positive negative film.In the embodiment of the invention, can choose in advance liquid crystal molecule along the evenly directed zone of a certain direction as measured zone.For the Security element that hidden image need use linear polarizer to observe, the rotation Security element can be realized the brightest state and the darkest state of measured zone with the angle between the polarization direction that changes its measured zone liquid crystal molecule optical axis direction and linear polarizer; For the Security element that hidden image need use left-hand polarization sheet or right-hand circular polarization sheet to observe,, can realize the brightest state and the darkest state of measured zone by changing the rotation direction of circular polarizing disk.
Fig. 2 is the process flow diagram of another embodiment of detection method of Security element hidden image light and shade region contrast of the present invention.As shown in Figure 2, the detection method of this embodiment comprises following flow process:
Wherein, step 203-204 and step 202 are carried out simultaneously.
According to a specific embodiment of the present invention, this step 208 is later than step 207 and carries out; In addition, according to another specific embodiment of the present invention, this step 208 also can be carried out prior to step 207, perhaps carries out simultaneously with step 207.
In the detection method of the various embodiments described above of the present invention, the polaroid of use can be a linear polarizer, also can be circular polarizing disk.At the polaroid that uses during as linear polarizer, in step 102 and the step 206, specifically can adjust polaroid in the following manner: change the polarization direction of linear polarizer and the angle between the liquid crystal molecule optical axis direction in the measured zone, for example: change the angle between Security element and the incident light incident direction, the polarization direction and the angle between the liquid crystal molecule optical axis direction in the measured zone of linear polarizer is respectively+45 degree and-45 degree, at this moment, can be observed hidden image the best in quality, the clear zone reflected light is the strongest, the dark space reflected light is the most weak, almost be black, thereby make the light and shade contrast reach maximum, pattern is the most clear, and the hidden image of Security element forms positive and negative film respectively.Wherein, the liquid crystal molecule optical axis direction in the measured zone can be demarcated in advance.
In order to guarantee the consistance of incident light polarization state and intensity, according to a concrete mode of the present invention, when the polaroid that uses during as linear polarizer, by the measured zone on the linear polarizer incident Security element.
When the polaroid that uses shakes sheet for circle, in step 102 and the step 206, specifically can adjust polaroid in the following manner: adopt Left-hand circular polarization sheet and right-hand circular polarization sheet respectively, concrete, if what adopt is the Left-hand circular polarization sheet, the hidden image of Security element forms positive or negative film, and what formed this moment is positive or negative film, and specifically the molecular structure of the crystal that is adopted by Security element is left-handed or the dextrorotation decision.After the reflectance spectrum of measured zone, the Left-hand circular polarization sheet is changed to the dextropolarization sheet when measuring positive or negative film, at this moment, corresponding formation negative film of the hidden image of Security element or positive, the reflectance spectrum of measured zone in the time of just can measuring negative film or positive.If what adopt is the right-hand circular polarization sheet, the hidden image of Security element forms positive or negative film, when then measuring positive or negative film after the reflectance spectrum of measured zone, the right-hand circular polarization sheet is changed to the left-hand polarization sheet, at this moment, corresponding formation negative film of the hidden image of Security element or positive, the reflectance spectrum of measured zone in the time of just can measuring negative film or positive.
In addition, according to another specific embodiment of the present invention, in the detection method of the various embodiments described above of the present invention, the incident light wave band specifically can comprise the visible light of 400nm～700nm.
According to another specific embodiment of the present invention, in order to guarantee that incident light effectively shines the measured zone of Security element, in the detection method of the various embodiments described above of the present invention, can make the facula area of the measured zone of selected Security element more than or equal to incident light, that is: the hot spot of incident light is less than or equal to measured zone, guarantees that incident light effectively shines in the measured zone.
According to another specific embodiment of the present invention, more clear for what the hiding positive negative image of Security element was observed, the judgement of the contrast in the positive negative image light and shade zone that Security element is hidden is more accurate, in the step 101 of the detection method of the various embodiments described above of the present invention and step 203, after can making incident light pass through polaroid, the measured zone on the vertical incidence Security element.In actual applications, can keep the polarization direction level of polaroid, and make the polarization direction of incident light perpendicular to polaroid, make incident light pass through polaroid after, the measured zone on the vertical incidence Security element.
According to further specific embodiment of the present invention, in the detection method of the various embodiments described above of the present invention, can be according to preset rule, by but be not limited to following mode, determine the contrast in Security element hidden image light and shade zone:
The difference of each wavelength reflectivity in the incident light wave band when obtaining positive and negative film, and determine maximum difference in each difference, determine the contrast in Security element hidden image light and shade zone by this maximum difference.This maximum difference is big more, illustrates that the light and shade contrast of the positive negative image that Security element is hidden is high more, and the quality of the positive negative image that Security element is hidden is good more, and the quality of Security element is also high more; Perhaps
The mean value of the difference of each wavelength reflectivity in the incident light wave band when obtaining positive and negative film is determined the contrast in Security element hidden image light and shade zone by this mean value.This mean difference is big more, illustrates that light and shade contrast's integral body of the positive negative image that Security element is hidden is high more, and the total quality of the positive negative image that Security element is hidden is good more, and the quality of Security element is also high more; Perhaps
Minimal difference in the difference of each wavelength reflectivity in the incident light wave band when obtaining positive and negative film is determined the contrast in Security element hidden image light and shade zone by this minimal difference.This minimal difference is big more, illustrates that light and shade contrast's integral body of the positive negative image that Security element is hidden is high more, and the total quality of the positive negative image that Security element is hidden is good more, and the quality of Security element is also high more; Perhaps
The ratio of each respective wavelength reflectivity in the incident light wave band when obtaining positive and negative film, and determine wherein maximum ratio, determine the contrast in Security element hidden image light and shade zone by this maximum ratio.This maximum ratio is big more, illustrates that the light and shade contrast of the positive negative image that Security element is hidden is high more, and the quality of the positive negative image that Security element is hidden is good more, and the quality of Security element is also high more; Perhaps
The mean value of the ratio of each wavelength reflectivity in the incident light wave band when obtaining positive and negative film is determined the contrast in Security element hidden image light and shade zone by this mean value.This mean ratio is big more, illustrates that light and shade contrast's integral body of the positive negative image that Security element is hidden is high more, and the total quality of the positive negative image that Security element is hidden is good more, and the quality of Security element is also high more; Perhaps
Minimum ratio in the ratio of each wavelength reflectivity in the incident light wave band when obtaining positive and negative film is determined the contrast in Security element hidden image light and shade zone by this minimum ratio.This minimum ratio is big more, illustrates that light and shade contrast's integral body of the positive negative image that Security element is hidden is high more, and the total quality of the positive negative image that Security element is hidden is good more, and the quality of Security element is also high more.。
Fig. 3 is the structural representation of an embodiment of pick-up unit of Security element hidden image light and shade region contrast of the present invention.The pick-up unit of this embodiment can be used for realizing the detection method flow process of the above embodiment of the present invention.As shown in Figure 3, the pick-up unit of this embodiment Security element hidden image light and shade region contrast comprises chopper 301, polaroid 302, thing photodetector 303, reference light detecting device 304 and counter 305.
Wherein, chopper 301 is used for the light beam of light emitted is divided into identical reference light of wave band and incident light.
Polaroid 302 is used for changing the incident light of incident into polarized light, by adjusting this polaroid 302, can make the hidden image of Security element form positive and negative film respectively.Particularly, this polaroid 302 can be a linear polarizer, also can be circular polarizing disk.At the polaroid that uses during as linear polarizer, specifically can adjust polaroid in the following manner: change the polarization direction of linear polarizer and the angle between the liquid crystal molecule optical axis direction in the measured zone, for example: change the angle between Security element and the incident light incident direction, the polarization direction and the angle between the liquid crystal molecule optical axis direction in the measured zone of linear polarizer is respectively+45 degree and-45 degree, at this moment, the hidden image of Security element forms positive and negative film respectively.When the polaroid that uses shakes sheet for circle, specifically can adjust polaroid in the following manner: adopt Left-hand circular polarization sheet and right-hand circular polarization sheet respectively, concrete, if what adopt is the Left-hand circular polarization sheet, the hidden image of Security element forms positive or negative film, when then measuring positive or negative film after the reflectance spectrum of measured zone, the Left-hand circular polarization sheet is changed to the dextropolarization sheet, at this moment, corresponding formation negative film of the hidden image of Security element or positive, the reflectance spectrum of measured zone in the time of just can measuring negative film or positive.If what adopt is the right-hand circular polarization sheet, the hidden image of Security element forms positive or negative film, when then measuring positive or negative film after the reflectance spectrum of measured zone, the right-hand circular polarization sheet is changed to the left-hand polarization sheet, at this moment, corresponding formation negative film of the hidden image of Security element or positive, the reflectance spectrum of measured zone in the time of just can measuring negative film or positive.
Reference light detecting device 304 is used to receive reference light, detects the reference light intensity of each wavelength in the incident light wave band, and this reference light intensity is converted to first electric signal sends to counter 305.
The pick-up unit of the Security element hidden image light and shade region contrast that the above embodiment of the present invention provides, make incident light be incident to measured zone on the Security element by polaroid, angle or adjustment polaroid by liquid crystal molecule optical axis direction and polaroid polarization direction in the adjustment Security element, make hidden image form positive and negative film respectively, and the reflectance spectrum of measured zone when measuring positive and negative film, and respectively at each respective wavelength in the reflectance spectrum, the difference of reflectivity or ratio when obtaining positive and negative film, thereby determine the contrast in Security element hidden image light and shade zone according to this difference or ratio, realized detection by quantitative to the contrast in the hiding positive negative image light and shade zone of Security element, compared with prior art, make that the evaluation criterion of contrast in positive negative image light and shade zone that Security element is hidden is more objective, unanimity, thus realized to the Security element quality accurately, accurately control.
Particularly, in the embodiment shown in fig. 3, counter 305 can be according to preset rule, by but be not limited to following mode, determine the contrast in Security element hidden image light and shade zone by difference: the difference of each wavelength reflectivity in the incident light wave band when obtaining positive and negative film, and determine maximum difference in each difference, determine the contrast in Security element hidden image light and shade zone by this maximum difference.This maximum difference is big more, illustrates that the light and shade contrast of the positive negative image that Security element is hidden is high more, and the quality of the positive negative image that Security element is hidden is good more, and the quality of Security element is also high more; Perhaps
The mean value of the difference of each wavelength reflectivity in the incident light wave band when obtaining positive and negative film is determined the contrast in Security element hidden image light and shade zone by this mean value.This mean difference is big more, illustrates that light and shade contrast's integral body of the positive negative image that Security element is hidden is high more, and the total quality of the positive negative image that Security element is hidden is good more, and the quality of Security element is also high more; Perhaps
Minimal difference in the difference of each wavelength reflectivity in the incident light wave band when obtaining positive and negative film is determined the contrast in Security element hidden image light and shade zone by this minimal difference.This minimal difference is big more, illustrates that light and shade contrast's integral body of the positive negative image that Security element is hidden is high more, and the total quality of the positive negative image that Security element is hidden is good more, and the quality of Security element is also high more; Perhaps
The ratio of each respective wavelength reflectivity in the incident light wave band when obtaining positive and negative film, and determine wherein maximum ratio, determine the contrast in Security element hidden image light and shade zone by this maximum ratio.This maximum ratio is big more, illustrates that the light and shade contrast of the positive negative image that Security element is hidden is high more, and the quality of the positive negative image that Security element is hidden is good more, and the quality of Security element is also high more; Perhaps
The mean value of the ratio of each wavelength reflectivity in the incident light wave band when obtaining positive and negative film is determined the contrast in Security element hidden image light and shade zone by this mean value.This mean ratio is big more, illustrates that light and shade contrast's integral body of the positive negative image that Security element is hidden is high more, and the total quality of the positive negative image that Security element is hidden is good more, and the quality of Security element is also high more; Perhaps
Minimum ratio in the ratio of each wavelength reflectivity in the incident light wave band when obtaining positive and negative film is determined the contrast in Security element hidden image light and shade zone by this minimum ratio.This minimum ratio is big more, illustrates that light and shade contrast's integral body of the positive negative image that Security element is hidden is high more, and the total quality of the positive negative image that Security element is hidden is good more, and the quality of Security element is also high more.
Fig. 4 is the structural representation of another embodiment of pick-up unit of Security element hidden image light and shade region contrast of the present invention.As shown in Figure 4, compare with embodiment shown in Figure 3, the pick-up unit of this embodiment also comprises analysis processor 306, reflectance spectrum when being used for the positive that obtains according to counter 305 and negative film, respectively at each respective wavelength in the reflectance spectrum, the difference of reflectivity or ratio when obtaining positive and negative film are so that determined the contrast in Security element hidden image light and shade zone by this difference or ratio.
Referring to Fig. 4, as one embodiment of the present of invention, pick-up unit can also comprise display 307 again, is used to show the reflectance spectrum that is obtained by counter 305.Alternatively, the further difference or the ratio of the reflectivity that gets access to of display analysis processor 306 of display 307.
In addition, again referring to Fig. 4, as an alternative embodiment of the invention, pick-up unit also can comprise light source 308, is used for to chopper 301 emission light beams.
Fig. 5 is the process flow diagram of an Application Example of detection method of Security element hidden image light and shade region contrast of the present invention.This Application Example adopts pick-up unit embodiment illustrated in fig. 4 to detect Security element hidden image light and shade region contrast, wherein the polaroid 302 of Cai Yonging is a linear polarizer, the area of Security element measured zone is the square of 5mm*5mm, the liquid crystal molecule optical axis direction unanimity of measured zone, the polarization direction level of retention wire polaroid 302 also makes the polarization direction of incident light perpendicular to polaroid.Before beginning detection, Security element is positioned on the sample stage at linear polarizer 302 rears, the measured zone outside surface that makes Security element is with vertical by the polarized light after the linear polarizer 302.The incident light wave segment limit of setting analyzing and processing is 400-700nm, afterwards, carries out following flow process:
Step 403 after thing photodetector 303 receives reflected light, detects the intensity of reflected light of each wavelength in the incident light wave band, and intensity of reflected light is converted to second electric signal sends to counter 305.
Step 404 after reference light detecting device 304 receives reference light, detects the reference light intensity of each wavelength in the incident light wave band, and this reference light intensity is converted to first electric signal sends to counter 305.
Particularly, step 404 can be carried out simultaneously with step 402-403.
As shown in Figure 6, show for display 307, by the reflected light spectrogram that present embodiment obtains, according to this reflected light spectrogram, the reflectivity R1 at the reflectance spectrum peak value place that measures during positive is 84%.Peak wavelength is 622.80nm.
As shown in Figure 6, the reflectivity R2 that measures peak wavelength 622.80nm during negative film is 5%.
Alternatively, the difference of reflectivity also can show by display 307 when positive and negative film, and is not shown in the embodiment of the invention.
According to Fig. 6, the difference DELTA R maximum of reflectivity when the positive of wavelength 622.80nm correspondence and negative film is 79%.If the maximum difference Δ R that preestablishes reflectivity is up-to-standard greater than 50% o'clock Security element, because the maximum difference Δ R of reflectivity is 79% when Security element positive of measuring among this embodiment and negative film, much larger than 50%, the reflectance spectrum peak difference that this Security element is hidden positive negative image is very not big, illustrates that the quality of Security element is fine.
Adopt the contrast to the hiding positive negative image light and shade zone of another Security element embodiment illustrated in fig. 5 to detect, obtain another reflected light spectrogram as shown in Figure 7.According to this reflected light spectrogram, the reflectivity R3 at the reflectance spectrum peak value place that measures during positive is 63.538%.Peak wavelength is 548.00nm, and the reflectivity R4 that measures peak wavelength 548.00nm during negative film is 9.554%, and the difference DELTA R maximum of reflectivity when the positive of 548.00nm correspondence and negative film is 53.984%.If the maximum difference Δ R that preestablishes reflectivity is up-to-standard greater than 50% o'clock Security element, because the maximum difference Δ R of reflectivity is 53.984% when Security element positive of measuring among this embodiment and negative film, greater than 50%, the reflectance spectrum peak difference that this Security element is hidden positive negative image is not bigger, illustrates that the quality of Security element is better.
Fig. 8 is the process flow diagram of the detection method Another application embodiment of Security element hidden image light and shade region contrast of the present invention.This Application Example adopts pick-up unit embodiment illustrated in fig. 4 to detect Security element hidden image light and shade region contrast, wherein the Security element of Cai Yonging is the cholesteric liquid crystal with left-handed molecular structure, polaroid 302 is a circular polarizing disk, comprise left-hand polarization sheet and right-hand circular polarization sheet, the area of Security element measured zone is the square of 5mm*5mm, the liquid crystal molecule optical axis direction unanimity of measured zone, before beginning detection, Security element is positioned on the sample stage at circular polarizing disk 302 rears.The incident light wave segment limit of setting analyzing and processing is 400-700nm, afterwards, carries out following flow process:
Step 502 behind the incident light process left-hand polarization sheet 302, change the measured zone of polarizing light irradiation to Security element into, and the reflected light after the surface reflection of Security element is received by thing photodetector 303.This moment, measured zone was the brightest, and the hidden image of Security element forms positive.
Step 503 after thing photodetector 303 receives reflected light, detects the intensity of reflected light of each wavelength in the incident light wave band, and intensity of reflected light is converted to second electric signal sends to counter 305.
Step 504 after reference light detecting device 304 receives reference light, detects the reference light intensity of each wavelength in the incident light wave band, and this reference light intensity is converted to first electric signal sends to counter 305.
Particularly, step 504 can be carried out simultaneously with step 502-503.
As shown in Figure 9, show for display 307, by the reflected light spectrogram that present embodiment obtains, according to this reflected light spectrogram, the reflectivity R5 at the reflectance spectrum peak value place that measures during positive is 77.438%.Peak wavelength is 464.00nm.
Step 506 is changed to dextropolarization sheet 302 with left-hand polarization sheet 302, and at this moment, measurement zone is the darkest, and the hidden image of Security element forms negative film.
As shown in Figure 9, the reflectivity R6 that measures peak wavelength 464.00nm during negative film is 17.808%.
Alternatively, the difference of reflectivity also can show by display 307 when positive and negative film, and is not shown in the embodiment of the invention.
According to Fig. 9, the difference DELTA R maximum of reflectivity when the positive of wavelength 464.00nm correspondence and negative film is 59.63%.If the maximum difference Δ R that preestablishes reflectivity is up-to-standard greater than 50% o'clock Security element, because the maximum difference Δ R of reflectivity is 59.63% when Security element positive of measuring among this embodiment and negative film, greater than 50%, the reflectance spectrum peak difference that this Security element is hidden positive negative image is not bigger, illustrates that the quality of Security element is better.
Each embodiment all adopts the mode of going forward one by one to describe in this instructions, and what each embodiment stressed all is and the difference of other embodiment that same or analogous part cross-references gets final product between each embodiment.For device embodiment, because it is similar substantially to method embodiment, so description is fairly simple, relevant part gets final product referring to the part explanation of method embodiment.
One of ordinary skill in the art will appreciate that: all or part of step that realizes said method embodiment can be finished by the relevant hardware of programmed instruction, aforesaid program can be stored in the computer read/write memory medium, this program is carried out the step that comprises said method embodiment when carrying out; And aforesaid storage medium comprises: various media that can be program code stored such as ROM, RAM, magnetic disc or CD.
The embodiment of the invention has realized the detection by quantitative to the contrast in the hiding positive negative image light and shade zone of Security element, make that the evaluation criterion of contrast in positive negative image light and shade zone that Security element is hidden is more objective, consistent, thus realized to the Security element quality accurately, accurately control.
Description of the invention provides for example with for the purpose of describing, and is not exhaustively or limit the invention to disclosed form.Many modifications and variations are obvious for the ordinary skill in the art.Selecting and describing embodiment is for better explanation principle of the present invention and practical application, thereby and makes those of ordinary skill in the art can understand the various embodiment that have various modifications that the present invention's design is suitable for special-purpose.
Claims (17)
1. the detection method of a Security element hidden image light and shade region contrast is characterized in that, comprising:
Incident light is by the measured zone on the polaroid incident Security element;
Adjust polaroid, make the hidden image of Security element form positive and negative film respectively, and the reflectance spectrum of measured zone when measuring positive with negative film, described reflectance spectrum is represented the reflectivity of interior each wavelength of incident light wave band;
Reflectance spectrum during according to positive and negative film, respectively at each wavelength in the reflectance spectrum, the difference of reflectivity or ratio when obtaining positive and negative film are so that determined the contrast in described Security element hidden image light and shade zone by described difference or ratio.
2. method according to claim 1 is characterized in that, also comprises: by chopper the light beam of light emitted is divided into identical reference light of wave band and described incident light; Receive described reference light by the reference light detecting device, detect the reference light intensity of each wavelength in the described incident light wave band, and this reference light intensity is converted to first electric signal;
Described incident light is by after the measured zone on the polaroid incident Security element, also comprise: receive the reflected light of described incident light after described measured zone reflection by the thing photodetector, detect the intensity of reflected light of each wavelength in the described incident light wave band, and described intensity of reflected light is converted to second electric signal;
By counter, respectively at each wavelength in the described incident light wave band, calculate the ratio of second electric signal and first electric signal, obtain reflectance spectrum.
3. method according to claim 2 is characterized in that, the reflectance spectrum of measured zone comprises when described measurement positive and negative film:
By described counter, when positive and negative film, respectively at each wavelength in the described incident light wave band, calculate the ratio of second electric signal and first electric signal, the reflectance spectrum of measured zone when obtaining positive and negative film.
4. method according to claim 3 is characterized in that, obtains also comprising after the reflectance spectrum:
Show described reflectance spectrum by display.
5. method according to claim 3 is characterized in that, described polaroid is a linear polarizer;
Described adjustment polaroid comprises: change the polarization direction of described linear polarizer and the angle between the interior liquid crystal molecule optical axis direction of described measured zone, the polarization direction of described linear polarizer and the angle between the interior liquid crystal molecule optical axis direction of described measured zone are respectively+45 degree and-45 degree.
6. method according to claim 5 is characterized in that, described incident light edge is perpendicular to the direction of the plane of polarization of described linear polarizer, by the measured zone on the described linear polarizer incident Security element.
7. method according to claim 1 is characterized in that, described polaroid is a circular polarizing disk;
Described adjustment polaroid comprises: adopt Left-hand circular polarization sheet and right-hand circular polarization sheet respectively.
8. according to any described method of claim 1 to 7, it is characterized in that described incident light wave band comprises 400nm～700nm.
9. according to any described method of claim 1 to 7, it is characterized in that the hot spot of described incident light is less than or equal to described measured zone.
10. according to any described method of claim 1 to 7, it is characterized in that described incident light comprises by the measured zone on the polaroid incident Security element:
Described incident light is by polaroid, the measured zone on the vertical incidence Security element.
11. according to any described method of claim 1 to 7, it is characterized in that, determine that by described difference the contrast in described Security element hidden image light and shade zone comprises:
Obtain the maximum difference in the difference of each wavelength reflectivity in the described incident light wave band, determine the contrast in described Security element hidden image light and shade zone by this maximum difference; Perhaps, obtain the mean value of the difference of each wavelength reflectivity in the described incident light wave band, determine the contrast in described Security element hidden image light and shade zone by this mean value; Perhaps, obtain the minimal difference in the difference of each wavelength reflectivity in the described incident light wave band, determine the contrast in described Security element hidden image light and shade zone by this minimal difference; Perhaps, obtain the ratio of positive and negative film each respective wavelength reflectivity in the incident light wave band, determine the contrast in Security element hidden image light and shade zone by this maximum ratio;
The contrast of being determined described Security element hidden image light and shade zone by described ratio comprises:
Obtain the maximum ratio in the ratio of each wavelength reflectivity in the described incident light wave band, determine the contrast in described Security element hidden image light and shade zone by this maximum ratio; Perhaps obtain the mean value of the ratio of each wavelength reflectivity in the described incident light wave band, determine the contrast in described Security element hidden image light and shade zone by this mean value; Perhaps obtain the minimum ratio in the ratio of each wavelength reflectivity in the described incident light wave band, determine the contrast in described Security element hidden image light and shade zone by this minimum ratio; Perhaps obtain the ratio of positive and negative film each respective wavelength reflectivity in the incident light wave band, determine the contrast in Security element hidden image light and shade zone by this maximum ratio.
12. the pick-up unit of a Security element hidden image light and shade region contrast is characterized in that, comprising:
Chopper is used for the light beam of light emitted is divided into identical reference light of wave band and incident light;
Polaroid is used for changing the described incident light of incident into polarized light, by adjusting described polaroid, can make the hidden image of Security element form positive and negative film respectively;
The thing photodetector is used to receive the reflected light of described polarized light after described measured zone reflection, detects the intensity of reflected light of each wavelength in the incident light wave band, and described intensity of reflected light is converted to second electric signal;
The reference light detecting device is used to receive described reference light, detects the reference light intensity of each wavelength in the described incident light wave band, and this reference light intensity is converted to first electric signal;
Counter, be used for when the hidden image of Security element forms positive or negative film, respectively at each wavelength in the described incident light wave band, calculate the ratio of second electric signal and first electric signal, reflectance spectrum when obtaining positive or negative film, so that the reflectance spectrum during according to positive and negative film, respectively at each wavelength in the reflectance spectrum, the difference of reflectivity or ratio when obtaining positive and negative film, thereby determine that by described difference or ratio the contrast in described Security element hidden image light and shade zone, described reflectance spectrum represent the reflectivity of each wavelength in the described incident light wave band.
13. device according to claim 12 is characterized in that, described polaroid is specially linear polarizer;
Adjusting described polaroid comprises: change the polarization direction of described linear polarizer and the angle between the liquid crystal molecule optical axis direction in the described measured zone, the polarization direction of described linear polarizer and the angle between the liquid crystal molecule optical axis direction in the described measured zone are respectively+45 degree and-45 degree.
14. device according to claim 12 is characterized in that, described polaroid is specially circular polarizing disk;
Adjusting described polaroid comprises: adopt Left-hand circular polarization sheet and right-hand circular polarization sheet respectively.
15. according to claim 13 or 14 described devices, it is characterized in that, also comprise:
Analysis processor, reflectance spectrum when being used for according to positive and negative film, at each wavelength in the reflectance spectrum, the difference of reflectivity or ratio when obtaining positive and negative film are so that determined the contrast in described Security element hidden image light and shade zone by described difference or ratio respectively.
16. according to claim 13 or 14 described devices, it is characterized in that, also comprise:
Display is used to the described reflectance spectrum that shows that described counter obtains.
17. device according to claim 16 is characterized in that, also comprises:
Light source is used for launching described light beam to described chopper.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201010514531 CN102183357B (en) | 2010-10-21 | 2010-10-21 | Method and device for detecting contrast ratio of bright and dark regions of hidden image in anti-counterfeiting element |
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201010514531 CN102183357B (en) | 2010-10-21 | 2010-10-21 | Method and device for detecting contrast ratio of bright and dark regions of hidden image in anti-counterfeiting element |
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| CN102759441A (en) * | 2012-07-20 | 2012-10-31 | 西北工业大学 | Multiband polarization imaging anti-counterfeiting element identification system |
| CN103528795A (en) * | 2012-07-03 | 2014-01-22 | 中国人民银行印制科学技术研究所 | Apparatus for on-line detection of hidden image in liquid crystal false proof element |
| CN107798320A (en) * | 2017-11-20 | 2018-03-13 | 信利光电股份有限公司 | A kind of implicit pattern identification system and discrimination method |
| CN111374713A (en) * | 2018-12-29 | 2020-07-07 | 重庆西山科技股份有限公司 | Chamber alignment calibration method for sample holder and biopsy device |
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| CN103528795A (en) * | 2012-07-03 | 2014-01-22 | 中国人民银行印制科学技术研究所 | Apparatus for on-line detection of hidden image in liquid crystal false proof element |
| CN103528795B (en) * | 2012-07-03 | 2015-12-02 | 中国人民银行印制科学技术研究所 | The device of hidden image in on-line checkingi liquid crystal Security element |
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| CN111374713B (en) * | 2018-12-29 | 2021-09-10 | 重庆西山科技股份有限公司 | Chamber alignment calibration method for sample holder and biopsy device |
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| CN102183357B (en) | 2012-11-14 |
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