DE102013003558B4 - System for determining the contrast of color pigments in tinted glasses - Google Patents

Abstract

Device (10; 10 ') for checking a coloring of a glass (12), comprising - an illumination device for diffuse emission of light on a radiating surface (16) of the illumination device; - an image recording device (30; 30'), which is designed for to capture each of a large number of spectral distributions of brightness data for the light emitted by the emission surface (16) and transmitted through the glass (12) to be checked as a two-dimensional image data set;- a colorant database (38) with a color density model which is used for each colorant from a set of dyes in each case represents a dye density value as a function of transmission values for the plurality of spectral distributions;- an analysis module (40) which is designed -- for each image data set recorded by the image recording device (30; 30') from the brightness data, local transmission values of the to to determine the glass (12) to be checked; and-- determining local color density values for each colorant of the set of colorants from the local transmission values according to the color density model; and - an image output device (42) adapted to output a graphical representation of a distribution of the local colorant density values for each colorant of the set of colorants, wherein the illuminating device is adapted to selectively provide light having each of the plurality of spectral distributions for illuminating the glass to be inspected ( 12) to radiate.

Description

The present invention relates to a device and a method for checking the coloring of a glass.

In the tinting technology for glasses, such as e.g. spectacle lenses, the glasses are colored with dyes, in particular with pigment dyes. Especially when the dyeing is done by hand, the glass to be dyed is visually inspected by an experienced dyer immediately after dyeing. If the desired color intensity, i.e. the desired dye density, has not yet been reached, the glass may need to be dyed again. If necessary, this is repeated until the desired color intensity of the glass is reached. Up to now, the coloring result has been assessed in the form of visual assessments of the colored glass. For example, cloudiness, edge shadowing, etc. are taken into account. A lot of experience is needed to get as close as possible to the desired target color and intensity.

For better quantification and objective evaluation of the coloring quality of glasses, there are effect-dependent transmission color measuring devices that measure color coordinates in a given color space (e.g. the Commission international de l'éclairage (CIE) L*a*b* at a point (roughly in the center of a glass) -color space). In order to be able to check not only the color intensity, but also the distribution or homogeneity, the glass to be checked can be scanned at points over the entire glass surface. Accordingly, the coloring can be carried out and evaluated in a spatially resolved manner at a large number of measuring points on the glass. A large-area analysis of a glass using such a transmission color measuring device is complex and very time-consuming given a high spatial resolution.

In DE 10 2010 055 939 A1 and DE 10 2004 048 937 A1 describe transmissive color matching of glasses, such as spectacle lenses. In addition, in DE 10 2010 055 939 A1 a post-dyeing process for glasses is described. DE 41 20 749 A1 and EP 0 319 769 A1 show color measurements using wavelength-selective elements and from DE 101 25 084 A1 and U.S. 8,372,321 B2 database or computer-aided methods for color formulation of colored polymers are known.

The object of the present invention is to provide a rapid, precise and cost-effective analysis of the staining result for glasses. This object is achieved by a device having the features specified in claim 9 or 10 and a method having the features specified in claim or . Preferred embodiments are subject of the dependent claims.

The invention thus offers in particular a device for checking the coloring of a glass. This device comprises an illumination device for the diffuse emission or emission of light on an emission surface of the illumination device.

The radiating surface is preferably at least as large as a glass to be checked, which can thereby be checked over its entire surface. For this purpose, the radiating surface preferably has an area of at least approximately 5 cm ² , more preferably at least approximately 10 cm ² , even more preferably at least approximately 25 cm ² , most preferably at least approximately 50 cm ² . In a preferred embodiment, the radiating surface is essentially square or circular, with this particularly preferably having a side length or a diameter of at least about 2 cm, more preferably at least about 3 cm, even more preferably at least about 5 cm, most preferably at least about 7 cm. The side length or the diameter of the radiating surface is preferably in a range from approximately 5 cm to approximately 20 cm.

Preferably, the radiated light intensity at all points on the entire emission area does not deviate by more than 50% from the average value of the light intensity on the entire emission area, more preferably no more than 30%, even more preferably no more than 20%, most preferably no more than 10%. This preferably applies at least to an emission direction that is perpendicular to the emission surface. In this way, a particularly good homogeneity of the light distribution is achieved, which simplifies later evaluation and improves the accuracy and reliability of the check.

The device also includes an image recording device which is designed to record brightness data for the light emitted by the emission surface and transmitted through the glass to be checked as a two-dimensional image data set, i.e. spatially resolved, for each of a large number of spectral distributions. The detected brightness data thus represents a measure of the local transmission of the glass to be checked for the respective spectral distribution, ie in the corresponding wavelength range, of the light emitted by the lighting device. By simultaneously detecting the brightness data at a large number of points on the glass to be checked in the form of the two-dimensional image data set, i.e. by simultaneously detecting a large number of pixels, a very rapid and partial check, preferably of the entire glass, is possible. In addition, local inhomogeneities can be measured very precisely as a result.

In one aspect of the invention, the lighting device is designed to emit light selectively (sequentially) with a multiplicity of different spectral distributions (ie in particular different colors) for illuminating the glass to be checked. The image recording device is designed in such a way that the brightness data for the light emitted by the emission surface and transmitted through the glass to be checked is recorded as a two-dimensional image data set for each of the plurality of spectral light distributions of the illumination device.

In another aspect of the invention, the imaging device defines each of the plurality of spectral distributions as spectral sensitivities of the imaging device. The image recording device thus captures (preferably simultaneously) a multiplicity of two-dimensional image data records, each of which describes the respective local brightness within one of the spectral distributions defined by the image recording device. In particular, the image recording device has a multiplicity of channels, each channel of which corresponds to a color of the recorded light. In this case, the lighting device is designed to emit the light in a broadband manner, in particular over the entire visible wavelength range.

Each of the two, in particular, alternative embodiments with regard to the spectral resolution brings with it corresponding advantages. While the spectral separation of the light on the image recording side opens up a very fast check of the glasses with a particularly low outlay on control technology, in particular due to the possibility of simultaneously detecting a large number of color channels, the spectral separation on the light source side offers a particularly high color selectivity.

The image recording device is preferably aligned or can be aligned in such a way that the emission surface of the illumination device lies at least partially, preferably completely, in a recording area of the image recording device. The image recording device particularly preferably has an optical axis which is or can be aligned perpendicular to the emission surface. The glass to be examined can then be arranged between the emission surface and the image recording device in such a way that a measure of the transmission of the glass in the various wavelength ranges can be recorded as brightness data by the image recording device. The device preferably includes a holder for arranging the glass to be checked in an area at least partially between the emission surface and the image recording device in order to ensure a reproducible positioning of the glass to be checked. The holder can be designed for screwable and/or clampable fixation of the lens, for example, or it can also be designed, for example, only as a support ring for placing the lens.

In particular, the image recording device is designed to record, for each spectral distribution, a brightness caused by the transmitted light for many points on the glass, that is to say spatially resolved. In this case, the image recording device records in particular only the brightness without spectral resolution. It is therefore preferably a monochrome image recording device. The spectral sensitivity of the image recording device can be different for the different spectral distributions (light colors) of the lighting device. If necessary, differences in spectral sensitivity can be compensated for by appropriate calibration or normalization of the acquired image data. For this purpose, the device preferably includes a reference data memory for loss-free storage of at least one reference image data set. The reference data memory particularly preferably provides a reference image data set for each spectral distribution of the lighting device.

In addition, the device includes a colorant database with a color density model, which represents a colorant density value for each colorant from at least one predetermined set of colorants as a function of transmission values for the multiplicity of spectral distributions. The transmittance values determine a measure of the light transmittance (i.e. the transmittance) of the glass in the respective spectral range. However, they are not limited to the specification in the form of the transmittance as the ratio of the intensities after and before passing through the glass. A different measure of the light transmission is also possible.

The color density model represents a specification that assigns a set of colorant density values to a set of values for the local transmission of a glass for different spectral distributions, ie for different wavelengths (colors) of the transmitted light. In this case, the set of values for the transmission (set of transmission values) each contains a transmission value for each spectral distribution, the set of dye density values containing a dye density value for each dye. Each dye density value of the set of dye density values does not have to depend on each transmission value of the set of transmission values in the color density model. However, each dye density value depends on at least one transmittance value in a manner specified by the color density model. Each colorant density value thus describes a modeled local density of the corresponding colorant.

In a preferred embodiment, the color density model assigns exactly one colorant to each spectral distribution of the illumination device by representing the corresponding colorant density value as a function of the transmission value for this spectral distribution. The color density model provided in the dye database therefore maps each of the large number of spectral distributions onto exactly one dye. In this case, the density distributions of the individual dyes are determined directly from the individual image data sets.

In another embodiment, the color density values of the different colorants in the color density model depend at least partially on transmission values of a plurality of spectral distributions (light colors). Such a color density model makes it possible, in particular, to improve the accuracy of the check and/or to carry out a redundancy check by taking into account a larger number of different spectral distributions than the number of colorants. The color density model is preferably provided in such a way that it represents the dye density values as linear combinations of the transmission values for the different spectral distributions.

In addition, the device includes an analysis module which is designed to determine local transmission values of the glass to be checked for each image data set recorded by the image recording device from the brightness data. In addition, the analysis module is designed to determine local colorant density values for each colorant of the set of colorants from the local transmission values according to the color density model.

In particular, a transmission value for the corresponding spectral distribution is assigned to each pixel, ie each brightness value of the two-dimensional image data set, for each two-dimensional image data set of the image recording device. A set of transmission values is thus determined for each pixel, which sets a transmission value for each spectral distribution. From this set of transmission values, a set of colorant density values is determined for each pixel according to the color density model, which set assigns the corresponding colorant density value to each colorant.

Finally, the device includes an image output device which is designed to output a graphical representation of a distribution of the local colorant density values over the glass to be checked for each colorant of the set of colorants. In particular, the local color density values are output in the form of a two-dimensional color distribution image.

Preferably, the device also includes a reference data memory, which is designed to store reference brightness data as a reference image data set for each spectral distribution, with the analysis module being designed for each spectral distribution, the local transmission values of the glass to be checked as a ratio of the brightness data of the corresponding To determine the image data set and the reference brightness data of the corresponding reference image data set.

The reference image data set is preferably recorded by the image recording device analogously to the corresponding image data set, with no glass or a reference glass being arranged in the optical beam path between the emission surface and the image recording device during the recording of the reference image data set. This reliably compensates not only for possible different brightnesses of the light of the different spectral distributions emitted by the illumination device or possible brightness inhomogeneities, but also for possible differences in the spectral sensitivity of the image recording device for the different spectral distributions.

The minimum spectral sensitivity of the imaging device in the wavelength range from 400 nm to 750 nm is preferably in a range of not less than about 10%, more preferably not less than about 20%, more preferably not less than about 30%, most preferably not less than about 40% of the maximum spectral sensitivity in that wavelength range. The image recording device particularly preferably comprises a (high-resolution) CCD camera or a CCD chip.

The lighting device of the device according to the invention is preferably configured in the manner described below according to a further aspect of the invention, in particular in one of the preferred embodiments also described.

Preferably, the lighting device comprises an emitter disk, which has at least one peripheral coupling surface for coupling light into the emitter disk and a planar, roughened emission surface for diffuse emission of at least part of the coupled light. In addition, the lighting device comprises a multiplicity of light sources which are designed and arranged in order to emit light selectively with different spectral distribution (ie in different colors) at least partially towards the coupling surface. The light sources are preferably at least partially arranged or attached to the coupling surface. In particular, the radiation disk is essentially transparent radially and thus allows good radial propagation of light within the disk. A glass to be checked can preferably be placed on the planar, roughened emission surface. This can be done, for example, either directly or indirectly by means of a support ring that supports the glass to be checked at least partially on its peripheral edge. This makes it possible, for example, to arrange the glass to be checked at a distance from the lighting device, in particular the emission surface.

In a preferred embodiment, the radiating disk essentially has a cylindrical shape, the lateral surface of which is formed by the coupling-in surface. In this case, the surface opposite the emission surface is preferably optically smooth or polished, in contrast to the emission surface. This means that this surface, at least for the most part, does not have any irregularities or roughness that are larger than approximately 400 nm, particularly preferably approximately 200 nm. In this way, undesired decoupling of the light on this surface can be avoided or at least kept to a minimum.

The emitting disk preferably has rotational symmetry in relation to an optical axis of the emitting disk which is perpendicular to the emitting surface. The circular shape of the emission surface associated with this symmetry and the preferably rotationally symmetrical arrangement of the coupling surface enable a particularly uniform light distribution. An optical axis of the image recording device also particularly preferably coincides with the optical axis of the radiation disk.

In a preferred embodiment, the multiplicity of light sources comprises a multiplicity of identical groups of light sources, each group of light sources for each spectral distribution comprising at least one light source which is designed to emit light with this spectral distribution. The light sources of the plurality of light sources are particularly preferably arranged at regular, preferably periodic, in particular equal distances from one another and preferably symmetrically with respect to an optical axis of the lighting device.

The multiplicity of light sources preferably comprises a multiplicity of sets of identical light sources which are designed to emit light with one of the multiplicity of spectral distributions. A set of light sources is therefore preferably available for each spectral distribution, which preferably all emit light with the same light spectrum. The light sources are preferably arranged in the plurality of identical groups of light sources in such a way that each group includes at least one light source from each set of light sources.

The light sources each have a spectral width or a spectrum that covers a sub-range of visible light. Preferably, at least some of the plurality of light sources have different spectra. At least two, more preferably at least three, different spectral distributions (spectra) are thereby generated. Preferably, each of the plurality of spectral distributions has a FWHM of no more than about 150 nm, preferably no more than about 100 nm, even more preferably no more than about 80 nm, most preferably no more than about 60 nm. This allows individual dyes to be examined or checked very selectively. In particular, in many cases it is very easy to distinguish different dyes from one another. Preferably, the plurality of light sources includes a plurality of LEDs. In this way, various comparatively narrow spectra can be realized very efficiently.

In addition to these narrow-band spectra, in a preferred embodiment the lighting device can also emit light with a broader spectral distribution. This can be done, for example, by using separate, broadband light sources or by simultaneously emitting light from narrowband light sources of different wavelengths, ie by superimposing narrowband spectra.

In another aspect, the invention features a method for inspecting the coloration of a lens. This method involves diffusely illuminating the glass to be inspected. In particular, the glass is illuminated areally with diffusely emitted light.

Depending on the color of the glass and the wavelength of the emitted light, at least part of the light penetrates the glass. Brightness data of the transmitted light are now recorded as a two-dimensional image data set for each of a multiplicity of spectral distributions, ie for each color from a multiplicity of (predetermined) colors. The brightness of the transmitted light is thus recorded in a spatially resolved manner and made available as an image data record. In particular, an image recording device such as a CCD camera is used for this purpose.

In addition, a color density model is provided in the method according to the invention, which represents a color density value for each colorant from a set of colorants as a function of transmission values for the multiplicity of spectral distributions. In particular, the set of dyes originally used for the coloring is used as the set of dyes. Each dye has a specific absorption spectrum and thus leads to more or less strong absorption of light of specific wavelengths or a corresponding wavelength range depending on the dye density locally generated in the glass. The higher the local density of the dye, the greater the absorption of the light with the corresponding wavelengths, while the light that is not in the wavelength range of strong absorption of this dye is less or hardly influenced by this dye and thus leads to the apparent coloring of the glass. In general, the higher the corresponding dye density, the stronger the apparent coloring effect.

In the method according to the invention, local transmission values of the glass to be checked are determined from the brightness data for each recorded image data set. Local color density values for each colorant of the set of colorants are in turn determined from this according to the color density model. Finally, a graphical representation of a distribution of the local colorant density values is output for each colorant of the set of colorants by means of an image output device.

Analogously to the device described above, in one aspect of the invention, the diffuse illumination takes place successively with light of a large number of different spectral distributions, ie different colors. In this aspect, brightness data are thus recorded as two-dimensional data sets for each of these multiplicity of spectral distributions.

In another aspect of the invention, the detection of brightness data for each of a multiplicity of spectral distributions takes place in a spectrally selective manner, in particular by means of an image recording device which defines the multiplicity of spectral distributions as spectral sensitivities (separate color channels). The diffuse illumination of the glass to be checked takes place in a spectrally broadband manner, in particular over the entire visible range.

In particular, at least the method steps of providing the color density model, determining local transmission values and local color density values and outputting the graphic representations are computer-implemented or automated. An illumination device for diffusely illuminating the glass to be checked is preferably also automated or controlled by the computer, in that the illumination device is automatically controlled in order to emit the different spectral distributions one after the other. A control unit preferably assigns each recorded image data set according to the respective spectral distribution emitted. Alternatively or additionally, a corresponding image data record is preferably assigned to each emitted spectral distribution by means of the control unit.

Reference brightness data is preferably also provided as a reference image data set for each spectral distribution, with the local transmission values of the glass to be checked being determined as the ratio of the brightness data of the corresponding image data set and the reference brightness data of the corresponding reference image data set for each spectral distribution.

In a preferred embodiment, the reference image data records are recorded without the glass to be checked. In particular, no glass is placed on the emission surface or positioned between the emission surface and the image recording device. In another preferred embodiment, the reference image data sets are recorded using a reference lens that has essentially the same refraction data as the lens to be checked but is essentially uncolored or provided with a known or specified color (reference color). This can be advantageous, especially for glasses with strongly curved surfaces, i.e. with a high effect or surface effect, in particular with locally different effects, in order to avoid inhomogeneities in the light intensity caused by the local differences in the effects despite the diffuse illumination of the glass to be able to distinguish inhomogeneities in the light intensity caused by an uneven coloring. As a rule, a reference measurement without glass will be sufficient, so that the material and time expenditure for a measurement is significantly reduced, since a corresponding reference glass does not have to be kept available and this does not have to be precisely adjusted for a reference measurement. This advantage results primarily from the procedure according to the invention, in particular with the aid of the lighting device according to the invention.

The diffuse illumination preferably takes place by means of an emitter disc which has at least one peripheral coupling surface for coupling light into the emitter disc and a planar, roughened emission surface for diffuse emission of at least part of the coupled light. A radiation disk according to the invention is particularly preferably used for this purpose, in particular in one of the preferred embodiments described here.

• 1 eine Darstellung des Farbraumes in den Koordinaten a* und b* des CIE-L*a*b*-Systems;
• 2 eine Vorrichtung zur Überprüfung der Färbung eines Glases gemäß einer bevorzugten Ausführungsform eines ersten Aspekts der vorliegenden Erfindung;
• 3 eine Beleuchtungseinrichtung für eine Vorrichtung zur Überprüfung der Färbung eines Glases gemäß einer bevorzugten Ausführungsform der vorliegenden Erfindung;
• 4 Details einer Beleuchtungstreibereinheit (also Treibereinrichtung) für eine Vorrichtung gemäß einer bevorzugten Ausführungsform der Erfindung;
• 5 gemessene Transmissionskurven für drei verschiedene Farbstoffe sowie ein verwendetes Trägermaterial;
• 6 spektrale Verteilungen für eine Vielzahl verschiedener LEDs;
• 7 spektrale Empfindlichkeit der Bildaufnahmeeinrichtung in einer beispielhaften Ausführungsform gemäß dem ersten Aspekt der Erfindung;
• 8 eine Vorrichtung zur Überprüfung der Färbung eines Glases gemäß einer bevorzugten Ausführungsform eines zweiten Aspekts der vorliegenden Erfindung;
• 9 spektrale Empfindlichkeit der Bildaufnahmeeinrichtung in einer beispielhaften Ausführungsform gemäß dem zweiten Aspekt der Erfindung;
• 10 grafische Darstellungen einer Verteilung der lokalen Farbstoffdichtewerte gemäß einer bevorzugten Ausführungsform der Erfindung in Form von Graustufen (10A) und in Form von Linien gleicher Werte (10B); und
• 11 radiale Verteilung von Farbstoffen, welche gemäß einer bevorzugten Ausführungsform der Erfindung ermittelt wurden.

The invention is described below using preferred embodiments with reference to the accompanying drawings. show:

• 1 a representation of the color space in the coordinates a* and b* of the CIE-L*a*b* system;
• 2 an apparatus for inspecting the coloring of a glass according to a preferred embodiment of a first aspect of the present invention;
• 3 an illuminating device for an apparatus for inspecting the coloring of a glass according to a preferred embodiment of the present invention;
• 4 Details of an illumination driver unit (ie driver device) for a device according to a preferred embodiment of the invention;
• 5 measured transmission curves for three different dyes and a carrier material used;
• 6 spectral distributions for a variety of different LEDs;
• 7 spectral sensitivity of the imaging device in an exemplary embodiment according to the first aspect of the invention;
• 8th an apparatus for inspecting the coloring of a glass according to a preferred embodiment of a second aspect of the present invention;
• 9 spectral sensitivity of the imaging device in an exemplary embodiment according to the second aspect of the invention;
• 10 graphical representations of a distribution of the local dye density values according to a preferred embodiment of the invention in the form of gray levels ( 10A) and in the form of lines of equal values ( 10B) ; and
• 11 radial distribution of dyes determined according to a preferred embodiment of the invention.

• • inhomogene flächige Farbverteilung in Form von Wolken, Schieren, etc.;
• • inhomogene Abschattungen an Glasrandbereichen;
• • keilförmige Farbverteilungen;
• • geometrieabhängige inhomogene Farbverteilungen

With the present invention, it is possible to check or analyze the coloring of a glass quickly, objectively and precisely. In particular, it is possible to examine the following features that are based on local contrast fluctuations, such as:

• • inhomogeneous, two-dimensional color distribution in the form of clouds, streaks, etc.;
• • inhomogeneous shading at the edges of the glass;
• • wedge-shaped color distributions;
• • Geometry-dependent inhomogeneous color distribution

If a certain degree of inhomogeneous color distribution occurs or is exceeded, appropriate corrections can be made when coloring subsequent glasses. While these features have usually been qualitatively evaluated optically visually or subjectively, this is now possible quantitatively and objectively in a very reproducible manner.

The resulting color of a glass is typically achieved by mixing, for example, three individual colors. For example, in order to produce a resulting color "grey", the colors red, yellow and blue are transferred to the glass surface in a suitable ratio (e.g. either by color bands or by sublimation / diffusion). The observer's visual perception perceives the resulting color as grey, although only the three individual colors were involved in the coloring process.

Up to now, when evaluating the colored glasses, the color impression was used to subjectively estimate which additional amounts of color had to be added in order to achieve the target color grey. In general, this correction has so far been performed intuitively. Quantitative information about the deviation from the "ideal" gray or the reference color could not be realized up to now.

1. a) Den Helligkeitsanteil, der mit den Werten L* = 0 (schwarz) bis L* 100 (weiß) die visuell empfundene Eindunklung der Farbe beschreibt, aber keine Information über die Farbigkeit enthält,
2. b) Die „reine Farbigkeit“ der Gläser die durch die Koordinaten a* und b* im Farbraum aufgespannt wird. Die Koordinaten a* und b* können vorzugsweise Werte in den Intervallen [-150;150] annehmen. Gemäß der Gegenfarbentheorie werden auf der a*-Achse für positive a*-Werte die Farben Rot und für negative a*-Werte die Farben Grün aufgetragen und entsprechend auf der b*-Achse für positive b*-Werte die Farben Gelb, und für negative b*-Werte die Farben Blau aufgetragen. 1 veranschaulicht diesen a*-b*-Farbmessraum gemäß CIE L*a*b* mit drei Farbvektoren für die Einzelfarben Rot (Pfeil 110), Gelb (Pfeil 112) und Blau (Pfeil 114).

With the present invention, on the other hand, not only a quantitative, but also a spatially resolved evaluation and check is now possible. In an exemplary embodiment, the invention even enables a quantitative evaluation in standard color coordinates, for example according to the CIE L*a*b* color system. These color coordinates approximately describe the color perception of the human eye. Such a color measurement provides device-independent color measurement data that can be broken down into two parts:

1. a) The lightness component, which describes the visually perceived darkening of the color with the values L* = 0 (black) to L* 100 (white), but contains no information about the colourfulness,
2. b) The "pure color" of the glasses, which is spanned by the coordinates a* and b* in the color space. The coordinates a* and b* can preferably assume values in the intervals [-150;150]. According to the opposite color theory, the colors red are plotted on the a*-axis for positive a* values and the colors green for negative a*-values, and accordingly yellow is plotted on the b*-axis for positive b*-values, and for negative b* values plotted the colors blue. 1 Illustrates this a*-b* color measurement space according to CIE L*a*b* with three color vectors for the individual colors red (arrow 110), yellow (arrow 112) and blue (arrow 114).

A change of the color locus in the a*-b* plane without considering the L* coordinate can be achieved by several combinations of, for example, three individual colors. A movement in the a* direction can be achieved either by increasing the proportion of red, or also by a reduction of the colors yellow and blue. With conventional visual assessment, this differentiation is not possible or only possible to a very limited extent. If conclusions about the pigment quantities of the individual dyes used are to be drawn from the color impression, this was not clearly possible in previous methods.

The present invention, on the other hand, can preferably make quantitative statements about the local pigment densities of the individual dyes or their required correction, preferably directly and with spatial resolution. In particular, it is not necessary to carry out an explicit evaluation on the basis of color norm coordinates. Rather, information can be obtained immediately about any necessary corrections to the coloring on the basis of the dyes and quantities of dyes used.

2 shows a device 10 for checking the coloring of a lens 12, in particular a spectacle lens. For this purpose, the device 10 includes an illumination device. The lighting device comprises in 2 illustrated embodiment, a radiation disc 14 with a planar emission surface 16 for diffuse emission of light. In this case, the light is coupled into the radiation disk 14 in particular via at least one peripheral coupling surface 18 . Radiating disk 14 is preferably essentially cylindrical, with at least one coupling surface 18 forming the lateral surface of the cylindrical shape. The light coupled in via the in-coupling surface 18 is guided within the transparent emitting disk 14 and at least partially out-coupled again via the emitting surface 16 and radiated diffusely. The radiating surface 16 preferably has a rough surface structure such that visible light is coupled out and diffusely radiated.

The coupled-in light is preferably generated by light-emitting diodes (LEDs) which are arranged on the coupling-in surface 18 . The LEDs are in 2 not shown, but are used in connection with the in 3 illustrated preferred embodiment described in more detail below. The LEDs form light sources of the lighting device in the illustrated embodiment of 2 are controlled and operated via a driver connection 20 by means of a driver device 22 preferably included in the lighting device. In particular, the driver device 22 supplies the necessary electrical power for the operation of the light sources. The driver device 22 itself is in turn controlled via a control connection 24 by means of a control unit 26 . In a preferred embodiment, the control unit 26 includes a USB interface for this purpose, via which the driver unit 22 is controlled by means of the control connection 24, which is preferably embodied as a USB connection.

in the in 2 illustrated preferred embodiment, the illumination device has an optical axis 28 which coincides with the optical axis of an image recording device 30, ie corresponds. Image recording device 30 is preferably embodied as a camera, in particular as a CCD camera, and is or can be positioned in such a way that glass 12 and/or even the entire radiation disk 14 is preferably located completely in the recording area (recording cone) of image recording device 30. The image recording device 30 is thus designed to simultaneously record the light emitted by the emission surface 16 and in particular the light transmitted through the glass 12 to be checked as a two-dimensional image, that is to say spatially resolved. In particular, an image data record is generated that represents a large number of pixels preferably arranged in a matrix-like manner and defines the brightness of the light of the emission surface 16 or of the glass 12 to be observed in the respective pixel on the image recording device 30 . Each data value of the image data set therefore preferably corresponds to a pixel, with each data value defining the brightness recorded by the image recording device in the corresponding pixel.

The image data set is transmitted to the control unit 26 via an image data line 32 . The control unit 26 preferably has a control module 34 which is designed to successively output control signals for activating the emission of a spectral distribution by the lighting device to the control connection 24 . Light with different colors is therefore emitted one after the other at the emission surface 16 . An image data set is preferably recorded for each color, ie each spectral distribution, by means of the image recording device 30 and is then transmitted to the control module 34 of the control unit 26 . The control module 34 is preferably designed to also activate the acquisition of the associated image data set synchronously with the activation of the emission of light of the respective spectral distribution. After the image data set has been received, it is preferably stored in an image data memory 36 of the control unit with reference to the associated spectral distribution. The image data sets with reference to the associated spectral distribution are thus available in the image data memory 36 for further analysis.

For further evaluation, the control unit 26 preferably includes a colorant database 38 with a color density model which represents a colorant density value for each colorant from a set of colorants as a function of transmission values for the multiplicity of spectral distributions emitted by the lighting device. The color density model associates a set of dye density values with a set of values that describe the local transmission of a glass at different spectral distributions. The set of values for the transmittance (set of transmittance values) contains a data value for each spectral distribution, the set of dye density values containing a data value for the dye density for each dye.

In the embodiment of 2 the control unit 26 also includes an analysis module 40. This is designed to determine local transmission values of the glass to be checked from the brightness data for each image data set recorded by the image recording device 30, which can then be applied to the color density model in order to determine dye density values. For this purpose, the analysis module 40 has a signal connection with the image data memory 36 for the transmission of stored image data sets.

In a preferred embodiment, the image data memory 36 also functions as a reference data memory, which is designed to store reference brightness data as a reference image data set without loss for each spectral distribution. The reference image data set is preferably captured in each case analogously to the corresponding image data set by image recording device 30, with no glass or a reference glass being arranged in the optical beam path between emission surface 16 and image recording device 30 during the recording of the reference image data set.

The analysis module is preferably designed to determine the local transmission values of the glass 12 to be checked for each spectral distribution as a ratio of the brightness data of the corresponding image data set and the reference brightness data of the corresponding reference image data set.

As in 2 shown, the control unit 26, in particular the analysis module 40, is connected to an image output device 42, in particular a screen, in order to output a graphical representation of a distribution of the local colorant density values over the glass to be checked, for example in the form of a two-dimensional color distribution image, for each colorant of the set of colorants. in the in 2 In the embodiment shown, the selected color density model is based on three colorants, the colorant density values of which are displayed simultaneously as three two-dimensional color distribution images by means of the screen 42 . In order to be able to intuitively assign the individual color distribution images to the corresponding dyes very quickly, the color distribution images are preferably displayed in a color that comes close to the apparent color of the respective dye produced in the glass. At least the radiation screen 14 with the glass 12 and the image recording device 30 are preferably arranged together in a darkroom in order to suppress undesired scattered light effects.

3 FIG. 1 shows a plan view of an emission surface of an emission disc 14 of an illumination device for a device for checking the coloring of a glass according to a preferred embodiment of the present invention. In particular, the radiating disc 14 could 3 in an apparatus according to the preferred embodiment of 2 find use. in the in 3 In the preferred embodiment illustrated, the radiation disc is essentially in a flat, cylindrical shape, that is to say with a circular cross-section parallel to the radiation surface.

In 3 a preferred configuration and arrangement of light sources 44 is shown in particular. The light sources are preferably formed as individual LEDs 44 . Compared to the width of the visible spectrum, LEDs have a relatively small spectral bandwidth, i.e. they can selectively emit light with a narrow spectral width. This will example from 6 evident. It shows the relative intensity (I) of the emitted light as a function of the wavelength, i.e. the spectral distribution, for ten different exemplary LEDs in the wavelength range λ of visible light. From left to right, these are the following LEDs: "blue 430 nm", "blue 465 nm", "verde 500 nm", "pure green 510 nm", "green 520 nm", "true green 525 nm", "yellow". 590 nm", "orange 610 nm", "amber 622 nm", "super-red 645 nm".

In the embodiment of 3 the LEDs 44 are arranged on the peripheral edge of the radiation disk 14, which forms the coupling-in surface of the radiation disk 14. In particular, in this preferred embodiment, three different sets of LEDs 46a, 46b, 46c are provided, each set comprising a plurality of substantially identical LEDs 44. In this case, essentially identical means that the LEDs within a set of LEDs have essentially the same spectral distribution. However, the sets of LEDs differ from one another in their spectral distribution. In other words, in the preferred embodiment of 3 LEDs with three different colors are provided, with each color forming a plurality of LEDs in the respective set. The LEDs of a set of LEDs 46a, 46b, 46c are preferably arranged regularly and/or periodically and/or symmetrically along the peripheral edge, ie along the coupling surface. In this case, one or more LEDs of another set are preferably arranged at least partially between the LEDs of one set. Preferably, the LEDs 44 are arranged to form a plurality of substantially identical groups of LEDs 48, with each group of LEDs 48 including at least one LED 44 from each set of LEDs 46a, 46b, 46c.

The LEDs 44 are preferably controlled and supplied with the required electrical power by means of the 2 already illustrated driver device 22. Further details of an exemplary driver device 22 according to a preferred embodiment of the present invention are in 4 shown. Accordingly, the driver device 22 preferably includes a power pack 50 which supplies a control device 54 with a corresponding electrical power via a mains switch 52 . The control device 54 is preferably controlled by the central control unit 26 by means of the control connection 24 . In a preferred embodiment, the control connection 24 is designed as a USB connection. However, other, preferably digital, data connections are also possible as the control connection 24 .

Depending on control signals on the control connection 24, the control device 54 generates and outputs one or more switching signals, which correspond to one or more corresponding control elements 56a, 56b, 56c activated/activated. At least one control element 56a, 56b, 56c is preferably provided for each set of LEDs 46a, 46b, 46c. in the in 4 In the preferred embodiment shown, the control elements 56a, 56b, 56c are in the form of transistors. For each activated control element, a corresponding line in the driver connection 20 supplies the required electrical power from the power supply 50 to the corresponding set of LEDs 46a, 46b, 46c.

5 illustrates the degree of transmittance of dyes that can preferably be used when coloring a glass. In particular, the transmission curves of the individual colors red (curve 120), yellow (curve 122) and blue (curve 124) as well as the transmission curve of a plastic as an exemplary carrier material (curve 126) are shown. As can be seen therein, the individual colors used for coloring have characteristic absorption bands that absorb in typical wavelength ranges. In the example of 5 the absorption bands are in the ranges from about 430 nm to about 460 nm (yellow), from about 490 nm to about 560 nm (red) and from about 600 nm to about 670 nm (blue). A comparison with the emission lines of the LEDs in 6 shows that for each individual color an LED can be selected in such a way that the emission maximum of the respective LED is preferably at a low absorption (in particular compared to at least one other individual color used) of the respective individual color. Different combinations of LEDs can be chosen to achieve the desired colorant assignment. If a fixed, in particular always the same range of dyes is used, the selection of the LEDs is preferably selected in such a way that the conversion matrices can be mapped in a particularly simple manner. However, if the intention is to measurably record a larger range of color pigments, then a large overlap between all pigments, eg all red pigments, and the color lighting is desirable. In this case in particular, there remains a compromise in the desired selection of the LEDs, depending on the desired application.

A glass to be examined is thus, for example, successively homogeneously illuminated with three different colors. Depending on the respective location of the glass and the color pigments present therein, the glass reflects or absorbs the luminous flux emitted by the emission surface 16 . The spatially resolved signal determined by the image recording device (e.g. black-and-white camera) is therefore both spectrally dependent on color and pigment

Looking at the spectral range of visible light with wavelengths λ from about 400 nm to about 800 nm, the intensity of the signal to be measured can be mapped as follows: $$I\left(fa\mathrm{right}be,Bele\mathrm{and}cHt\mathrm{and}nG\right)\sim {\displaystyle \int q\left(\lambda \right)\cdot ƒ\left(\lambda \right)\cdot \mathrm{i.e}\left(\lambda \right)}$$

Here, q is the intensity of the light source (e.g. the LEDs including the radiation disc), f is the transmission of the glass to be examined and d is the sensitivity of the image recording device (camera).

A spectral emission q(λ) can thus be specified for each illumination. A spectral transmission f(A) can also be specified for each color (color pigments) that is in the measurement object (glass) to be tested. The measured signal thus depends on both the color (the coloring pigments) and the lighting of the measurement object. A measured intensity can be determined metrologically for each combination of color and illumination using the above equation. A respective example for intensities q(λ) of the illumination source and for the transmission of the test glass or the color pigments is shown in the representations of FIG 5 or. 6 shown. In addition, 7 represents an example of a relative spectral sensitivity q(λ) of the image recording device (e.g. CCD camera).

Another preferred embodiment of a device 10' is in 8th shown. In particular, to the extent that the same reference numbers are used as in 2 illustrated embodiment will be used on the corresponding embodiment in the description of 2 referred, preferably also to the embodiment of 8th to be applied in an analogous manner. In particular, the device 10' comprises an illumination device. In this preferred embodiment, too, the lighting device comprises a radiation disk 14′ with a planar radiation surface 16 for the diffuse emission of light. An extended, homogeneous light source is now preferably used as the radiation disk 14′, which enables homogeneous illumination over the entire visible wavelength range. Essentially white light is therefore preferably emitted. In preferred embodiments, the radiation disk 14' comprises a cold cathode tube (e.g. a computer monitor with a cold cathode tube) and/or an LED lighting unit (e.g. a computer monitor with an LED lighting unit) and/or an LED panel and/or another lighting system that one over the radiating surface 16 Weitge enables homogeneous illumination in a wide spectral range across the visible light spectrum. A diffuse diffusing screen is preferably positioned directly above the illumination system in order to achieve diffuse illumination of the test glass 12 .

Unlike in the embodiment of 2 it is in the embodiment of 8th It is possible, but not necessary, for different colors to be controlled independently of one another via a driver connection 20' by means of a driver device 22', which is preferably included in the lighting device. Rather, in this embodiment, white light in particular can always be emitted with a defined spectral distribution. The spectral resolution, ie the dependence of the transmission of the glass to be examined on the wavelength (color) of the light, is achieved in this embodiment by an image recording device 30'. The image recording device 30' is preferably embodied as a camera, in particular as a CCD camera (e.g. 3-color CCD camera) and is or can be positioned in such a way that the glass 12 and/or even the entire radiation disk 14' is preferably completely in the recording area (recording cone ) of the image recording device 30'.

The image recording device 30' is thus designed to simultaneously record the light emitted by the emission surface 16 and in particular the light transmitted through the glass 12 to be checked as a two-dimensional image, that is to say spatially resolved. In addition, the image recording device 30′ is designed in particular to record brightness data for the light emitted by the emission surface 16 and transmitted through the glass 12 to be checked as a two-dimensional image data set for a large number of spectral distributions. In particular, for each of the spectral distributions defined by the image recording device 30', an image data set is generated which represents a large number of pixels preferably arranged in a matrix-like manner and the brightness of the light of the emission surface 16 or of the glass 12 to be observed in the respective pixel on the image recording device 30' of the respective spectral distribution. Each data value of the respective image data record therefore preferably corresponds to a pixel, with each data value defining the brightness within the spectral range detected by the image recording device in the corresponding pixel.

9 FIG. 12 illustrates, by way of example, relative spectral sensitivities of the image recording device 30' according to a preferred embodiment, in which the image recording device is designed to distinguish three spectral distributions (three-color camera). In particular, the relative spectral sensitivities of the three colors red (curve 130), green (curve 132) and blue (curve 134) are shown.

The image data records are transmitted via an image data line 32 to a control unit 26'. The image data records of all spectral distributions are preferably transmitted simultaneously, that is to say in parallel, via the image data line 32 . The control unit 26′ preferably has a control module 34′ which is designed to acquire the image data sets simultaneously. The control module 34' is preferably designed to also activate the acquisition of the image data sets synchronously with the activation of the emission of light. After the image data sets have been received, they are preferably stored with reference to the associated spectral distribution in the image data memory 36 of the control unit. The image data sets with reference to the associated spectral distribution are thus available in the image data memory 36 for further analysis. This analysis can then preferably be carried out analogously to the embodiment of FIG 2 take place.

The individual color components can be determined in a spatially resolved manner by sequentially transilluminating the glass with the respective LED color or by sequentially or simultaneously capturing image data using a color-resolved image capturing device. Deviating from the examples of preferred embodiments shown, four individual dyes (e.g. red, yellow, green, blue) and corresponding LEDs or a corresponding color-resolved image acquisition device could also be used for the analysis.

• - Division der Datenwerte des Bilddatensatzes mit Glas durch die Datenwerte des Referenz-Bilddatensatzes;
• - Normierung der Ergebnisse;
• - (evtl. Reduzierung der Ergebnisse auf wenige Freiheitsgrade);
• - Anzeige der Ergebnisse in der zu analysierenden Einzelfarbe.

A camera recording, ie an image data set with the glass to be checked and a reference image data set without the glass to be checked, is preferably recorded for each dye or for each corresponding LED color. The following steps preferably then take place for each LED color (i.e. each spectral distribution) or, in the case of a color-resolved image acquisition device, for each color data set (image data set):

• - dividing the data values of the image data set with glass by the data values of the reference image data set;
• - normalization of the results;
• - (Possibly reducing the results to a few degrees of freedom);
• - Display of the results in the single color to be analyzed.

Normalization reference image data records are preferably generated for the normalization. In particular, in the case of an embodiment in which the light emission takes place spectrally selectively, a dark reference image data record and for each spectral distribution a light reference image data record are recorded. In particular when using three different spectral distributions of the lighting device, the normalization reference image data sets are preferably recorded according to one of the schemes illustrated in the two tables below. Each row represents a normalization reference image data set, with the first three columns showing the respective relative intensity of the different spectral distributions emitted: Red Green Blue detector 0% 0% 0% dark frame 100% 0% 0% Max Bright Red 0% 100% 0% Max Bright Green 0% 0% 100% Max Bright Blue

In a first possible variant (3-color variant), a dark reference image data set (“Detector” column: “Dark image”) is recorded, while all light sources of the three different exemplary spectral distributions (“red”, “green”, “blue ") are switched off ("0%"). In addition, a light reference image data record is recorded for each individually activated spectral distribution ("100%"). Red Green Blue detector 0% 0% 0% dark frame 100% 0% 0% Max Bright Red 0% 100% 0% Max Bright Green 0% 0% 100% Max Bright Blue 100% 100% 0% Max Bright Red + Green 0% 100% 100% Max Bright Green + Blue 100% 0% 100% Max Bright Blue + Red 100% 100% 100% Max Bright Red + Green + Blue

In a second possible variant (7-color variant), a dark reference image data set is also recorded while all light sources of the three different spectral distributions are switched off. In addition, a light reference image data record is also recorded for each individually activated spectral distribution. In addition, however, a corresponding bright reference image data record is also recorded for each combination of two of the three or of all three spectral distributions.

In the case of an embodiment in which the image datasets are recorded spectrally selectively by the image recording device, i.e. if the spectral distributions are defined in particular by corresponding spectral sensitivities of the image recording device, a dark reference image dataset and a bright reference image data set is recorded. A corresponding preferred scheme for capturing the normalization reference image data sets is illustrated in the table below: panel Red Green Blue 0% dark frame dark frame dark frame 100% max bright red maximum light green maximum light blue

In particular, when using three different spectral distributions of the imaging device, dark reference image datasets (“dark image”) for each of the three spectral distributions (“red”, “green”, “blue”) are switched off while the lighting device (“panel”) is switched off is ("0%"). In addition, light reference image data sets are recorded for each of the three spectral distributions while the lighting device is activated ("100%").

1. a) LED 3 Farben: Rot, Grün, Blau
2. b) LED 7 Farben: Rot, Grün, Blau, Rot+Grün, Grün+Blau, Blau+ Rot, Rot+Grün+Blau
3. c) Farb-CCD: Rot, Grün, Blau

For the normalization, the intensity of the dark image is mapped to 0% for each measured location and the intensity to 100% for each of the possible light image measurements for each measured location. This means that before a measurement object can be measured, the bright images and the dark image are recorded first. In this case, preferably no measurement object is inserted, particularly in the bright image. For the measurement of a test glass, the following measurement vectors are available for each location-dependent measurement value of the image field of the camera V(x,y):

1. a) LED 3 colors: red, green, blue
2. b) LED 7 colors: Red, Green, Blue, Red+Green, Green+Blue, Blue+Red, Red+Green+Blue
3. c) Color CCD: Red, Green, Blue

Each measured value is scaled from 0% to 100% based on the intensity of the individual color channels. The individual measurements initially provide a set of intensities determined in the detector, which are then normalized to light/dark. In order to be able to use this normalized data to draw conclusions about the pigment distributions (dye density value), a dye database with a color density model is provided, which represents a dye density value for each dye from a set of dyes as a function of transmission values for the large number of spectral distributions. In order to provide the color density model, preferably homogeneously colored sample glasses are measured over a finite spatial area (approximately the middle of the sample glasses). The color pigment quantities (in particular the dye density or the dye density value) in these sample glasses are known. The case of a three-channel measuring system (3-color LED or color CCD) is described below as an example: In the simplest case, 8 sample glasses are each colored with a minimum or maximum amount of pigment. pigments Measurement sample Red Yellow Blue 1 minutes minutes minutes 2 minutes minutes Max 3 minutes Max minutes 4 minutes Max Max 5 Max minutes minutes 6 Max minutes Max 7 Max Max minutes 8th Max Max Max

In accordance with the generally known rules of statistical test planning for full factorial test plans, a multilinear mapping between the pigments and the individual measurements is thus preferably created according to the following vector equation. $$\overrightarrow{V}={\overrightarrow{V}}_0+\overleftrightarrow{M}\cdot \overrightarrow{f}$$

enthält dabei drei Freiheitsgrade von normierten Rot/Grün/Blau-Messwerten. Der Farbvektor $\overrightarrow{F}$

enthält in diesem Beispiel die drei Farbpigmente mit Masszahlen der Pigmentmenge für z.B. Pigment Rot, Pigment Gelb, Pigment Blau. Die Matrix $\overleftrightarrow{M}$

ist gemäß der Regeln der statistischen Versuchsplanung erstellt worden. Damit die Farbwerte $\overrightarrow{F}$

aus den Messwerten der für die zu untersuchenden Gläser erfassten Bilddatensätzen berechnet werden können, muss jedoch der umgekehrte Zusammenhang bekannt sein. Sofern die Matrix $\overrightarrow{M}$

quadratisch und invertierbar ist, kann diese Gleichung invertiert werden. Ist dies jedoch nicht der Fall, so kann im allgemeinen jedoch eine Nullstellenbestimmung insbesondere gemäß eines verallgemeinerten Newtonverfahrens für die Gleichung $$0={\overrightarrow{V}}_0+\overleftrightarrow{M}\cdot \overrightarrow{F}-\overrightarrow{V}$$

bestimmt werden. Weiterhin sind iterative Verfahren bekannt, die diesen Zusammenhang hinreichend genau numerisch lösen können.The measurement vector $\overrightarrow{V}$

contains three degrees of freedom of normalized red/green/blue measured values. The color vector $\overrightarrow{f}$

contains in this example the three color pigments with numbers of the pigment amount for eg pigment red, pigment yellow, pigment blue. The Matrix $\overleftrightarrow{M}$

has been created according to the rules of statistical design of experiments. Thus the color values $\overrightarrow{f}$

can be calculated from the measured values of the image data records recorded for the glasses to be examined, however, the reverse relationship must be known. Unless the matrix $\overrightarrow{M}$

is quadratic and invertible, this equation can be inverted. However, if this is not the case, then in general a zero point determination can be carried out, in particular in accordance with a generalized Newton method for the equation $$0={\overrightarrow{V}}_0+\overleftrightarrow{M}\cdot \overrightarrow{f}-\overrightarrow{V}$$

to be determined. Furthermore, iterative methods are known which can solve this relationship numerically with sufficient accuracy.

angenommen werden. Analog können beispielsweise für den Fall einer oben beschriebenen 7-Farbenvariante 7 Freiheitsgrade für den Messvektor angenommen werden. Auch für diesen Fall kann ein Modell angegeben werden, das den Farbvektor mit den Messvektoren in Beziehung zueinander setzt. Es können auch Versuchspläne in Betracht gezogen werden, die etwa quadartische Abhängikeiten $\overrightarrow{V}\sim F^2$

beschreiben. Eine Begrenzung der mathematischen Methoden ist hierbei nicht gegeben, sondern wird allein durch die hinreichende Genauigkeit der Messergebnisse gerechtfertigt.As briefly outlined here, 3 degrees of freedom for the measurement vector $\overrightarrow{V}$

be accepted. Analogously, 7 degrees of freedom can be assumed for the measurement vector in the case of a 7-color variant described above, for example. For this case, too, a model can be specified that relates the color vector to the measurement vectors. Experimental designs can also be considered that have, for example, quadratic dependencies $\overrightarrow{V}\sim {\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="DE102013003558B4\_0014.png"\; state="\{\{state\}\}">f</figure-callout>}}^2$

describe. A limitation of the mathematical methods is not given here, but is justified solely by the sufficient accuracy of the measurement results.

After the individual channels have been normalized and the color quantities have also been normalized, the unknown color pigment distributions (color density values) of the glasses to be checked can now be determined. Further characterizations are preferably carried out for the results.

In particular, gradient-colored glasses can be described with this system in relation to the respective pigment density (dye density) of the individual dyes. 10A and 10B show exemplary plots of a distribution of local dye density values for one of the set of dyes used for a gradient colored glass. In doing so 10A represents the dye density distribution, for example, as a grayscale image, while 10B in particular, represents the same dye density distribution in the form of lines of equal dye density values. In a preferred embodiment, one of these graphical representations is output by means of the image output device together with corresponding graphical representations of the colorant density distributions for the other colorants used. The output for each dye is particularly preferably in a color of the graphic representation that correlates particularly intuitively for the user with the optically effective color of the corresponding dye, i.e. the graphic representation for a blue dye is preferably in blue, etc.

If the glasses have a gradient coloring and the center of the gradient coincides (approximately) with the middle point of the glass, a radius decomposition of the measurements can be made for each of the three individual colors. The gradient proportion for each of the three pigment colors can be specified for each radius.

In another application, it can be demonstrated, for example, how edge shadowing or edge lightening can be determined by a radial evaluation of the color pigment results. In this way, the local color density values can be converted into color pigment elements by means of a radial decomposition. 11 shows an exemplary radial distribution for the three different dyes red (curve 140), yellow (curve 142) and blue (curve 144).

• a) Summenkanal (grau) ohne Pigmentberechnung
  • • allgemeine Kontrastdarstellung
  • • lokale Kontrastfehler, Flecken, etc.
  • • allg. Dokumetation von Kontastprofilen
• b) Farbpigmente Ortsaufgelöst
  • • Dokumentation von Farbvariationen
  • • Dokumentation von Gradientengläsern
• d) Farbpigmente Linienschnitte
  • • Linienschitte prallel von Gradienten
  • • Farbunterschiede entlang ausgezeichneter Glasorientierungen
• e) Farbpigmente Polarschnitte
  • • Farbunterschiede antlang von Glasrändern
• f) Farbpigmente Radialzerlegung
  • • radiale Farbverteilungen
  • • Randabschattungen
• g) Farbpigmente radiale Gradientenzerlegung
  • • radiale Farbgradienten
  • • Farbschwächen bei prismatischen Gläsern
• h) Farbpigmente radiale Quadrupolzerlegung
  • • Farbschwächen bei Cylindergläsern

Depending on the area of application, one of the following preferred evaluation modes is preferably used:

• a) Sum channel (grey) without pigment calculation
  • • general contrast display
  • • local contrast errors, stains, etc.
  • • General documentation of contrast profiles
• b) Color pigments spatially resolved
  • • Documentation of color variations
  • • Documentation of gradient lenses
• d) color pigments line cuts
  • • Line intersections of gradients
  • • Color differences along excellent lens orientations
• e) Color pigments polar sections
  • • Color differences along glass edges
• f) Color pigments radial decomposition
  • • radial color distributions
  • • Edge shadowing
• g) Color pigments radial gradient decomposition
  • • radial color gradients
  • • Color weaknesses in prismatic lenses
• h) Color pigments radial quadrupole decomposition
  • • Color weaknesses in cylinder glasses

The invention thus enables a spatially resolved individual color analysis. A "map" of the pigment density can be specified for each individual colour, i.e. for each individual dye used. With this, gradients and/or edge shadowing of the individual colors can be quantitatively described very reliably and quickly. The mottling of the glass can be examined and specified separately according to individual colors. For the homogeneous colouring, the degree of homogeneity can be broken down into individual colours. In particular, a particularly targeted tracking or correction for each of the individual colors can thus be predicted.

Reference List

10

contraption

12

Glass

14

radiating disc

16

radiating surface

18

coupling surface

20

driver connection

22

driver setup

24

control connection

26

control unit

28

optical axis

30

image capture device

32

image data line

34

control module

36

image data storage

38

dye database

40

analysis module

42

image output device

44

Light sources (LEDs)

46

Sets of light sources

48

Groups of light sources

50

power adapter

52

main switch

54

control device

56

Controls (Transistors)

110

single color red

112

Single color yellow

114

Single color blue

120

Degree of transmittance of the single color red

122

Degree of transmittance of the single color yellow

124

Degree of transmittance of the single color blue

126

Degree of transmission of the carrier material

130

Color sensitivity for the color red

132

Color sensitivity for the color green

134

Color sensitivity for the color blue

140

Dye density distribution for the color red

142

Dye density distribution for the color yellow

144

Dye density distribution for the color blue

Claims (12)

Device (10; 10') for checking a coloring of a glass (12), comprising - An illumination device for the diffuse emission of light on an emission surface (16) of the illumination device; - an image recording device (30; 30') which is designed to record brightness data for the light emitted by the emission surface (16) and transmitted through the glass (12) to be checked as a two-dimensional image data set for each of a large number of spectral distributions; - a colorant database (38) with a color density model which, for each colorant from a set of colorants, represents a colorant density value as a function of transmission values for the plurality of spectral distributions; - an analysis module (40) which is designed -- determining local transmission values of the glass (12) to be checked for each image data set recorded by the image recording device (30; 30') from the brightness data; and -- determine local color density values for each colorant of the set of colorants from the local transmission values according to the color density model; and - an image output device (42) which is designed to output a graphical representation of a distribution of the local colorant density values for each colorant of the set of colorants, wherein the illuminating device is designed to emit light selectively with each of the plurality of spectral distributions for illuminating the glass (12) to be inspected. Device (10; 10') for checking a coloring of a glass (12), comprising - An illumination device for the diffuse emission of light on an emission surface (16) of the illumination device; - an image recording device (30; 30') which is designed to record brightness data for the light emitted by the emission surface (16) and transmitted through the glass (12) to be checked as a two-dimensional image data set for each of a large number of spectral distributions; - a colorant database (38) with a color density model which, for each colorant from a set of colorants, represents a colorant density value as a function of transmission values for the plurality of spectral distributions; - an analysis module (40) which is designed -- determining local transmission values of the glass (12) to be checked for each image data set recorded by the image recording device (30, 30') from the brightness data; and -- determine local color density values for each colorant of the set of colorants from the local transmission values according to the color density model; and - an image output device (42) which is designed to output a graphical representation of a distribution of the local dye density values for each colorant of the set of colorants, wherein the image recording device (30') is designed to spectrally selectively detect brightness data for each of the plurality of spectral distributions. device after claim 1 or 2 , which also includes a reference data memory (36) which is designed to store reference brightness data as a reference image data set for each spectral distribution, the analysis module (40) being designed to store the local transmission values of the glass to be checked ( 12) to be determined as the ratio of the brightness data of the corresponding image data set and the reference brightness data of the corresponding reference image data set. Device according to one of Claims 1 until 3 , wherein the lighting device comprises: - a radiation disk (14) which has at least one peripheral coupling surface (18) for coupling light into the radiation disk (14) and a planar, roughened radiation surface (16) for diffuse radiation of at least part of the coupled light ; and - a multiplicity of light sources (44) which are designed and arranged in order to emit light optionally with different spectral distribution at least partially towards the coupling surface (18). device after claim 4 , wherein the radiating disk (14) has a cylindrical shape, the outer surface of which is formed by the coupling surface (18). device after claim 4 or 5 , wherein the multiplicity of light sources (44) comprises a multiplicity of identical groups (48) of light sources, each group (48) of light sources for each spectral distribution comprising at least one light source which is designed to emit light with this spectral distribution. Device according to one of Claims 4 until 6 , wherein each of the plurality of spectral distributions has a FWHM of no more than about 150 nm, preferably no more than about 100 nm, even more preferably no more than about 80 nm, most preferably no more than about 60 nm. Device according to one of Claims 4 until 7 , wherein the plurality of light sources (44) comprises a plurality of LEDs. A method of inspecting a tint of a lens (12) comprising: - diffusely illuminating the glass to be checked (12); - Acquiring brightness data of the light transmitted through the glass to be checked as a two-dimensional image data set for each of a multiplicity of spectral distributions; - providing a color density model which, for each colorant from a set of colorants, represents a colorant density value as a function of transmission values for the plurality of spectral distributions; - Determining local transmission values of the glass (12) to be checked from the brightness data for each recorded image data set; - determining local color density values for each colorant of the set of colorants from the local transmission values according to the color density model; and - outputting a graphical representation of a distribution of the local colorant density values for each colorant of the set of colorants by means of an image output device (42), the diffuse illumination being carried out sequentially with light of the plurality of spectral distributions. A method of inspecting a tint of a lens (12) comprising: - diffusely illuminating the glass to be checked (12); - Acquiring brightness data of the light transmitted through the glass to be checked as a two-dimensional image data set for each of a multiplicity of spectral distributions; - providing a color density model which, for each colorant from a set of colorants, represents a colorant density value as a function of transmission values for the plurality of spectral distributions; - Determining local transmission values of the glass (12) to be checked from the brightness data for each recorded image data set; - determining local color density values for each colorant of the set of colorants from the local transmission values according to the color density model; and - outputting a graphical representation of a distribution of the local colorant density values for each colorant of the set of colorants by means of an image output device (42), the acquisition of brightness data for each of the plurality of spectral distributions being effected spectrally selectively. procedure after claim 9 or 10 , which also includes providing reference brightness data as a reference image data set for each spectral distribution, wherein for each spectral distribution the local transmission values of the glass to be checked are determined as the ratio of the brightness data of the corresponding image data set and the reference brightness data of the corresponding reference image data set will. Procedure according to claims 9 , 10 or 11 , wherein the diffuse illumination takes place by means of a radiation disk (14) which has at least one peripheral coupling surface (18) for coupling light into the radiation disk (14) and a planar, roughened radiation surface (16) for diffuse radiation of at least part of the coupled light .

Images