Method and device for determining optical characteristics of multilayer objects

FIELD: method and device can be used for determining optical characteristics of multilayer objects (layers of enamel and dentine) containing internal matter which is partially transparent and dissipates light diffusely.

SUBSTANCE: radiation is applied to surface of tested object and subsequently registered at output of receiving light guide. Area of partial darkening is formed onto surface of object at the receiving light guide's exit window. Area of darkening provides distribution of dissipated radiation power density, which changes within space. Dissipated radiation enters input window of light guide and is registered. Optical characteristics of multilayer object are judged from the dissipated radiation. Device for realization of the method has illuminating unit provided with exit window, radiation registration unit, at least two photosensitive elements, signal control and processing unit, and receiving light guide. Illuminating unit's exit window and receiving light guide are mounted coaxial to each other. Photosensitive elements of radiation registration unit are optically matched with exit window of receiving light guide and are disposed coaxial to each other for registration of volumetric distribution of radiation power dissipated by tested object.

EFFECT: improved precision.

7 cl, 5 dwg

 

The invention relates to the field of optical measurement and can be used to determine the optical characteristics of multilayer objects partially transparent and diffuse light-scattering internal environment, mainly teeth.

There is a method of determining the optical characteristics of multilayer objects, mainly teeth, which illuminate the object under investigation and set beside the items of the scale, having different optical characteristics such as color scale), determine the element of the scale that comes closest optical characteristics (such as color) to the object under investigation and which is then taken as a measure of desired optical characteristics (for example, for measure color) for the object under study [1].

A device for implementing this method includes standard lighting device, and a scale (for example, the colour colorings VITA in the study of teeth) [1].

A disadvantage of the known method and device is the low accuracy in determining the optical characteristics of the object, due to subjective factors (e.g., color perception is different operators are different and varies from state of the organism). In addition, this method cannot determine the optical characteristics of the different layers (e.g., enamel, dentine tooth).

Closest to the proposed technical solution is the method of determining the optical characteristics of multilayer objects partially transparent and diffuse light-scattering internal environment, which consists in applying radiation to the surface of the investigated object is coaxially relative to the receiving fiber, the formation of the object in the area of the entrance window of the receiving light conductor in the shaded area, Desk scattered radiation emanating from the shaded area, the parameters of which are judged on the optical characteristics of the object [2].

The device for implementing the method comprises a lighting unit with an output window, the registration unit of the radiation output connected to the control unit and signal processing, the output of which is connected to the input of a lighting unit, a receiving optical fiber, the output window which is optically connected with an input window of the registration unit of radiation, the output window of the lighting unit and the receiving light conductor mounted coaxially relative to each other and the input window of the receiving light guide is intended for installation on the surface of the object [2].

A disadvantage of the known method and device is the inability to determine the optical characteristics of the individual layers, for example the spectral indices of the light scattering enamel and dentin of the tooth as the test object.

The invention solves the problem of providing registration of the optical characteristics of the individual layers of the multilayer object with partially transparent and diffuse light-scattering internal environment, mainly teeth.

The invention consists in automation technology determine the optical characteristics of the individual layers of objects with partially transparent diffuse light-scattering internal environment.

The technical result from the use of the invention is to provide a definition of optical characteristics of the layers (enamel and dentin) objects, such as, for example, teeth.

This technical result is achieved in that in the method of determining the optical characteristics of multilayer objects partially transparent and diffuse light-scattering internal environment, mainly teeth, which consists in applying radiation to the surface of the investigated object is coaxially relative to the receiving light conductor and the radiation output of the receiving light conductor, in the area of the entrance window of the receiving light conductor form a region of partial blackout and register the spatial distribution of power density of the scattered radiation in the region of partial shading, which is judged on the optical characteristics of the multilayer object.

It is expedient in the area frequent knogo dimmable to generate time-varying spatial distribution of power density of the scattered radiation.

This technical result is also achieved by the fact that the device for determining the optical characteristics of multilayer objects containing the lighting unit with the output window, the registration unit of the radiation output connected to the control unit and signal processing, the output of which is connected to the input of a lighting unit, a receiving optical fiber, the output window which is optically connected with an input window of the registration unit of radiation, the output window of the lighting unit and the receiving light conductor mounted coaxially relative to each other and the input window of the receiving light guide is intended for installation on the surface of the object registration unit radiation has at least two photosensitive elements.

It is advisable that the photosensitive elements of the registration unit of radiation were performed coaxially relative to each other.

The receiving light guide may be made of at least two optical waveguides, each of which is optically connected to an individual photosensitive element block registration of radiation.

It is advisable that the optical waveguides of the receiving light conductor were made coaxial relative to each other.

It is advisable that the device contained a second lighting unit, the output of which is optically connected to one of the optical is anomodon of the receiving light conductor, and the output of another optical waveguide optically connected to the input of block registration of radiation, the inputs of the second lighting unit is electrically connected with the outputs of the control unit and signal processing.

The analysis of the prior art, including searching by the patent and scientific and technical information sources and identify sources that contain information about the analogs of the invention, allows to establish that the applicant is not found technical solutions, characterized by signs, identical to all the essential features of the claimed invention. The definition from the list of identified unique prototype allowed us to identify a set of essential (with respect to perceived by the applicant to the technical result) distinguishing features of the claimed object set forth in the claims.

Therefore, the claimed invention meets the requirement of "novelty" under the current law.

Information about the popularity of the distinctive features in the combination of features of known technical solutions to achieve the same as the claimed invention, the positive effect is not there. On this basis it is concluded that the proposed solution meets the criterion of "inventive step".

Method and device for determination of optical x is the new multi-layered objects with partially transparent and diffuse light-scattering internal environment, mostly teeth, illustrated by figure 1-5.

Figure 1 shows a coaxial feed radiation relative to the receiving light guide on the object surface (front view).

Figure 2 shows the installation of the receiving light conductor directly on the object surface (side view).

Figure 3 presents a device for determining the optical characteristics of multilayer objects.

4 shows a co-axial configuration of the photosensitive elements and the receiving light conductor with a coaxial placement of optical waveguides relative to each other.

Figure 5 presents a device for determining the optical characteristics of multilayer objects with additional lighting unit.

The method of determining the optical characteristics of multilayer objects, mainly teeth, is as follows.

On the surface of the examined object 1 serves radiation, formed coaxially relative to the receiving light guide 2. Part of the radiation incident on the object surface, penetrates it, absorbed and diffused diffused layers of the object (tooth - enamel and dentine). Since the light guide 2 closes against the radiation of the surface of the object 1 located under the input window of the receiving light conductor 1, the object of investigation in the area of the entrance window of the optical fiber occurs, the area of the partial blackout. Figure 2 curve 3 describes the spatial intensity distribution of the scattered radiation within the optical object (longitudinal cross-section of the object relative to the optical axis of the receiving optical fiber). It should be noted that when the change in the spectral index of the light scattering layer (e.g., enamel) changes the slope of the curve 3 in the transition from the illuminated area of the object in "blackout" (figure 2). With the increase in light scattering above the transition is smoother. The teeth in the first layer (enamel) with weak diffuse scattering is strongly scattering absorbing layer (dentin), so for enamel curve 3 (figure 2) has a pronounced failure in the zone, blackout, and for dentin curve 3 is smooth, almost without fail. Thus, if we define the steepness of the above transition (near failure) curve 3, it is possible to define and measure light scattering layer (enamel of the tooth). This register separately radiation from at least two sites in the shaded area. Suitable sites should be chosen in such a way that they are coaxially located relative to each other. While the Central (first) the site should be at most a darkened area (minimum curve 3, figure 2)and the outer edge of the second (or last) of the site which should be as far removed from the Central. In this case, it is possible to determine more precisely the desired steepness of the curve 3, and consequently, the rate εe(λ) light scattering layer (tooth enamel) for different wavelengths λ (useful to determine at three wavelengths). εe(λ) is determined from the obtained experimentally function (defined for different types of enamel, different types of teeth and the position of the measuring point)

where P1(λ), P2(λ) - power radiation emanating respectively from the first (Central) and the second (ring) plots the shaded area.

The index εd(λ) light scattering dentin (the second layer) is determined from the function obtained experimentally for different types of dentin

It should be noted that in the study of objects with a large number of layers than the teeth, the number of lots in the shaded area, which is registered radiation must be greater than 2.

The indicators light scattering εe(λ), εd(λ) you can define and otherwise, if in the field of partial blackout form a time-varying spatial distribution of power density of the scattered radiation, which can be provided by feeding on the object of interest at different points in time Svetova the flows with different divergence. In this expression (1)to(3) do not change, but P1(λ) - power radiation, the corresponding one of the spatial distribution of power density of the scattered radiation in a partially shaded area (for one time interval), when applying a light flux with one divergence, and P2(λ) - power radiation corresponding to a different spatial distribution of power density of the scattered radiation in a partially shaded area (for the second time interval), when applying a light flux with a different divergence.

The method of determining the optical characteristics of multilayer objects partially transparent and diffuse light-scattering internal environment, mainly teeth, is implemented using a device, a block diagram is shown in figure 3 (power supply not shown). The device comprises a lighting unit 4 to the output window 5, block 6 registration of radiation outputs connected to the unit 7 control and signal processing, the output of which is connected to the input of the lighting unit 4, the receiving light guide 2, the output window which is optically connected to the input unit 6 for recording radiation.

The light guide 2 may be made of optically transparent material (glass) in the form of a cylinder. The light guide 2 may also be made of at least two optical waveguides 8, 9, coax is installed but relative to each other (figure 4, the image of the end face of the light guide). To improve the mechanical strength of the receiving light conductor 2 and avoid penetration of the radiation-side window 5 is set in solid optically opaque (metal) tube (figure 3 not shown).

The output window 5 of the lighting unit 4 is made in the form of a cylinder made of an optically transparent material, which is installed inside the receiving light conductor 2.

The lighting unit 4 can be performed in three groups of 10, 11, 12 elements of radiation, working in different areas of the spectrum of the radiation. All elements of the radiation are mounted in a circle on the inner side of the window 5. Moreover, the elements of each color are set with the same angular displacement relative to each other. For example, as elements of radiation can be used elements of multi-element LEDs LF59EMBGMBC.

Unit 6 registration of radiation includes at least two photodetectors for an area of the shaded area, which is registered diffuse radiation) 13, 14. For efficient optical matching of the output window of the receiving light conductor 2 with the photodetection devices 13, 14 their photosensitive elements 15, 16 (4) should be implemented with a coaxial arrangement relative to each other (figure 4).

One of the variants of block 7 of the management and the processing of the signals presented in figure 3. Block 7 contains the microcontroller 17, with the analog inputs to which are connected the outputs of the photodetectors 13, 14, the switch, its output connected to the input of analog-to-digital Converter (e.g., microcontroller type MSP430P325), digital display 18 and an electric button 19 launch. Thus one part (three outputs) of the microcontroller 17 through ballast resistors (figure 3 not shown) connected to the LEDs 10, 11, 12 of the lighting unit 4, the second part of the outputs to the inputs of the indicator 18. Button 19 launch is connected to the input of the start of the microcontroller.

When implementing the method, when the partial blackout form a time-varying spatial distribution of power density of the scattered radiation, the device (figure 5) additionally, we introduce the second lighting unit 20, which may consist of three groups of radiation elements 21, 22, 23, similar to the radiation elements 10, 11, 12. Thus the output of the lighting unit 20 is optically connected to one of the optical waveguides of the receiving light conductor 2, the output of another optical waveguide receiving light conductor 2 is optically connected to the input unit 6 for recording radiation. The inputs of the lighting unit 20 is electrically connected to the outputs of the block 7 control and signal processing. It should be noted that the optical waveguide receiving svetovoda, which is radiation from the unit 20 may not apply to the test object (acts as a step) and should be located closer to the object than the output window of the lighting unit 5. For the company, which provides different divergence of the light flux incident on the object of interest, coming from the optical waveguide receiving light guide 2 and the output window of the lighting unit 5.

The device operates as follows. In the first stage, the input window of the receiving light guide 2 is mounted onto the surface of the examined object 1, press the button 19. At the control input of the microcontroller 17 receives the signal, by which the outputs of the microcontroller turns on the radiation elements 10, 11, 12 receives electrical impulses (impulses backlight), causing the illumination of these elements. Light signals from the output of the elements 10, 11, 12 are output window 5, which is an incoherent fiber, creating a uniform and co-axial distribution of the power density of the light fluxes on the surface of the calibration plate. Part of the light scattered in the internal environment of the calibration plate, enters in the input box of the receiving light conductor 2. If the light guide 2 is made monolithic, the photosensitive elements 8, 9 must be installed at this distance (about 5 mm and C is dependent on the diameter of the fiber), to the majority of the direct light beams from the fiber output (they correspond to the Central area of the shaded area, curve 3, figure 2) falling on the photosensitive element 8, and the majority of inclined beams (which corresponds to the boundary of the plot in the shaded area, curve 3, figure 2) on the photosensitive element 9. If the light guide 2 is made of two (at least two) is coaxially located relative to each other of the optical waveguides, the end face of the optical fiber 2 should be installed close to the sensors 8, 9. The diameter of the element 8 must be equal to the diameter of the waveguide 15 (registered radiation from the Central area of the shaded area, curve 3, figure 2) and the outer diameter of the element 9 should not be less than the external diameter of the waveguide 16 (recorded radiation boundary of the area of the shaded area, curve 3, figure 2). During the time of operation of each group of radiation elements 10, 11 or 12 outputs of the photodetectors sequentially through the switch, the microcontroller 17 is connected to the input of the analog-to-digital Converter of the microcontroller 17. Thus, in the memory of the microcontroller 17 recorded digital equivalents P1(λ), P2(λ). Valued functions (2), (1) stored in the memory of the microcontroller 17, which is given P1(λ), P2(λ) calculates εe(λ), ε(λ)Resultat calculation is displayed on the digital display 18.

Should the markings that to improve accuracy before (or after) the measurement of the optical characteristics of the studied object, you can measure the optical characteristics of the calibrated plate, which are known. Then in expressions (1), (2) instead of P1(λ), P2(λ) should be used:

where P10(λ), P20(λ) - power radiation, registered respectively from the Central (first) and the ring (second) plots the shaded area when working with a calibration plate. The calibration plate should be carried out in a two-layer (when used as the study objects of teeth) of white material. The upper layer must be made of material with weak scattering (equivalent to enamel), and the lower layer of material with strong scattering (equivalent dentin).

The device of figure 5 operates almost similarly to the device of figure 3. The only difference is that alternately turn on the lighting units 4 and 20. And block the registration of the radiation 6 registers at the output of the waveguide (much of the waveguide) of the light guide 2 alternately radiation P10(λ), P20(λ).

On the basis of the claimed invention was an experimental device. Research has shown that it correctly identifies indicators of svetorusie the Oia enamel and dentin of the teeth, on the basis of which was determined and the color of the teeth in accordance with the dental colour colorings VITA.

SOURCES of INFORMATION

1. Bruise M.A. Spectrophotometer: an inside look / / ' Publish ' - 2000, No. 2.

2. U.S. patent 5759030 And, 02.06.1998.

1. The method of determining the optical characteristics of multilayer objects partially transparent and diffuse light-scattering internal environment, mainly teeth, which consists in applying radiation to the surface of the investigated object is coaxially relative to the receiving light conductor and the radiation output of the receiving light guide, characterized in that on the surface of the object in the area of the entrance window of the receiving light conductor form a region of partial blackout, providing spatially variable distribution of power density of the scattered radiation that reaches the receiving window of the receiving light conductor, record the spatial power distribution of the scattered radiation in the region of partial shading, which is judged on the optical characteristics of the multilayer object.

2. The method according to claim 1, characterized in that in the area of partial blackout form a time-varying spatial distribution of power density of the scattered radiation.

3. A device for determining the optical characteristics of the multilayer object is in, containing lighting unit with an output window, the registration unit of radiation, having at least two photosensitive elements connected outputs to the control unit and signal processing, the output of which is connected to the input of a lighting unit, a receiving optical fiber, the output window which is optically connected with an input window of the registration unit of radiation, the output window of the lighting unit and the receiving light conductor mounted coaxially relative to each other and the input window of the receiving light guide is intended for installation on the surface of the investigated object, wherein the photosensitive elements of the registration unit of radiation is optically aligned with the output window of the receiving light conductor and are arranged coaxially relative to each other with the possibility of registration of the spatial power distribution of radiation scattered by the studied object.

4. The device according to claim 3, characterized in that the receiving light guide is made of at least two optical waveguides, each of which is optically connected to an individual photosensitive element block registration of radiation.

5. The device according to claim 4, characterized in that the optical waveguides of the receiving light guide is made coaxial with respect to each other.

6. The device according to claim 4, characterized in that it comprises the second is educational unit, the output of which is optically connected to one of the optical waveguides, the output waveguides and the output of another optical waveguide optically connected to the input of block registration of radiation, the inputs of the second lighting unit is electrically connected with the outputs of the control unit and signal processing.



 

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