A study on tooth colored optical algorithm using a smartphone

Transcription

1 Volume 118 No , ISSN: (printed version); ISSN: (on-line version) url: ijpam.eu A study on tooth colored optical algorithm using a smartphone Sang-Sik Lee 1, Jin-Hyoung Jeoung 2 and Chang-Dong Lee 3 1 Department of Biomedical Engineering, Catholic Kwandong University, Gangneung, Korea lsskyj@cku.ac.kr1, 2 Department of Biomedical Engineering, Catholic Kwandong University, Gangneung, Korea wlsgud0201@naver.com 3 FTS, WonJu, Korea cd1225@hanmail.net February 12, 2018 Abstract Background/Objectives: Through comparative evaluation of any standard result of the color measurement on smartphones for colors and various forms colorimetric result equipped with an optical system, and to provide an optical system capable of low-cost Methods/Statistical analysis: Install smart phones Camera Color Picker (V1.1.0) provided by Zetetic Company on smartphones and extract each of the RGB Code prepared for the standard colors Replaced in the order of the close-up of the optical system lens polarization close-up lens polarization closeup lens + polarized light ring light source (cross) polarization close-up lens + polarized light ring light source (parallel), to measure the RGB extraction value of each of the standard color

2 Findings: The difference between the measured value by the optical appears largely in the brightness or reflectivity than the chromaticity. The average value of E is highest at on smartphones not equipped with another optical system, for close-up lens to which the polarizing film21.66, when only attached macro lens became When not wearing a different light source, typically, the color difference becomes larger. When fitted with a ring light source, an optical system applying crossed polarizing film was lower than parallel to the applied optical system. The standard deviation(sd) of the Chrominance( E) of the measured value is the same as the Table II. If set in parallel when the polarizing film of the standard deviation, largest 5.35,In the case of close-up lens to which the polarizing film, was 2.37 the smallest Improvements/Applications: Using the future cross polarized ring light source, through the correction of concurrent distortion in a controlled situation, the development of algorithms that can generalize the features of smartphone camera It is planning to present the measurement universal inexpensive color process. Key Words : smartphone, tooth, colorimetry, light source, optical algorithm 1 Introduction It intended to provide an aesthetically effects among various features of nature teeth may be the form of a tooth, the color, texture, arrangement, and transparency. The exact determination of tooth color is one of the most fundamental and important for the aesthetic treatment areas. However, the color measurement methods and color science that are used in dental development, it is difficult to satisfy the needs of the patient A method for determining the color of the teeth has a colorimetric method and colorimetric method. Visual and colorimetric measurement is subjective, Colorimetric method is a mechanical objective measurement.[1-4] The first of the colorimetric method, accuracy and reproducibility rate already a lot of research has been considered a non-scientific

3 way. However, colorimetric method is a state in which the problem has been raised by the already large number of previous studies us Paravina, Power, Sproull, the existing color sample does not reproduce the entire color of the natural tooth Array of Shade tap is systematic and anxiety of the color space On the other hand it was reported to be biased Grajower Between the natural tooth and shade tap reflection curve has been reported does not match. in addition, Color stability problems of Resin sample Color and Such as issues related to the form of the shade tap, many problems have been reported. The second method is a light source emitted from equipment specifically designed for tooth color measurement to standardize the surrounding environment and analyzed using a computer connected to the image obtained using the CCD camera in most systems, the analyzed color are multiple manufacturers and outputs it to the color code to provide. It has the disadvantage of not completely overcome the color difference due to the position and the bending of the teeth. Finally, the direct way to measure the color of teeth by using a spectrophotometer is represented by the standardized Colorimetric measured values of Munsell color order system or CIE regulation system. The accuracy and reproducibility of significant advantages over other methods and the measured value it is difficult to select the material that is currently available. In contact with the surface of the tooth, it is necessary to measure color, new design of the measuring instrument is required.[5] Also it requires a special structure that is not affected by the curvature of the tooth surface near the light source or a measuring instrument is correctly positioned on the tooth surface, but can t do to solve this problem. In addition to equipment name called shade eye spectrophotometer which is applied to clinical has the disadvantage that is designed to output the color code of the same company. In this paper, we propose a structure of an optical system capable of colorimetric in a lower cost by comparing the results of colorimetric mounting of various types of optical system and the resulting colorimetric a smartphone evaluated for any of the standard color.[6,7,8]

4 2 Extension-Rule Based Theorem Proving Method 2.1 Research material The standard colors used in this study are listed in the PANTONE company COLORBRIDGE(Coated) we used eight standard color of PANTONE 100C, PANTONE 7401C, PANTONE 705C, PAN- TONE 670C, PANTONE 7436C, PANTONE 663C, PANTONE 649C, PANTONE 656C Smartphone for measurement is to use the LG Volt LTE, the optical system was used close-up lenses, polarizing close-up lens, a polarized light close-up lens in the form of a combination of polarizing ring light source.[9] 2.2 Research methods 1) Preparation of standard color PANTONE company of COLORBRIDGE (Coated) contained in the standard colors from the PANTONE 100C, PANTONE 7401C, PANTONE 705C, PANTONE 670C, PANTONE 7436C, PANTONE 663C, PANTONE 649C, PANTONE 656C and the RGB Code contained extracts were together.[10] 2) Standard color measurement Install smartphones Camera Color Picker (V1.1.0) provided by Zetetic Company on smartphones and extract each of the RGB Code prepared for the standard colors

5 Replaced in the order of the close-up of the optical system lens polarization close-up lens polarization close-up lens + polarized light ring light source (cross) polarization close-up lens + polarized light ring light source (parallel), to measure the RGB extraction value of each of the standard color.[11-13] 3) Color difference calculation It was converted to XYZ tristimulus the measured RGB values for the calculation of the color difference by using the following formula varr=(r/255) varg=(g/255) varb=(b/255) v {r.g.b} V {varr,varg,varb} Inverse srgb Companding { V/12.92 V ( V )2.4 V > Linear RGB to XYZ X Y = [M][v] (1) Z In this section, Matrices M is in the srgb as follows: [M] = Using the formula (2) the transformed XYZ tristimulus values for the calculation of color difference, in terms of CIE L * ab, by utilizing this, to derive the color difference between a standard color. Calculation of color difference, by using the standard color and the measured color of L * ab value was calculated by applying

6 the formula (3). Y = Y n f 1 ( X = X n f 1 ( Z = Z n f 1 ( ) 1 (L +16) (L +16) a ) (L +16) b ) { f 1(t) = t 3 if t > ( ) 6 2(t (2) E = [( L) 2 + ( a) 2 + ( b) 2 ] 1 2 (3) 2.3 Measurement results Figure 1-8, not so large difference in the chromaticity in another measurement type of standard color optical system of x, y chromaticity diagram. The difference between the measured value by the optical appears largely in the brightness or reflectivity than the chromaticity. Figure C - x,y chromaticity diagram Figure 1 is a standard color PANTONE100C, it can be seen to have little in and chromaticity difference that displays a value

7 measured by using an optical system that is described in the right side of figure. Figure C - x,y chromaticity diagram Figure 2 is obtained by displaying the value measured using an optical system that the standard color PANTONE7401C listed on the right side of figure. It can chromaticity difference to see that there is little difference by type of optical system Figure C - x,y chromaticity diagram Figure 3 is a standard color PANTONE 705C, it can be seen to have little in and chromaticity difference that displays a value

8 measured by using an optical system that is described in the right side of figure. Figure C - x,y chromaticity diagram Figure 4 is a standard color PANTONE 670C, it can be seen to have little in and chromaticity difference that displays a value measured by using an optical system that is described in the right side of figure. Figure C - x,y chromaticity diagram Figure 5 is a standard color PANTONE 7436C, it can be seen to have little in and chromaticity difference that displays a value

9 measured by using an optical system that is described in the right side of figure. Figure C - x,y chromaticity diagram Figure 6 is a standard color PANTONE 663C, it can be seen to have little in and chromaticity difference that displays a value measured by using an optical system that is described in the right side of figure. Figure C - x,y chromaticity diagram Figure 7 is a standard color PANTONE 649C, it can be seen to have little in and chromaticity difference that displays a value measured by using an optical system that is described in the right side of figure

10 Figure C - x,y chromaticity diagram Figure 8 is a standard color PANTONE 656C, it can be seen to have little in and chromaticity difference that displays a value measured by using an optical system that is described in the right side of figure. In the Table 1, a variety of reasons, such as the lens distortion, the distortion of the image pickup device, light. The difference between the value and the measured value representation severe to represent the color difference in the real color space has a great difficulty.[14] So to apply the illumination optical system and require effort to minimize external distortion. The comparison according to the color difference than the measure to do so is expected to be first. In the future after the measurement is measured should be parallel the color difference compared by the color coordinate conversion

11 Using the above equation (2), (3) the respective results were derived for a color difference of primary color and as shown in Table 5. In the Table 5 is thought to be important to apply a variety of external factors to find that the small environment the standard deviation of the color difference.[15,16] After you perform the same experiment with diversified external variables such as lighting, the best way is to find a small standard deviation be helpful in algorithm development

12 In Table 6 a comparison is required between a smartphone and a color difference and the result of this macro lens color code was applied in the previous experiment.[17] Then a choice of the standard deviation is small over the color difference conversion method. In the Table 7, 8, 9 may be some errors in the measurement optical system is not a combination of hard and smart phones.[18] Need to worry about the design of the prototype structure it can be easily combined with strong smartphone and optics

13 The average value of E is highest at on smartphones not equipped with another optical system, For close-up lens to which the polarizing film 21.66, when only attached macro lens became When not wearing a different light source, typically, the color difference becomes larger. When fitted with a ring light source, an optical system applying crossed polarizing film was lower than parallel to the applied optical system. Standard deviation for the color difference ( E) of the measured values (SD) is the same as Table 10. For a close up lens is applying the largest 5.35, if the polarizing film is parallel to the setting for the standard deviation was the smallest polarizing film 2.37.In the case of close-up lens to which the polarizing film, was 2.37 the smallest. 3 Conclusions Most scientific reliable methods in several ways to determine the color of the teeth is a method of measuring the color reproducible structured value using a machine such as a spectrophotometer. It is used spectrophotometer, tooth color measurement is, lighting and sensors, to the three-dimensional structure of the subject It will be subject to close influence. In the case of color measurement using a smart phone, and a sensor, it will be measured in the state that have lost the control force with respect to the structure of the subject, control method as in lighting characteristic can be generalized to the sensor different for each smart phone models (camera) is most important. For this purpose, for teeth colorimetric, it is first necessary standardization of certain colorimetric conditions. In the present study, and whether or not to illuminate, the ring

14 light source to which the cross-polarized light through the whether the intersection of polarization When applied, it was confirmed that the color difference between the measured value and the primary colors appear the least. Using the future cross polarized ring light source, through the correction of concurrent distortion in a controlled situation, the development of algorithms that can generalize the features of smartphone camera It is planning to present the measurement universal inexpensive color process 4 Acknowledgments It will support by Catholic Kwandong University and Small Business Administration academic-industrial collaborative technology development projects(c ). References [1] Sproull RC. Color matching in dentistry. Part II: Practical applications of the organization of color. J Prosthet Dent 29: , [2] Miller LL. Organizing color in dentistry. J Am Dent Assoc () December:26-40, [3] McPhee ER. Light and color in dentistry. Part I Nature and perception. J Mich Dent Assoc 1978;60: [4] Goodkind RJ, Keenan KM, Schwabacher WB. A comparison of Chromascan and spectrophotometric color measurements of 100 natural teeth. J Prosthet Dent 1985;53: [5] Jorgenson MW, Goodkind RJ. Spectrophotometric study of five porcelain shades relative to the dimensions of color, porcelain thickness, and repeated firings. J Prosthet Dent 1979;42: [6] O Brien WJ, Boenke KM, Groh CL. Coverage error of two shade guide. Int J Prosthet 4:45-50,

15 [7] O Neal SJ, Powell WD. Color discrimination and shade matching ability of third year dental student. J Prosthet Dent 63:174, [8] Paravina RD, Powers JM, Fay RM. Color comparison of two shade guides. Int J Prosthodont 2002;15:73-8. [9] Sproull RC. Color matching in dentistry. II. Practical applications of the organization of color. J Prosthet Dent 1973;29: [10] Grajower R, Revah A, Sorin S. Reflectance spectra of natural and acrylic resin teeth. J Prosthet Dent 1976;36: [11] Cernavin I. Effects of chlorine-containing disinfecting compounds on shade guides made of acrylic resin. J Prosthet Dent 1996;75:574. [12] Sykora O. Fabrication of a posterior shade guide for removable partial dentures. J Prosthet Dent 1983;50: [13] JOURNAL OF THE KOREA CONTENTS ASSOCIATION 16(2), , (10 pages) [14] Yong-Jin Choi, et al. INFLUENCE OF THE LABIAL SUR- FACE IRREGULARITY ON THE MEASUREMENT OF THE TOOTH COLOR BY SPECTROMETER. Journal of Korean Academy of Conservative Dentistry 32.5 (2007). [15] Chang-Dong Lee, Jin-Hyoung jeong, Sang-Sik Lee An optical system design for smart phones, for measuring tooth color. Bio- Medical System Conference [16] J. S. Yorty, M. W. Richard, A. Kanawati, S. Davis, R. C. House, and S. R. Okubo, A simple screening test for color matching in dentistry, Gen Dent, Vol.48, No.3, pp , 2000(5-6). [17] S. J. Chu, A. Devigus, and A. J. Mieleszko, Fundamen tals of color, Queintessence Publishing Co, Inc, pp ,

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