Showing papers on "Colorimeter published in 2010"

Assessment of Color Parameters of Composite Resin Shade Guides Using Digital Imaging versus Colorimeter

Abstract: Purpose: This study evaluated the color parameters of resin composite shade guides determined using a colorimeter and digital imaging method. Materials and Methods: Four composite shade guides, namely: two nanohybrid (Grandio [Voco GmbH, Cuxhaven, Germany]; Premise [KerrHawe SA, Bioggio, Switzerland]) and two hybrid (Charisma [Heraeus Kulzer, GmbH & Co. KG, Hanau, Germany]; Filtek Z250 [3M ESPE, Seefeld, Germany]) were evaluated. Ten shade tabs were selected (A1, A2, A3, A3,5, A4, B1, B2, B3, C2, C3) from each shade guide. CIE Lab values were obtained using digital imaging and a colorimeter (ShadeEye NCC Dental Chroma Meter, Shofu Inc., Kyoto, Japan). The data were analyzed using two-way analysis of variance and Bonferroni post hoc test. Results: Overall, the mean ΔE values from different composite pairs demonstrated statistically significant differences when evaluated with the colorimeter (p 6.8). For all shade pairs evaluated, the most significant shade mismatches were obtained between Grandio-Filtek Z250 (p = 0.021) and Filtek Z250-Premise (p = 0.01) regarding ΔE mean values, whereas the best shade match was between Grandio-Charisma (p = 0.255) regardless of the measurement method. Conclusion: The best color match (mean ΔE values) was recorded for A1, A2, and A3 shade pairs in both methods. When proper object-camera distance, digital camera settings, and suitable illumination conditions are provided, digital imaging method could be used in the assessment of color parameters. Interchanging use of shade guides from different composite systems should be avoided during color selection. CLINICAL SIGNIFICANCE The shade guides of nanohybrid and hybrid composites do not give consistent color match with exception of A1, A2, and A3 shade pairs. (J Esthet Restor Dent 22:379–390, 2010)

Could digital imaging be an alternative for digital colorimeters

Abstract: This study evaluated the colour parameters of composite and ceramic shade guides determined using a colorimeter and digital imaging method with illuminants at different colour temperatures. Two different resin composite shade guides, namely Charisma (Heraeus Kulzer) and Premise (Kerr Corporation), and two different ceramic shade guides, Vita Lumin Vacuum (VITA Zahnfabrik) and Noritake (Noritake Co.), were evaluated at three different colour temperatures (2,700 K, 2,700-6,500 K, and 6500 K) of illuminants. Ten shade tabs were selected (A1, A2, A3, A3,5, A4, B1, B2, B3, C2 and C3) from each shade guide. CIE Lab values were obtained using digital imaging and a colorimeter (ShadeEye NCC Dental Chroma Meter, Shofu Inc.). The data were analysed using two-way ANOVA, and Pearson's correlation. While mean L* values of both composite and ceramic shade guides were not affected from the colour temperature, L* values obtained with the colorimeter showed significantly lower values than those of the digital imaging (p 0.05). For both composite and ceramic shade guides, L* and b* values obtained from colorimeter and digital imaging method presented a high level of correlation. High-level correlations were also acquired for a* values in all shade guides except for the Charisma composite shade guide. Digital imaging method could be an alternative for the colorimeters unless the proper object-camera distance, digital camera settings and suitable illumination conditions could be supplied. However, variations in shade guides, especially for composites, may affect the correlation.

In vivo and in vitro assessment of an intraoral dental colorimeter.

Abstract: Purpose: The purpose of this study was to assess the performance of an intraoral dental colorimeter. Materials and Methods: In vivo repeatability of an intraoral colorimeter was assessed by performing color measurements of 30 individuals’ right maxillary central incisor. Three consecutive measurements from each individual were made. In the in vitro part of the study, 25 metal-ceramic and 25 all-ceramic specimens were prepared. Five shades of metal-ceramic and all-ceramic specimens were selected for color determination. A widely recognized in vitro colorimeter was used as the control group for the in vitro performance assessment of the in vivo colorimeter. The color differentiation capability of two colorimeters was compared with the readings obtained from ceramic specimens. ΔE values between shade groups of ceramic specimens were calculated and statistically analyzed with Student's t-test. The repeatability of the intraoral instrument was evaluated statistically with Intraclass correlation coefficient. Results: The in vivo evaluation results showed that the overall repeatability coefficient values of L*, a*, and b* notations of the intraoral colorimeter were “excellent.” The color differences (ΔE) calculated between the colorimeters were significant only between shades A1-B1 for metal-ceramic specimens (p= 0.002); however, from 5 of 10 shade couples of all-ceramic specimens, the color differences obtained from the readings of the in vivo colorimeter were significantly different from that of the in vitro colorimeter (p < 0.001). For all specimens, the differences between ΔE values were within clinically acceptable limits (<3.5). Conclusions: Within the limitations of this study, the intraoral colorimeter exhibited successful in vivo repeatability; however, the color difference detection performance of the device varied depending on the translucency of the specimens.

Development of a low-cost portable colorimeter for the estimation of fluoride in drinking water

Abstract: People in many countries are affected by fluorosis owing to the high levels of fluoride in drinking water. An inexpensive method for estimating the concentration of the fluoride ion in drinking water would be helpful in identifying safe sources of water and also in monitoring the performance of defluoridation techniques. For this purpose, a simple, inexpensive, and portable colorimeter has been developed in the present work. It is used in conjunction with the SPADNS method, which shows a color change in the visible region on addition of water containing fluoride to a reagent solution. Groundwater samples were collected from different parts of the state of Karnataka, India and analysed for fluoride. The results obtained using the colorimeter and the double beam spectrophotometer agreed fairly well. The costs of the colorimeter and of the chemicals required per test were about Rs. 250 (US$ 5) and Rs. 2.5 (US$ 0.05), respectively. In addition, the cost of the chemicals required for constructing the calibration curve was about Rs. 15 (US$ 0.3).

Iodide/Iodate Chemical Actinometry Using Spherical Vessels for Radiation Exposure as well as for Monitoring Absorbance Changes

Abstract: Spherical quartz vessels containing an iodide/iodate chemical actinometer are useful for measuring the fluence of omnidirectional germicidal radiation. It is shown here that such vessels can be used not only for exposure purposes but also for measuring the absorbance of the resulting triiodide endpoint. A hand-held commercially available colorimeter using a 420 nm LED light source was adapted to hold the spheres in the optical light path. The absorbance at 420 nm obeyed Beer's Law and the dose response showed linear kinetics following irradiation at 254 nm. The determination of the fluence obtained in this manner was consistent with that obtained following transfer of the contents of the spheres to a 1 cm cuvette and measuring the absorbance at 352 nm in a conventional spectrophotometer. Hence, dose response data can be obtained making absorbance measurements on the same sample following sequential or continuous irradiation. Furthermore, because the expression for the fluence is independent of the radius of the sphere, there is no need to measure and keep track of the volume of each sphere, thus simplifying the experimental procedure. Furthermore, the use of an inexpensive colorimeter circumvents the need for a more expensive spectrophotometer and allows measurements to be made in the field.

Matrix-based color measurement corrections of tristimulus colorimeters

Abstract: For colorimetric imaging the tristimulus technique is still the best practical method to keep the measurement time within reasonable limits. However, the achievable color measurement uncertainties for special sources can be large. It is described how the systematic errors can be significantly reduced by using matrix-based color corrections and how the matrix elements can be optimized to obtain the smallest spectral mismatch errors for different light-source distributions. An approach for decreasing the systematic errors is to increase the number of the colorimeter channels (or filters) used for a measurement. Using five channels in a colorimeter is an optimum choice. Determination of the optimum matrices for the five channels is discussed. The correction matrices are designed such that the spectral mismatch errors of the realized functions are minimized relative to the CIE standard color matching functions for several selected test-source distributions. The optimum matrix depends on the (test) light source to be measured. Adaptive matrix values are determined by using the channel outputs and the spectral power distribution of color LEDs approximated with a simple approximation function. The systematic errors are evaluated for a number of colored and white LEDs. The noise propagation with the applied matrix corrections is investigated.

Colorimeter and white calibration method

Abstract: PROBLEM TO BE SOLVED: To provide a colorimeter and a white calibration method highly precisely calibrating white even when materials inexpensive compared to ceramics are employed as a white calibration plate. SOLUTION: A coefficient memory part 252 stores a previously calculated correction coefficient K based on a colorimetry data D1 when a color of a white calibration plate 123 is measured under first condition of removing a transparent protective member 122 and a colorimetry data D2 when a color of the white calibration plate 123 is measured under second condition of attaching the transparent protective member 122. A white calibration value calculation part 254 corrects a standardizing value A stored in an evaluating value memory part 251 to a standardizing value A' measured under the second condition based on the correction coefficient K and calculates a white calibration value W by A'/D3. A color information calculation part 256 calculates color information of a sample using the white calibration value W calculated by the white calibration value calculation part 254 and a sample colorimetry data D4. COPYRIGHT: (C)2010,JPO&INPIT

Effects of background, direction and intensity of ambient light, measuring position, and adjacent teeth, on anterior tooth colour measurement in vitro.

Abstract: Objective to investigate the effects of different background colours (black, white or pink), direction and intensity of ambient light, measuring position, and the adjacent teeth, on the in vitro colour measurement of maxillary anterior teeth, using the Minolta CR-321 colorimeter. Methods ten extracted human maxillary central incisors were selected. A fibre-optic light MI-150 was used as the ambient illuminant. Teeth were irradiated from a 3- or 12-o'clock direction. L*a*b* values of seven sites on the labial surfaces were obtained by means of the Minolta CR-321 colorimeter, using three background colours, with or without the adjacent teeth. The recorded data were analysed with two-tailed Student t tests and analysis of variance (α = 0.05). Results the ambient light did not affect the colour measurement of anterior teeth, regardless of the presence or absence of the adjacent teeth. There were no statistically significant differences in L*a*b* values at the same position under different background colours, except ΔE12 (colour difference between site 1 and site 2) between black and white backgrounds. ΔE12 (under black background), ΔE13 and ΔE15 were greater than 1.5, while the others were lower than 1.5. Conclusion the background, ambient light and the presence of adjacent teeth did not affect the colour measurement of anterior teeth using the Minolta CR-321 colorimeter in vitro. The inherent disadvantages of using the naked eye during clinical visual shade assessment may be overcome by the colorimeter.

Method and system for calibrating standard colorimetric plate for cotton colorimeter

Abstract: The invention provides a special method for calibrating a standard colorimetric plate for a cotton colorimeter, comprising the following steps: irradiating a standard white plate with symmetric visible light source in the 45-degree angle direction; receiving and focusing reflected light and eliminating parasitic light; transmitting the reflected light signal; obtaining the reflected signal intensity of each wavelength of the standard colorimetric plate to be tested; and calibrating the reflectance of each wavelength of the standard colorimetric plate. The invention also provides a system for calibrating the standard colorimetric plate for the cotton colorimeter, comprising a microprocessor, a testing bench, a symmetric continuous spectrum visible light source, a first optical system; a second optical system, a monochromator, a photomultiplier tube, an amplifier and an analog/digital converter. The amplified electrical signal is sampled under the control of the microprocessor and is transmitted to the microprocessor. The testing condition is closer to the cotton color testing condition, is beneficial to controlling the cotton colorimeter calibration precision and is available to the more accurate test and calibration of the standard colorimetric plate of different area.

A Simple and Cheap Device for Colorimetric Determination of Serum Iron

Abstract: A simple and cheap device for colorimetric determination of serum iron and TIBC (total iron-binding capacity) was devised. The proposed device employs an LED as a light source and a common light dependent resistor (LDR) as a detector. This device functions on the basis of the light intensity received by LDR, connected to a digit multimeter, yielding resistance readings. The serum, standard, and blank solutions were prepared according to the kits instructions and introduced into the colorimeter with a disposable syringe. The iron content of the serum was calculated from the resistance difference of serum and standard solutions. The precision of the method was assessed with two commercially available serum-based chemistry controls. The values obtained with the proposed device indicated that the serum iron concentrations correlated well with the values obtained with the commercial automated analyzer. The calibration graph was linear for iron concentrations up to 90 μmol/L (500 μg/dL). The proposed fabricated colorimeter is considerable cheaper, requires smaller sample volumes, and is suitable for serum iron assay.

Image forming apparatus, image forming method, program and recording medium

Abstract: PROBLEM TO BE SOLVED: To more accurately perform control of a fixing condition using surface diffused light by: measuring the surface diffused light with good accuracy even when a toner adhesion amount is varied; and measuring the surface diffused light by using paper to be actually used by a user. SOLUTION: A fixing device 30 fixes a patch image transferred to recording material. A spectral colorimeter 41 measures a spectral reflectance factor 1 of the fixed patch image. The recording material is restored to the front side of the fixing device 30 by a transfer roller, and a transparent toner image is transferred to the recording material through a transfer belt. The recording material passes through the fixing device 30 again, whereby the transparent toner image is fixed on the patch image. Then, a spectral reflectance factor 2 is measured by the spectral colorimeter 41, the measured spectral reflectance factors 1 and 2 are input in an image characteristic acquiring part 150, and the surface diffused light is calculated. A fixing condition controller 110 controls a fixing condition (temperature) based on the calculated surface diffused light. COPYRIGHT: (C)2010,JPO&INPIT

Liquid analysis colorimeter

Abstract: The utility model relates to a liquid analysis colorimeter, belonging to the technical field of a chemical analysis instrument. The colorimeter comprises a bracket, a light source and a light receiver, wherein the bracket can be arranged at both sides of a liquid transparent channel; the light source is arranged at one side of the bracket; the light receiver is arranged at at least one side of thebracket; at least one reflecting mirror is arranged at at least one side of the bracket; and the light emitted by the light source is reflected to the light receiver through the reflecting mirror. The colorimeter has the advantages that the optical path can be multiplied, the analysis sensitivity can be greatly improved, the reaction liquid with lower concentration can be detected, and the liquidabsorbance and concentration measuring accuracy can be further improved.

Colour and appearance analysis of fruit and vegetable soup using a digital colour imaging system.

Abstract: Within Food R&D scientists, chefs and engineers aim to develop natural fruit and vegetable based soups with optimal flavour, texture, appearance and health benefits whilst maintaining product safety. The colour and appearance has a major influence on the perceived quality (e.g. nutrition and freshness). This paper describes a method for the determination of the colour of soups containing vegetable particles. Digital images were made under controlled lighting using a DigiEye imaging system. It allows documenting the appearance by making colorimetrically accurate images which are suitable for the measurement of colour uniformity, size and shape. The uniformity of the light under diffuse and directional illumination was investigated using different targets and soup samples. For accurate colour analysis the images have to be corrected for non-uniform illumination and the colour has to be measured at a fixed location outside the centre of the lighting cabinet. Directional illumination (angled light with additional mirrors) was used to introduce gloss resulting in images matching the actual appearance of soups and vegetable particles very closely. Imaging glossy soups under diffuse illumination resulted in dull images with dark spots. No significant difference was found between the colours of soups analysed under diffuse or directional illumination. Under directional illumination a better repeatability was observed. Additionally, for 36 different soups, the measured results from the DigiEye system were compared to two different colorimeters (0 o /45 o and diffuse/0 o geometry). Linear relations were found between the CIE Lab values measured by the DigiEye system and those measured by two different colorimeters. Best correlations were obtained between DigiEye and 0 o /45 o colorimeter (r 2 =0.980-0.996). The short term precision of the DigiEye system is somewhat better than those of the colorimeter.

Method, device, and program of displaying printed matter to monitor

Abstract: PROBLEM TO BE SOLVED: To provide a method of displaying printed matter for reducing trouble for correcting a difference in an observation illumination environment as much as possible in reproduction of visual performance of printed matter to a monitor, and to provide a display and a program for the display. SOLUTION: In the method of displaying printed matter on monitors, a color patch 26a having the smallest color difference is selected from respective colors of 256 color patches 26 created by the same print process as the printed matter 22 in advance to a color, where a place of a focused-on color to be matched to the color of a print image 20 in the printed matter 22 is designated on a proof image 120 displayed on the monitor 14, the color of the selected color patch 26a is measured under an observation illumination environment 200 by a telephoto type colorimeter 32 to obtain measurement colorimetry values Xp, Yp, Zp, and a print profile 50 is corrected based on the obtained measurement colorimetry values Xp, Yp, Zp, thus allowing the focused-on color to be matched to coincide with color on the proof image 120 displayed on the monitor 14 in the colors of the print image 20 of the printed matter 22. COPYRIGHT: (C)2010,JPO&INPIT

Real-time color measurement using active illuminant

Abstract: This paper proposes a method for real-time color measurement using active illuminant. A synchronous measurement system is constructed by combining a high-speed active spectral light source and a high-speed monochrome camera. The light source is a programmable spectral source which is capable of emitting arbitrary spectrum in high speed. This system is the essential advantage of capturing spectral images without using filters in high frame rates. The new method of real-time colorimetry is different from the traditional method based on the colorimeter or the spectrometers. We project the color-matching functions onto an object surface as spectral illuminants. Then we can obtain the CIE-XYZ tristimulus values directly from the camera outputs at every point on the surface. We describe the principle of our colorimetric technique based on projection of the color-matching functions and the procedure for realizing a real-time measurement system of a moving object. In an experiment, we examine the performance of real-time color measurement for a static object and a moving object.

Color chart reading device, color chart reading method, and color chart reader program

Abstract: PROBLEM TO BE SOLVED: To provide a method for automatically determining errors of user operation and a colorimeter generated when manually sliding a colorimeter to measure colors of color patches in one line unit, and to further provide a method enabling error determination and scan direction determination by using characteristic values obtained from calorimetric values without using reference values and thresholds of each fixed patch. SOLUTION: A color chart reading method measures the colors of color charts having the color patches in which a feature value of color arrangement obtained from the calorimetric values is varied in each measuring row in one row unit. The method uses the calorimetric values of the color patches of one row part obtained with the colorimeter to retrieve the patches largely changing the values of the patches in the measuring rows and compares whether the previously stored measuring rows are matched with a place in which the values of the patches largely change. If they are not matched with it, error determination is performed. In addition, when they are matched with the feature values in a reverse directional scan, the calorimetric values are inverted. COPYRIGHT: (C)2010,JPO&INPIT

Information processing apparatus, method, and, program

Abstract: PROBLEM TO BE SOLVED: To provide an information processing apparatus for easily performing calibration specialized in accordance with a printing object. SOLUTION: The information processing apparatus is connected with a colorimeter and a printer for calibrating image data to be printed by measuring a calibration patch using the colorimeter. The information processing apparatus includes: an analysis means for analyzing a color represented with the image data to be printed and storing in a storage area the color information obtained on the basis of a result of the analysis; a generation means for generating calibration patch data in accordance with the color information; a print control means for outputting to the printer the calibration patch data generated by the generation means and exerting control to print the calibration patch using the printer; and a calibration means for calibrating the image data to be printed on the basis of colorimetric data obtained by measuring the calibration patch printed by the printer by using the colorimeter. COPYRIGHT: (C)2010,JPO&INPIT

Method and device for converting colorimetric value in running printed matter, method and device for controlling printing, and method and device for determining printing state

Abstract: PROBLEM TO BE SOLVED: To precisely perform conversion from a colorimetric value detected for a change in printing material conditions and printing conditions to another colorimetric value for a method, and to provide a device for performing conversion from a detected colorimetric value of running printed matter to another colorimetric value. SOLUTION: A method of converting a colorimetric value of printed matter measures printed matter running through a printing machine by a first colorimeter, to obtain a first colorimetric value, measures a specific place of the printed matter by a second colorimeter to obtain a second colorimetric value, and converts measured value of the first colorimetric value obtained by measuring the running printed matter by the first colorimeter, into a second colorimetric value obtained by measurement by using the second colorimeter, according to a preset correspondence of colorimetric values, when the same color is measured by the first and second colorimeters and according to the first and second measured colorimetric values. COPYRIGHT: (C)2011,JPO&INPIT

Application of advanced technologies in shade matching: A spectrophotometer

Abstract: One of many challenges in cosmetic dentistry is to accomplish appropriate and satisfactory reproduction of natural shade of teeth and in that way to make successful restoration. The procedure of choosing a shade can be performed using visual method or by an instrument. The kind of shade guide, individual ability to choose shades and conditions the choice is made under, all have influence on reliability and accuracy of the procedure. Therefore, it is necessary to introduce instrumental color determination in everyday work. The instrumental color determination method considers use of a spectrophotometer, a colorimeter and a digital camera or even the combination of all three in shade matching. The purpose of this article was to present all amenities and advantages of the instrumental color determination in shade matching through the demonstration of the clinical performances of an intraoral spectrophotometer VITA Easyshade Compact device. VITA Easyshade Compact device provides fast and reliable measuring and gives results that are not influenced by the conditions under which the shade was chosen or by the person who made choice. Shade matching using a spectrophotometer meets all the requirements for choosing the shade by vision, therefore it is recommended for clinical work.

A Research about the Development of the Simple Colorimeter and the Application to the Determination of Equilibrium Constant on the Chemical Reaction

Abstract: The simple colorimeter was built using blue-diode, UV cell, CdS photoresistor, galvanometer and was used for the determination of the equilibrium constant on chemical reactions. The precision and accuracy of the simple colorimeter were high enough for the determination of the equilibrium constant on the chemical reactions shown in the high school and undergraduate curricula.