Color Measurement System Research Articles

Assessing color stability of orthodontic esthetic wires in different staining solutions.

Esthetic orthodontic wires are preferred for their ease to fit in with natural tooth color, but their susceptibility to staining in the oral environment poses a concern. Various Coatings such as Teflon and Epoxy aim to enhance appearance and biocompatibility but may still result in discoloration. Understanding the color stability of these wires under different staining conditions is crucial for a better and enhanced treatment plan. This study intended to assess the color stability of esthetic orthodontic wires under various staining solutions that are often used in daily life. Color changes of Teflon and Epoxy-coated esthetic orthodontic wires were meticulously measured at baseline, 7, 14, and 21-day intervals utilizing the precise CIE Lab* color measurement system. A total of thirty-two samples of wires from each brand were prepared (n= 8/group) and immersed in staining solutions (coffee, tea, cola, and saffron). The color change within and between the groups was statistically evaluated (p< 0.05). Significant variations in color stability were observed across different staining solutions. Saffron emerged as the most potent agent, inducing the most pronounced color changes, whereas cola demonstrated the least impact. Furthermore, Epoxy-coated wires consistently exhibited superior color stability compared to their Teflon-coated counterparts across all staining solutions and time intervals. This study underlines the significance for orthodontists to consider staining agents' possible effects on orthodontic wires into account when selecting the orthodontic wires. The findings suggest that Epoxy-coated wires hold promise in mitigating discoloration issues during orthodontic therapy.

Polymer Color Intelligence: Effect of Materials, Instruments, and Measurement Techniques - A Review.

Transparent polymers and plastics are used to create molded parts and films for many applications. The colors of these products are of great importance for the suppliers, manufacturers, and end-users. However, for simplicity of the processing, the plastics are produced in the form of small pellets or granules. The predictive measurement of the color of such materials is a challenging process and needs consideration of a complex set of factors. A combination of color measurement systems in transmittance and reflectance modes need to be used for such materials, along with the techniques for minimizing the artifacts based on surface texture and particle sizes. This article provides an extensive overview and discussion of the various factors that can affect the perceptive colors and the methods used for the characterization of the colors and minimizing the measuring artifacts.

Investigating the agreement between polarized and unpolarized densitometry in offset lithography printing

AbstractAutomated color measurement systems have become significant components of offset lithographic printing presses for better process control and reduced job waste. Some European press manufacturers are known to offer automated color measurement equipment that is confined to polarized density readings, which is uncommon in US. Introducing polarized densitometry into an environment where unpolarized densitometry is utilized can be problematic. Print professionals are on the lookout for a solution that is evidenced by a recent feature in a post from the IDEAlliance G7 Professionals forum seeking for a methodology to convert polarized to unpolarized readings. The present study applies the Bland–Altman method together with other statistical analyses to determine if a conversion between polarized and unpolarized densitometry can be established within a limited set of parameters. Three spectrodensitometers were used to record densitometric readings of wet and dry process inks on coated and uncoated drawdown proofs. The results showed that coated papers had significantly less variation between instruments compared to uncoated papers. Wet inks had more minor variations compared to dry inks. Furthermore, pure difference values and a Mann–Whitney U test indicated differences between unpolarized and polarized densitometric readings in all cases. Finally, t‐tests performed on the resulting difference data for both unpolarized versus polarized and unpolarized versus predicted polarized that showed fixed bias by means of the computed p‐values.

Study on Preparation and Properties of Glass Fibre Fabric Reinforced Polyphenylene Sulphide Composites.

In this paper, glass fiber fabric reinforced polyphenylene sulfide composites were prepared by hot pressing. The effects of glass fibre modification and hot pressing temperature on the properties of the composites were investigated using a scanning electron microscope, infrared spectrometer, universal testing machine, and DIGEYE digital imaging colour measurement system. The results show that after the treatment with a silane coupling agent, the silane coupling agent was more uniformly distributed on the surface of the glass fibres, and the bonding effect between the glass fibre fabric and polyphenylene sulphide was significantly improved. The strength of the composites increased and then decreased with the increase of hot pressing temperature, and the surface colour of the composites became darker and darker. When the hot-pressing temperature is 310 °C, the mechanical properties of glass fabric-reinforced polyphenylene sulfide composites are at their best, the tensile strength reaches 51.9 MPa, and the bending strength reaches 78 MPa.

New software for comparing the color gamuts generated by printing technologies

In the color industry, it is vital to know the color gamut of a given device. Several tools for visualizing and comparing color gamuts are available but they each have some drawbacks. Therefore, the aim of this work was to develop and validate new software for comparing the color gamuts generated by printing devices; we also developed an automated color measurement system. The software simultaneously represents the gamuts in the 3D CIELAB space. It also calculates the Gamut Comparison Index and the volume using two algorithms (Convex Hull and Alpha Shapes). To evaluate the performance of our software, we first compared the results it obtained for the color gamuts with those from other comparison methods such as representation in the CIE 1931 chromaticity diagram or other color spaces. Next, we used Interactive Color Correction in 3 Dimensions (ICC3D) software to compare the gamut representations and volumes. Our software allowed us to identify differences between color gamuts that were not discriminated by other methods. This new software will enable the study and comparison of gamuts generated by different printing technologies and using different printing substrates, International Color Consortium profiles, inks, and light sources, thereby helping to achieve high quality color images.

LabVIEW Based Real-time Color Measurement System

Colorimetry is of paramount importance to the agricultural industry. Colorimetry refers to the processing of agricultural products for consumer needs from a marketing point of view, and therefore the agricultural industry spends a lot of money and time classifying each product. In the past, agricultural professionals had to use program codes that are difficult to learn, and even the most basic image analysis for agricultural product classification required mastering different program libraries. Today, the LabVIEW platform offers a flexible, fast, easy-to-learn, and complete image analysis infrastructure with various useful modules. For this reason, in this study, a method analysis for color perception with a simple USB webcam and software developed for real-time color analysis on the LabVIEW platform is presented and its success in the basic color analysis is tried to be revealed. The basic application developed for this purpose in LabVIEW v2019 using NI Vision Development Module v19 and NI IMAQ v19 modules. The basic fact that is the LabVIEW application is the idea that LabVIEW can only be analyzed with expensive IEEE 1394, but it should be known that these analyzes can be done with USB webcams. For this purpose, the application includes a USB webcam driver that can be stacked seamlessly. USB Webcam and colorimeter measurement-based results of ƔR factors for each of RGB color channels are 1.161232, 0.506287, 0.432229; ƔG factors for each of RGB color channels are 0.519619, 1.025383, 1.201444; at last ƔB factors for each of RGB color channels are 0.600362, 0.714016, 1.413406, respectively.

Study on the Relationship between Accelerated Aging, Color Characterization and Properties of Natural Fibers

ABSTRACT Fiber yellowing is an important indicator to distinguish the quality of natural fibers. Natural fibers such as cotton, kenaf and wool are subjected to production conditions such as UV light, heat and acid-base treatment during their growth and processing. These will affect the fiber appearance and performance. In this paper, the laboratory accelerated aging method was used to replace the natural aging of the fabric, and the color characteristics of the aged fiber are quantitatively analyzed through the color measurement system and image processing method. Meanwhile, the property changes of fiber composition destruction and fiber strength decrease were also measured and compared by infrared spectrum analysis and monofilament tensile test. Thermal aging destroyed the surface composition of cotton and kenaf fibers, thereby reducing the mechanical properties of fibers. Among them, the strength of kenaf fiber was reduced to 1/2 of the original after 8 hours of thermal aging. On the contrary UV aging damaged wool fiber even more. The most obvious result was that after 8 hours of UV irradiation, the strength of silk fiber dropped to 1/3 of its original strength. The mechanical properties of kenaf fiber were affected more obviously by acid and alkali than protein fiber.

Calibrated color measurement of cashmere using a novel computer vision system

Color of cashmere fiber is a key component of textile quality inspection. However, the inspection of cashmere color was determined by human vision system, which was less accuracy and time-consuming. Computer vision system (CVS) is considered as a promising technique to objectively and precisely test color. In the present work, a novel color measurement system for cashmere was proposed. Totally 29 cashmere samples with different color were adopted as standard samples to calibrate color conversion model. The correlation coefficient of L, a, b values between the two systems was separately calculated high to 0.99, 0.96 and 0.93 for the whole samples. The proposed method was further validated by other 15 samples, indicating the accuracy of the novel CVS. Besides, due to the high accuracy and strong representativeness of the new method, the categories of cashmere, which were normally tested by subjective visual assessment, could be determined by the present results.

A High-throughput Color Measurement System for Evaluating Flesh Browning in Apples

The development of new high-quality apple (Malus ×domestica) cultivars that are resistant to flesh browning is needed to expand the use of apples in the food service and catering industry. However, conventional methods for evaluating apple flesh browning can be both time-consuming and costly, thereby rendering such methods unsuitable for breeding programs that must characterize a large number of product samples. Therefore, it is necessary to develop new, simple, and inexpensive methods. The aim was to develop a method for simultaneously measuring the color values of 42 apple samples using a digital camera. The processing time per sample was reduced to less than one-tenth of that of the conventional method. The measurement dispersion [sd of the color difference between two colors ] of this system was less than 0.08, equivalent to the nominal value of a general colorimeter. Time-series analysis of six apple cultivars using this method showed that the calculated browning index values correlated well with the degree of browning judged by human perception. Further, the measurement data showed that the CIE L* a* b* value trends associated with browning in reddish- and watercored-flesh samples, was different from the corresponding trends in yellowish-flesh samples. This work reports the development of a high-throughput analytical system of apple browning and provides cautionary notes for evaluating reddish- and watercored-flesh browning, which should be measured on a different basis from that used for normal-flesh browning.

Determining the visual Impression of cotton fabrics while Rotating.

In order to identify the light reflectance from cotton fabrics produced from various (spun yarn., ( carded – open end ) ,an attempted measured Light reflectance distribution (CIELAB L*) by using a (GCMS-4 Gonio)-( Spectrophotometric color measurement system) at various Illumination angle (θi) and Viewing angle(θv) with turning point(θw) from ( 0-90)o in both direction .Results clarify the relations between the distribution pattern (L*) with fabrics made from different spun yarn which had an effect for fabrics on visual sense of hymen and indicate more about aesthetics of cotton fabric while rotating. Therefore, the results indicate that L* reflectance measurement for cotton woven fabric shows that lightness values depended on method of spinning but in closer values, weave density also give parameter in light reflectance from woven fabric in weft direction , Illumination angle and Viewing angle also indicate an important parameter for visual sense from fabrics and its related to aesthetic properties. In shorts: (θw) was found to be the most accurate parameter for determining the change of lightness from shiny to dull in visual assessment for cotton woven fabrics.

Supercritical CO2 dyeing of polyester fabric with photochromic dyes to fabricate UV sensing smart textiles

Photochromic molecules are well-established colourants in the manufacturing of niche products, providing reversible colour change effects when irradiated with ultraviolet (UV) light. The high material cost of such speciality dyes along with the general high carbon footprint and extensive water consumption of textile products necessitates resource-efficient production processes. The use of supercritical CO2 (scCO2) dyeing technique enables the economic production of textile high-end products, where a uniform through colouration is desired. This study investigates the potential application of two commercial photochromic dyes based on spirooxazine (Sea Green – SO-SG) and naphthopyran (Ruby Red – NP-RR) to polyester fabric using scCO2 dyeing technique and examines their photochromic behaviour. The dyeing was carried out at 120 °C and 25 MPa for 1 h. The photochromic performance was evaluated using a specially designed online colour measurement system capable of simultaneous UV irradiation and continuous measurement of photochromic colour change even after the shutdown of the UV source. The colour yields (K/S values), photoswitching rates and durability against washing were the main parameters examined. The results showed that scCO2 dyed photochromic polyester fabrics exhibited reversible colour changing properties upon UV exposure and removal. The samples dyed with SO-SG demonstrated a comparable degree of photo-colouration, lower background colour, faster colouration and decolouration speeds, but inferior wash fastness compared with NP-RR dyed samples. Particularly, the same class of dyes applied by scCO2 dyeing showed faster fading rates compared with conventionally dyed and screen printed samples. This study shows that scCO2 dyeing method is a potential alternative to develop uniformly coloured photochromic textiles providing excellent photochromic performance with additional economic and environmental benefits.

Development of a Color Object Classification and Measurement System Using Machine Vision

Development of a Color Object Classification and Measurement System Using Machine Vision

PERENDAMAN PLAT RESIN AKRILIK POLIMERISASI PANAS PADA EKSTRAK BUNGA ROSELLA (Hibiscus sabdariffa L.) TERHADAP PERUBAHAN WARNA

The color of acrylic resin plate is one of particular concern, because it's related with aesthetics of oral tissue. An acrylic resin can absorb colored fluids and cause a color change, which reduces the aesthetic value of the denture. This study aims to determine discoloration of acrylic resin plate heat cured after submersion of rosella flower extract. This study used 25 samples, divided into 5 samples for 20% rosella flower extract, 5 samples for 40% rosella flower extract, 5 samples for 60% rosella flower extract, 5 samples negative control (aquades) and 5 samples positive control (fifftydent). Soaking time is 10 minutes per day for a week. The type of research used was experimental pretest-posttest with control group design. Measurements using Adobe Photoshop and the CIELab color measurement system. Furthermore, statistically using the Shapiro wilk test, Leven's test, One Way Anova and Least Significant Diffence. The results of the study are shows the mean color change of CIELab (DE) in the five groups after treatment significantly different (p &lt;0.05). Least Significant Difference - test (LSD) test shows the results of immersion test on extract 20% and 40% are not different from negative controls, extract 60% is different from negative controls, extract 60% is same like positive control. The conclusions in this study are concentration of immersion with rosella flower (Hibiscus sabdariffa L.) extract 20% and 40% can't change the color of the acrylic resin plate heat cured, however extract rosella flowers (Hibiscus sabdariffa L.) 60% can change the color of&nbsp; acrylic resin plate heat cured.

Laser Projection Television Color Measurement System

Color measurement is important for TV color display performance evaluation indicators. Photochromic basic parameters of laser projection TV measurement are introduced, including color temperature, contrast ratio, color gamut, uniformity of illuminance luminous and so on. At last, a laser projection TV color measurement system is given out.

Comparison of the photochromic behaviour of dyes in solution and on polyester fabric applied by supercritical carbon dioxide

Photochromic textiles are of considerable interest for smart and functional textile applications due to their remarkable dynamic colour changing effect when irradiated with light of a certain wavelength. The use of resource efficient processes, such as digital inkjet printing and supercritical carbon dioxide (scCO2) dyeing techniques enables an economic production of those high-end functional products with high material costs. In this study, photochromic polyester fabric has been prepared by applying two commercially important photochromic dyes from spirooxazine (SO) and naphthopyran (NP) dye classes using scCO2-dyeing technique. The properties of scCO2 dyed photochromic fabrics were compared with the properties of the same dyes in a non-polar solvent, hexane. UV-Vis spectroscopy and a specially designed online colour measurement system capable of simultaneous UV irradiation and colour measurement were used to evaluate the photochromic colour behaviour. Both photochromic dye types embedded in textile as well as in solution showed significant reversible colour changing properties when exposed to UV light and revert to their original non-coloured form when the UV light is removed. The scCO2 dyed polyester fabrics exhibited similar trends of colour build-up as in solution, while contrasting behaviour was observed in terms of colour changing rates compared to their behaviour in solution.

Hunter versus CIE color measurement systems for analysis of milk-based beverages

The objective of our work was to determine the differences in sensitivity of Hunter and International Commission on Illumination (CIE) methods at 2 different viewer angles (2 and 10°) for measurement of whiteness, red/green, and blue/yellow color of milk-based beverages over a range of composition. Sixty combinations of milk-based beverages were formulated (2 replicates) with a range of fat level from 0.2 to 2%, true protein level from 3 to 5%, and casein as a percent of true protein from 5 to 80% to provide a wide range of milk-based beverage color. In addition, commercial skim, 1 and 2% fat high-temperature, short-time pasteurized fluid milks were analyzed. All beverage formulations were HTST pasteurized and cooled to 4°C before analysis. Color measurement viewer angle (2 vs. 10°) had very little effect on objective color measures of milk-based beverages with a wide range of composition for either the Hunter or CIE color measurement system. Temperature (4, 20, and 50°C) of color measurement had a large effect on the results of color measurement in both the Hunter and CIE measurement systems. The effect of milk beverage temperature on color measurement results was the largest for skim milk and the least for 2% fat milk. This highlights the need for proper control of beverage serving temperature for sensory panel analysis of milk-based beverages with very low fat content and for control of milk temperature when doing objective color analysis for quality control in manufacture of milk-based beverages. The Hunter system of color measurement was more sensitive to differences in whiteness among milk-based beverages than the CIE system, whereas the CIE system was much more sensitive to differences in yellowness among milk-based beverages. There was little difference between the Hunter and CIE system in sensitivity to green/red color of milk-based beverages. In defining milk-based beverage product specifications for objective color measures for dairy product manufacturers, the viewer angle, color measurement system (CIE vs. Hunter), and sample measurement temperature should be specified along with type of illuminant.

Effect of Steaming on the Colorimetric Properties of Eucalyptus saligna Wood

ABSTRACT This study aimed to homogenize the color of Eucalyptus saligna wood by means of steaming and compare the resulting color with that of Cariniana legalis wood, a species of high commercial value. To this end, two steaming curves were tested: 100% relative humidity for 12 (T1) and 24 (T2) hours at 90 °C followed by drying in a pilot-scale conventional kiln. The colorimetric parameters L*, a*, b*, C*, and h were determined according to the CIE L*a*b* color measurement system after drying. Results showed that steaming can be used for color homogenization between heartwood and sapwood. The treatment conducted for 24 hours (T2) presented the best results.

Calibration Method for the Wavelength and Uniformity of Pixel Response in Photodetector Arrays

Abstract Digital cameras are photodetector arrays that respond to particular bands of the electromagnetic spectrum, and specifically those in the visible spectrum between 380 and 780 nm are the most commonly used. The main cameras function is store the image from an aesthetic point of view, when these are used in home applications. For this reason, several processes are used in image reconstruction to improve the visual appearance, even from the manufacturing process of sensor decreasing the possibility to obtain optical measurements with this cameras. However, digital cameras can also be used as optical measuring instruments knowing their features in depth. Therefore, in this paper is proposed a calibration method for monochrome digital camera using a monochromator and an automatic rotation system. In this way, the uniformity of the pixels response is verified, bad pixels are detected, and the sensitivity curve is obtained. The results show the advantages of the method to find regions of pixels turned off. Also, the value of sensitivity as a function of wavelength is obtained to verify the regions with significant changes of uniformity. This work aims to the prototyping of a color measurement system and it is very important a comprehensive understanding of the camera.

Swingle citrumelo seed vigor and storability associated with fruit maturity classes based on RGB parameters

Citrus seeds normally have low storability. Identifying an optimal fruit harvest time for production of high vigor seeds is important for nurseries; however, identifying this stage for Swingle citrumelo fruits has been based only on visual color examination, and research related to this parameter has been inconsistent. The main objective of this study was to evaluate a red-green-blue (RGB) color measurement system for successful identification of Swingle citrumelo fruits possessing seeds with maximum physiological potential and storability. Fruits were harvested at three ripening stages identified as green (G), greenish-yellow (GY), and yellow (Y) pericarp, photographed, and the images processed using ImageJ software. Data were expressed as the average pixel value of R, G and B color components and a mean RGB pixel value (R+G+B/3). After harvest, seeds were evaluated for water content, germination, seedling emergence, length, dry mass and vigor as measured by the Seed Vigor Imaging System - SVIS (uniformity and vigor indexes) after 0 and 5 months storage (5 °C and 65 % relative humidity). Percentage of ruptured coat seeds was also evaluated after extraction. The R color component provided the best identification of each G, GY and Y fruits. Seeds extracted from GY fruits had higher storage potential compared with seeds from G and Y fruits. Thus, precise fruit ripening classification can be generated using the RGB color system to identify the best time for harvest to obtain seeds with greater physiological and storage potential.

Illumination compensation in textile colour constancy, based on an improved least‐squares support vector regression and an improved GM(1,1) model of grey theory

In many colour‐related fields, such as textile colour measurement systems based on computer vision as well as dyestuff synthesis, colour constancy with illumination variation is a key problem to be solved. A new algorithm of illumination compensation for colour constancy for textured textiles is proposed in this paper, combining an improved least‐squares support vector regression (LSSVR) and an improved GM(1,1) model of grey theory. The LSSVR algorithm was improved by determining the error limitation according to the distance between a standard sample and a test sample, while the improved GM(1,1) model used the average value of the sequence as the initial iteration value. The disadvantage of LSSVR, that it easily falls into global optimisation, can be compensated for by the local optimisation capacity of the GM(1,1) model. Experimental results show that the algorithm of this paper is very stable and provides good illumination compensation, whereby the time complexity of compensation is reduced by repeatedly processing fractional data with the LSSVR algorithm, and the prediction accuracy is improved by combining the improved GM(1,1) model and the LSSVR algorithm.