Gradation trajectories as an analog of gradation curves in the metric CIE Lab space: discrete approach

As color gamut of digital output device greatly affects image appearance, accurate and effective gamut description for output device is intensively required for developing high-quality image reproduction technique based on gamut mapping. In this paper, we present a novel method to determine color gamut of output device by using a specific 3D reconstruction technology and device ICC profile. First, we populate the device color space by uniform sampling in the RGB 3-Dimensional space, and convert these sampling points to CMYK color space. Then, we work out the CIE LAB value of these points according to the ICC profile of output device. At last, in CIE LAB color space the boundary of these points is determined by using a gamut boundary descriptor based on Ball-Pivoting Algorithm (BPA) proposed by Bernardini. Compared with the results generated by ICC3D, our proposed method can compute device gamut more efficiently and at the same time give a more accurate gamut description of the output device. It will be help to develop effective gamut mapping algorithms for color reproduction.

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A discrete approach to the calculus

International Journal of Mathematical Education in Science and Technology ◽

10.1080/0020739790100104 ◽

1979 ◽

Vol 10 (1) ◽

pp. 21-31 ◽

Cited By ~ 2

Author(s):

Sheldon P. Gordon

Keyword(s):

Discrete Approach

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The Accuracy and Reliability of Tooth Shade Selection Using Different Instrumental Techniques: An In Vitro Study

Sensors ◽

10.3390/s21227490 ◽

2021 ◽

Vol 21 (22) ◽

pp. 7490

Author(s):

Nattapong Sirintawat ◽

Tanyaporn Leelaratrungruang ◽

Pongsakorn Poovarodom ◽

Sirichai Kiattavorncharoen ◽

Parinya Amornsettachai

Keyword(s):

Intraclass Correlation ◽

In Vitro Study ◽

Control Group ◽

Intraoral Scanner ◽

Control Groups ◽

B Values ◽

Cie Lab ◽

And Control ◽

Shade Selection

This study aimed to investigate and compare the reliability and accuracy of tooth shade selection in the model using 30 milled crowns via five methods: (1) digital single-lens reflex (DSLR) camera with twin flash (TF) and polarized filter (DSLR + TF), (2) DSLR camera with a ring flash (RF) and polarized filter (DSLR + RF), (3) smartphone camera with light corrector and polarized filter (SMART), (4) intraoral scanner (IOS), and (5) spectrophotometer (SPEC). These methods were compared with the control group or manufacturer’s shade. The CIE Lab values (L, a, and b values) were obtained from five of the methods to indicate the color of the tooth. Adobe Photoshop was used to generate CIE Lab values from the digital photographs. The reliability was calculated from the intraclass correlation based on two repetitions. The accuracy was calculated from; (a) ΔE calculated by the formula comparing each method to the control group, (b) study and control groups were analyzed by using the Kruskal–Wallis test, and (c) the relationship between study and control groups were calculated using Spearman’s correlation. The reliability of the intraclass correlation of L, a, and b values obtained from the five methods showed satisfactory correlations ranging from 0.732–0.996, 0.887–0.994, and 0.884–0.999, respectively. The ΔE from all groups had statistically significant differences when compared to the border of clinical acceptance (ΔE = 6.8). The ΔE from DSLR + TF, DSLR + RF, SMART, and SPEC were higher than clinical acceptance (ΔE > 6.8), whereas the ΔE from IOS was 5.96 and all of the L, a, and b values were not statistically significantly different from the manufacturer’s shade (p < 0.01). The ΔE of the DSLR + RF group showed the least accuracy (ΔE = 19.98), whereas the ∆E of DSLR + TF, SMART, and SPEC showed similar accuracy ∆E (ΔE = 10.90, 10.57, and 11.57, respectively). The DSLR camera combined with a ring flash system and polarized filter provided the least accuracy. The intraoral scanner provided the highest accuracy. However, tooth shade selection deserves the combination of various techniques and a professional learning curve to establish the most accurate outcome.

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Marginal Bone Loss and Aesthetics Around Zirconia and Titanium Dental Implants-A Metanalysis

10.1101/2020.05.09.20096271 ◽

2020 ◽

Author(s):

Pulijala Sathwika ◽

Rampalli Viswa Chandra

Keyword(s):

Bone Loss ◽

Randomized Controlled Trials ◽

Meta Analysis ◽

Titanium Implants ◽

Controlled Trials ◽

Marginal Bone Loss ◽

Randomized Controlled ◽

Cie Lab ◽

Titanium Dental Implants ◽

Zirconia Implants

AIM: To evaluate and compare the marginal bone loss and aesthetic outcomes of zirconia implants with titanium implants in randomized controlled trials (RCTs). MATERIAL AND METHODS: Electronic [PubMed] and hand searches were performed to identify randomized controlled trials that were published between January 2008 to April 2020 which investigated and compared various outcomes between zirconia and titanium dental implants. Outcomes included assessment of marginal bone loss and aesthetics using spectrophotometric measurements. Meta-analysis was performed to estimate the above parameters among various studies. RESULTS: A total of 58 articles were screened for titles and abstracts. Subsequently 8 articles were selected for data extraction and evaluation. Zirconia implants were investigated and compared to titanium implants for marginal bone loss [MBL]. Customized zirconia and titanium abutments seated over implants were analyzed for aesthetic outcomes using spectrophotometric method using CIE-Lab measurements. Meta-analysis estimated that zirconia implants exhibited marginal bone loss reduction of 0.179mm (95% CI, 0.02 to 0.33) and -0.242mm (95% CI, -4.026 to 3.542) in aesthetic measurements than titanium implants. CONCLUSIONS: No heterogeneity was observed among studies analyzed for marginal bone loss and significant differences were noticed between two groups. Noticeable heterogeneity was observed among studies assessing aesthetics using spectrophotometry and CIE-Lab measurements and results revealed no many significant differences between the two groups.

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Image Colorization

10.30987/graphicon-2019-2-207-210 ◽

2019 ◽

Cited By ~ 1

Author(s):

Дарья Михалина ◽

Daria Mikhalina ◽

Александр Кузьменко ◽

Aleksandr Kuz'menko ◽

Константин Дергачев ◽

...

Keyword(s):

Neural Network ◽

Urban Areas ◽

Black And White ◽

Number Of Layers ◽

The Neural Network ◽

Natural Landscapes ◽

Video Card ◽

Trained Neural Network ◽

Lab Color Model ◽

Cie Lab

The article discusses one of the latest ways to colorize a black and white image using deep learning methods. For colorization, a convolutional neural network with a large number of layers (Deep convolutional) is used, the architecture of which includes a ResNet model. This model was pre-trained on images of the ImageNet dataset. A neural network receives a black and white image and returns a colorized color. Since, due to the characteristics of ResNet, an input multiple of 255 is received, a program was written that, using frames, enlarges the image for the required size. During the operation of the neural network, the CIE Lab color model is used, which allows to separate the black and white component of the image from the color. For training the neural network, the Place 365 dataset was used, containing 365 different classes, such as animals, landscape elements, people, and so on. The training was carried out on the Nvidia GTX 1080 video card. The result was a trained neural network capable of colorizing images of any size and format. As example we had a speed of 0.08 seconds and an image of 256 by 256 pixels in size. In connection with the concept of the dataset used for training, the resulting model is focused on the recognition of natural landscapes and urban areas.

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Generation I and Generation II Elastomeric Chains Characteristics Comparison in Artificial Saliva Immersion

Brazilian Dental Science ◽

10.14295/bds.2021.v24i1.2180 ◽

2020 ◽

Vol 24 (1) ◽

Author(s):

Marisa Icha Aisya Subroto ◽

Anindita Permata Hardarini Putri ◽

Leliana Sandra Devi Ade Putri ◽

Lusi Hidayati

Keyword(s):

Artificial Saliva ◽

Orthodontic Force ◽

Force Decay ◽

Significant Difference ◽

Chain Force ◽

Cie Lab ◽

Elastomeric Chains ◽

Research Period ◽

Color Reader

Objective: To determine the force decay and discoloration in Generation I and Generation II elastomeric chain on artificial saliva immersion. Material and methods: Generation I and Generation II elastomeric chains stretched on an acrylic board and immersed in artificial saliva for 1, 7, 14, 21, and 28 days according to the group of days. On each specified day, the force of each sample measured by an orthodontic force gauge and the magnitude of the force obtained is entered to the formula to find out the force decay in percentage, whereas discoloration of each sample analyzed by the color reader with CIE Lab analysis. Results: The force decay between Generation I and Generation II elastomeric chains showed a statistically significant difference in every group of days, in which Generation II is more effective in maintaining stretch force. Similar to force decay, the discoloration in Generation I elastomeric chains on the 14th day showed significant value and Generation II elastomeric chains were more stable in maintaining color compared to Generation I. Conclusions: over the entire research period time, Generation II elastomeric chains are more stable in maintaining stretch forces and color compared to Generation I elastomeric chains. KEYWORDS Discoloration; Elastomeric chain; Force decay; Generation I; Generation II.

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Impact of mineral and organic absorbent during the discoloration of avocado oil by comparing with olive oil

Journal of the Cameroon Academy of Sciences ◽

10.4314/jcas.v16i2.4 ◽

2021 ◽

Vol 16 (2) ◽

pp. 113-121

Author(s):

Orléans Ngomo ◽

Joseph Sieliechi ◽

Etienne Dongo

Keyword(s):

Activated Carbon ◽

Shelf Life ◽

Olive Oil ◽

Nutritional Quality ◽

The Other ◽

Added Value ◽

Avocado Oil ◽

Before And After ◽

Valuable Product ◽

Cie Lab

Avocado is a versatile and valuable product. Its oil is comparable to olive oil in terms of nutritional quality. It can also be used in cosmetics, in particular, in soaps, shampoos and lotions. Despite all these important attributes that avocado has, it is highly perishable and coupled with the lack of farm-to-market roads, a lot of it is lost after harvest during the peak season. The introduction of methods that will transform avocado to products with a long shelf life and added value will go a long way to solving the problem of post-harvest losses and poverty. One of these methods is the production of avocado oil. In addition, in order to reduce the colour of the pigments without altering their quality, discoloration tests were carried out by adsorption on bleaching grounds (a montmorillonite, a kaolinite and activated carbon). The colour intensities of the oils before and after adsorption were determined using two complementary methods: a UV-Vis spectrophotometer and a Konica Minolta spectrophotometer CM-5. The UV-Vis spectrophotometer show that the activated carbon has a best fixing capacity of the pigments; According to the Colorimetric parameters (CIE-Lab) the coordinates L* a* b* that showed brightness (L*) of the avocado oil was half of the olive oil (41.13±0.02 vs 84.85±0.02). The activated carbon was better in fixing the red (a*) (4.99±0.01vs 15.73±0.01 before adsorption) and yellow (b*) (63.71±0.09 vs 70.07±0.09 before adsorption) pigments, while the other two adsorbents have very little influence on the red colour of avocado oil. RésuméL’avocat est un produit versatile et de grande valeur. Son huile est comparable à huile d’olive en terme de qualité nutritionnelle ; elle peut également être utilisée en cosmétique en occurrence dans les savons, champoings et lotions. En pleine saison, l’on fait face à une abondance des avocats dans les zones de production qui sont très souvent enclavées ; c’est ainsi que face aux difficultés de transport et les routes peu praticables pour l’importation, l’on se retrouve en train de perdre de très importantes quantités d’avocats après les récoltes. Or la production d’huile d’avocats permettrait de réduire les pertes post récolte, réduirait le chômage et permettrait de lutter contre la pauvreté après la vente des huiles extraites. De plus, dans le but de réduire les pigments colorés, des tests de décolorations effectués par adsorption sur des terres décolorantes (une montmorillonite en provenance de Maroua, une kaolinite en provenance de Douala et le charbon actif) sont effectués. Les couleurs des huiles mesurées avant et après adsorption à l’aide deux appareils complémentaires : Le spectrophotomètre UV-Vis et du Konica Minolta spectrophotomètre CM-5 montrent. Les analyses spectrophotométriques UV-Vis montrent que c’est le charbon activé qui présente la meilleure adsorption des pigments ; D’après les coordonnées L*a*b*, la clarté de l’huile d’avocat est pratiquement la moitié de celle de l’huile d’olive (41,13±0,02 contre 84,85±0,02), le charbon activé fixe mieux les pigments rouges (a*) (4,99±0,01 contre 15,73±0,01 avant adsorption) et jaunes (b*) (63,71±0,09 contre 70,07±0,09 après adsorption), tandis que les deux autres adsorbants influencent très peu sur la coloration des huiles.

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