Small Color Differences Research Articles

Tung Oil Microcapsules Prepared with Different Emulsifiers and Their Effects on the Properties of Coating Film

In water-based coatings, the addition of tung oil microcapsules coated with urea formaldehyde resin (UF) can effectively repair the microcracks in the coating film on the surface of wood. The tung oil as a repairing agent plays an important role in the preparation of microcapsules. In this paper, Span-80, SDBS, OP-10, Tween-80 and SDS were used as five emulsifiers to study the influence of different emulsifiers on the preparation of tung oil microcapsules, and the properties of the coating film added to the waterborne coatings. According to the coating process of three bottoms and three sides, tung oil microcapsules were added to the water-based paint with a content of 12% and coated on the wood surface. The appearance and microstructure of the microcapsules, as well as the mechanical, optical and self-repairing properties of the paint film were analyzed to find out the best emulsifier suitable for the core material. The tung oil microcapsules prepared by Tween-80 have the best morphology, concentrated particle size distribution, particle size of 6–15 μm, and spherical morphology. The film with the microcapsules prepared by Tween-80 had the best performance, small color difference, high gloss, hardness of 5H, adhesion grade 1, elongation at break of 47.23%, impact resistance of 20 kg∙cm, and good toughness. At the same time, the repair rate reached 37.9%. The results provide the application reference for the use of self-repairing microcapsules in coatings.

Classification and detection using hidden Markov model‐support vector machine algorithm based on optimal colour space selection for blood images

Patients with cerebral haemorrhages need to drain haematomas. Fresh blood may appear during the haematoma drainage process, so this needs to be observed and detected in real time. To solve this problem, this paper studies images produced during the haematoma drainage process. A blood image feature selection recognition and classification framework is designed. First, aiming at the characteristics of the small colour differences in blood images, the general RGB colour space feature is not obvious. This study proposes an optimal colour channel selection method. By extracting the colour information from the images, it is recombined into a 3 × 3 matrix. The normalised 4-neighbourhood contrast and variance are calculated for quantitative comparison. The optimised colour channel is selected to overcome the problem of weak features caused by a single colour space. After that, the effective region in the image is intercepted, and the best colour channel of the image in the region is transformed. The first, second and third moments of the three best colour channels are extracted to form a nine-dimensional eigenvector. K-means clustering is used to obtain the image eigenvector, outliers are removed, and the results are then transferred to the hidden Markov model (HMM) and support vector machine (SVM) for classification. After selecting the best color channel, the classification accuracy of HMM-SVM is greatly improved. Compared with other classification algorithms, the proposed method offers great advantages. Experiments show that the recognition accuracy of this method reaches 98.9%.

Crop Disease Recognition Based on Modified Light-Weight CNN With Attention Mechanism

The agricultural production is greatly affected by various plant diseases. Classifying the severity of crop diseases is the requirement for formulating disease prevention and control strategies. However, the differences between different severity of the same crop disease are very tiny. It increases the difficulty of correct crop disease recognition. For example, at the early stage of the disease, the lesions on the leaves are not obvious. And it is very difficult to extract the features of the lesions. However, these very small color and texture differences of the lesions are the key patterns to distinguish different kinds of diseases of the same species. In order to achieve better performance in the fine-grained classification of the crop diseases, a modified light-weight convolution neural network was proposed. Multi-scale convolution kernel and coordinate attention mechanism are introduced in SqueezeNext to extract the features of the lesions accurately. The performance of the proposed model was evaluated using the AI challenger 2018 plant disease recognition dataset, and the recognition accuracy can reach 91.94%, which is 3.02% point higher than the original SqueezeNext model. In order to verify the effectiveness of the proposed model, comparative experiments were carried out using ReseNet50, Xception and mobilenetv2. The experimental results showed that the accuracy of the proposed method was slightly better than Xception, while the model size is only 2.83 MB, which is only 3.45% of Xception. The proposed method balances the performance and efficiency very well. Thus, it is suitable for deployment on mobile terminals and other embedded resource-constrained devices, which help to promote the popularization of smart agriculture application.

Investigating the Possibility of Determining the Sequence Intersecting Lines between LaserJet Printing and Handwriting in Document Examination using Color Measurement Technique

In Questioned Documents Examination, the sequence of crossing lines in the intersection of handwriting and printed area can be important clues for detecting tampered documents. Recognition of such documents is a arduous task and requires people with experience and expertise. In the present work, we investigated the possibility of determining the sequence of intersecting lines between LaserJet printing and handwriting for a series of simulated laboratory specimens in the document examination using color measurement technique. The spectral reflectance curves and color coordinates of some points on and out of the cross lines were compared. Four different commercial ballpoint pens and a black toner LaserJet were used to prepare the specimens. The color change of the intersecting lines was subjectively considered through the captured images and a visual assessment process. It was also objectively determined by determining the color difference values from the colorimetric data in CIELAB and CIELCH color spaces in the visible range. The color change evaluation showed that the order in which printing or handwriting is applied alters colorimetric results. Moreover, the investigations showed small color difference values of less than 2 units between a point of printed area individually, and intersection could be applied as a tolerance limit for pass/fail judgments.

Fly pollination drives convergence of flower coloration.

Plant-pollinator interactions provide a natural experiment in signal evolution. Flowers are known to have evolved colour signals that maximise their ease of detection by the visual systems of important pollinators such as bees. Whilst most angiosperms are bee pollinated, our understanding on how the second largest group of pollinating insects, flies, may influence flower colour evolution is limited to the use of categorical models of colour discrimination that do not reflect the small colour differences commonly observed between and within flower species. Here we show by comparing flower signals that occur in different environments including total absence of bees, a mixture of bee and fly pollination within one plant family (Orchidaceae) from a single community, and typical flowers from a broad taxonomic sampling of the same geographic region, that perceptually different colours, empirically measured, do evolve in response to different types of insect pollinators. We show evidence of both convergence among fly-pollinated floral colours but also of divergence and displacement of colour signals in the absence of bee pollinators. Our findings give an insight into how both ecological and agricultural systems may be affected by changes in pollinator distributions around the world.

Application of Various Methods to Evaluate the Postoperative Characteristics of Expanded Pedicled Deltopectoral Flap for Large Facial Scars.

The expanded pedicled deltopectoral flap (EPDF) has been widely used to repair large facial scars. Although doctors and patients are usually satisfied with the outcomes, the actual functional recovery and cosmetic effects of EPDF are still unknown. It is, therefore, necessary to objectively investigate the effect of transferred EPDF by using a variety of methods. From January 2008 to December 2018, 52 patients who underwent EPDF surgery at Xijing Hospital were enrolled. Sense of touch, static 2-point discrimination, elasticity, and color were measured. Thermesthesia and algesthesia were also tested. Postoperative scars were evaluated using the patient and observer scar assessment scale. Satisfaction of patients, doctors, and laypersons was investigated. The algaesthesis, thalposis, and rhigosis scores were 4.7 ± 0.7, 3.7 ± 0.9, and 4.5 ± 0.8, respectively. The tactile score was 0.3 ± 0.2 mN, and 2-point discrimination was 10.1 ± 4.8 mm. L ∗ , a ∗ hemoglobin, and melanin content of the flaps were significantly different when compared with normal skin ( P < 0.05). The satisfaction of doctors, patients, and laypersons was 88.5%, 71.2%, and 67.3%, respectively. The higher satisfaction of patients was mainly associated with the smaller color difference between the flap and the surrounding skin, and lower patient and observer scar assessment scale score. These results confirm that excellent functional recovery and reliable cosmetic effects are observed when facial scars are repaired with EPDF. The methods used in this study can be applied to the evaluation of functional recovery and cosmetic outcomes of transferred flaps, which may provide a more comprehensive understanding of flap assessment.

Research on Mosaic Tile Color Model Based on HIS Color Space Model and Particle Square Optimization Algorithm

Based on the conversion between RGB color space and HSI color space, combined with the relevant knowledge of optimization problems, this paper reasonably solved the color selection problem of mosaic tiles.Firstly, this paper establishes a color selection model based on his color space. Based on the conversion relationship between RGB color space and HSI color space, the original RGB parameters in the topic are converted into HSI parameters which are more suitable for calculation. The color difference is used to quantify the similarity between different colors, and a more reasonable formula for calculating color difference is determined to improve the accuracy of color selection results. Finally, the color difference between the original color and each existing tile color is compared, and the tile color with the smallest color difference is determined as the color selection result.Next, because this problem is about the optimal solution of the whole color difference value, it is nonlinear and has a large solution space. In this paper, a heuristic global search algorithm based on swarm intelligence, Particle Swarm Optimization, is adopted to gradually approach the global optimum by updating the individual optimal solution and global optimal solution of particles. When searching for the global optimal solution, it is easy to fall into the trap of local optimal solution, and the PSO algorithm used in this paper can take many measures to avoid it. By continuously debugging the size of population size, iteration times and learning factors, the optimal solution for developing new colors is finally obtained.In this paper, when considering the similarity between different colors and the follow-up problems, the HIS color space model is used reasonably, which greatly improves the accuracy of color selection results.

A binocular reconstruction method fused with Laplacian image information for pavement texture evaluation

3D reconstruction technology based on image processing has the advantages of fast speed and high resolution to reconstruct pavement texture morphology for detecting the skid resistance. However, the small color difference and unobvious feature points of asphalt pavement lead to low accuracy in texture morphology reconstruction. A binocular technology fused with Laplacian image information was proposed to improve the precision of texture reconstruction as follow: the first mode without region segmentation, the second mode with laser region segmentation and the third mode with the region segmentation used template. The results show that the proposed algorithm improves the binocular reconstruction accuracy of pavement texture compared with the traditional SGBM algorithm. The proposed method and the laser scanner are compared through areal texture parameters. The results of the proposed method are relatively close to those of laser scanners.

Intelligent Splicing Method of Virtual Reality Lingnan Cultural Heritage Panorama Based on Automatic Machine Learning

With the increasing expansion of virtual reality application fields and the complexity of application content, the demand for real-time rendering of realistic graphics has increased sharply. This research mainly discusses the intelligent mosaic method of virtual reality Lingnan cultural heritage panorama based on automatic machine learning. In order to effectively make up for the impact of the insufficiency of the collection process on the quality of the final panoramic image of Lingnan cultural heritage, it is necessary to minimize the irregular rotation of the camera and collect images according to the overlapping area between adjacent images of appropriate size. In order to make Lingnan cultural heritage panoramic images have better visual effects, it is necessary to preprocess the images before image registration and fusion. Image preprocessing mainly includes image denoising and image projection transformation. In this study, cylindrical projection is used to construct the panorama of Lingnan cultural heritage. For each Lingnan cultural heritage training image, we first perform image segmentation to obtain multiple regions and extract the visual features of each region. We use automatic machine learning models to train the visual feature set and use the bagging method to generate different training subsets. In order to generate each component classifier, we determine the overlap area of the two images according to the matched SIFT feature points and determine the best stitching line during the implementation of stitching. In this paper, the number of pixels in the first row of the overlapping area is used to determine the candidate stitching line column, and the best stitching line position should be determined in consideration of the smallest color difference in the stitching area and the most similar texture on both sides. This article uses a Java Applet-based approach to realize virtual roaming of viewing panoramic images of Lingnan cultural heritage in IE browser. The highest accuracy of SIFT is 82.22%, and the lowest recognition time is 0.01 s. This research will promote the development of Lingnan cultural heritage.

Monkey V1 epidural field potentials provide detailed information about stimulus location, size, shape, and color

Brain signal recordings with epidural microarrays constitute a low-invasive approach for recording distributed neuronal signals. Epidural field potentials (EFPs) may serve as a safe and highly beneficial signal source for a variety of research questions arising from both basic and applied neuroscience. A wider use of these signals, however, is constrained by a lack of data on their specific information content. Here, we make use of the high spatial resolution and the columnar organization of macaque primary visual cortex (V1) to investigate whether and to what extent EFP signals preserve information about various visual stimulus features. Two monkeys were presented with different feature combinations of location, size, shape, and color, yielding a total of 375 stimulus conditions. Visual features were chosen to access different spatial levels of functional organization. We found that, besides being highly specific for locational information, EFPs were significantly modulated by small differences in size, shape, and color, allowing for high stimulus classification rates even at the single-trial level. The results support the notion that EFPs constitute a low-invasive, highly beneficial signal source for longer-term recordings for medical and basic research by showing that they convey detailed and reliable information about constituent features of activating stimuli.

The effect of luminance on the perception of small color differences

AbstractThe objectives of this study were two‐fold; to determine how variations in practical illuminance range (from ~300 to ~2300 lx) affect the perception of suprathreshold small color differences for a range of object stimuli across the color space, and to investigate the role of variations in luminance on intra‐ and inter‐observer variability in repeated psychophysical trials. STRESS index and conventional statistical methods suggest the presence of a significant difference between visual responses for large changes in luminance. Inter‐ and intra‐observer variability also varied according to luminance. Calculated color differences based on recent CAM models show good agreement with visual results over the luminance range examined.

Color Properties at the Mars InSight Landing Site

AbstractThe color properties observed at the InSight landing site by the lander cameras are spectral mixtures of two source materials: gray‐black rocky material with chromaticity values of x = 0.32, y = 0.32 (standard deviations of σx = 0.02 and σy = 0.03) and yellowish‐brown dust with chromaticity values of x = 0.42, y = 0.36 (standard deviations of σx = 0.02 and σy = 0.03). These results are consistent with published values from other Mars landed missions. The InSight measurements also include the first published value of the white point of Mars daylight, chromaticity of x = 0.35, y = 0.34 (standard deviations of σx = 0.01 and σy = 0.02), which is redder than earth daylight by δx = 0.04 and δy = 0.01. InSight measurements also show a small color difference (δx = 0.02 and δy = 0.01) between the near field terrain (within 20 m of the lander) and the far field area beyond. This color difference is believed to be caused by dust being blown off by near field terrain by the lander rockets during the landing event. The visual difference between these two regions is caused primarily by the brightness variation. Chromaticity measurements of the Martian sky also match previous missions with additional variability caused by differences in dust loading and the dynamic nature of the Martian atmosphere.

Visual validation of the appearance of chromatic objects rendered from spectrophotometric measurements.

We validate a physically based and spectral rendering framework with improved color reproduction. With a recently developed model, we take into account both the colorimetric specifications of the rendering display as well as the spectral and angular characteristics of lighting and also the spectral reflectance of the objects. Therefore, it should provide much better color reproduction than those based on the common standard red, green, blue (sRGB) color space. In addition, it allows real-time rendering on modest hardware and displays. We evaluated the color reproduction of the new rendering framework by psychophysical tests using spectrophotometric measurements of 30 chromatic paint samples. They were rendered on an iPad display, as viewed inside the Byko-spectra effect light booth. We asked 16 observers to evaluate the color match by directly comparing the rendered samples with the physical samples, using two different psychophysical assessment methods. The color reproduction was found to be strongly improved with respect to results obtained with default sRGB color encoding space. The average color reproduction match was found to be equivalent to ΔE00=1.6, which is a small but noticeable color difference. In 80% of the visual assessments, the color reproduction was described as being at least as good as between "difference visible but still acceptable" and "difference visible, doubtful match."

Color and Translucency Stability of Three-Dimensional Printable Dental Materials for Crown and Bridge Restorations.

The purpose of this study was to examine and compare color and translucency stability of three-dimensional (3D) printable dental materials for crown and bridge restorations. Five different materials were investigated, and twelve disc-shaped specimens of two different thicknesses (1 and 2 mm) were prepared using a digital light processing 3D printer. Color measurements were made according to the CIELAB color scale (L*, a*, and b*) using a spectrophotometer 1 h, 1 day, 1 week, one month, and six months after post-curing of the materials, and the translucency parameter (TP) was calculated. The L*, a*, b*, and TP values were compared among the different materials and storage periods using repeated measures analysis of variance. Color and translucency changes of the specimens after the different storage periods were compared with 1 h measurements to determine whether they exceeded clinically perceivable thresholds. The L*, a*, b*, and TP values showed significant differences according to the storage periods, as well as among the materials. Until one month, some materials demonstrated distinct color differences, while others showed small color differences below a clinically perceivable threshold. The translucency differences were not clinically perceivable for any specimen. After six months, all specimens demonstrated large color changes, whereas the changes in translucency were relatively small. In conclusion, the color of 3D printable dental materials changed with time, and the differences varied with the materials used. On the contrary, the changes in translucency were small. Overall, the materials became darker, more yellowish, and more opaque after six months of water storage.

About quantifying small color differences in digital images

We discuss aspects of the use and possibilities provided by three-color colorimeters or digital cameras in problems of detecting small color differences by computer vision methods. The spectral dependence of the total color differences between pairs of visually indiscernible monochromatic stimuli is experimentally revealed. An experimental setup based on the UM-2 monochromator is created for producing a digital atlas of monochromatic stimuli at 1-nm increments. The atlas serves to test the color gamut and color differentiation of cameras. It is experimentally shown that in the visible spectral range a color difference of 3 units is detected by pairs of stimuli that are unevenly distributed across the spectrum and differ in wavelengths from 1 to 6 nm. The capabilities of computer vision are tested on the examples of identifying additional texts during a technical and forensic examination of documents. A new algorithm is developed for finding and quantitatively characterizing color difference of inserts based on a digital image of the inscription. In the algorithm, the objective analysis of the image is divided into a block of color segmentation and that of color tone and color difference assessment. With such an approach, the color segmentation block performs preprocessing functions, making a border map for the classes with different colors for the subsequent calculations. The Otsu method of optimal global threshold transformation is for the first time applied to a problem of image segmentation by color saturation. The trial of the algorithm confirms its efficiency in the solution of expert tasks.

Application of genetic algorithm to color recipe formulation using reactive and direct dyestuffs mixtures

AbstractColor reproduction is a science in constant development. In this article, a new model to solve the color recipe prediction problem using a genetic algorithm is proposed. The objective is to optimize the color recipe prediction stage by determining the dyes to use in a mixture and their respective proportions to reproduce the target color. Two ranges of dyes were used for dyeing 100% cotton woven fabrics: three reactive dyes (CI Reactive Red 238, CI Reactive Yellow 145, and CI Reactive Blue 235) and four direct dyes (CI Direct Orange 34, CI Direct Red 227, CI Direct Blue 85, and CI Direct Black 22). The criterion of optimization, in reproducing the desired shades, is to minimize the CMC color difference between the desired reference color and the color resulting of the predicted recipe. The proposed algorithm revealed good results with small CMC color differences between target and reproduced colors. The effectiveness of the algorithm was also evaluated and proven by calculating errors between the predicted concentrations in the proposed recipes and the actual concentrations.

Comparison study of static and alternating magnetic field treatments on the quality preservation effect of cherry tomato at low temperature

AbstractThe objective of this study is to investigate the effects of a static magnetic field (SMF) and alternating magnetic field (AMF) treatment on thermophysical property and preservation quality of cherry tomato. Freshly harvested cherry tomatoes were treated with SMF and AMF at 40 Gs and 80 Gs when hydrocooling pretreatment was performed at 2°C for 30 min. Control tomato fruits were hydrocooled without magnetic field treatment at 2°C for 30 min. The cooling rate, weight loss, color difference, electrical conductivity, malondialdehyde, and catalase were measured. The results showed that the cooling time of SMF treatment was decreased by 16.7% compared with the control treatment. SMF and AMF treatments significantly (p &lt; .05) increased catalase activity and improved the quality of cherry tomatoes during storage. AMF strength at 80 Gs, was the best treatment for reducing weight loss and increasing catalase activity, while the smallest color difference was observed when the SMF at 40 Gs was applied. The results demonstrated that SMF is an alternative method to delay the postharvest ripening process and maintaining the quality of the cherry tomato, which could be due to the higher activity of the antioxidant enzyme catalase.Practical applicationsThe main aim of this study was to compare the effects of SMF and AMF treatment on the preservation quality of cherry tomato. The results demonstrated that magnetic field technology could be applied to fruit and vegetable preservation, and SMF treatment was more helpful to inhibit the ripening of the cherry tomato. This study will broaden the knowledge of food preservation engineers and provide an alternative technology of fruit and vegetable preservation. The parameters used in this study can provide a reference for the development of commercial equipment.

Antibacterial Finishing of Vat Dyed Cotton Fabrics with a Reactive N-Halamine

To obtain antibacterial properties for colored cotton fabrics, vat dyes were chosen to dye cotton because they can avoid serious discoloration during chlorination. In this study, we synthesized a reactive N-halamine precursor, 4-(4-(2,2,6,6-tetramethyl-4-piperidinol)-6-chloro-1,3,5-triazinylamino)-benzenesulfonate (BTMPT), and coated it on colored cotton fabrics that were dyed with three different vat dyes. The optimum pH for chlorination of the treated cotton fabrics was investigated. Chlorination at pH 11 achieved a small color difference and greater than 0.2% of active chlorine loading. When challenged, the chlorinated fabrics inactivated all inoculated Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) within 5 min. The treated cotton fabric had greater breaking strength than those treated with the traditional process, as well as good washing stability.

Antioxidant capacity of the extracts from flowers of Erica australis L.: Comparison between microwave hydrodiffusion and gravity (MHG) and distillation extraction techniques - Formulation of sunscreen creams

Microwave hydrodiffusion and gravity (MHG) extraction of Erica australis flowers was optimized evaluating different microwave irradiation powers (25−200 W). Collected extracts were compared with the liquid phase obtained by conventional distillation. Their total phenolic content, antioxidant capacity and color features were evaluated. Microscopical properties of the flower tissues allowed assessing the distinct effects of the extraction processes. The cosmetic application of the collected bioactive extracts in the formulation of sunscreen creams with waters from three different thermal spring waters and the corresponding characterization (e.g. chemical, bioactive and rheological features) and sensory analysis were also made. For cosmetic comparative purposes, extracts from Ulex europaeus flowers obtained by MHG procedure was also analyzed. The stability of these oil-in-water model emulsions was tested during accelerated oxidation conditions. Results indicated that MHG at 50 W for 130 min was the most adequate work conditions for the extraction of antioxidant compounds from these wild flowers (around 0.27 mg Trolox eq/g flower dry weight and 0.01 mg ascorbic acid/g flower dry weight or 0.04 mg FeSO4 * 7H2O/g flower dry weight). This procedure also led a drop of energy consumption environmental impact (about 8 times less) in comparison with distillation method. Small total color differences were detected between the gathered extracts. The incorporation of flower extracts produced similar effects when compared with added commercial antioxidants except for viscous behavior. Sensorially, E. australis extract incorporated with thermal waters displayed a positive effect on the skin cream application of the formulated cosmetic, mainly with thermal water 3.

Study on color stability under different light sources based on color difference analysis

Product color is an important indicator to measure product quality. Since the change of the light sources in the product circulation environment cannot be avoided, the color of the product will be affected by the change of the light sources undoubtedly. Therefore, it is of practical significance to study the color stability under different light sources. D65 light source was used as the standard light source, A and F2 light sources were used as the test light sources, a large number of color blocks were chosen as samples, and the color difference of the sample under different light sources was used to measure the color stability of the sample under different light sources. Firstly, by analyzing samples with different excitation purity, it was found that there was a positive correlation between the color difference and the excitation purity; Secondly, by analyzing samples with different dominant wavelength/complementary wavelength, it was found that the color difference was related to the dominant wavelength/complementary wavelength closely. When the dominant wavelength of the sample was 479nm, ΔEab*(D65/A), ΔEab*(D65/F2) were 14.50, 13.81 respectively. When the dominant wavelength of the sample was 561nm, ΔEab*(D65/A), ΔEab*(D65/F2) were only 5.17, 2.78 respectively. After corresponding to the dominant wavelength/complementary wavelength and the hue, it showed that the samples with purple, yellow, yellow-green hue had smaller color difference under different light sources, while the samples with red, cyan, light blue hue had larger color difference. The results showed that the color stability under different light sources was related to the excitation purity and the dominant wavelength/complementary wavelength. In actual production and application, there are two ways to improve the color stability of the product under different light sources, one is to choose a color with lower excitation purity, and the other is to choose a color with purple, yellow, yellow green hue.