Color Contrast Research Articles

Rectangling and enhancing underwater stitched image via content-aware warping and perception balancing

Single underwater images often face limitations in field-of-view and visual perception due to scattering and absorption. Numerous image stitching techniques have attempted to provide a wider viewing range, but the resulting stitched images may exhibit unsightly irregular boundaries. Unlike natural landscapes, the absence of reliable high-fidelity references in water complicates the replicability of these deep learning-based methods, leading to unpredictable distortions in cross-domain applications. To address these challenges, we propose an Underwater Wide-field Image Rectangling and Enhancement (UWIRE) framework that incorporates two procedures, i.e., the R-procedure and E-procedure, both of which employ self-coordinated modes, requiring only a single underwater stitched image as input. The R-procedure rectangles the irregular boundaries in stitched images by employing the initial shape resizing and mesh-based image preservation warping. Instead of local linear constraints, we use complementary optimization of boundary-structure-content to ensure a natural appearance with minimal distortion. The E-procedure enhances the rectangled image by employing parameter-adaptive correction to balance information distribution across channels. We further propose an attentive weight-guided fusion method to balance the perception of color restoration, contrast enhancement, and texture sharpening in a complementary manner. Comprehensive experiments demonstrate the superior performance of our UWIRE framework over state-of-the-art image rectangling and enhancement methods, both in quantitative and qualitative evaluation.

자전거 교통안전표지 시인성 개선을 위한 연구

In South Korea, personal mobility devices such as bicycles have recently gained attention due to air pollution concerns and eco-friendly policies.. However, as of 2023, bicycle paths in Seoul only account for 15% of all roads, and more than 10% of bicycle accidents in 2022 occurred while cyclists were walking or crossing the sidewalk. Since bicycles are legally prohibited from riding on sidewalks, there is an increasing need to improve bicycle traffic safety signs to ensure safe riding. This study assessed the condition of various bicycle traffic safety signs on road and surveyed bicycle users to evaluation their visibility when riding. The evaluation criteria included visibility, information usefulness, and color contrast. The findings showed that the effectiveness of signs is influenced by the use of colors and reflective materials that stand out from the surrounding environment. Based on these results, new design direactions were proposed to enhance bicycle safety. The outcomes of this study are expected to serve as foundational direaction of improvements for reducing bicycle-related accidents and promoting the use of bicycles.

Predator perception of aposematic and cryptic color morphs in two Oophaga species.

Animals that are toxic often advertise their unprofitability to potential predators through bright aposematic colors while cryptic ones blend in with their natural background to avoid predators. In the poison dart frogs, Oophaga pumilio and O. granulifera, some populations in Costa Rica and Panama display cryptic green and aposematic red color morphs. We herein used reflectance spectra from the dorsum of red and green morphs of these frogs to estimate their perception by the visual systems of three potential predators (birds, lizards, and crabs) against three natural backgrounds (leaves, trunks and leaf litter). Statistical analyses revealed no strong differences in color contrast against backgrounds between the two frog species. However, strong effects of frog morph, predator, background, and their interactions were observed. When viewed against diverse backgrounds, red frogs of both Oophaga species are more color conspicuous to birds and Anoline lizards than to crabs. A strong effect of species was observed on luminance contrast. Concerning the latter, green frogs particularly in O. granulifera appear more conspicuous than red frogs, while birds perceive higher brightness contrasts than lizards or crabs. Our results further support the importance of birds and lizards as Oophaga predators and provide a first quantitative comparison of conspicuousness between these two frog species.

Quality Improvements in Dementia Care in an Acute Hospital Setting

Abstract Background Dementia care in acute hospital settings requires targeted quality improvement initiatives based on national standards. This poster highlights key interventions to enhance care, aligning with local hospital group key performance indicators (KPIs), in one large teaching hospital. Methods Delirium screening (4AT) was implemented in the Emergency Department and geriatric ward, with education to increase staff awareness of delirium screening, prevention, and management. Audits assessed compliance with the 4AT tool. An audit evaluated the geriatric ward environment, including dementia-friendly painting, decorating, and signage, at baseline. Psychotropic prescribing practices were audited in 20 inpatient charts. A Life story Information tool (Sunflower Tool) was implemented to display personalized patient information at the end of the bed. Semi-annual audits assessed usage and effectiveness in the geriatric ward. Results The initial audit showed 85% compliance with the 4AT tool, dropping to 40% in a repeat audit after 6 months. Initially, 17 of 20 charts had complete 4AT scores; in the re-audit, 11 of 20 had scores recorded, with only 8 fully completed. The first environmental audit revealed poor compliance with dementia-friendly standards, especially in signage, clutter, and bedroom colour contrasts. Best compliance was seen with colour contrast in bathroom toilets and handrails. A quality improvement plan was developed to address gaps. The adoption and impact of the Sunflower tool improved patient-staff interactions and personalized care. All ward staff were trained in using the Sunflower tool. Conclusion A robust quality improvement plan, with measurable, achievable, relevant, and time-defined actions, aligned with national standards and local KPIs, is crucial to achieve and sustain positive audit results. Continuous education, resource allocation, and regular audits are required to ensure high-quality care for patients with dementia. Future efforts will focus on addressing identified challenges, refining interventions based on audit feedback, and maintaining care improvements.

A customised ConvNeXt-SCC network: integrating improved principal component analysis with ConvNeXt to enhance tire crown defect detection

ABSTRACT Defects such as bubbles and rubber shortages occasionally occur during vehicle tire production. Tiny defects in the crown gradually expand under load, ultimately causing tire failure. However, machine-vision-based crown defect detection faces challenges like limited datasets, varying groove patterns, low colour contrast, and small defect sizes. Therefore, this article integrates principal component analysis (PCA) and deep learning techniques for the visual detection of tire crown defects. A dataset of tire crown defects suitable for deep learning was constructed using an improved-PCA method and composite sampling. We propose the ConvNeXt-Shallow Conv CBAM (ConvNeXt-SCC) model, which includes an improved convolutional block attention module (CBAM) in a shallow stacked structure. And we propose an efficient and accurate method called Improved Selective Search (ISS) to detect and locate tire crown defective regions. The ISS pre-selected box generation method, enhanced with a priori knowledge filtering module, was used alongside a classification model to achieve online inference detection of large-size tire crown images. The experimental results show that the performance indices of the proposed ConvNeXt-Shallow Conv CBAM (ConvNeXt-SCC) model significantly improve compared to the original ConvNeXt-T. The defect detection and localisation method based on ISS meets the online inspection requirements of tire production.

Sustainable rewritable paper based on photoresponsive tungsten oxide quantum dots for anti-counterfeiting and waterproofing

Ink-free printing using photochromic paper has emerged as a promising technology for information recording, transmission, and secure interaction applications. Tungsten oxide quantum dots (WO3 QDs), with their rapid UV response, excellent photochemical stability, and outstanding fatigue resistance, exhibit significant potential as an ink-free medium in the construction of sustainable rewritable paper. However, challenges such as low binding force, poor stability, and weak scalability limit the development of reversible photochromic paper based on WO3. In this study, a novel sustainable rewritable paper based on a scalable strategy of covalent modification and hydrophobic layer protection has been reported. Specifically, cellulose papers modified with silane coupling agent were directly grafted with amino-modified WO3 QDs by covalent bonding through the addition reaction between epoxy and amine groups. Subsequently, the sustainable rewritable paper was obtained by the deposition of hydrophobic layer of polydimethylsiloxane (PDMS) via a dip-coating method. The rewritable paper exhibits exceptional properties, including high color contrast, extended color-retention (over 21 days), good rewritability (20 cycles) and excellent resistance to water or stains. Based on ink-free writing technology, the photo-responsive rewritable papers were utilized for anti-counterfeiting and encryption or decryption, demonstrating their great potential for information recording, storage, and security protection.

The effects of varying in incubation time and temperature of methyl salicylate as a clearing agent on the quality of breast tissue slides

Non-polar clearing agents have the ability to dissolve breast adipose tissue. While fat dissolution occurs during the clearing process, careful monitoring of adipose cell membranes mis crucial due to their impact on the behavior of breast cancer cells and disease progression. Xylol is a widely employed clearing agent. However, its toxicity and prolonged clearing time necessitate the exploration of alternatives. In this context, methyl salicylate emerges as a viable substitute. It is non-polar nature facilitates efficient fat dissolution, leading to quicker tissues clarification. This study adopted a quasi-experimental method, utilizing 24 pieces of breast tissue as the sample. These tissue sample were divided into six groups according to the treatment regimen. The treatment groups involved breast tissue clearing using xylol for 2x60 minutes at room temperature, methyl salicylate for 2x30 minutes at room temperature, and methyl salicylate at 60°C for 20 minutes, 30 minutes, 2x20 minutes, and 2x30 minutes. The quality of breast tissue slides was assessed by analyzing the color contrast between the nucleus and cytoplasm using ImageJ software, along with the clarity of adipose cell cell membrane using microscopy. The results indicated that prolonged exposure at high temperature resulted in poor quality breast tissue slides. Conversely, tissue clearing with methyl salicylate for 2x30 minutes at room temperature exhibited excellent contrast between the nucleus and cytoplasm, as well as clear adipose cell membranes. Further study is warranted to explore the applicability of methyl salicylate as a clearing agent in tissues with lower fat content.

Eccentricity, but not color contrast, influences microsaccadic prevention of visual fading

Eccentricity, but not color contrast, influences microsaccadic prevention of visual fading

A Survey of Image Enhancement and Dehazing Algorithms to Improving Autonomous Navigation in Fog and Dust.

Video captured during sand-dust weather conditions indicates significant degradation, diminished contrast, and pronounced color distortion. The reason behind this phenomenon is the impact of sand-dust particles, which result in the dispersion and assimilating of light. Consequently, resultant image seems blurred and lacks contrast. Additionally, the alteration in color is attributed to the swift reduction of blue light. Adverse weather circumstances, such as fog, sand, and dust storms, cause problems with vision for deploying self-driving automobiles. To guarantee secure and seamless operations during frequent adverse weather conditions, video enhancement plays a vital role in facilitating vehicular mobility and navigational in both road and air transportation. To improve the safety and efficiency of operation, it is imperative to employ video dehazing techniques, particularly in adverse weather conditions. The purpose of our overview is to offer interested researchers a thorough and methodical examination of image enhancement approaches, serving as an important point of reference for their work. The text explored different image enhancement methods, along with the challenges, constraints, advantages, and drawbacks associated with using these techniques throughout the past five years. Specifically, it focused on three aspects: supervised algorithms, unsupervised algorithms, and quality evaluation.

Application of interlayer perforation and installation of transparent elements in the technology of duplicated decorative polymer films

Objectives. To develop technologies for producing multilayer films of transparent thermoplastic polymers; to study methods of modifying their supramolecular structure; and to determine their optical properties by means of optical-polarization methods for the use of modified films as decorative and design materials in modern architecture.Methods. Industrial samples of polystyrene, low-density polyethylene, polypropylene, and polyvinyl chloride films from various manufacturers (Don Polimer, Vektor, and Sibur) were the objects of the study. The optical properties of the films were studied by means polarized-light spectrophotometry. In order to modify the supramolecular structure of the polymers, the surfaces of the films were treated under isometric conditions with volatile solvents or their aqueous solutions. Parts of the layers of multilayer films were removed by cutting with a punching knife using a press or with a manual device for perforating printing materials.Results. The spectral characteristics of multilayer films of several transparent thermoplastic polymers in polarized light were determined. The study showed that a wide palette of colors and contrasting images can be obtained by mechanically removing part of the layers of multilayer films. The phenomenon of pseudo-disappearance of the outermost layer was discovered after treatment of a stack of films under isometric conditions with volatile solvents or their aqueous solutions.Conclusions. Based on the example of large-scale production thermoplastics, it was shown that a combination of technological methods of stacking, perforation, and local plasticization of films of transparent thermoplastic polymers can produce pleochroic multicolor materials for a range of human activities. The possibility of hidden coding of information on multilayer packaging materials, and its visualization and instrumental reading in polarized light was confirmed by color differential and contrast of 150 and 60 units, respectively. It was also shown that several monochrome tones of different lightness and brightness can be obtained by varying the number of layers or perforating the films in multilayer materials.

Identifying images in the biology literature that are problematic for people with a color-vision deficiency.

To help maximize the impact of scientific journal articles, authors must ensure that article figures are accessible to people with color-vision deficiencies (CVDs), which affect up to 8% of males and 0.5% of females. We evaluated images published in biology- and medicine-oriented research articles between 2012 and 2022. Most included at least one color contrast that could be problematic for people with deuteranopia ('deuteranopes'), the most common form of CVD. However, spatial distances and within-image labels frequently mitigated potential problems. Initially, we reviewed 4964 images from eLife, comparing each against a simulated version that approximated how it might appear to deuteranopes. We identified 636 (12.8%) images that we determined would be difficult for deuteranopes to interpret. Our findings suggest that the frequency of this problem has decreased over time and that articles from cell-oriented disciplines were most often problematic. We used machine learning to automate the identification of problematic images. For a hold-out test set from eLife (n=879), a convolutional neural network classified the images with an area under the precision-recall curve of 0.75. The same network classified images from PubMed Central (n=1191) with an area under the precision-recall curve of 0.39. We created a Web application (https://bioapps.byu.edu/colorblind_image_tester); users can upload images, view simulated versions, and obtain predictions. Our findings shed new light on the frequency and nature of scientific images that may be problematic for deuteranopes and motivate additional efforts to increase accessibility.

Visual Interpretation of High-Resolution Aerial Imagery: A Tool for Land Managers

Abstract Remotely sensed imagery from various collection platforms (e.g., satellites, crewed and uncrewed aircraft) are used by biologists and other conservation personnel to support management activities ranging from monitoring invasive species to assessing land cover and vegetation characteristics. Although remote sensing–based vegetation indices and models have been developed and used for some management applications, straightforward visual interpretation of imagery by on-the-ground personnel may be a pragmatic approach for obtaining time-sensitive and spatially relevant information to support and guide local management activities. Our primary objective was to qualitatively assess our ability to identify patches of target invasive plant species based on simple visual interpretation of high-resolution aerial imagery. We also sought to compare the high-resolution imagery to widely available imagery (e.g., National Agriculture Imagery Program) to determine the efficacy of each for assessing vegetation communities and land-cover features in support of management activities. To accomplish these objectives, we obtained high-resolution imagery and visually scanned and assessed the imagery by using standard geographic information system software. We were able to differentiate patches of crownvetch Securigera varia (L.) Lassen and wild parsnip Pastinaca sativa L., but not spotted knapweed Centaurea stoebe L. or leafy spurge Euphorbia esula L. The relative success in identifying these species had a relationship to plant characteristics (e.g., flower color and morphology, height), time of year (phenology), patch size and density, and potentially site characteristics such density of the underlying vegetation (e.g., grasses), substrate color characteristics (i.e., color contrast with flowers), and physical disturbance. Our straightforward, qualitative assessment suggests that visual interpretation of high-resolution imagery, but not some lower-resolution imagery, may be an efficient and effective tool for supporting local invasive species management through activities such as monitoring known patches, identifying undetected infestations, assessing management actions, guiding field work, or prioritizing on-the-ground monitoring activities.

Effect of hydrothermal aging on color stability and translucency of two zirconia generations compared to lithium disilicate ceramics.

An esthetically acceptable ceramic restoration should have optical properties like the teeth and reflect, transmit, and absorb light. The present investigation compared how hydrothermal aging affected the properties of two types of zirconia and lithium disilicate. Thirty rectangular samples (12×14×1 mm) were prepared and sectioned from three different ceramic blocks/blanks (n=10), then assigned into three groups according to the ceramic type: group Z: IPS e.max ZirCAD prime, gradient zirconia (3Y/5Y-TZP); group K: Katana UTML (5Y-TZP); and group E: IPS e.max CAD (lithium disilicate). Color analysis of samples was performed before and after hydrothermal aging (1, 3, and 5 hours) using a spectrophotometer. Color difference (∆E00), translucency parameter (TP00), and contrast ratio (CR) were evaluated. The microstructural analysis was performed using x-ray diffraction (XRD). Data were statistically analyzed at a significance level of P<0.05. A statistically significant variation was observed across means of ∆E00, TP00, and CR at different times. Group Z displayed the highest statistically significant mean ∆E00. Group E demonstrated the greatest statistically significant mean TP00. Group K exhibited the most statistically significant mean CR. Hydrothermal aging significantly affected the optical characteristics of lithium disilicate and zirconia ceramics. The translucency of samples increased with aging.

Underwater image restoration method based on Walsh–Hadamard transform and attenuation coefficient estimation

Abstract Underwater images often exhibit color distortion and low contrast due to the scattering and absorption of light as it travels through water. Changes in lighting conditions further complicate the restoration and enhancement of these images. Improving the quality of underwater images is crucial for advancements in fields such as marine biology research, underwater measurement, and environmental monitoring. This paper proposes an underwater image restoration method based on the Image Formation Model (IFM), utilizing the Walsh–Hadamard transform and attenuation coefficient estimation. Traditional methods rely on dark channel prior and maximum intensity prior to estimate background light (BL) and transmission maps (TMs), often performing poorly in various underwater environments. Our method uses image blur to estimate BL and depth maps and derives three-channel attenuation coefficients using the gray-world theory to obtain a more accurate TM. Experimental results on real underwater images show that our method effectively eliminates color deviation and contrast distortion while preserving image details, significantly outperforming other IFM-based restoration techniques. Compared to the closest competing algorithms, our method achieves better UIQM and UCIQE scores.

Accuracy of a commonly used mobile ophthalmology application's vision assessment tools in measuring five vision assessment parameters.

The use of mobile ophthalmology applications (MOA) is increasing, but many of these tools have not been validated. This study was performed to assess the accuracy of a popular MOA, Eye Handbook, in measuring five commonly-tested vision assessment parameters (distance visual acuity (DVA), near visual acuity (NVA), colour vision testing (CVT), contrast sensitivity (CS), and pupillary distance (PD)) was compared with traditional vision assessment methods (TVAM) [i.e. Snellen chart, Rosenbaum near card, Ishihara, Pelli Robson test, etc.] performed in the eye clinic setting. Prospective crossover clinical trial of 129 patients meeting inclusion criteria. Participants averaged significantly better DVA (p = 0.0008), NVA (p < 0.0001), and CVT (p = 0.0105) in the MOA than the TVAM, but all three MOA assessments were predictive of the TVAM values. CS was significantly better with the MOA (p < 0.0001). Linear regression and Spearman correlation tests were applied to assess the effect of CS on NVA, which showed no clear relationship between the difference in NVA and the difference in CS. PD using the two methods was in agreement with no significant difference (p = 0.2889). The studied MOA offers an effective means of measuring four common vision parameters: DVA, NVA, CVT, and PD. The MOA can potentially be used by eye care providers, health care providers, and patients, both as a screening tool with correction factor and to monitor ocular pathologies. Atypical MOA measurements should prompt testing in the clinic with formal TVAMs.

Retinomorphic Color Perception Based on Opponent Process Enabled by Perovskite Bipolar Photodetectors.

The ability to perceive color by the retina can be attributed to both its trichromatic photoreceptors and the antagonistic neural wiring known as the opponent process. While neuromorphic sensors have been shown to demonstrate memory and adaptation capabilities, color perception is still challenging due to the intrinsic lack of spectral selectivity in narrow bandgap semiconductors. Furthermore, research on emulating neural wiring is severely lacking. The combination of halide perovskite materials with a tunable bandgap and a novel bipolar photodetector design emulates the efficiency of the retina in processing color information. The stimuli-responsive material is also responsible for maintaining partial color constancy-an adaptation feature. Leveraging the unique enhancement of color contrasts, an in-sensor data compression and edge detection can also be demonstrated. The color perception, chromatic adaptation, and color contrast enhancement make perovskite bipolar photodetectors a unique example where the sensor and neural wiring can be co-developed in conjunction.

A robust underwater polarization image recovery based on Angle of Polarization with low-rank and sparse decomposition

Underwater imaging method based on the Angle of Polarization (AoP) is extremely popular due to its ability to remove the backscattered light effectively. However, existing methods overlook a potentially important phenomenon: the AoP contains significant noise in the real world, which leads to inaccurate estimations of key parameters. In this study, we propose a novel robust underwater polarization image recovery method based on AoP with low-rank and sparse decomposition. Based on the analysis of polarization, the AoP of backscattering exhibits low-rank characteristics, whereas the AoP of noise and targets demonstrates sparsity. Considering different sparsity of AoP, we combine Robust Principal Component Analysis and Alternating Direction Multiplier Method (RPCA-ADMM) with an adaptive threshold shrinkage method for low-rank and sparse decomposition, the AoP of the backscattering is obtained. Moreover, according to the low-rank component of the AoP, the Degree of Linear Polarization (DoLP) of backscattering can be effectively and automatically estimated without considering whether the background region exists, relying on a frequency prior strategy. Finally, the degraded image is recovered utilizing underwater polarization imaging model. Extensive experimental results demonstrate that the recovered images from the proposed method have abundant detail, high contrast, and minimal color distortion, which is competitive with most state-of-the-art methods.

Color Maps: Facilitating the Clinical Impact of Quantitative MRI.

Presenting quantitative data using non-standardized color maps potentially results in unrecognized misinterpretation of data. Clinically meaningful color maps should intuitively and inclusively represent data without misleading interpretation. Uniformity of the color gradient for color maps is critically important. Maximal color and lightness contrast, readability for color vision-impaired individuals, and recognizability of the color scheme are highly desirable features. This article describes the use of color maps in five key quantitative MRI techniques: relaxometry, diffusion-weighted imaging (DWI), dynamic contrast-enhanced (DCE)-MRI, MR elastography (MRE), and water-fat MRI. Current display practice of color maps is reviewed and shortcomings against desirable features are highlighted. EVIDENCE LEVEL: 5 TECHNICAL EFFICACY: Stage 2.

Contrast Sensitivity, Color Discrimination and Visual Acuity as Risk Factors for Visual Dysfunction in Non-Proliferative Diabetic Retinopathy

Contrast Sensitivity, Color Discrimination and Visual Acuity as Risk Factors for Visual Dysfunction in Non-Proliferative Diabetic Retinopathy

Thermochromic Properties of 3C-, 6H- and 4H-SiC Polytypes up to 500°C

The thermochromic properties (color change with temperature) of n type doped SiC wafers of different polytypes (3C, 4H and 6H) have been investigated up to 500°C under air. It was found that 3C-SiC color passes from bright yellow at room temperature to deep orangeat 500°C leading to a color contrast (ΔE) as high as 64. The hexagonal polytypes undergo also a color change upon heating but far less pronounced, with ΔE values &lt;20. All these semiconductors undergo band gap shrinkage upon heating which effect largely participated to the observed color change. This effect is very sensitive for 3C polytypesince its bandgap is already in the visible energy range at room temperature. The thermochromicity of 3C-SiC was found to be reversible thanks to its thermal stability and its resistance towards oxidation.