Handheld dermatoscope versus digital camera for hair counts in laser facial hair removal.

The lack of uniform and objective techniques to evaluate treatment efficacy in photo-epilation studies leads to contradictory results. Thus, there is an urgent need to explore commonly accepted assessment tools. One of the most common methods uses hair counts via digital photography. However, macrophotography may not be able to depict the vellus-like hair induced by photo-epilation. On the other hand, handheld dermatoscopy is practical, affordable and offers high-quality magnification. Hair counts from a handheld dermatoscope and a digital camera were compared in 73 women who underwent 6 sessions with the Alexandrite 755 nm laser. Significantly more hairs were counted using the dermatoscope than using the digital camera (76.9 ± 41.3 vs. 58.6 ± 31.4, p < .005), independently of hair thickness and hair density. The difference in hair counts between the two instruments was inversely related to hair thickness and directly related to hair density. The handheld dermatoscope may be a more effective tool than the widely used digital camera in evaluating the response to laser hair removal treatment.

Color Conversion of Wide-Color-Gamut Cameras Using Optimal Training Groups.

The colorimetric conversion of wide-color-gamut cameras plays an important role in the field of wide-color-gamut displays. However, it is rather difficult for us to establish the conversion models with desired approximation accuracy in the case of wide color gamut. In this paper, we propose using an optimal method to establish the color conversion models that change the RGB space of cameras to the XYZ space of a CIEXYZ system. The method makes use of the Pearson correlation coefficient to evaluate the linear correlation between the RGB values and the XYZ values in a training group so that a training group with optimal linear correlation can be obtained. By using the training group with optimal linear correlation, the color conversion models can be established, and the desired color conversion accuracy can be obtained in the whole color space. In the experiments, the wide-color-gamut sample groups were designed and then divided into different groups according to their hue angles and chromas in the CIE1976L*a*b* space, with the Pearson correlation coefficient being used to evaluate the linearity between RGB and XYZ space. Particularly, two kinds of color conversion models employing polynomial formulas with different terms and a BP artificial neural network (BP-ANN) were trained and tested with the same sample groups. The experimental results show that the color conversion errors (CIE1976L*a*b* color difference) of the polynomial transforms with the training groups divided by hue angles can be decreased efficiently.

Estimating Fluor Emission Spectra Using Digital Image Analysis Compared to Spectrophotometer Measurements.

This paper describes a practical method for obtaining the spectra of lights emitted by a fluor in a liquid scintillator (LS) using a digital camera. The emission wavelength results obtained using a digital image were compared with those obtained using a fluorescence spectrophotometer. For general users, conventional spectrophotometers are expensive and difficult to access. Moreover, their experimental measurement setup and processes are highly complicated, and they require considerable care in handling. To overcome these limitations, a feasibility study was performed to obtain the emission spectrum through image analysis. Specifically, the emission spectrum of a fluor dissolved in a liquid scintillator was obtained using digital image analysis. An image processing method was employed to convert the light irradiated during camera exposure into wavelengths. Hue (H) and wavelength (W) are closely related. Thus, we obtained an H-W response curve in the 400~450 nm wavelength region, using a light-emitting diode. Another relevant advantage of the method described in this study is its non-invasiveness in sealed LS samples. Our results showed that this method has the potential to accurately investigate the emission wavelengths of fluor within acceptable uncertainties. We envision the use of this method to perform experiments in chemistry and physics laboratories in the future.

Investigation of the Hue-Wavelength Response of a CMOS RGB-Based Image Sensor.

In this study, a non-linear hue-wavelength (H-W) curve was investigated from 400 to 650 nm. To date, no study has reported on H-W relationship measurements, especially down to the 400 nm region. A digital camera mounted with complementary metal oxide semiconductor (CMOS) image sensors was used. The obtained digital images of the sample were based on an RGB-based imaging analysis rather than multispectral imaging or hyperspectral imaging. In this study, we focused on the raw image to reconstruct the H-W curve. In addition, several factors affecting the digital image, such as exposure time or international organization for standardization (ISO), were investigated. In addition, cross check of the H-W response using laser was performed. We expect that our method will be useful as an auxiliary method in the future for obtaining the fluor emission wavelength information.

The Spectrum of Light Emitted by LED Using a CMOS Sensor-Based Digital Camera and Its Application.

We introduced a digital photo image analysis in color space to estimate the spectrum of fluor components dissolved in a liquid scintillator sample through the hue and wavelength relationship. Complementary metal oxide semiconductor (CMOS) image sensors with Bayer color filter array (CFA) technology in the digital camera were used to reconstruct and decode color images. Hue and wavelength are closely related. To date, no literature has reported the hue and wavelength relationship measurements, especially for blue or close to the UV region. The non-linear hue and wavelength relationship in the blue region was investigated using a light emitting diode source. We focused on this wavelength region, because the maximum quantum efficiency of the bi-alkali photomultiplier tube (PMT) is around 430 nm. It is necessary to have a good understanding of this wavelength region in PMT-based experiments. The CMOS Bayer CFA approach was sufficient to estimate the fluor emission spectrum in the liquid scintillator sample without using an expensive spectrophotometer.

Pixel Image Analysis and Its Application with an Alcohol-Based Liquid Scintillator for Particle Therapy.

We synthesized an alcohol-based liquid scintillator (AbLS), and we implemented an auxiliary monitoring system with short calibration intervals using AbLS for particle therapy. The commercial liquid scintillator used in previous studies did not allow the user to control the chemical ratio and its composition. In our study, the chemical ratio of AbLS was freely controlled by simultaneously mixing water and alcohol. To make an equivalent substance to the human body, 2-ethoxyethanol was used. There was no significant difference between AbLS and water in areal density. As an application of AbLS, the range was measured with AbLS using an electron beam in an image analysis that combined AbLS and a digital phone camera. Given a range-energy relationship for the electron expressed as areal density, the electron beam range (cm) in water can be easily estimated. To date, no literature report for the direct comparison of a pixel image analysis and Monte Carlo (MC) simulation has been published. Furthermore, optical tomography of the inverse problem was performed with AbLS and a mobile phone camera. Analyses of optical tomography images provide deeper insight into Radon transformation. In addition, the human phantom, which is difficult to compose with semiconductor diodes, was easily implemented as an image acquisition and analysis system.

DisCaaS: Micro Behavior Analysis on Discussion by Camera as a Sensor.

The emergence of various types of commercial cameras (compact, high resolution, high angle of view, high speed, and high dynamic range, etc.) has contributed significantly to the understanding of human activities. By taking advantage of the characteristic of a high angle of view, this paper demonstrates a system that recognizes micro-behaviors and a small group discussion with a single 360 degree camera towards quantified meeting analysis. We propose a method that recognizes speaking and nodding, which have often been overlooked in existing research, from a video stream of face images and a random forest classifier. The proposed approach was evaluated on our three datasets. In order to create the first and the second datasets, we asked participants to meet physically: 16 sets of five minutes data from 21 unique participants and seven sets of 10 min meeting data from 12 unique participants. The experimental results showed that our approach could detect speaking and nodding with a macro average f1-score of 67.9% in a 10-fold random split cross-validation and a macro average f1-score of 62.5% in a leave-one-participant-out cross-validation. By considering the increased demand for an online meeting due to the COVID-19 pandemic, we also record faces on a screen that are captured by web cameras as the third dataset and discussed the potential and challenges of applying our ideas to virtual video conferences.

Estimation of Fluor Emission Spectrum through Digital Photo Image Analysis with a Water-Based Liquid Scintillator.

In this paper, we performed a feasibility study of using a water-based liquid scintillator (WbLS) for conducting imaging analysis with a digital camera. The liquid scintillator (LS) dissolves a scintillating fluor in an organic base solvent to emit light. We synthesized a liquid scintillator using water as a solvent. In a WbLS, a suitable surfactant is needed to mix water and oil together. As an application of the WbLS, we introduced a digital photo image analysis in color space. A demosaicing process to reconstruct and decode color is briefly described. We were able to estimate the emission spectrum of the fluor dissolved in the WbLS by analyzing the pixel information stored in the digital image. This technique provides the potential to estimate fluor components in the visible region without using an expensive spectrophotometer. In addition, sinogram analysis was performed with Radon transformation to reconstruct transverse images with longitudinal photo images of the WbLS sample.

Mix-and-read method for assessment of milk pasteurization using a smartphone or a common digital camera.

Alkaline phosphatase (ALP) is the most widely used marker of the adequacy of milk pasteurization since it is inactivated at temperatures slightly higher than those required for elimination of pathogens. The cutoff level is 350 mU/L. The approved colorimetric, fluorometric, and chemiluminometric methods require specialized readers with photomultipliers as detectors, and the samples are usually analyzed one-by-one. We developed a low-cost mix-and-read method that exploited a smartphone or a common digital camera as detectors for the chemiluminometric determination of ALP in milk. As samples, we used pasteurized cow and sheep milk spiked with ALP, as well as mixtures of pasteurized and raw (non-pasteurized) milk. Chemiluminescence images acquired by the smartphone or the digital camera were analyzed by the ImageJ software. The limits of detection (LODs), for images captured by the smartphone, were 4.4 mU/L and 11.1 mU/L for cow milk and sheep milk, respectively, while with the digital camera, the respective LODs were 6.2 mU/L and 6.7 mU/L, respectively. The coefficients of variation (CVs) at the cutoff level of 350 mU/L were 8% and 8.5% for the cow and sheep milk, respectively. For images by the digital camera, the CVs were 5.8% and 5% for cow and sheep milk, respectively. The performance of the method is similar to methods that use a microtiter plate and a luminometer for chemiluminescence measurements. Sample pretreatment is not necessary. The microtiter well format combined with detection by a smartphone enables the analysis of multiple samples simultaneously. It is anticipated that the method will prove useful for the rapid assessment of milk pasteurization efficiency in dairy industries, especially in remote areas where expensive instruments are not available. Graphical abstract.

Quality and Feasibility of Automated Digital Retinal Imaging in the Emergency Department.

BACKGROUND: Emergency physicians (EPs) frequently evaluate patients at risk for sight-threatening conditions but may have difficulty performing direct ophthalmoscopy effectively. Digital fundus photography offers a potential alternative. OBJECTIVE: We sought to assess the performance of an automated digital retinal imaging platform in a real-world emergency department. METHODS: We performed a prospective, observational study of emergency department patients who were at risk for acute, nontraumatic, posterior segment pathology. Photographs were obtained using an automated digital retinal camera and were subsequently reviewed by an ophthalmologist. We recorded the number of attempts required, total time required, patient comfort, and findings on EP-performed direct ophthalmoscopy, if performed. RESULTS: Of 123 participants completing the study, 93 (75.6%) had ≥1 eye with a diagnostically useful image, while 29 (23.6%) had no photographs of diagnostic value. The mean number of attempts required to obtain images was 1.45 (range 1-3) and the mean elapsed time required to complete photography was 109.6 s. The mean patient comfort score was 4.6 on a 5-point scale, where 5 was the most comfortable. Direct ophthalmoscopy was performed by an emergency department provider for 19 (15.4%) patients. Acute findings were noted in 14 patients during expert review of fundus photographs, though in only 2 of these cases was direct ophthalmoscopy performed by an EP with only 1 finding ultimately identified correctly. CONCLUSIONS: Automated digital imaging of the ocular fundus is rapidly performed, is well tolerated by patients, and can be used to obtain diagnostic quality images without the use of pharmacologic pupillary dilation in most emergency department patients who are at risk for acute posterior segment pathology.

Direct Georeferencing for the Images in an Airborne LiDAR System by Automatic Boresight Misalignments Calibration.

Airborne Light Detection and Ranging (LiDAR) system and digital camera are usually integrated on a flight platform to obtain multi-source data. However, the photogrammetric system calibration is often independent of the LiDAR system and performed by the aerial triangulation method, which needs a test field with ground control points. In this paper, we present a method for the direct georeferencing of images collected by a digital camera integrated in an airborne LiDAR system by automatic boresight misalignments calibration with the auxiliary of point cloud. The method firstly uses an image matching to generate a tie point set. Space intersection is then performed to obtain the corresponding object coordinate values of the tie points, while the elevation calculated from the space intersection is replaced by the value from the LiDAR data, resulting in a new object point called Virtual Control Point (VCP). Because boresight misalignments exist, a distance between the tie point and the image point of VCP can be found by collinear equations in that image from which the tie point is selected. An iteration process is performed to minimize the distance with boresight corrections in each epoch, and it stops when the distance is smaller than a predefined threshold or the total number of epochs is reached. Two datasets from real projects were used to validate the proposed method and the experimental results show the effectiveness of the method by being evaluated both quantitatively and visually.

Heat Transfer and Temperature Characteristics of a Working Digital Camera.

Digital cameras represented by industrial cameras are widely used as image acquisition sensors in the field of image-based mechanics measurement, and their thermal effect inevitably induces thermal-induced errors of the mechanics measurement. To deeply understand the errors, the research for digital camera's thermal effect is necessary. This study systematically investigated the heat transfer processes and temperature characteristics of a working digital camera. Concretely, based on the temperature distribution of a typical working digital camera, the heat transfer of the working digital camera was investigated, and a model describing the temperature variation and distribution was presented and verified experimentally. With this model, the thermal equilibrium time and thermal equilibrium temperature of the camera system were calculated. Then, the influences of thermal parameters of digital camera and environmental temperature on the temperature characteristics of working digital camera were simulated and experimentally investigated. The theory analysis and experimental results demonstrate that the presented model can accurately describe the temperature characteristics and further calculate the thermal equilibrium state of working digital camera, all of which contribute to guiding mechanics measurement and thermal design based on such camera sensors.

Measurement of Water Leaving Reflectance Using a Digital Camera Based on Multiple Reflectance Reference Cards.

With the development of citizen science, digital cameras and smartphones are increasingly utilized in water quality monitoring. The smartphone application HydroColor quantitatively retrieves water quality parameters from digital images. HydroColor assumes a linear relationship between the digital pixel number (DN) and incident radiance and applies a grey reference card to derive water leaving reflectance. However, image DNs change with incident light brightness non-linearly, according to a power function. We developed an improved method for observing and calculating water leaving reflectance from digital images based on multiple reflectance reference cards. The method was applied to acquire water, sky, and reflectance reference card images using a Cannon 50D digital camera at 31 sampling stations; the results were validated using synchronously measured water leaving reflectance using a field spectrometer. The R2 for the red, green, and blue color bands were 0.94, 0.95, 0.94, and the mean relative errors were 27.6%, 29.8%, 31.8%, respectively. The validation results confirm that this method can derive accurate water leaving reflectance, especially when compared with the results derived by HydroColor, which systematically overestimates water leaving reflectance. Our results provide a more accurate theoretical foundation for quantitative water quality monitoring using digital and smartphone cameras.

A highly sensitive colorimetric assessment of hexavalent chromium using a digital camera.

Simple, low-cost, and sensitive methods for the assessment of hexavalent chromium as an important environmental pollutant are highly desirable, especially under resource-limited settings. Therefore, herein we propose an original approach for the simple, low-cost, selective, and extremely sensitive assessment of Cr(VI) utilizing its catalysis of the micellar sensitized o-dianisidine (DA)-hydrogen peroxide reaction. The initial rate of the amended reaction is monitored by tracing the oxidation product, either by a digital camera video recording or spectrophotometrically at 440 nm, for 120 s from mixing the reactants. The optimized reaction conditions were 5 mmol L-1 DA, 0.6 mol L-1 H2O2, 2.0 v/v% Tween 20, and 10 mmol L-1 chloroacetate buffer (pH 4.5 ± 0.1), at 30 °C. The linear calibration graph extends to 90.0 ng mL-1 Cr(VI) with detection limits (3Sb) of 0.8 and 1.0 ng mL-1, for the video recording and spectrophotometric procedures, respectively. The amended method was successfully applied to the assessment of Cr(IV) in natural and polluted industrial wastewaters. The analytical data were in excellent statistical harmony with those of the standard ETAAS method. The proposed method is two orders of magnitude more sensitive than the diphenylcarbazide standard spectrophotometric method.Graphical abstract.

[Assessment Tool of Image Quality for Medical Liquid-crystal Displays Using Commercially Available Digital Cameras].

We developed a simplified tool for measuring image quality of medical liquid-crystal displays (LCDs) using a commercially available color digital camera. This tool implemented as a plug-in software for ImageJ (open-source image processing program) was designed to compute modulation transfer functions (MTFs) and Wiener spectra (WS) of monochrome and color LCDs from LCD photographed images captured by a camera. The intensities of the red (R), green (G), and blue (B) signals of the unprocessed image data depend on the spectral sensitivity of the image sensor used in the camera. In order to evaluate image quality based on LCD luminance, the plug-in software calibrates the RGB signals from the camera using measured luminance of the LCD and converts them into grayscale signals that correspond to the luminance of the LCD. The MTFs and WS are determined based on the line response from a one-pixel line image and the one-dimensional noise profiles acquired by scanning the uniform image using numerically synthesized slit, respectively. With this plug-in software for ImageJ, we are able to readily compute MTFs and WS of both monochrome and color LCDs from unprocessed image data of cameras. Our simplified tool is helpful to evaluate and understand the physical performance of LCDs for a large number of display users in hospitals and medical centers.

Simple method to detect year-to-year variability of blooming phenology of Cerasus × yedoensis by digital camera.

The year-to-year variability of the blooming phenology of cherry trees is important as a proxy climate indicator and strongly affects cultural ecosystem services. Observation of blooming phenology at multiple points requires a simple and flexible approach. We examined changes in the canopy gap fraction extracted from binarized upward images taken periodically beneath a Cerasus × yedoensis 'Somei-yoshino' tree. The gap fraction decreased rapidly after the start of bloom, reached a minimum value at full bloom, and began to increase again, but then decreased rapidly during leaf flush. These changes reflect the phenology of blooming and leaf flush after flower drop of 'Somei-yoshino'. These characteristics allow detection of the year-to-year variability of the bloom and leaf-flush phenology of cherry and other deciduous tree species that show the same patterns.

Colorimetric detection of Hg(II) by measurement the color alterations from the "before" and "after" RGB images of etched triangular silver nanoplates.

It is shown that triangular silver nanoplates (TAgNPs) are viable colorimetric probes for the fast, sensitive and selective detection of Hg(II). Detection is accomplished by reducing Hg(II) ions to elemental Hg so that an Ag/Hg amalgam is formed on the surface of the TAgNPs. This leads to the inhibition of the etching TAgNPs by chloride ions. Correspondingly, a distinct color transition can be observed that goes from yellow to brown, purple, and blue. The color alterations extracted from the red, green, and blue part of digital (RGB) images can be applied to the determination of Hg(II). The relationship between the Euclidean distances (EDs), i.e. the square roots of the sums of the squares of the ΔRGB values, vary in the 5 nM to 100 nM Hg(II) concentration range, and the limit of detection is as low as 0.35 nM. The color changes also allow for a visual estimation of the concentrations of Hg(II). The method is simple in that it only requires a digital camera for data acquisition and a Photoshop software for extracting RGB variations and data processing. Graphical abstract Hg2+ detection was achieved by anti-etching of TAgNPs caused by the formation of silver amalgam, along with vivid multicolor variations from yellow to brown, purple, and eventually to be blue.

Evaluation to prevent the Physical Changes in Colored Elastomeric Modules when exposed to various Dietary Media.

AIM AND OBJECTIVE: The aim of the study is to analyze and compare the variation of lumen size and thickness of the elastomeric colored modules when immersed in four selected dietary media. MATERIALS AND METHODS: Sample size of 40 modules on each color - such as red, blue, green, and black - was taken and immersed in four dietary media (artificial saliva, coke mixed with artificial saliva, turmeric mixed with artificial saliva, and coffee mixed with artificial saliva). Beakers containing different dietary media and color modules are kept in the incubator at 37°C for 72 hours. After incubation period, all the segments of module strips removed from the dietary media were placed under the electric lamp and photographs were taken using Canon camera (SX400 IS). Photographs were transferred to GIMP software, and lumen size and thickness variation in the modules was measured. RESULTS: Statistical analysis were performed using analysis of variance and t-test in Statistical Package for the Social Sciences software. It showed significant difference in thickness of black module in all dietary media. Significant difference existed between all the lumen sizes of four color modules in four dietary media. CONCLUSION: This study was done to identify the material that has more changes in physical properties when exposed to various dietary media. CLINICAL SIGNIFICANCE: According to the results obtained, black color modules have increased in lumen size in all dietary media. In thickness, red color module showed less variation and black color module exhibited more variation.

Digital camera and smartphone as detectors in paper-based chemiluminometric genotyping of single nucleotide polymorphisms.

Chemi(bio)luminometric assays have contributed greatly to various areas of nucleic acid analysis due to their simplicity and detectability. In this work, we present the development of chemiluminometric genotyping methods in which (a) detection is performed by using either a conventional digital camera (at ambient temperature) or a smartphone and (b) a lateral flow assay configuration is employed for even higher simplicity and suitability for point of care or field testing. The genotyping of the C677T single nucleotide polymorphism (SNP) of methylenetetrahydropholate reductase (MTHFR) gene is chosen as a model. The interrogated DNA sequence is amplified by polymerase chain reaction (PCR) followed by a primer extension reaction. The reaction products are captured through hybridization on the sensing areas (spots) of the strip. Streptavidin-horseradish peroxidase conjugate is used as a reporter along with a chemiluminogenic substrate. Detection of the emerging chemiluminescence from the sensing areas of the strip is achieved by digital camera or smartphone. For this purpose, we constructed a 3D-printed smartphone attachment that houses inexpensive lenses and converts the smartphone into a portable chemiluminescence imager. The device enables spatial discrimination of the two alleles of a SNP in a single shot by imaging of the strip, thus avoiding the need of dual labeling. The method was applied successfully to genotyping of real clinical samples. Graphical abstract Paper-based genotyping assays using digital camera and smartphone as detectors.

Accuracy of Three Shade-matching Devices in Replicating the Shade of Metal Ceramic Restorations: An in vitro Study.

INTRODUCTION: In restorative dentistry, the clinician commonly encounters the challenge of replicating the color of natural teeth due to the subjectivity of perceptual evaluation. Recent advances in photography and computing have resulted in the widespread use of the digital camera for color imaging. These instruments can be used effectively for shade matching and communication to yield predictable results. MATERIALS AND METHODS: The study sample consisted of 20 freshly extracted noncarious premolars. The Commission Internationale de l'Eclairage (CIE) L*a*b* values of the tooth were obtained through a spectrophotometer, digital camera, and digital camera with a polarizer. Shade selection was carried out using VITA 3D Master and calculating the Euclidian distance. The fabricated metal ceramic crowns were then evaluated to check the shade replication by comparing the CIE L*a*b* values of the crowns with the reference shade tab images. RESULTS: The three-way analysis of variance (ANOVA) and comparative analysis using Bonferroni test reveals that the difference in the mean L*a* values between spectrophotometer and polarization dental imaging modality (PDIM) was insignificant. The difference in the mean L*a*b* of spectrophotometer and digital camera was statistically significant. The mean ΔE for metal ceramic crowns and shade tabs was 4.2 that was greater than the clinically acceptable level (3.2). CONCLUSION: A statistically significant correlation was found to exist between the spectrophotometer and PDIM for all CIE L*, a*, and b* color coordinates. CLINICAL SIGNIFICANCE: The present study was undertaken to assess the shade-matching ability of three shade-matching devices, such as spectrophotometer, digital camera, and PDIM, in the accuracy of replication of metal ceramic restorations.