A digital imaging method for measuring banana ripeness

Visually assessed appearance is undoubtedly of great importance to the selection of fruit by the consumer at the point of sale while the food supply chain also heavily relies on colour assessment methodologies for the determination of product quality. The use of printed colour charts to assess the ripening stages of fruits (i.e., banana ripeness charts) and/or vegetables is common in the fresh produce supply chain, even though they have limitations. However, the development of a more reliable and an objective instrumental method is necessary to describe fruit ripeness using set colour appearance parameters rather than subjective evaluations based on colour charts. In this article, we report a novel digital imaging methodology that could be used by the fresh produce industry to estimate the ripening stages of bananas more accurately. © 2012 Wiley Periodicals, Inc. Col Res Appl, 38, 364–374, 2013     

Optimal selection of representative samples for efficient digital camera-based spectra recovery

For digital camera-based spectra recovery, the spectral reflectance of the object being imaged always needs to be accurately recovered using training samples from available database. Considering the heavy workload when using all samples in database as training samples in practice, a new representative samples selection method is proposed for efficient digital camera-based spectra recovery based on single RGB image. The representative simulation system is firstly constructed through correlation analysis of spectra recovery results of different systems, and based on the representative simulation system, a few number of representative samples are selected from the database based on minimum of the defined simulate spectra recovery error. The effectiveness of the proposed method is evaluated and compared with existing method. As the results show, the proposed method outperforms the existing methods, and the robustness of the selected representative samples is consistent with the database in practical applications.     

Experimental study of particle rotation characteristics with high-speed digital imaging system

Particle rotation plays an important role on several aspects in gas-solid two-phase flow. However, it has not been paid much attention due to a lack of appropriate measurement methods. An attempt has been made in the present paper on the experimental study of particle rotation characteristics in a cold pilot-scale Circulating Fluidized Bed (CFB) riser, by using a high-speed digital imaging measurement system. It is found that one can measure rotation speeds manually for particles with special speckles on their surfaces or irregular shapes by observing particle image sequences. A dual-frequency imaging method was presented to enlarge the maximal measurable rotation speed at finite frame frequency and the measured rotation speeds are validated theoretically. Furthermore, particle rotation characteristics in a cross-section in upper dilute-phase zone were analyzed statistically. The results show that the average particle rotation speed is about 300 rev/s with the top speed of 2000 rev/s, when the superficial gas velocity U_g, external solids mass flux G_s and average particle diameter are 5 m/s, 1.5 kg/(m² s) and 0.5 mm, separately. The average particle rotation speed near the wall area is higher than that in the center area at the testing cross-section. Those particles, with either smaller size or higher radial component of translational speed, may have higher average rotation speed. The average rotation speed of irregular particles is apparently higher than that of the spherical ones.     

Assessing color performance of whole‐slide imaging scanners for digital pathology

The color performance of two commercial whole‐slide imaging (WSI) scanners was compared against the ground truth and a hypothetical monochrome scanner. Three biological tissue slides were used to test the WSI scanners. A multispectral imaging system was developed to obtain the color truth of the biological tissue slides at the pixel level. The hypothetical monochrome scanner was derived from the color truth as a lower bound for comparison. The CIEDE2000 formula was used to measure color errors. Results show that color errors generated by the modern commercial WSI scanner, the legacy commercial WSI scanner, and the monochrome WSI scanner are in the range of [8.4, 13.0], [18.0, 26.33], and [17.4, 17.6] ΔE₀₀, respectively. The legacy commercial WSI scanner was outperformed by not only the modern commercial WSI scanner but also by the hypothetical monochrome scanner.     

Concerning the calculation of the color gamut in a digital camera

Several methods to determine the color gamut of any digital camera are shown. Since an input device is additive, its color triangle was obtained from their spectral sensitivities, and it was compared with the theoretical sensors of Ives‐Abney‐Yule and MacAdam. On the other hand, the RGB digital data of the optimal or MacAdam colors were simulated to transform them into XYZ data according to the colorimetric profile of the digital camera. From this, the MacAdam limits associated to the digital camera are compared with the corresponding ones of the CIE‐1931 XYZ standard observer, resulting that our color device has much smaller MacAdam loci than those of the colorimetric standard observer. Taking this into account, we have estimated the reduction of discernible colors by the digital camera applying a chromatic discrimination model and a packing algorithm to obtain color discrimination ellipses. Calculating the relative decrement of distinguishable colors by the digital camera in comparison with the colorimetric standard observer at different luminance factors of the optimal colors, we have found that the camera distinguishes considerably fewer very dark than very light ones, but relatively much more colors with middle lightness (Y between 40 and 70, or L* between 69.5 and 87.0). This behavior is due to the short dynamic range of the digital camera response. © 2006 Wiley Periodicals, Inc. Col Res Appl, 31, 399–410, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20245     

Development of green-colour-emitting pyrotechnics as a core for 3D temperature imaging sensors inside coal boilers

Efficiency in the control operation of the boilers for coal and coal with biomass can be further improved if the flue gas temperature distribution can be better characterized. This is very difficult in these harsh environmental systems, where spatially resolved measurements are nearly impossible with solid-state sensors. In this work, we evaluate the development of pyrotechnic compounds that would serve as the basis for a novel optical mapping of the temperature inside coal boilers. For this purpose, various green-colour-emitting pyrotechnics using BaCl₂ · 2H₂O and Ba(NO₃)₂ as the green light source were prepared, as this colour offers a distinct signal from the combustion-based background in the boiler. These pyrotechnics were characterized using thermogravimetric analysis (TGA) and X-ray diffraction (XRD) and tested using a flat-flame burner. Furthermore, the composition was varied to evaluate the effect of different metal fuels such as Sn, Co, and Mg, as well as various binders such as ethylcellulose, shellac, parlon, and PVC on green light emission. The emission intensity and the apparent ignition temperature were strongly dependent on the metal type, with Mg showing higher intensities. On the other hand, the effect of the binder showed that the ignition behaviour, emission intensity, and spectral purity were influenced by the nature and exothermicity of the binder. The addition of other potential green light-producing materials, such as boric acid, increased the intensity of emission by 17% for a BaCl₂ · 2H₂O-based composition. This study identified prospective compositions with intense and bright green-colour emissions that have high spectral purities.     

感光元件CMOS的灵敏度特性分析

数码相机的感光元件是相机的核心部位,是成像质量的关键影响因素。利用相机在不同条件下拍摄的照片,通过专业的图像处理软件分析照片的数据特点,并利用这些数据建立曝光量和灰度值之间的关系,对比分析不同相机、不同感光度等方面对感光特性曲线的影响。探讨了感光器件CMOS在不同条件下的感光规律。结果表明,利用数码相机拍照时应遵循多曝光不如少曝光的原则。     

4-Amino-1,8-naphthalimide based fluorescent photoinduced electron transfer (PET) pH sensors as liposomal cellular imaging agents: The effect of substituent patterns on PET directional quenching

Four new fluorescent sensors (1-4) based on the 4-amino-1,8-naphthalimide fluorophores (Naps) have been synthesized based on the classical fluorophore-spacer-receptor model. These four compounds all gave rise to emission bands centred at ca. 535 nm, which were found to be highly pH dependent, the emission being ‘switched on’ in acidic media, while being quenched due to PET from the amino moieties to the excited state of the Nap at more alkaline pH. The luminescent pH dependence for these probes was found to be highly dependent on the substitution on the imide site, as well as the polyamine chain attached to the position 4-amino moiety. In the case of sensor 2 the presence of the 4-amino-aniline dominated the pH dependent quenching. Nevertheless, at higher pH, PET quenching was also found to occur from the polyamine site. Hence, 2 is better described as a receptor₁-spacer₁-fluorophore-spacer₂-receptor₂ system, where the dominant PET process is due to (normally less favourable) ‘directional’ PET quenching from the 4-amino-aniline unit to the Nap site. Similar trends and pH fluorescence dependences were also seen for 3 and 4. These compounds were also tested for their imaging potential and toxicity against HeLa cells (using DRAQ5 as nuclear stain which does now show pH dependent changes in acidic and neutral pH) and the results demonstrated that these compounds have reduced cellular viability at moderately high concentrations (with IC₅₀ values between ca. 8–30 µmol∙L⁻¹), but were found to be suitable for intracellular pH determination at 1 µmol∙L⁻¹concentrations, where no real toxicity was observed. This allowed us to employ these as lysosomal probes at sub-toxic concentrations, where the Nap based emission was found to be pH depended, mirroring that seen in aqueous solution for 1-4, with the main fluorescence changes occurring within acidic to neutral pH.     

Development of a novel tissue‐mimicking color calibration slide for digital microscopy

Digital microscopy produces high resolution digital images of pathology slides. Because no acceptable and effective control of color reproduction exists in this domain, there is significant variability in color reproduction of whole slide images. Guidance from international bodies and regulators highlights the need for color standardization. To address this issue, we systematically measured and analyzed the spectra of histopathological stains. This information was used to design a unique color calibration slide utilizing real stains and a tissue‐like substrate, which can be stained to produce the same spectral response as tissue. By closely mimicking the colors in stained tissue, our target can provide more accurate color representation than film‐based targets, whilst avoiding the known limitations of using actual tissue. The application of the color calibration slide in the clinical setting was assessed by conducting a pilot user‐evaluation experiment with promising results. With the imminent integration of digital pathology into the routine work of the diagnostic pathologist, it is hoped that this color calibration slide will help provide a universal color standard for digital microscopy thereby ensuring better and safer healthcare delivery.     

Synthesis and evaluation of hexafluoroisopropanol‐functionalized polysiloxane as a new coating material for sensors

A new polysiloxane polymer as a coating material for surface acoustic wave (SAW) sensors was synthesized. The polymer was a linear polysiloxane functionalized with hexafluoroisopropanol (HFIP) groups, poly{methyl [4‐(hexafluoroisopropanol) phenylethyl] siloxane}. The polymer was spin‐coated on a 200‐MHz SAW sensor for the detection of a 2,4‐dinitrotoluene vapor. A fast response time of 30 s and good reproducibility were achieved. It was found that the frequency shift decreased as the polymer concentrations decreased. The new polysiloxane coatings showed excellent properties, such as a high sensitivity, high permeability, and low glass‐transition temperature (?40.5 ± 1°C). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Feasibility of using digital color imaging devices for the determination of cationic dyes compatibility

In the present research, the compatibility of dyes was evaluated using a scanner by the application of the method proposed by Khalili and Amirshahi, which had been proved as a novel and accurate method for evaluating the compatibility behavior of dye mixtures. A dip‐test method was employed to dye samples, compatibility panels, in binary combinations of cationic dyes on acrylic fibers. In order to use the scanner, first the device was colorimetrically characterized using a regression technique. The tristimulus values obtained from the scanner were, then, used for the reconstruction of the reflectance of the compatibility panels by principal component analysis. Next, the reconstructed reflectance of the panels were transferred to the corresponding K/S spectra and the Khalili and Amirshahi proposed method applied to the spectra in order to obtain the percentage variance (PV), which is the criterion of the dye compatibility. The comparison between the PVs obtained from the scanner and the corresponding one calculated by the spectrophotometrically measured reflectance of the compatibility panels showed a very significant correlation of the compatibility results regarding Pearson correlation coefficients and their K values. It was concluded that due to the smoothness of the reconstructed spectra and the performance of the PCA method of the reconstruction, which manifest itself in the good spectral reconstruction, the scanner method joined with the Khalili and Amirshahi proposed method can reliably be used for the determination of dye mixtures compatibility by a dip test. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 337–345, 2017     

污水管网远程数字化管理系统设计

结合重庆市污水管理处对排水管网进行数字化管理的工程实例,介绍了基于虚拟专用网的污水管网数字化管理系统的设计方案和组成结构。由于管辖的污水管网覆盖面积大、流通里程长,因此采用逐级分区、区域分片和终端远传的分级分区监控布局设计。使用非对称数字用户线路挂载虚拟专用网的网络拓扑方案,实现对远程分散泵站的自动化控制和管理,同时实现对污水各项参数指标数据和图像的实时监控存储。测试结果表明,该污水管网数字化管理系统的数据传输实时性、可靠性较好,具备远程访问功能,达到了项目设计要求。     

Approaches for multicopper oxidases in the design of electrochemical sensors for analytical applications

We report an effective approach for the construction of a biomimetic sensor of multicopper oxidases by immobilizing a cyclic-tetrameric copper(II) species, containing the ligand (4-imidazolyl)ethylene-2-amino-1-ethylpyridine (apyhist), in the Nafion^® membrane on a vitreous carbon electrode surface. This complex provides a tetranuclear arrangement of copper ions that allows an effective reduction of oxygen to water, in a catalytic cycle involving four electrons. The electrochemical reduction of oxygen was studied at pH 9.0 buffer solution by using cyclic voltammetry, chronoamperometry, rotating disk electrode voltammetry and scanning electrochemical microscopy techniques. The mediator shows good electrocatalytic ability for the reduction of O₂ at pH 9.0, with reduction of overpotential (350 mV) and increased current response in comparison with results obtained with a bare glassy carbon electrode. The heterogeneous rate constant (k^′ME) for the reduction of O₂ at the modified electrode was determined by using a Koutecky-Levich plot. In addition, the charge transport rate through the coating and the apparent diffusion coefficient of O₂ into the modifier film were also evaluated. The overall process was found to be governed by the charge transport through the coating, occurring at the interface or at a finite layer at the electrode/coating interface. The proposed study opens up the way for the development of bioelectronic devices based on molecular recognition and self-organization.     

成品油油库三维数字化安全管理系统研究与应用

基于虚拟现实技术,研究油库数字化安全管理系统总体框架,并以某现代化成品油油库为例,开发了具有油库设备综合管理、三维可视化动态监控、管网综合管理等功能的成品油油库三维数字化安全管理系统。     

Design and development of low‐cost optical‐fiber sensors for temperature metrology: Process monitoring of an epoxy resin system

This article reports the design and deployment of two optical‐fiber temperature sensors based on the fiber Fabry–Perot etalon. The first involved the use of an extrinsic fiber Fabry–Perot sensor, but in this instance, the coefficient of thermal expansion of the reflector and/or capillary was chosen to offer a mismatch. Hence, the cavity length could increase or decrease according to the coefficient of thermal expansion of the fiber and/or capillary. For comparison, single‐mode and multimode optical‐fiber Bragg gratings were also used as temperature sensors. The Fabry–Perot sensors operated from ?50 to 410°C. The accuracy of the measurements was up to ±0.5°C with a low‐cost charged‐coupling‐device spectrometer. The sensors also worked effectively in a microwave oven and in a composite panel in an autoclave. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 83–95, 2004     

Comparative performance analysis of spectral estimation algorithms and computational optimization of a multispectral imaging system for print inspection

We have analyzed the performance of simulated multispectral systems for the spectral recovery of reflectance of printer inks from camera responses, including noise. To estimate reflectance we compared the performance of four algorithms which were not comparatively tested using the same data sets before. The criteria for selection of the algorithms were robustness against noise, amount of data needed as inputs (training set, spectral responsivities) and lacking of use of dimensionality reduction techniques. Three different sensor sets and training sets were used. We analyzed the differences in the spanning of the subspaces found for the three training sets, concluding that the ink reflectances have characteristic features. The best performance was obtained using the kernel and the radial basis function neural‐net‐based algorithms for the training set composed of printer inks reflectances, whereas for the other two training sets (composed of samples from the ColorChecker DC and Vhrel's reflectances' set) the quality of the recovered samples was more uniform among the algorithms. We also have performed an optimization to choose the best sensor set for the multispectral system with a reduced number of sensors. © 2012 Wiley Periodicals, Inc. Col Res Appl, 39, 16–27, 2014     

The implementation of an optimal control policy for a batch thermal system

A system comprising a steam heated exchanger through which fluid is pumped into a tank containing a steam heating coil has been constructed. This system has been modelled and the optimal charge rate to bring the tank to known conditions of mass and temperature in minimum time has been calculated by use of Pontryagin's maximum principle.The optimal policies calculated in this way have been implemented on the experimental equipment and comparisons with an equivalent constant charge rate made. Time advantages up to nearly 20% have been achieved over the constant charge rate by use of the optimal policy.Four control schemes have been compared to implement the optimal policy. These have been the control of mass alone, the control of temperature alone an two policies involving switching between mass and temperature. The two policies involving switching have given much closer agreement with predictions t those involving a single control variable.     

PVC生产过程优化控制系统工程

介绍了以计算机、DCS为核心设备,以网络为信息平台,把PVC生产过程中工业优化过程控制和优化生产管理结合,构建PVC生产过程优化控制系统工程的情况。