Characterization of the corrosion of iron using a smartphone camera

Smartphone technology provides bountiful opportunities for greater participation in scientific and technological research. Digital camera image sensors have been used for the detection, measurement, and monitoring of corrosion; this work extends that capability to the smartphone. It has been observed that as the corrosion increased in clean iron, red responses decreased proportionally. Green and blue responses quantifiably decreased faster, matching the observed overall reddening as the corrosion increased. Potential noise sources due to the variable texture of the corroded samples had a negligible effect on the results. The effectiveness of this method for the characterization of a smartphone image sensor response to the degree of iron corrosion was reflected in congruent validation tests and errors less than 5%. These results demonstrate that the smartphone may be employed as a low cost and efficient means for the evaluation of surface corrosion.     

Detection of ultraviolet B radiation with internal smartphone sensors

Smartphones have the potential to monitor ultraviolet radiation within the terrestrial solar spectrum. Additionally, the ability to accurately estimate personal ultraviolet exposure using a smartphone may one day allow an individual control of their ultraviolet exposure. Previous studies have demonstrated the detection of ultraviolet A from 320 to 400?nm with a smartphone. However, the measurement of ultraviolet B from 280 to 320?nm is desirable to monitor biological effects such as erythema. No previous reports have been reported for the detection of ultraviolet B detection with a smartphone camera. This study characterized the ultraviolet B response of smartphone cameras and shows that these devices detect this radiation without additional hardware. Three smartphones were tested in the ultraviolet B waveband for dark response, temperature response, irradiance response, and spectral response. The used protocols adhered to international standards where applicable. All characterized smartphones were sensitive to ultraviolet B radiation; however, each type provides a unique response.     

Colorimetric determination of mercury vapor using smartphone camera-based imaging

The smartphone camera presents a convenient, portable, and low-cost innovation in colorimetric measurements. In this paper, a smartphone camera was applied for the colorimetric detection of gaseous elemental mercury, an atmospheric pollutant of concern in environment, and workplace monitoring. A cuprous iodide (CuI)/polystyrene composite was used as the recognition element, which exhibited a reddish color in the presence of Hg⁰. Digital images of the sensing reagent phase were captured by a smartphone camera and were analyzed in red–green–blue color space using ImageJ, an open source image processing program. Parameters for the digital colorimetric sensing including the color values, polymer reagent binder, amount of CuI, exposure time, and Hg⁰ concentration were investigated and optimized. The linear working range of the sensor was from 61 to 270?μg/m³ Hg⁰ with a correlation coefficient of 0.978. The limit of detection is 16?μg/m³ Hg⁰. This method shows the feasibility of applying a smartphone camera for a simple, reliable, and inexpensive colorimetric measurement of Hg⁰ vapor in a gas mixture such as air.     

Impact of low temperature on smartphone battery consumption

Most smartphones employ Li-ion （or Li-polymer） batteries as their power sources.Though battery consumption significantly varies along with the cell temperature,which is severely affected by ambient temperature,many studies simply assume that the cell temperature is equal to room temperature.Furthermore,there has not been any study that has quantitatively analysed the impact of ambient temperature on battery consumption.In this paper,it can be shown that low ambient temperature significantly affects battery consumption of a smartphone.To show the impact of the cell temperature on battery consumption,the battery consumption at low ambient temperature （-20 ℃） is compared with that at room temperature.As a result,high power consumption results in more severe battery consumption at low ambient temperature.Real measurements show that the battery consumption increases by up to 113.1％ at low ambient temperature in comparison with the same discharge condition at room temperature.     

基于点云中心的激光雷达与相机联合标定方法研究

针对激光雷达与相机联合使用遇到的点云稀疏、相机受环境光照影响失真等问题,提出一种基于点云中心的激光雷达与相机自动配准方法,避免了传统联合标定需要手动选择特征点以及连续采集多帧等问题。该方法在对点云与图像预处理后,利用平面法向量的一致性实现多标定板点云自动分割,提取标定板在激光坐标系和相机坐标下的点云;然后通过点云聚集迭代求解中心点,实现两个传感器标定板对应点云中心的粗配准;最终利用迭代最近点算法进行精配准,获得标定参数,完成联合标定。实测表明,在激光雷达误差±3 cm范围内,点云正确投影比例达到97.93%,可以有效获取高精度联合标定参数,满足空间环境对激光雷达和相机数据融合的要求。     

Determination of iron in zeolite catalysts by a smartphone camera-based colorimetric analyzer

A colorimetric analyzer was improved to determine iron in zeolites prepared by incipient wetness impregnation. Software was installed in an Android smartphone for measuring red, green, and blue light intensities. The blue color was suitable for creating a calibration relationship for iron. The optimum distance from the smartphone camera to the sample holder was 5 cm. The brightness was controlled by a table lamp with a 7 W light emitting diode located at 25 cm above the sample holder. Under these conditions, there was no influence from ambient light. A calibration equation was created from 0–1.2% (w/w) iron and stored in the program for analysis. The results agreed well with flame atomic absorption spectrophotometric measurements with a sample throughput exceeding 40 h^?1. The relative standard deviation and the relative error were less than 1%. This method was convenient, rapid, simple, inexpensive, and easy with little chemical waste produced.     

Time‐lapse microscopy using smartphone with augmented reality markers

A prototype system that replaces the conventional time‐lapse imaging in microscopic inspection for use with smartphones is presented. Existing time‐lapse imaging requires a video data feed between a microscope and a computer that varies depending on the type of image grabber. Even with proper hardware setups, a series of tedious and repetitive tasks is still required to relocate to the region‐of‐interest (ROI) of the specimens. In order to simplify the system and improve the efficiency of time‐lapse imaging tasks, a smartphone‐based platform utilizing microscopic augmented reality (μ‐AR) markers is proposed. To evaluate the feasibility and efficiency of the proposed system, a user test was designed and performed, measuring the elapse time for a trial of the task starting from the execution of the application software to the completion of restoring and imaging of an ROI saved in advance. The results of the user test showed that the average elapse time was 65.3 ± 15.2 s with 6.86 ± 3.61 μm of position error and 0.08 ± 0.40 degrees of angle error. This indicates that the time‐lapse imaging task was accomplished rapidly with a high level of accuracy. Thus, simplification of both the system and the task was achieved via our proposed system. Microsc. Res. Tech. 77:243–249, 2014. © 2014 Wiley Periodicals, Inc.     

Accurate assessment of nonalcoholic fatty liver disease lesions in liver allograft biopsies by a smartphone platform: A proof of concept

Macrovesicular steatosis (MS) is a major risk factor for liver graft failure after transplantation and pathological microscopic examination of a frozen tissue section remains the gold standard for its assessment. However, the latter requires an experienced in‐house pathologist for correct and rapid diagnosis as well as specific equipment that is not always available. Smartphones, which are must‐have tools for everyone, are very suitable for incorporation into promising technology to generate moveable diagnostic tools as for telepathology. The study aims to compare the microscopic assessment of nonalcoholic fatty liver disease (NAFLD) spectrum in liver allograft biopsies by a smartphone microscopy platform (DIPLE device) to standard light microscopy. Forty‐two liver graft biopsies were evaluated in transmitted light, using an iPhone X and the microscopy platform. A significant correlation was reported between the two different approaches for graft MS assessment (Spearman's correlation coefficient: r = .93; p < .001) and for steatohepatitis feature (r = .56; p < .001; r = .45; p < .001). Based on these findings, a smartphone integrated with a cheap microscopy platform can achieve adequate accuracy in the assessment of NAFLD in liver graft and could be used as an alternative to standard light microscopy when the latter is unavailable.     

免散瞳眼底照相机精密调焦技术研究

提出采用双光楔裂像调焦技术实现在被观测眼底图像很暗情况下的精确调焦,将一条矩形狭缝成像到眼底,在双光楔的作用下,通过矩形狭缝上下两半部的光线传播方向不同,在精确聚焦的情况下,上下两半条矩形亮斑将位于一条直线上,如果聚焦不准确,上下两半条矩形亮斑将分离,分离的方向和大小由离焦的情况决定。实验证实通过判断上下两条矩形亮斑是否位于一条直线上来调焦具有操作简单、精确度高等优点。     

数码望远镜解析不同步浅析

从技术实现的角度,对数码望远镜的原理、关键环节如望远镜与数码相机解析同步问题作探讨性论述,并通过对已量产的实例型号DB100为例,就解析不同步的问题进行浅析,同时在不更改任何系统设计的前提下,根据生产工艺的实际条件,对此种解析不同步的状况提出可供参考的解决方向。     

基于眼模型的数字眼底相机设计

本文基于Gullstrand-Le Grand眼光学模型设计了一个视场角为30°免散瞳手持式的数字眼底相机,在综合考虑人眼本身和外部系统的像差后,实现了全视场200万像素的高清晰眼底成像;引入眼模型辅助设计,解决了人眼自身的色差问题,从而适用于白光照明。同时,为避免角膜中心曲率大的区域反射引入杂散光,专门设计了环形光阑和共轴照明相结合的照明系统。结果显示,该相机系统成像分辨率高于120lp/mm,场曲值小于0.86mm,畸变仅为7.2%,并且具有较大调焦能力,对-10D至7D屈光度人眼普遍适用。     

胶片型空间相机的快门设计和研究

为满足胶片型空间相机对地摄影的需要,设计了焦面帘幕式快门,利用快门前、后2层帘布在运动过程中形成的狭缝使胶片曝光.论述了应用于大口径胶片型空间相机的焦面帘幕式快门的基本原理、结构设计、各组成部分的功能及应用.通过实验验证了研制的焦面帘幕式快门运动平稳、可靠,具有大于5×104次的寿命,曝光时间调节范围大(1/30～1/1 500 s)且无级连续可调,曝光量误差小于10%,满足总体要求的技术指标.     

航空光电成像消旋电视数字控制器

介绍了消旋电视摄像系统的工作原理,通过对系统的分析,得出了消旋系统保证像质所允许的最大旋转角速度。根据消旋速度要求,设计了消旋系统的电视数字控制器。该控制器以DSP为核心微处理器;以测速机为速度敏感元件,作为系统速度环的反馈;速率陀螺测得飞行器的扰动速率,用作速度环的前馈。系统采用了传统的超前滞后补偿方法,并加入了积分环节以减小稳态时的漂移角速度。实验结果表明,在消旋拍摄过程中,消旋速度满足设计要求,拍摄图片清晰,消旋速率精度为14.3(°)/s。理论分析和实验结果都证明了该消旋摄像系统的可行性。     

机器人手眼镜的光学设计

手眼视觉系统是一类重要的机器人视觉系统,具体介绍了一个用于机器人手眼视觉系统中的手眼镜的光学设计。该镜头设计采用了反远距的结构型式,满足了大视场、短焦距、长工作距的设计要求。在选用光学材料时又避免使用在一般大视场、短焦距、长工作距系统中常用的镧系玻璃,选用了常用的两种普通光学玻璃。     

宽覆盖、离轴空间相机光学系统的设计

当前空间相机的光学系统的要求是 :在多光谱范围内,系统要有高分辨率、大视场、小体积、质量轻且像面为平像场,TMA(Threemirroranastigmat)可以满足上述要求。为此给出了这方面的设计,所研究的TMA系统三个反射面都是二次曲面,将主镜和第三镜离轴放置,避免中心遮拦的影响,系统的视场可达到 5°× 0.2°,焦距为 6m,像质接近衍射极限。     

面阵图像传感器在位移测量中的应用研究

在位移测量中,探索采用普通面阵ＣＣＤ取代线阵ＣＣＤ显得具有重大实用价值。本文将讨论微型ＣＭＯＳ电视摄像机作为图像卖座器在实时光电位移测量时的处理生能分析。理论和实际测试结果表明,在体积、成本、测量精度和抗干扰能力等方面,面阵图像传感器都优于线阵ＣＣＤ。     

Testing feasibility of an accurate microscopic assessment of macrovesicular steatosis in liver allograft biopsies by smartphone add‐on lenses

Light microscopy is an essential tool in histological examination of tissue samples. However, the required equipment for a correct and rapid diagnosis is sometimes unavailable. Smartphones and mobile phone networks are widespread, and could be used for diagnostic imaging and telemedicine. Macrovesicular steatosis (MS) is a major risk factor for liver graft failure, and is only assessable by microscopic examination of a frozen tissue section. The aim of this study was to compare the microscopic assessment of MS in liver allograft biopsies by a smartphone with eyepiece adaptor (BLIPS device) to standard light microscopy. Forty liver graft biopsies were evaluated in transmitted light, using an Iphone 5s and 4 different mini‐objective, add‐on lenses. A significant correlation was reported between the two different approaches for graft MS assessment (Spearman's correlation coefficient: r_s = 0.946; p < .001). Smartphone with eyepiece adaptor had similar discriminatory power to identify MS in liver grafts than standard light microscopy. Based on these findings, a smartphone integrated with a low‐cost eyepiece adaptor can achieve adequate accuracy in the assessment of MS in liver graft, and could be used as an alternative to standard light microscope when unavailable.     

一款新型同步调焦双筒望远数码相机的光学设计

介绍了一种同步可调式双筒望远数码相机的光学设计。同步调焦曲线的设计使双目望远物镜和数码照相物镜在3m到∞范围内同步可调,使望远镜真正成为数码相机的取景器,从而实现了真正的"所拍即所看"功能。检测证明产品可用于望远观察、同步拍摄、调查取证等。     

多TDI-CCD拼接相机非均匀性校正方法

针对多TDI-CCD拼接相机成像存在非均匀性问题,开展了对拼接相机输出图像片内及片间综合校正算法的研究。首先,结合CCD相机特性,介绍了TDI-CCD的工作原理以及拼接相机非均匀性的产生机理。然后,分别对拼接相机片内及片间非均匀性校正的原理进行分析,提出了片内采用两点法校正、片间采用比值平均校正的综合校正算法。最后,对片内及片间综合非均匀性校正的参数标定及校正方法进行了探讨;实验结果表明,在原拼接输出图像存在8.4%非均匀性的条件下,采用片内与片间综合校正法校正后,图像非均匀性达到2.7%。该校正方法基本满足了对TDI-CCD拼接相机非均性校正的指标要求,算法有效实用。     

高精度智能相机光电跟踪控制系统的研制

主要研究空间光通信中光束抖动的跟踪控制,建立了以可开窗口高帧频CMOS相机和大规模FPGA芯片为核心的全功能camera link光束跟踪控制硬件平台.并在FPGA芯片中嵌入实现了全部跟踪控制算法,包括图像处理中将二元线性插值结合重心算法实现光斑的高精度定位,以及流水线并行运算的模糊增益自调整PID跟踪控制的状态机等.实验结果表明系统实时性强,算法的时间开销很小,光斑的定位精度高,跟踪带宽达到200 Hz以上,低频时跟踪精度约为2 μrad,实现了光束抖动的高带宽高精度的跟踪控制.