基于MTF评价医用硬性内窥镜的分辨率

根据国内外相关检测标准,确定视觉分辨率和调制传递函数模量作为评价指标,设计检测装置和标靶,编写Matlab程序对采集到的标靶图像进行分析,对13支不同品牌、种类的硬性内窥镜进行检测。实现基于机器视觉检测医用硬性内窥镜分辨率的设备和方法,13支内镜的视觉分辨率为5~16 LP/mm,MTF阈值集中于0.2~0.3之间。结果表明:1)硬性内窥镜镜体、中心、边缘的MTF值均呈现随着线对数增大而减小的趋势;2)每支硬性内窥镜均具有合适的亮度使其分辨率最高;3)硬性内窥镜整体的MTF值偏向由中心决定;4)同一区域下,不同亮度所对应的MTF值相关程度较高,说明内窥镜的分辨率由自身决定。     

基于LabVIEW图像处理的医用内窥镜光学性能自动检测系统

为了提高检测医用内窥镜光学性能的准确性,减少检测过程由于人工判断图像特征导致的误差,设计了医用内窥镜光学性能自动检测系统。检测过程中通过控制步进电机移动CCD相机与标准测标的相对位置,CCD相机通过被检硬制内窥镜不断获取标准测标图像,在LabVIEW平台下使用检测系统对测试图像进行图像处理,提取图像清晰轮廓,计算测量参数。与人工控制视检相比,自动检测系统的光学性能检测设备能显著提高检测重复性。     

电子靶标式医用硬性内窥镜光学性能校准装置的研制

提出一种电子靶标式医用硬性内窥镜光学性能校准装置。该装置由专用电子靶标显示屏,专用高清摄像镜头、视频图像采集系统、数字图像处理计算机、多维度调整台及角度编码器和软件模块组成。可在校准客户现场分析医用硬性内窥镜视场角、视向角、几何畸变和光学传递函数等多项光学参数。     

医用硬性内窥镜光学成像部分校准方法

随着医用硬性内窥镜在临床中的大量使用,内窥技术已成为很多疾病诊断和治疗的重要手段。国内至今没有对医用硬性内窥镜计量的标准设备,使得该类仪器无法开展检定工作。本文针对医用硬性内窥镜的工作环境和光学性能,设计一种仿人体组织的标准器,用于校准医用硬性内窥镜光学指标。     

CIELAB色空间内窥镜色彩还原能力对比分析

基于CIELAB色空间评价硬性内窥镜色彩还原能力,并进行4支硬性内窥镜色彩还原能力对比分析.通过与内窥镜连接的工业相机拍摄内窥镜观测到的色彩标靶图像,拍摄图像发送至计算机保存并处理.处理后得到图像中红绿蓝色块的RGB值,将RGB值转换至CIELAB色空间进而求得图像的L*、a*、b*值,最后利用已知标靶色块的L*、a*、b*值和求得的图像L*、a*、b*值计算CIELAB色差△Eab*,即色彩还原误差值.实验数据表明:4支内窥镜的色彩还原误差值都在47.9以上;4号腹腔镜对红、绿、蓝三色块的色彩还原误差值最小,色彩还原能力最好;2号宫腔检查镜对三色块色彩还原误差值比较大,色彩还原能力最差;1号鼻窦镜和3号关节镜的色彩还原能力处于中间水平.CIELAB色空间作为国际通用的测色标准,可以用于评价硬性内窥镜色彩还原能力.     

医用内窥镜光能传递效率的评价方法

建立医用硬性内窥镜光能传递效率的评价方法.通过影响光能传递效率的原因分析并结合光能传递效率的实际应用意义,提出了有效光度率定义和表达式,以表示医用硬性内窥镜的光能传递效率.运用光度学原理导出有效光度率测量的应用公式,并通过对相关的模拟视场面与光度量关系的理论推导,得出有效光度率测量的应用公式与模拟视场形状无关的结果,并进一步采用几个典型视场面下的实际测量,验证了该应用公式的通用性.此方法可用于医用硬性内窥镜光能传递效率的评价,便于实际测量应用.     

基于FPGA实现医用电子内窥镜畸变图象实时校正的研究

本文针对医用电子内窥镜广角成像系统图像采集过程中存在的光学畸变色差^[1],提出了一种有效的实时校正技术。这种技术充分利用FPGA的优点：集成度高、速度快和易于实现复杂逻辑功能,设计出实时电镜畸变图象校正系统。采用硬件实现图象的畸变实时校正,不仅达到了减小系统光学结构体积、降低系统造价的目的,而且提高了诊断的准确性,改善了电镜系统的性能,使医用电子内窥镜在临床诊断和医学研究方面成为更加可靠和有效的手段。     

医用内窥镜照明用光缆的应用特征

本文介绍了医用内窥镜照明光缆的应用形式,指出了传统医用内窥镜照明光缆缺陷,提出了符合医疗发展要求的医用内窥镜照明光缆应用特征,包括:光纤原材料具备环保并符合Rohs认证要求、适合药物法医用消毒、具有高传输的光学性能、同时具备耦合部件标准化和整体密封、耐高压的结构特征。     

加强对医用内窥镜检测的必要性

本文介绍了医用内窥镜的用途及性能,强调丁加强对医用内窥镜检测的必要性。     

电视图像传感器检测平台的研制

为了准确、客观评价面阵CCD器件和整机多项性能参数,研制了电视图像传感器试验检测平台系统.整套系统装置采用组合式的设计理念,由两部分构成,电视图像传感器性能参数测试系统测量噪声、响应度、饱和照度、阈照度、动态范围、系统信噪比(SNR)、信号传递函数(SiTF)、均匀性等,其测试系统误差为4.28%;电视图像传感器成像系统组件定标与试验检测系统测量系统调制传递函数(MTF)、系统畸变、视场角与焦距、系统分辨率、系统光学同轴度等,其系统误差为4.48%.     

利用系统辨识的星敏感器模型修正与测角精度检测

2.中国科学院大学,北京100049)摘要:为了提高星敏感器的测角精度,提出了一种采用系统辨识法对星敏感器模型进行修正以及测角精度检测的方法。首先分析了星敏感器的理论测量模型以及像面坐标与星点目标的空间位置关系,然后给出了用模型修正来提高星敏感器测角精度的原理和数学模型。修正模型由系统辨识方法得到,同时为了提高辨识精度,文中采用将星敏感器像面划分为多个区域,每个区域单独建模辨识的方式。最后利用某星敏感器进行了实验,利用该方法进行模型修正后,星敏感器的测角精度为σx=1.68″、σy=1.91″,而修正前的测角精度为σx=17.43″、σy=23.46″。结果表明,采用该方法可以使星敏感器测角精度得到大幅提高,同时也完成了测角精度的检测。     

Random-phase-shift Fizeau interferometer

A new and potentially cost efficient kind of vibration-tolerant surface measurement interferometer based on the Fizeau-principle is demonstrated. The crucial novelty of this approach is the combination of two optoelectronic sensors: an image sensor with high spatial resolution and an arrangement of photodiodes with high temporal resolution. The photodiodes continuously measure the random-phase-shifts caused by environmental vibrations in three noncollinear points of the test surface. The high spatial resolution sensor takes several "frozen" images of the test surface by using short exposure times. Under the assumption of rigid body movement the continuously measured phase shifts of the three surface points enable the calculation of a virtual plane that is representative for the position and orientation of the whole test surface. For this purpose a new random-phase-shift algorithm had to be developed. The whole system was tested on an optical table without vibration isolation under the influence of random vibrations. The analysis of the root-mean-square (RMS) over ten different measurements shows a measurement repeatability of about 0.004 wave (approximately 2.5 nm for 632.8 nm laser wavelength).     

Cross-cumulative residual entropy-based medical image registration via hybrid differential search algorithm

Image registration is the process of overlaying images of the same scene taken at different times by different sensors from different viewpoints. The cross-cumulative residual entropy (CCRE)-based medical image registration could achieve a high precision and a strong robustness performance. However, the optimization problem formulated by CCRE consists of some local extrema, especially for noise images. In order to address these difficulties, this article proposes a new optimization algorithm named hybrid differential search algorithm (HDSA) to optimize CCRE. As HDSA consists of simple control parameters, it is independent of the initial searching point. In addition, HDSA ameliorated the search method and the iterative conditions. As a result, the optimization process is more stable and efficient. Image registration experiments of HDSA are performed and compared with the conventional differential search algorithm (DSA) and adaptive differential evolution with optional external archive (JADE). The results show that HDSA does not only overcome the difficulties of sticking in the local extrema but also enhances the precision of registration. It is effective, robust, and fast for both the single-mode rigid medical image registration and the multispectral-mode rigid medical image registration.     

中波红外全景成像仪线扩散函数的模拟分析与验证

线扩散函数是评价成像系统成像质量的一个重要参数,线扩散函数的模拟分析与验证对成像仪的研制至关重要。本文首先分析中波红外全景成像仪探测器所接收到的辐亮度,从理论上估算了全景成像仪的线扩散函数,然后通过斜缝法加以验证,试验结果证实了理论模型的正确性。并对线扩散函数经离散傅里叶变换计算而得MTF传递函数,结果与理论得出的系统MTF基本符合,进一步证明了这种模拟分析方法的可行性。     

A Highly Responsive Organic Image Sensor Based on a Two‐Terminal Organic Photodetector with Photomultiplication

Highly responsive organic image sensors are crucial for medical imaging applications. To enhance the pixelwise photoresponse in an organic image sensor, the integration of an organic photodetector with amplifiers, or the use of a highly responsive organic photodetector without an additional amplifying component, is required. The use of vertically stacked, two‐terminal organic photodetectors with photomultiplication is a promising approach for highly responsive organic image sensors owing to their simple two‐terminal structure and intrinsically large responsivity. However, there are no demonstrations of an imaging sensor array using organic photomultiplication photodetectors. The main obstacle to a sensor array is the weak‐light sensitivity, which is limited by a relatively large dark current. Herein, a highly responsive organic image sensor based on monolithic, vertically stacked two‐terminal pixels is presented. This is achieved using pixels of a vertically stacked diode‐type organic photodetector with photomultiplication. Furthermore, applying an optimized injection electrode and additionally stacked rectifying layers, this two‐terminal device simultaneously demonstrates a high responsivity (>40 A W^?1), low dark current, and high rectification under illumination. An organic image sensor based on this device with an extremely simple architecture exhibits a high pixel photoresponse, demonstrating a weak‐light imaging capability even at 1 µW cm^?2.     

Calibration and performance of a pyramid wavefront sensor for the eye

We describe the calibration and performance of a pyramid wavefront sensor designed for use in a retinal imaging camera. The effect of the image modulation and the sensor binning on the measurements are explained in detail and various tests to validate the performance are described. The wavefront sensor was incorporated into an adaptive optics system that used a magnetically actuated deformable mirror, and results on static test optics are shown.     

Pattern Recognition in Photoacoustic Dataset

In photoacoustic imaging, optical absorption properties of matter are imaged by detecting the ultrasound that is produced when the material is illuminated by a laser. For medical imaging, photoacoustics is a useful tool since matter in the human body has different optical absorption properties. In this study, pattern recognition systems are used to study a set of medical images for tumor identification and extraction—to detect the specific area in which the tumor is present. The objective is to incorporate this information into real-time image acquisition systems to improve medical diagnosis. Preliminary results obtained by studying the image dataset demonstrated the interchangeability of the proposed system. A system of automatic classification was constructed, using a set of images with and without cancerous tumors to evaluate the proposed method. The training set used was manually labeled, and the test set was never seen by the training set. The results helped us determine the feasibility of the proposed system.     

高密度栅测应变

将高密度光栅应用于力学参量的测量中。通过测得试件变形前后正交光栅衍射点阵的偏移移量，可逐点得到试件因载荷作用而引起的面内应变、离面位移和刚体传动分量。     

3D Strain Field Measurement by Correlation of Volume Images Using Scattered Light: Recording of Images and Choice of Marks

Abstract:  We have extended the Digital Image Correlation technique to the case in three dimensions. This new technique, allowing the full three-dimensional (3D) strain measurement in the bulk of a solid, needs volume images containing a 3D variation of the grey levels. Generally, volume images are obtained by X-ray computed tomography. In this paper, we present a procedure that is easier to implement and enables to generate volume image in transparent materials. The principle consists in the optical slicing of the specimen. To obtain a random distribution of grey levels within the volume image, we use the scattered light phenomenon induced by particles included in the specimen. The recording of 3D images by optical slicing is presented and the influence of different kinds of particles on the scattered light and on the accuracy of measurement is described. Through several tests involving rigid body displacements and a tensile test we show the performance of this technique and we evaluate the measurement error of displacement and strain components.