基于粒子群优化的自适应对比度增强算法在中子照相中的应用

由于成像机理和中子源的限制,中子照相成像图像易出现对比度不足的缺陷,利用对比度增强算法改善图像质量成为解决问题的常用方法.新提出的自适应对比度增强算法利用粒子群优化算法对中子图像全局像素进行迭代分析,确定自适应处理过程中的关键增益因子系数,可实现图像对比度自动寻优增强.利用该算法对多幅中子图像进行处理并与传统优化算法处...     

基于灰度冗余和小波变换融合的彩色人脸图像增强

针对不同光照下的人脸图像存在过暗或过亮,视觉效果不好、不易识别的情况,提出了一种基于灰度冗余和小波变换融合的彩色图像增强算法。该方法通过灰度级的线性映射去除灰度冗余,增强图像的对比度,再通过基于小波变换的图像融合方法,对低频和高频采用不同的融合准则,实现了彩色图像的增强,克服了原图像在亮度和细节上的缺陷,又避免了信息损失,提高了图像的清晰度。     

基于遗传算法的辐射图像对比度增强

基于遗传算法和非完全Beta函数,介绍了一种自适应的图像对比度增强方法,并将其应用到辐射图像的增强处理中。Tubbs利用归一化的非完全Beta函数（Incomplete Beta Function）,来实现几种典型的灰度变换曲线的自动拟合。在实现了该函数的基础上,通过基于遗传算法的自适应搜索确定Beta函数的最佳参数,并对遗传算子做了一定改进,从而确定相应的最佳变换曲线。将该方法应用于集装箱检测图像的对比度增强,通过对实验结果的比较,说明了该方法的优越性。     

辐射成像技术的初步应用研究

介绍了辐射成像技术的工作原理和一种基于USB接口技术的二维辐射成像系统的软硬件设计.针对电子线路工艺检测的要求,阐述了图像信息的采集方式和重建方法.并采用灰度增强、伪彩色增强、空间滤波、边缘增强、几何处理等二维数字图像处理算法,完成了数字图像的恢复.目前,系统在电子线路板焊接检测流程中,用以排除焊接过程中虚焊、短路等问...     

辐射成像系统图像灰度的自适应显示方法

辐射成像系统图像变换处理中,通常采用线性变换或对数变换等方法来获得较高的图像显示质量,但这些方法只突出图像的部分灰度段,不利于获得辐射图像的整体信息。本文改进了原有的线性变换方法,研究了在保持图像细节基本无损情况下,根据被检图像特点自适应确定变换参数进行数据变换的方法。实验表明,在保证图像质量同时,该方法能利用8位灰度最大程度地一次性显示16比特图像中整体信息,提高辐射检测速度。     

伪彩色数字高程模型在工业CT断层图像检查中的应用

在工业CT断层图像缺陷检测应用中，提出了将数字高程模型DEM与伪彩色技术一起应用于二维灰度图像缺陷检测领域的算法流程。应用该算法流程，能够充分利用CT断层灰度图像信息，获得清晰的视觉检查效果，从而大大增强了系统检测缺陷的能力。在大型工业CT图像重建与检查分系统中采用该算法流程已经取得了较为理想的效果。     

低对比度锥束CT图像缺陷分割算法

根据锥束CT图像的特点,通过获取切片图像中的灰度拓扑结构,将整幅图像中的低对比度分割问题转化为在局部拓扑结构中的较高对比度分割问题.然后针对每个拓扑结构,根据设置的2个阈值和4个检测模板,判断当前模板区域是缺陷区域、噪声区域或者背景材质区域,并将4个方向的检测结果相加得到该拓扑结构的检测结果,最终的检测结果为各拓扑结构的检测结果之和.对空心涡轮叶片蜡模锥束CT图像的实验表明,该算法可有效提取低对比度缺陷信息.     

推扫型背散射成像系统图像质量优化

推扫型背散射成像技术是一种成像布局灵活、对有机物敏感的新型成像技术。在以较高速度进行成像的情况下,其探测效率和图像对比度受到一定限制。本文基于自主研发的推扫型背散射成像系统,设计开发了一套专用图像处理算法,包括归一化校正、衰减校正,图像去噪,图像增强,图像分割等,以降低图像噪声和提高图像对比度。目前此算法已实际应用于成像系统进行实验验证,图像质量具有明显改善,是一种行之有效的算法。     

大型集装箱检测系统中图像的去噪增强算法

提出了基于图像边缘信息的去噪增强算法，能有效区分错误噪声行，随机噪声和有用边缘，分别进行不同的图像处理，能在抑制噪声的同时增强图像边缘，提高大型集装箱检测系统的图像质量。     

双线性插值图像放大算法优化及硬件实现

提出了一种基于双线性插值图像放大的优化算法,在算法中加入轮廓增强处理,保留了图像边缘的高频信息,改善了双线性插值算法引起的边缘模糊问题.改进后的双线性插值放大算法处理速度快,硬件实现简单,且有较好的图像质量.实验表明,该算法适合于对图像进行实时放大处理.     

Study of talcum charging status in parallel plate electrostatic separator based on particle trajectory analysis

Electrostatic separation has been extensively used in mineral processing, and has the potential to separate gangue minerals from raw talcum ore. As for electrostatic separation, the particle charging status is one of important influence factors. To describe the talcum particle charging status in a parallel plate electrostatic separator accurately, this paper proposes a modern images processing method. Based on the actual trajectories obtained from sequence images of particle movement and the analysis of physical forces applied on a charged particle, a numerical model is built, which could calculate the charge-to-mass ratios represented as the charging status of particle and simulate the particle trajectories. The simulated trajectories agree well with the experimental results obtained by images processing. In addition, chemical composition analysis is employed to reveal the relationship between ferrum gangue mineral content and charge-tomass ratios. Research results show that the proposed method is effective for describing the particle charging status in electrostatic separation.     

行人放射性快速识别仪谱数据处理软件设计

介绍了行人放射性快速识别仪中实现谱数据部分快速处理的软件设计。利用FPGA内嵌硬件DSP模块和硬件资源,构建了浮点乘和累加运算单元、浮点除法运算单元、浮点指数运算单元和浮点开方运算单元,在0.7 s内完成谱数据处理运算,使快速识别仪能在1 s内完成γ辐射探测、同位素识别及自动分类,最低可探测活度41.9 k Bq,可用于放射性物质的快速检测。     

Dust tracking techniques applied to the STARDUST facility: First results

An important issue related to future nuclear fusion reactors fueled with deuterium and tritium is the creation of large amounts of dust due to several mechanisms (disruptions, ELMs and VDEs). The dust size expected in nuclear fusion experiments (such as ITER) is in the order of microns (between 0.1 and 1000 μm). Almost the total amount of this dust remains in the vacuum vessel (VV). This radiological dust can re-suspend in case of LOVA (loss of vacuum accident) and these phenomena can cause explosions and serious damages to the health of the operators and to the integrity of the device. The authors have developed a facility, STARDUST, in order to reproduce the thermo fluid-dynamic conditions comparable to those expected inside the VV of the next generation of experiments such as ITER in case of LOVA. The dust used inside the STARDUST facility presents particle sizes and physical characteristics comparable with those that created inside the VV of nuclear fusion experiments. In this facility an experimental campaign has been conducted with the purpose of tracking the dust re-suspended at low pressurization rates (comparable to those expected in case of LOVA in ITER and suggested by the General Safety and Security Report ITER-GSSR) using a fast camera with a frame rate from 1000 to 10,000 images per second. The velocity fields of the mobilized dust are derived from the imaging of a two-dimensional slice of the flow illuminated by optically adapted laser beam. The aim of this work is to demonstrate the possibility of dust tracking by means of image processing with the objective of determining the velocity field values of dust re-suspended during a LOVA.     

Iterative noise removal from temperature and density profiles in the TJ-II Thomson scattering

TJ-II Thomson Scattering diagnostic provides temperature and density profiles of plasma. The CCD camera acquires images that are corrupted with some kind of noise called stray-light. This noise degrades both image contrast and measurement accuracy, which could produce unreliable profiles of the diagnostic. So far, several approaches have been applied in order to decrease the noise in the TJ-II Thomson scattering images. Since the presence of the noise is not global but located in some particular regions of the image, advanced processing techniques are needed. However such methods require of manual fine-tuning of parameters to reach a good performance. In this contribution, an iterative image processing approach is applied in order to reduce the stray light effects in the images of the TJ-II Thomson scattering diagnostic. The proposed solution describes how the noise can be iteratively reduced in the images when a key parameter is automatically adjusted during the iterative process.     

Risk assessment on hazards for decommissioning safety of a nuclear facility

A decommissioning plan should be followed by a qualitative and quantitative safety assessment of it. The safety assessment of a decommissioning plan is applied to identify the potential (radiological and non-radiological) hazards and risks. Radiological and non-radiological hazards arise during decommissioning activities. The non-radiological or industrial hazards to which workers are subjected during a decommissioning and dismantling process may be greater than those experienced during an operational lifetime of a facility. Workers need to be protected by eliminating or reducing the radiological and non-radiological hazards that may arise during routine decommissioning activities and as well as during accidents. The risk assessment method was developed by using risk matrix and fuzzy inference logic, on the basis of the radiological and non-radiological hazards for a decommissioning safety of a nuclear facility. Fuzzy inference of radiological and non-radiological hazards performs a mapping from radiological and non-radiological hazards to risk matrix. Defuzzification of radiological and non-radiological hazards is the conversion of risk matrix and priorities to the maximum criterion method and the mean criterion method. In the end, a composite risk assessment methodology, to rank the risk level on radiological and non-radiological hazards of the decommissioning tasks and to prioritize on the risk level of the decommissioning tasks, by simultaneously combining radiological and non-radiological hazards, was developed.     

Medical Image Processing in Diagnostic Radiology

There exists a need to quantify the radiological information contained in the digital measurements of the imaging technologies. These imaging technologies include computed tomography, nuclear medicine examinations, diagnostic ultrasound imaging, computer radiography and digitization of radiographic film images. A rapidly growing number of studies suggest that useful quantitation of radiographic information includes linear measurements for organ estimation, estimation of surface areas and volumes, estimation of tissue density, and the visualization of three-dimensional organ sites.     

Parameter Estimation for Dynamic Studies in Emission-Tomography Systems Having List-Mode Data

Maximum-likelihood parameter estimation for dynamic tracer-studies is investigated for emission-tomography systems having time-of-flight measurements in the form of list-mode data. It is shown how the EM iterative algorithm of statistics can be used to estimate compartmental parameters just as it is also used to reconstruct images of activity distributions. Retrospective processing of list-mode data for dynamic studies requires that the influence of each measurement point to the region of interest in the reconstructed images be identified; a procedure for accomplishing this is given.     

Image Processing in Nuclear Medicine

A survey of various image processing techniques as applied to images in nuclear medicine is presented. These have been classified as procedures to improve detectability, to correct for distortion, to compress, and to aid automation. On evaluation, rather disappointing results fromconventional image'enhancing' techniques have been found. On the other hand, the use of image 'transforming' procedures is highly satisfactory and of increasing importance in this field. This survey has been prepared for the image processor who knows little of nuclear medicine, or the nuclear medicine practitioner who knows little of image processing.     

Advances in Processor Architecture, Display, and Device Technology for Biomedical Image Processing

Many new biomedical imaging modalities have arisen during the past decade which exploit the creation of images via computed tomography, or the processing of images generated by conventional radiographic techniques. These improved imaging capabilities are motivating advancements both in the capabilities of the computers which carry out the processing steps, and in the flexibility of display devices for rapid visualization of the result of the image creation and post processing procedures. Several important trends in the technology of advanced processors and displays relevant to the biomedical environment will be described.     

我国医用辐射及其防护标准体系的现状与展望

放射学以及介入放射学、临床核医学、放射肿瘤学等电离辐射的医学应用分支学科,已成为现代医学不可或缺的重要组成部分。医用辐射的发展,使得医用辐射防护成为辐射防护领域影响面最广的重要课题。医用辐射防护涵盖职业照射、医疗照射和公从照射的防护,同时也存在潜在照射防护问题。为有效加强医用辐射防护,必须建立并不断健全医用辐射防护标准３体系。