经络可视化系统中的双目立体视觉定位

目的针对磁定位经络可视化系统的精度较低并且极易受周围环境影响问题,提出精度及可靠性更高的双目立体视觉定位方法。方法首先采用张正友标定法完成摄像机标定,得到左右摄像机内外参数;其次完成立体匹配,使用双目立体视觉定位系统提取皮肤阻抗检测仪电极板上十字型角点X的亚像素级坐标,并根据对称性和灰度跳变性筛选出X角点,根据唯一性和旋转不变性匹配左右摄像机图像上的X角点;最后利用得到的摄像机内外参数以及X角点匹配的结果计算出经络点的三维坐标并将其投影到场景二维图像上,利用曲线拟合方法连接经络点,从而实现经络的可视化。结果根据标定及匹配结果计算出3个X角点的三维坐标,并结合多通道皮肤阻抗检测仪得到的电极通道,从而得到经络点的三维坐标,最后利用图像融合实现经络的可视化,实验结果精度较高。结论下一步的工作就是优化二值化方法,进一步提高图像融合配准的精度。     

摄像机畸变矫正的一种简单有效的方法

从光学测量角度出发,结合计算机视觉中的摄像机标定方法,解决了摄像系统的畸变校正问题。与摄像机标定不同,畸变校正中仅标定内部参数,外部参数作为已知条件。采用线性畸变模型,由最小二乘法解线性方程组得到摄像系统畸变模型的畸变系数。     

基于阻抗与双目视觉的经络可视化系统

为了使经络能够在人体体表准确测量和显示,提出了一种基于阻抗与双目视觉的经络可视化方法.首先,利用交变恒流源在人体皮肤表面注入电流信号,然后采用多通道皮肤阻抗检测仪根据经络的低阻抗特性检测各对电极之间人体皮肤的电压,从而间接获取经络点对应的通道,通过串口通信,将数据传输至上位机.其次,利用张氏摄像机标定法获取摄像机内外参数,对光学标靶进行角点筛选与匹配,获得经络点的三维信息,再根据双目视觉原理对三维信息进行坐标变换,最后利用曲线拟合和图像融合技术,实现经络可视化.测试结果表明,该系统能实现经络的实时检测与准确显示.     

基于ImageJ的伽马刀质量控制检测技术的应用研究

目的:基于ImageJ图像处理软件,制定一套实用性强、准确可靠的γ刀检测分析方法,以解决γ刀检测中的胶片分析问题。方法:利用ImageJ图像处理软件,并结合宏命令(macro)编写脚本程序,对γ刀检测的胶片图像进行分析,分别实现胶片剂量标定、机械等中心与辐射野等中心的偏差、照射野尺寸、半影宽度等关键参数的分析与计算。结果:胶片剂量标定中,用不同的拟合函数建立胶片的灰度-剂量曲线,对于EBT3胶片,多项式拟合和Devic方法均能取得可接受的拟合结果,相关系数r²>0.99;利用图像处理方法对等中心偏差的结果进行了验证,偏差≤0.05 mm;辐射野尺寸和半影宽度的计算结果与γ刀厂家的分析软件得到的结果具有较好一致性,二者偏差<1 mm。结论:制定的γ刀检测分析方法可为γ刀质量控制检测工作提供技术支撑,提高检测结果的准确性与可靠性。     

一种电阻抗断层成像的图像后处理算法

目的：研究电阻抗断层成像的图像处理方法,改善图像显示效果.方法：先利用相邻三角形单元的电导率估计节点的电导率,然后根据三角形单元3个顶点的电导率进行二维线性插值获得单元内任意点的电导率.结果：原始的按三角形单元分块显示的电阻抗断层成像的图像,可转换为光滑的图像.结论：图像显示效果得到很大的改善;此方法适用于所有三角形剖分的电阻抗断层成像的图像处理.     

西瓜模拟人脑在CT/MR联合定位立体定向手术中的实验研究

目的:为了克服颅脑CT立体定向手术中软组织分辨率低的不足,而MR立体定向手术的禁忌症较多,探索在脑CT立体定向手术中辅以MR模拟定位的可行性。方法:将5粒鱼肝油丸置入西瓜的不同深处,在MR机上做2mm断层扫描,在CT机上做1mm断层扫描。利用软件进行CT/MR图像配准,测量5个鱼肝油检测点的CT的坐标和MR的坐标,分析检测点CT实测坐标与MR的指示坐标的误差。结果:MR的模拟坐标和CT实际坐标误差<2mm,利用软件配准在MR图像上进行CT立体定向的模拟可视化是可行的。结论:医学图像配准是医学图像处理中的关键技术,CT/MR联合定位具有很重要的临床应用价值。     

日本XT-2000A监示器图像上下跳动故障维修

<正>1.故障现象:日本岛津800毫安X线机与XT-2000A电视系统相配套用于胃肠道检查,在透视中发现监示器图像在操作床部分各种运动时有间断性的上下跳动现象,有时无法观看,严重时图像全无.2.故障检修:应首先排除是否监示器本身的问题,进行透视仔细观察在图像跳动时光栅正常可以确定监示器工作正常.在拆摄像机中发现晃动与摄像机相接的电缆时监示器的圆上下跳动,重新安上摄像机进行透视用手触动电缆线故障出现.关机用万用表欧姆档测量该电缆芯线发现④号线V·DEF·D断开,更换接线后开机透视故障消失.     

X线机摄像系统故障分析

1 HYX-01型医用摄像机故障一例故障现象:图像模糊,有黑横道出现,以左边较多(面对监视器看)。故障检查:观察主,副监视器图像一样,重点检查增强器与摄像机。把摄像机从增强机上卸下放好。开机,选透视档,踩脚闸,观察增强器输出窗,图像明亮清晰,增强器正常。故障应在摄像机电路。关机,打开摄像机外壳,开机后用万用表测量摄像     

结构光相机点云图与CT图像配准算法对比研究

目的:针对人脸结构光相机点云图与CT图像配准,寻找最优的特征面部点云提取方法、特征描述法和配准算法的组合,为颅脑穿刺活检手术中基于导航机器人实现精确快速定位提供依据.方法:基于Ubuntu 18.04系统对Inter-RealSense D415结构光相机点云图与CT图像进行三维配准.首先进行相机动态标定,其次进行特征...     

Zernike矩在医学图像处理中的应用

矩技术是描述图像特征的一种有效方法,在图像处理的各个领域得到了广泛应用.Zernike矩是一种连续正交矩,可以描述图像形状的全局特征,其最重要的性质是具有旋转不变性.Zernike矩能够构造任意的高阶矩,较容易地从矩特征中对图像进行重构,具有最小的信息冗余,并且对噪声不敏感、鲁棒性好.目前,在医学图像处理中Zernike矩较多应用于边缘检测和图像配准领域.Zernike矩可以达到亚像素级的边缘定位,且抗干扰性强;基于Zernike矩的配准代价函数降低了需要对比的自由度对数,从而显著减少了迭代次数;利用Zernike矩作为图像特征点描述子的算法,在图像存在比例缩放、旋转等情况下具有良好的配准效果.     

Determination of aluminium content in aluminium hydroxide formulation by FT-NIR transmittance spectroscopy

A method for determining the aluminium content of an aluminium hydroxide suspension using near infrared (NIR) transmittance spectroscopy has been developed. Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) was used as reference method. The factors influencing the NIR analysis, such as different sample containers (transmission cell and cuvette), sedimentation in the suspension, day-to-day variation and batch-to-batch variation have been studied before constructing a calibration model. Seven dilutions (0–4100 mg Al/L) of five batches of aluminium hydroxide suspension samples were measured by NIR transmission each on five different days, with total of 175 spectra used for the calibration set. The multivariate data analysis technique partial least square regression (PLSR) was applied to build the calibration model. Six batches of aluminium hydroxide samples were used for the test set. ICP-AES and NIR transmittance spectroscopy exhibit comparable precision and accuracy. The NIR method provides several advantages: no complicated sample preparation; easy to operate; fast and non-destructive. In conclusion, NIR transmittance spectroscopy can be an alternative analytical method for determining aluminium content in aluminium hydroxide suspension.     

Quality Control During Processing of Feta Cheese—NIR Application

This work examines the possibility of using near infrared (NIR) spectroscopic method for the production process control of the traditional Greek feta cheese. A NIR apparatus (Instalab 600-Dickey–John) was employed. Moisture, fat and protein determinations were selected as calibration set for the instrument. Samples were drawn from well-defined critical points of production. In all the samples conventional chemical methods were applied for the quantitative determination of the above ingredients. Results were compared with the respective data from NIR apparatus. All data were processed by a suitable computer program so that the calibration constants could be calculated and then stored in the apparatus. Their accuracy was verified using an independent set of analyzed samples. Because the NIR apparatus used in this work was not suitable for liquid products, a novel technique was developed using “quartz fine granular washed and calcined GR” (pro analysi). This technique proved to be reliable with a significant accuracy. From this study it can be concluded that NIR technique can be applied successfully for the on-line quality control of the feta cheese production. The reliability, significant reduction of human errors, precision and quickness of NIR spectroscopy experienced during this work, support the implementation of this method.     

多模式医学图像融合体位固定通用床板

目的：设计一种能固定受检者体住、与受检者一同搬动、适用于多种影像检查的通用床板。方法：床板呈“簸箕”槽状,采用低密度塑料注塑而成,其内置有规则走形、充满多功能显影剂的管线,床板上面设有负压真空气垫和固定人体的系带。图像融合时,先进行单模式的图像容积重建,再依据冠状和矢状显影标志管线进行配准容积融合．结果：床板在软组织窗下CT、MRI、PET、SPECT均不显影。受检者在多种影像检查的体位一致。图像融合配准标志的显影管线明显,已申报国家专利。结论：利用通用床板进行多模式图像融合,快捷迅速,简单准确,可行有效,易于推广普及。     

钼靶摄影与近红外扫描诊断乳腺疾病的临床研究

目的评价钼靶摄影与近红外扫描在乳腺疾病诊断中的价值和相关年龄段乳腺良、恶性疾病发病交叉情况在诊断早期乳腺癌中的意义。方法对151例同时进行了钼靶摄影、近红外扫描和经手术、病理证实的乳腺病进行回顾性研究。结果钼靶摄影对乳腺良性疾病、恶性肿瘤和早期乳腺癌的诊断符合率分别为93.10%、93.75%和78.13%,而近红外扫描分别为72.41%、73.44%和57.81%。良性疾病与恶性肿瘤在36~40岁、41~45岁、46~50岁3个年龄段出现发病交叉高峰,发病率分别为56.32%和54.67%,这对鉴别诊断早期乳腺癌意义重大。结论无论良、恶性乳腺疾病的诊断,钼靶优于近红外扫描,尤其在诊断早期乳腺癌方面,钼靶诊断的价值是肯定的。对于处于乳腺良、恶性疾病发病年龄高峰(36岁以上)的妇女或临床可疑乳腺癌患者,均应首选钼靶摄影检查。     

Evaluation of open-path FTIR spectrometers for monitoring multiple chemicals in air

There has been mounting interest in the use of open-path Fourier transform infrared (OP-FTIR) spectrometers for occupational and environmental air monitoring. Although this technology is gaining acceptance in the environmental field, there has not yet been a comprehensive assessment of instrument performance and the analytical limitations of this method have not been thoroughly delineated. Unlike extractive FTIR spectrometers, calibration of OP-FTIR spectrometer systems presents unique problems because the optical beam is exposed to the atmosphere. Therefore, it is difficult to get an adequate clean background and perform evaluation tests used by extractive instruments. One solution to the problem of evaluating an open-path system is to place a sample cell directly in the path of the infrared beam. The purpose of this study was to investigate the use of a specially designed external calibration cell as a tool for laboratory and field evaluation of the accuracy of OP-FTIR spectrometers and to investigate various commonly used instrument performance parameters such as root mean square (RMS) noise, return intensity, instrument precision, and detector saturation. These performance parameters were measured to see if they could be used to predict whether an instrument is operating correctly. Six instruments from the same manufacturer were evaluated with a prototype calibration cell using NIST traceable sulfur hexafluoride, n-hexane, and cyclohexane. Reference concentrations generated in the calibration cell were compared with OP-FTIR spectrometer measured concentrations measured through the cell. Excellent correlation and slopes were obtained for all three chemicals. The instrument performance measures could not be used to predict accuracy. The external calibration cell shows promise as a method of validating the operation of an OP-FTIR spectrometer for quality assurance and for quality control.     

External calibration models for the measurement of tomato carotenoids by infrared spectroscopy

A new method for the rapid construction of calibration models for the measurement of carotenoids in tomato by infrared spectroscopy was developed using a low-carotenoid tomato variety. Different amounts of lycopene and β-carotene were spiked in low-carotenoid tomato juice and homogeneously dispersed using a continuous stream of nitrogen and agitation. The protocol allowed for the production of homogeneous tomato juice standards with ∼90% carotenoid retention as determined by HPLC and UV-vis spectroscopy. Partial least-squares regression (PLSR) was used to create calibration models correlating infrared spectra from tomato lipid fractions and puree to their carotenoid content. The best calibration performance was obtained using lipid fraction models. PLSR calibration produced a high correlation coefficient (0.99) and a standard error of cross-validation of 0.81 mg/100 g for lycopene in the 0.0-14.0 mg/100 g range. Similarly, a high correlation coefficient (0.99) was obtained for β-carotene in the 0.0-9.0 mg/100 g range with a standard error of cross-validation of 0.36 mg/100 g. Calibration models were evaluated by predicting lycopene content in genetically diverse tomatoes from local markets. Results correlated well with concentrations determined by HPLC. This approach permitted the rapid preparation (∼3 min) of highly reproducible tomato juice standards that can be customized as needed to construct external calibration curves for the high-throughput measurement of carotenoids by FTIR, and potentially by other colorimetric and spectrometric techniques. The method eliminates the need for a large number of tomato samples for calibration and allows UV-vis spectroscopy to be used as an alternative reference method to HPLC.     

基于多光谱的地面伤员识别技术实验研究

目的:为解决战场环境中身着迷彩服伤员难以被快速发现的问题,提出一种无人机搭载多光谱相机的地面伤员识别技术.方法:使用ATP9100地物光谱仪采集草地和林地迷彩服的光谱强度和反射率数据,提取曲线特征选取特征谱段,根据该特征谱段选定MS600型通用多光谱相机搭载至大疆M100四旋翼无人机,采集草地环境下林地迷彩服多光谱图像...     

液体推进剂系列毒气监测仪器的研究

目的:通过研究可用于肼类燃料和硝基氧化剂毒气泄漏检测的各种技术方法,研制液体推进剂系列毒气泄漏监测仪器.方法:采用电化学和红外光谱技术,通过探讨其原理和关键技术设计液体推进剂毒气泄漏监测仪器,并测试其相关性能.结果:设计的电化学类毒气监测仪器具有灵敏度高的优点,但使用寿命短,响应慢；而红外光谱类毒气监测仪器使用寿命长,响应快,无需经常标定,但灵敏度不及电化学类仪器.结论:电化学类毒气监测仪器性能上有局限性,但经过几十年的发展业已成熟；光谱类毒气监测仪应用前景广阔,但尚需在优化性能方面做进一步工作.     

Use of electronic portal imaging devices for electron treatment verification

This study aims to help broaden the use of electronic portal imaging devices (EPIDs) for pre-treatment patient positioning verification, from photon-beam radiotherapy to photon- and electron-beam radiotherapy, by proposing and testing a method for acquiring clinically-useful EPID images of patient anatomy using electron beams, with a view to enabling and encouraging further research in this area. EPID images used in this study were acquired using all available beams from a linac configured to deliver electron beams with nominal energies of 6, 9, 12, 16 and 20 MeV, as well as photon beams with nominal energies of 6 and 10 MV. A widely-available heterogeneous, approximately-humanoid, thorax phantom was used, to provide an indication of the contrast and noise produced when imaging different types of tissue with comparatively realistic thicknesses. The acquired images were automatically calibrated, corrected for the effects of variations in the sensitivity of individual photodiodes, using a flood field image. For electron beam imaging, flood field EPID calibration images were acquired with and without the placement of blocks of water-equivalent plastic (with thicknesses approximately equal to the practical range of electrons in the plastic) placed upstream of the EPID, to filter out the primary electron beam, leaving only the bremsstrahlung photon signal. While the electron beam images acquired using a standard (unfiltered) flood field calibration were observed to be noisy and difficult to interpret, the electron beam images acquired using the filtered flood field calibration showed tissues and bony anatomy with levels of contrast and noise that were similar to the contrast and noise levels seen in the clinically acceptable photon beam EPID images. The best electron beam imaging results (highest contrast, signal-to-noise and contrast-to-noise ratios) were achieved when the images were acquired using the higher energy electron beams (16 and 20 MeV) when the EPID was calibrated using an intermediate (12 MeV) electron beam energy. These results demonstrate the feasibility of acquiring clinically-useful EPID images of patient anatomy using electron beams and suggest important avenues for future investigation, thus enabling and encouraging further research in this area. There is manifest potential for the EPID imaging method proposed in this work to lead to the clinical use of electron beam imaging for geometric verification of electron treatments in the future.     

用于康普顿相机的成像探测系统研制

目的 针对核设施热点成像应用设计康普顿相机的探测器和读出电子学系统。方法 采用两块像素型碲锌镉探测器分别作为康普顿相机的散射层和吸收层,利用SRE4002模块、信号处理电路、模数转换电路和主控板等构成读出电子学系统,并针对康普顿相机应用设计了数据采集逻辑和控制程序,可对探测器每个像素的能量响应进行实际校准测试。结果 测试发现该探测系统的位置分辨与像素设计一致;校准后662 keV处总能量分辨和平均能量分辨约为3%。结论 该系统的位置分辨和能量分辨符合康普顿相机研究需求,单像素能量校准有效改善了能量分辨,可为康普顿散射成像研究提供硬件支持,并对其他γ成像系统设计具有借鉴意义。