共查询到19条相似文献，搜索用时 46 毫秒
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针对相移结构光中相位计算环节,提出了一种基于一维查找表的相位实时解码算法。首先根据相位计算公式中的反正切函数性质,得到四个象限之间的相位转化关系。基于得到的转换关系,使用线性函数将第一象限中的所有坐标点映射至某个离散整数区间中,结合该区间与线性函数提前建立相位的一维查找表。在相位计算过程中,首先利用相关信息计算一维查找表的索引,直接获取相位值,然后利用线性插值法与相位转换关系调整该相位值,得到最终的真实相位。通过实验验证了所提算法的有效性,与使用传统相位计算方法相比,本文提出的方法最快可提升3.97倍,使用线性插值后,相位精度可达${10^{ - 8}}$。与传统的多项式逼近算法相比,该算法速度提升了1.29倍;与传统的一维查找表算法相比,该算法速度提升了1.22倍。 相似文献
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SHR22000是日本滨松光子学株式会社开发的人体全身用正电子发射断层扫描仪. 扫描仪具有32层探测器环, 二维采集可形成63个切片, 病人孔径为60cm, 单个体位数据采集时间为3—5min.扫描仪的轴向视野为22.5cm, 经5个体位可以完成全身扫描, 视野中轴10mm处平均横向分辨率可达到3.2mm. 本文依照国际标准IEC 61675-1(亦即GB/T18988.1-2003)规定的各项指标对该扫描仪的空间分辨率、灵敏度、散射和计数率特性以及复原系数进行了测试, 并给出结果数据. 相似文献
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PET设备中探测器的研发, 一直是很活跃且具有高创新性的领域。 提高现有基于闪烁晶体探测器的性能, 研究适用于多模式成像设备（PET/CT和PET/MRI）的新型探测器, 满足TOF和DOI技术的需求并促进其发展应用, 构成PET探测器的几个主要研究方向。 介绍了PET探测器在闪烁晶体、 光电探测器和半导体探测器等方面的最新进展, 指出未来最有潜力的探测器设计方案。 The research on PET detector is a very active and highly innovative field. The main research interests of PET detector include improving performances of scintillation crystal detectors, investigating new detectors being suitable for multimodality imaging (e.g., PET/CT and PET/MRI), meeting needs of TOF and DOI technologies in order to promote their development and application. In this paper, new developments in PET detector technology about scintillation crystal, photodetector and semiconductor detector are introduced and the most potential detector design scheme in the future is brought forward. 相似文献
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根据实验的数据建立了CRT的设备颜色空间(RGB空间)与标准颜色空间(CIELAB空间)之间的颜色特性转换模型。通过分析大量的实验测量数据,以改进的三维查找表形式建立了RGB和L*a*b*之间的正逆转换关系。其中正向查找表的建立是按照三维线性的插值方法,逆向查找表的建立则利用一种插值和迭代相结合的新方法,使L*a*b*查找到较为准确的RGB值。通过用标准图像的的随机误差检验,其转换的平均色差ΔE为0.9286色差单位。 相似文献
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王子龙;徐洪志;杨玲玲;侯文慧;刘路 《光学学报》2024,(9):113-121
在利用查找表（LUT）降低相位误差的同时,考虑到相位误差具有周期性和对称性,提出一种基于1/6周期LUT(sLUT)的误差补偿方法,极大地缩短了误差补偿的计算时间,实现了快速相位误差补偿。实验结果表明,在查找表的参数量降低83%的基础上,sLUT的误差补偿效果不受影响,同时sLUT的误差校正时间仅为LUT的1/8。 相似文献
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由于正电子发射型计算机断层显像(PET)噪声较大,现有图像降噪效果不理想,提出了一种结合残差U-Net神经网络和深度图像先验(DIP)的PET图像降噪.在U-Net网络中引入残差学习,提高网络表达能力和收敛速度;提出一种无训练数据的DIP算法,将神经网络解释为图像的参数化,利用图像噪声参数化后呈现高阻抗的特性将其去除,... 相似文献
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为实现正电子发射断层成像（PositronEmissionTomography,PET）探测器的作用深度（DepthOfInteraction,DOI）信息获取,本文提出一种基于分光技术的探测器设计方案.探测器采用晶体单元与硅光电倍增管（SiliconPhotomultiplier,SiPM）一对一耦合、蛇形光路的设计和单端Anger加权读出方法进行DOI解码.基于GATE软件进行蒙特卡罗模拟,建立8×1的LSO晶体阵列（单根晶体尺寸3.1×3.1×20mm 相似文献
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设计了双层LSO晶体和位置灵敏型光电倍增管耦合构成的用于小动物PET成像的深度编码探测器. 众所周知, 晶体的不同的表面处理影响着光输出量, 进而影响着它们构建的PET探测器的性能. 为了优化设计的深度编码探测器的性能, 测试了两种不同表面处理的LSO闪烁晶体阵列探测器的晶体分辨能力及其能量、时间和空间分辨率, 结果表明, 光滑表面LSO晶体构建的深度编码探测器显示出良好的空间、能量及时间分辨特性. 相似文献
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正电子发射断层扫描(positron emission computed tomography, PET)是核医学领域最先进的临床检查影像技术. PET技术是目前临床上用于诊断和指导治疗肿瘤的最佳手段之一. 正电子发射断层成像设备探测器采集到的数据需要进行数据处理, 把原始数据转换成正弦图形式的数据才能用于图像重建. 平行束断层重建和扇形束图像重建是图像重建的两种方法, 分别对应平行束和扇形束形式的数据处理方法. 对原始数据的操作不可避免地破坏了原始数据的完整性. 现今, 正电子发射断层设备在重建过程中普遍采用平行束重建的方法. 平行束的数据分离会对PET数据进行插值操作, 扇形束的数据分离不会对PET数据进行插值操作. 本文通过对比平行束图像重建和扇形束图像重建结果, 研究了数据插值对PET图像重建结果的影响.关键词：正电子发射计算机断层扫描数据插值图像重建原始数据 相似文献
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Hamamatsu SHR74000 is a newly designed full three-dimensional (3D) whole body positron emission tomography (PET)scanner with small crystal size and large field of view (FOV). Withthe improvement of sensitivity, the scatter events increasesignificantly at the same time, especially for large objects.Monte Carlo simulations help us to understand the scatter phenomena andprovide good references for scatter correction. In this paper, weintroduce an effective scatter correction method based on singlescatter simulation for the new PET scanner, which accounts for thefull 3D scatter correction. With the results from Monte Carlosimulations, we implement a new scale method with specialconcentration on scatter events from outside the axial FOV andmultiple scatter events. The effects of scatter correction areinvestigated and evaluated by phantom experiments; the results show good improvements in quantitative accuracy and contrast of the images, even for large objects. 相似文献
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Irene V. J. Feiner Krishna R. Pulagam Vanessa Gómez-Vallejo Kepa Zamacola Zuriñe Baz María M. Caffarel Charles H. Lawrie Ane Ruiz-de-Angulo Mónica Carril Jordi Llop 《Particle & Particle Systems Characterization》2020,37(12):2000200
Boron neutron capture therapy (BNCT) is a binary approach for cancer treatment in which boron-10 atoms and thermal neutrons need to colocalize to become effective. Recent research in the development of BNCT drug candidates focuses increasingly on nanomaterials, with the advantages of high boron loadings and passive targeting due to the enhanced permeability and retention (EPR) effect. The use of small boron-rich gold nanoparticles (AuNPs) in combination with a pretargeting approach is proposed. Small sized polyethylene glycol–stabilized AuNPs (core size 4.1 ± 1.5 nm), are synthesized and functionalized with thiolated cobalt bis(dicarbollide) and tetrazine. To enable in vivo tracking of the AuNPs by positron emission tomography (PET), the core is doped with [64Cu]CuCl2. For the pretargeting approach, the monoclonal antibody Trastuzumab is functionalized with trans-cyclooctene-N-hydroxysuccinimide ester. After proving in vitro occurrence of the antibody conjugation onto the AuNPs by click reaction and the low toxicity of the AuNPs, the boron delivery system is evaluated in vivo using breast cancer xenograft bearing mice and PET imaging. Tumor uptake due to the EPR effect can be witnessed with ≈5% injected dose (ID) cm−3 at 24 h postinjection, but with slower clearance than expected. Therefore, no increased retention can be observed using the pretargeting strategy. 相似文献
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A point spread function(PSF)for the blurring component in positron emission tomography(PET)is studied.The PSF matrix is derived from the single photon incidence response function.A statistical iterative reconstruction(IR)method based on the system matrix containing the PSF is developed.More specifically,the gamma photon incidence upon a crystal array is simulated by Monte Carlo(MC)simulation,and then the single photon incidence response functions are calculated.Subsequently,the single photon incidence response functions are used to compute the coincidence blurring factor according to the physical process of PET coincidence detection.Through weighting the ordinary system matrix response by the coincidence blurring factors,the IR system matrix containing the PSF is finally established.By using this system matrix,the image is reconstructed by an ordered subset expectation maximization(OSEM)algorithm.The experimental results show that the proposed system matrix can substantially improve the image radial resolution,contrast,and noise property.Furthermore,the simulated single gamma-ray incidence response function depends only on the crystal configuration,so the method could be extended to any PET scanner with the same detector crystal configuration. 相似文献
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通过使用基于Geant4的蒙特卡罗模拟代码GATE对全身用全3D正电子发射断层成像仪和含有挡板的2D/3D小动物用正电子发射断层成像仪进行建模,系统地分析了3D采集条件下正电子发射断层成像仪的散射分数、散射分布、多次散射、视野外散射四个主要方面和2D采集条件下挡板对散射分数和散射分布的影响.针对全3D散射校正的难点: 多次散射和视野外散射,设计了附加实验,拟合得到了多次散射光子的百分比随体模横截面积变化的关系和不同环的位置受到视野外散射光子的影响;针对2D散射校正,对挡板引入的散射光子进行分离,单独分析,关键词：正电子发射断层成像仪（PET）蒙特卡罗模拟散射特性散射校正 相似文献