Anisotropy of Trabecular Bone from Ultra-Distal Radius Digital X-Ray Imaging: Effects on Bone Mineral Density and Age

Background: When applied to trabecular bone X-ray images, the anisotropic properties of trabeculae located at ultra-distal radius were investigated by using the trabecular bone scores (TBS) calculated along directions parallel and perpendicular to the forearm. Methodology: Data from more than two hundred subjects were studied retrospectively. A DXA (GE Lunar Prodigy) scan of the forearm was performed on each subject to measure the bone mineral density (BMD) value at the location of ultra-distal radius, and an X-ray digital image of the same forearm was taken on the same day. The values of trabecular bone score along the direction perpendicular to the forearm, TBSx, and along the direction parallel to the forearm, TBSy, were calculated respectively. The statistics of TBSx and TBSy were calculated, and the anisotropy of the trabecular bone, which was defined as the ratio of TBSy to TBSx and changed with subjects’ BMD and age, was reported and analyzed. Results: The results show that the correlation coefficient between TBSx and TBSy was 0.72 (p BMD and age was reported. The results showed that decreased trabecular bone anisotropy was associated with deceased BMD and increased age in the subject group. Conclusions: This study shows that decreased trabecular bone anisotropy was associated with decreased BMD and increased age.

Anisotropic creep behavior of soft-hard interbedded rock masses based on 3D printing and digital imaging correlation technology

Three-dimensional(3D)printing technology is increasingly used in experimental research of geotechnical engineering.Compared to other materials,3D layer-by-layer printing specimens are extremely similar to the inherent properties of natural layered rock masses.In this paper,soft-hard interbedded rock masses with different dip angles were prepared based on 3D printing(3DP)sand core technology.Uniaxial compression creep tests were conducted to investigate its anisotropic creep behavior based on digital imaging correlation(DIC)technology.The results show that the anisotropic creep behavior of the 3DP soft-hard interbedded rock mass is mainly affected by the dip angles of the weak interlayer when the stress is at low levels.As the stress level increases,the effect of creep stress on its creep anisotropy increases significantly,and the dip angle is no longer the main factor.The minimum value of the long-term strength and creep failure strength always appears in the weak interlayer within 30°–60°,which explains why the failure of the layered rock mass is controlled by the weak interlayer and generally emerges at 45°.The tests results are verified by comparing with theoretical and other published studies.The feasibility of the 3DP soft-hard interbedded rock mass provides broad prospects and application values for 3DP technology in future experimental research.

Imaging Analysis of Trabecular Bone Texture Based on the Initial Slope of Variogram of Ultra-Distal Radius Digital X-Ray Imaging: Effects on Bone Mineral Density and Age

Background: When applied to trabecular bone X-ray images, a method for analyzing trabecular bone texture based on the initial slope of variogram (ISV) was used to assess the trabecular bone health. Methodology: Data from more than two hundred subjects were retrospectively studied. For each subject, a DXA (GE Lunar Prodigy) scan of the forearm was performed, and bone mineral density (BMD) value was measured at the location of ultra-distal radius, X-ray digital image of the same forearm was taken on the same day, and ISV value over the same location of ultra-distal radius was calculated. Pearson’s correlation coefficients were calculated to examine the correlation between BMD and ISV of the trabecular bones located at the same ultra-distal radius. ISV values changed with subjects’ age were also reported. Results: The results show that ISV value was highly correlated with the DXA-measured BMD of the same trabecular bone located at the ultra-distal radius. The correlation coefficient between ISV and BMD with the 95% confident was 0.79 ± 0.09. They also demonstrated that the age-related changes in trabecular bone health and differentiated age patterns in males and females, respectively. The results showed that the decrease in BMD was accompanied by a decrease in the initial slope of variogram (ISV). Conclusions: This study suggests that ISV might be used to quantitatively evaluate trabecular health for osteoporosis and bone disease diagnosis.

The First International Digital Printing and Image Technology Exhibition & The Sixth International Exhibition of Quick Printing Equipment & Technology

Time: Sept.4-6, 2008Venue: Shenzhen Convention & Exhibition CenterSponsor: Printing and Printing Equipment Industries Association of China (PEIAC)Organizers: The Exhibition Department of

A cadaveric breast cancer tissue phantom for phase-contrast X-ray imaging applications

Background:As mammography X-ray imaging technologies advance and provide elevated contrast in soft tissues,a need has developed for reliable imaging phantoms for use in system design and component calibration.In advanced imaging modalities such as refraction-based methods,it is critical that developed phantoms capture the biological details seen in clinical precancerous and cancerous cases while minimizing artifacts that may be caused due to phantom production.This work presents the fabrication of a breast tissue imaging phantom from cadaveric breast tissue suitable for use in both transmission and refraction-enhanced imaging systems.Methods:Human cancer cell tumors were grown orthotopically in nude athymic mice and implanted into the fixed tissue while maintaining the native tumor/adipose tissue interface.Results:The resulting human–murine tissue hybrid phantom was mounted on a clear acrylic housing for absorption and refraction X-ray imaging.Digital breast tomosynthesis was also performed.Conclusion:Both attenuation-based imaging and refraction-based imaging of the phantom are presented to confirm the suitability of this phantom's use in both imaging modalities.

Fine Characterization and Analysis of Drying Strain of the ELM Board via DIC Technology

In this paper,the occurrence and development mechanism of strain on the cross-section during the wood drying is explored.Therefore,strain regularity on the cross-section of 50 mm thickness elm(Ulmus rubra)board at the temperature of 40℃and 80℃is detected via digital image correlation technology.Hence,the difference between tangential and radial strain at surface and core layers was denoted.The results showed that strain distribution in the width direction of the board is uneven.Moreover,a large drying shrinkage strain occurs at the near-core layer,while the maximum strain difference reaches 4.08%.Hence,the surface of the board is cracked along the thickness direction.The radial strain of the board is higher than the tangential strain in the early stage of drying,while these strains are reversed in the later stage of drying.The temperature is related to the difference between the tangential and radial strains of the elm board.These differences at the core layer are larger than those of the surface layer.The conducted research results provide a theoretical basis for process optimization.

Rapid digitalization and panoramic evaluation of weld X-ray film

The computer evaluation of weld X-ray film is an attractive technique for weld seam NDT （ nondestructive testing）. To achieve this target, digitalization of film is the first step and automatic defect identification is another key technique. In this paper, a weld X-ray film digitalizing system has been established with linear array CCD and highlight LED light source. Its space resolution can reach 0. 04 mm/pixel and scanning speed can reach 100 mm/s for an industrial film. The transfer function curves of the system have been measured and the results indicate that its image gray resolution can reach 88 G/D at 4. 5D, and its dynamic range can be wider than 2. OD. In order to facilitate the evaluation of large welded structure, a panoramic evaluation algorithm is developed also. The algorithm includes image matching, image fusion and panoramic evaluation of the long linked film image.

Hydrophobic long-chain two-dimensional perovskite scintillators for underwater X-ray imaging

The underwater X-ray imaging technology development is significant to subaqueous target reconnaissance/detection/identification, subfluvial archaeology,submerged resource exploration, etc. As the core of X-ray imaging detection, the scintillator has been plagued by inherent moisture absorption and decomposition, and strict requirements for seamless packaging and waterproofing.Here, we designed a manganese-doped two-dimensional(2D) perovskite scintillator modified by hydrophobic longchain organic amine through the combination of component and doping engineering. The modified perovskites show high water repellency that can be used as an underwater X-ray scintillator. X-ray images of aquatic organisms or other objects with a high spatial resolution of10 lp·mm^(-1) at a big view field(32 mm × 32 mm) were obtained by scintillation screen. This hydrophobic perovskite scintillator based on molecular design is of great promise in underwater X-ray nondestructive testing technology development.

An Improved Neural Network Method for Forearm Bone Imaging Segmentation

In this paper, we propose several improved neural networks and training strategy using data augmentation to segment human radius accurately and efficiently. This method can provide pixel-level segmentation accuracy through the low-level features of the neural network, and automatically distinguish the classification of radius. The versatility and applicability can be effectively improved by learning and training digital X-ray images obtained from digital X-ray imaging systems of different manufacturers.

城市更新背景下公共艺术塑造城市形象的创新策略研究

在中国当前的城市更新背景下,对城市形象的塑造是城市未来发展的主要方向,也是国家文化战略的重要内容。公共艺术与城市形象之间有着十分密切的联系,是塑造城市形象的重要手段。在当前的数字化时代背景下,把数字化技术介入公共艺术之中用以塑造城市形象已成为公共艺术创作者的普遍选择。立足于中国当前的城市更新背景,首先对公共艺术与城市形象之间的关系进行分析,然后在此基础上探讨公共艺术以塑造城市形象的创新途径和方式。通过研究表明,在中国当前的城市更新背景下,数字化技术的介入是公共艺术塑造城市形象的重要创新途径,在数字化技术介入下所创作的数字化公共艺术为公众营造多元化、多维度的体验感受是公共艺术塑造城市形象的重要创新方式。

ECC疲劳损伤规律及微观结构研究

为研究工程水泥基复合材料(ECC,engineered cementitious composites)的疲劳规律并探究其损伤原因,利用疲劳试验机对ECC试件进行单轴拉伸循环加载试验,分析其疲劳规律及损伤界面微观形态。研究结果表明:ECC试件破坏规律与其累积轴向应变速率有关,在加载初始阶段,累积轴向应变会随着循环荷载作用次数增加而明显增大,随后进入稳定变形阶段;进一步加载将导致累积轴向应变快速增长,并最终导致试件断裂破坏;ECC的裂纹宽度发展呈现出中间低、两端高的趋势;ECC试件在循环荷载过程中初次开裂后,不会迅速进入破坏阶段,是因为纤维仍然具有抗拉能力,可继续承受循环荷载加载;通过对纤维-基体界面的微观分析发现,纤维与基体结合较好,可整体耗散能量,为ECC具有高疲劳性能的主要原因。

“任务链+研学支架”教学模式的建构——新工科视角下“遥感数字图像处理”课教学改革

目前,传统教学在内容的系统性、认知活动高阶性、价值引领实效性、促学效果等方面存在着较严重的问题,为此,“遥感数字图像处理”课程基于新工科教学理念,以遥感技术的综合应用情境重构课程体系,开启“任务链+研学支架”教学模式,加强培养学生遥感应用能力和创新能力,以遥感技术服务社会需求为育人路径。新模式的构建,实现了应用与研学互动、研学与研教并举、育人与育才同构的效果,对同类型新工科课程具有借鉴意义。

口腔临床诊疗中数字牙片影像技术的应用价值

目的探讨口腔临床诊疗中数字牙片影像技术的应用价值。方法选择2022年1月至2023年5月期间在本院口腔科就诊且需要拔牙治疗的50例正畸患者作为研究对象。患者在治疗前,完成数字化牙片摄影和传统牙片摄影。记录投照上、下颌牙齿X线倾斜的垂直平均角度,并统计牙齿根尖片的曝光时间,对比两种摄影技术对牙齿长度的测量结果。结果传统牙片摄影时,上颌和下颌切牙位、单尖牙、双尖牙位、第一磨牙位、第二及三磨牙位(足侧倾斜)选择投射角度低于数字化牙片摄影(P<0.05)。数字化牙片摄影投照上颌和下颌切牙位、单尖牙位、双尖牙位、第三磨牙位及第一、二磨牙位牙齿根尖片的曝光时间低于传统牙片摄影(P<0.05)。数字化牙片摄影对待拔除牙齿单根、双根颊和双根腭测量结果与游标卡尺测量结果相比,差异无统计学意义(P>0.05);传统牙片摄影对待拔除牙齿单根、双根颊和双根腭测量结果低于游标卡尺测量结果,差异具有统计学意义(P<0.05);以游标卡尺测量结果为依据,数字化牙片摄影和传统牙片摄影对待拔除牙齿单根、双根颊和双根腭测量结果相比,差异具有统计学意义(P<0.05)。结论数字牙片影像技术投照条件宽容度相对较大,投射时曝光时间短,对牙齿根尖的测量准确度较高,便于细致观察牙齿,应用于口腔临床诊疗的价值较高。

数字图像相关技术测量位移的算法和试验研究

基于空间几何知识,通过建立空间直角坐标系、确定位移在Π平面上的投影,以及反推实际位移向量等三步,推导出数字图像监测系统在二维平面内的位移测量数学原理。然后选择不同场景展开现场应用,通过分析人工与自动化监测成果数据,发现光照强度变化、温度变化和距离增加,均会降低监测精度。

2D-SiC/SiC复合材料的弹丸冲击损伤及冲击后拉伸性能

连续纤维增韧陶瓷基复合材料以其良好的高温性能而被广泛应用在航空发动机等高温部件处,但服役过程中容易受到异物碎片冲击,这受到了广泛关注。研究采用轻气炮对化学气相渗透(CVI)技术制备的2D-SiC/SiC试样进行弹丸冲击,利用高速摄像机记录冲击过程,使用光学显微镜和CT观察异物损伤(FOD)的表面和内部结构,探讨了2D-SiC/SiC复合材料的高速冲击损伤特性。结果表明,2D-SiC/SiC复合材料的高速冲击损伤形式包括锥形裂纹、层间分层、纤维断裂以及基体压溃等。通过表征损伤发现,试件背部损伤和边缘处分层损伤由反射拉伸波造成,随着冲击速度提升,弹丸与拉伸波共同作用会造成试件穿透,试件边缘分层损伤减弱。对高速冲击后的试件进行准静态拉伸试验,明确了剩余力学性能与冲击速度、弹丸直径的关系,表明剩余拉伸强度是表征冲击损伤程度的有效参数。同时,采用数字图像相关(DIC)方法获得拉伸过程中的应变分布,并结合不同弹丸直径、冲击速度冲击后的剩余拉伸强度,进一步对比探究不同变量对冲击损伤的影响。研究结果表明弹丸直径是高速冲击损伤程度的主要影响因素。

一种高精度图像套准系统的设计与实现

在数字印后工艺生产中,介质传送误差常导致套准困难,通常需要对印刷品进行精确定位。目前,常用的定位方法是在印刷品空白处加入套印标识物,通过检测标识物进行定位。然而,这种方法在图像幅面占据整个印刷品幅面时无法使用。为了解决这一问题,本研究设计并实现了一套高精度智能图像套准系统,在保证图像采集与印刷的实时性与效率的同时,通过利用预先设计好的模板,在实时采集的图像中寻找匹配程度最高的区域,从而在印刷品中未加入套印标识的情况下,仍可实现印刷套准。印刷生产环境中实验结果表明,本方法的准确性和效率等均可满足实际工业生产的需求,具有较高的泛用性与实际的生产应用价值。

基于X射线CT原位试验的平纹SiC_(f)/SiC压缩损伤演化机理

为揭示陶瓷基复合材料的损伤演化及失效机理,开展了平纹SiC_(f)/SiC复合材料X射线CT原位压缩试验,得到了材料加载过程中和破坏后的CT原位图像数据;采用数字体积相关(DVC)技术获得了材料的位移场和应变场,利用图像处理软件建立复合材料内部三维可视化模型,借助深度学习算法获得纤维束劈裂等损伤的空间分布,进行了压缩损伤演化定性分析以及定量分析.结果表明:在单向压缩过程中,材料在厚度方向出现较大鼓出变形,在宽度方向则发生较小的收缩;厚度方向鼓出变形是引起材料压缩损伤的主要原因.载荷较大时出现表层基体脱落、纤维束劈裂、分层等损伤;纤维束压缩弯折导致材料压缩失效,断口处出现明显V形剪切带.平纹SiC_(f)/SiC的压缩损伤演化分析表明,DVC技术和基于深度学习的图像分割方法可以有效地揭示陶瓷基复合材料压缩损伤演化机理.

Three-dimensional finite element simulation and reconstruction of jointed rock models using CT scanning and photogrammetry

The geometry of joints has a significant influence on the mechanical properties of rocks.To simplify the curved joint shapes in rocks,the joint shape is usually treated as straight lines or planes in most laboratory experiments and numerical simulations.In this study,the computerized tomography (CT) scanning and photogrammetry were employed to obtain the internal and surface joint structures of a limestone sample,respectively.To describe the joint geometry,the edge detection algorithms and a three-dimensional (3D) matrix mapping method were applied to reconstruct CT-based and photogrammetry-based jointed rock models.For comparison tests,the numerical uniaxial compression tests were conducted on an intact rock sample and a sample with a joint simplified to a plane using the parallel computing method.The results indicate that the mechanical characteristics and failure process of jointed rocks are significantly affected by the geometry of joints.The presence of joints reduces the uniaxial compressive strength (UCS),elastic modulus,and released acoustic emission (AE) energy of rocks by 37%–67%,21%–24%,and 52%–90%,respectively.Compared to the simplified joint sample,the proposed photogrammetry-based numerical model makes the most of the limited geometry information of joints.The UCS,accumulative released AE energy,and elastic modulus of the photogrammetry-based sample were found to be very close to those of the CT-based sample.The UCS value of the simplified joint sample (i.e.38.5 MPa) is much lower than that of the CT-based sample (i.e.72.3 MPa).Additionally,the accumulative released AE energy observed in the simplified joint sample is 3.899 times lower than that observed in the CT-based sample.CT scanning provides a reliable means to visualize the joints in rocks,which can be used to verify the reliability of photogrammetry techniques.The application of the photogrammetry-based sample enables detailed analysis for estimating the mechanical properties of jointed rocks.

DR及DTS在寰枢关节半脱位诊断及分型中的价值研究

目的观察寰枢关节半脱位的影像学表现,探讨DR和X线数字化断层融合成像(DTS)技术在其诊断及分型中的价值。方法回顾性收集67例经临床及影像学检查诊断为寰枢关节半脱位的患者,分析其CT影像学表现,比较寰枢关节X线张口正位+侧位片、断层正位+侧位片的图像质量、诊断准确率、诊断一致性。结果寰椎关节前脱位的患者共有6例,侧方脱位40例,旋转脱位17例,复合脱位4例。有57%的DR片能用于诊断,有94%的DTS片能用于诊断,差异有统计学意义(P<0.05)。DR图像的诊断总准确率为42%,DTS图像的诊断总准确率为81%,差异具有统计学意义(P<0.05)。DR图像的诊断总准确率为24%,DTS图像的诊断总准确率为76%,差异具有统计学意义(P<0.05)。DR片诊断侧方脱位的准确率最高,为38%,诊断前脱位的准确率为17%。DTS片诊断前断脱位的准确率最高,为100%,诊断侧方脱位的准确率为92%,诊断旋转脱位的准确率为29%,诊断复合脱位的准确率为75%。二者诊断前脱位的诊确率没有统计学差异,而诊断侧方脱位的准确率差异具有统计学意义(P<0.05)。DR片诊断寰枢关节半脱位的一致性差(Kappa=0.28,P<0.05),DTS片的诊断一致性中等(Kappa=0.68,P<0.05)。结论DTS图像质量明显优于DR,在寰枢关节半脱位诊断及分型中的准确率、一致性也明显高于后者。