目的:对比三维多回波恢复梯度回波(3D MERGE)、三维可变反转角快速自旋回波(3D SPACE STIR)序列在腰椎间盘突出症(LDH)检查中的应用效果。方法:选择2020年1月~2022年11月收治的135例LDH患者,回顾性分析患者临床和磁共振成像(MRI)资料,...目的:对比三维多回波恢复梯度回波(3D MERGE)、三维可变反转角快速自旋回波(3D SPACE STIR)序列在腰椎间盘突出症(LDH)检查中的应用效果。方法:选择2020年1月~2022年11月收治的135例LDH患者,回顾性分析患者临床和磁共振成像(MRI)资料,所有患者均接受常规MRI扫描及3D MERGE、3D SPACE STIR序列扫描,对比3D MERGE、3D SPACE STIR序列测量神经根直径的一致性,评价两种序列的图像质量参数[信噪比(SNR)、对比噪声比(CNR)]、图像清晰度评分。结果:3D MERGE和3D SPACE STIR序列测量的L3~S1神经根直径比较差异无统计学意义(P>0.05),且两组序列测量的L3、L4、L5和S1直径均显示出较高相关性(r=0.957,0.986,0.975,0.972,P<0.05);3D MERGE序列的SNR及CNR均高于3D SPACE STIR序列,神经根显示分级、图像清晰度评分优于3D SPACE STIR序列,差异有统计学意义(P<0.05)。结论:3D MERGE、3D SPACE STIR序列在LDH神经根直径测量中具有极高一致性,3D MERGE序列较3D SPACE STIR序列能够更清晰显示神经跟的解剖形态,图像质量更好。展开更多
This paper presents a principle and a method of col or 3D laser scanning measurement. Based on the fundamental monochrome 3D measureme nt study, color information capture, color texture mapping, coordinate computati o...This paper presents a principle and a method of col or 3D laser scanning measurement. Based on the fundamental monochrome 3D measureme nt study, color information capture, color texture mapping, coordinate computati on and other techniques are performed to achieve color 3D measurement. The syste m is designed and composed of a line laser light emitter, one color CCD camera, a motor-driven rotary filter, a circuit card and a computer. Two steps in captu ring object’s images in the measurement process: First, the color CCD camera ta kes the color picture of the object to be used for texture mapping in post proce ssing. Secondly, the monochrome data of the object is taken. The laser light emi tter is started; the light plane and the surface of the object intersect to form an undulate line, which forms an image on the CCD sensor. After the optic- electronics transformation, the electronic signals are captured and send to the computer. A new color 3D measurement model was derived, and a rapid calibra ting method to measure the system parameters was proposed--optical plane equat ion calibrating method. A calibrating drone was designed and built. 3D color sca nning system not only provides an object’s individual point information in the 3D coordinate, in the mean time, it provides the color information of each indiv idual point. This paper also advances a multi-frame auto-merging method, i.e. several frames of color 3D digital images measured are merged quickly according to their curvature characteristics and RGB information. Initial matching and fin e tune of the registration are completely performed by the computer; initial mat ching is via user interface in helping computer to find the transformation matri x. The transformation matrix is found according to the geometric characteristics chosen by hand. After the initial transformation matrix is found, fine tune of the registration is preformed to do the optimum adjustment to achieve a complete color textured 3D model. The system can be broadly used in the fields of produc t design, mold manufacture, multimedia, game development, animation, medical eng ineering, antique digitization, etc.展开更多
This paper deals with the massive point cloud segmentation processing technology on the basis of machine vision, which is the second essential factor for the intelligent data processing of three dimensional conformati...This paper deals with the massive point cloud segmentation processing technology on the basis of machine vision, which is the second essential factor for the intelligent data processing of three dimensional conformation in digital photogrammetry. In this paper, multi-model fitting method is used to segment the point cloud according to the spatial distribution and spatial geometric structure of point clouds by fitting the point cloud into different geometric primitives models. Because point cloud usually possesses large amount of 3D points, which are uneven distributed over various complex structures, this paper proposes a point cloud segmentation method based on multi-model fitting. Firstly, the pre-segmentation of point cloud is conducted by using the clustering method based on density distribution. And then the follow fitting and segmentation are carried out by using the multi-model fitting method based on split and merging. For the plane and the arc surface, this paper uses different fitting methods, and finally realizing the indoor dense point cloud segmentation. The experimental results show that this method can achieve the automatic segmentation of the point cloud without setting the number of models in advance. Compared with the existing point cloud segmentation methods, this method has obvious advantages in segmentation effect and time cost, and can achieve higher segmentation accuracy. After processed by method proposed in this paper, the point cloud even with large-scale and complex structures can often be segmented into 3D geometric elements with finer and accurate model parameters, which can give rise to an accurate 3D conformation.展开更多
In this study, we quantitatively compared relaxation enhanced compressed sensing(RECS-3D MERGE) with conventional 3D MERGE techniques on blood suppression efficiency, wall-lumen contrast and plaque burden measurement ...In this study, we quantitatively compared relaxation enhanced compressed sensing(RECS-3D MERGE) with conventional 3D MERGE techniques on blood suppression efficiency, wall-lumen contrast and plaque burden measurement for carotid atherosclerotic imaging in equal scan time. Twelve patients were recruited in the study. RECS-3D MERGE and conventional 3D MERGE were implemented. 2D DIR-FSE was carried out as a reference standard. The lumen signal-to-tissue ratio(STR) was used as the quantitative measure of blood suppression efficiency. The contrast-to-tissue ratio(CTR) was used as the quantitative measure of wall-lumen contrast. Vessel lumen area(LA) and wall area(WA) were measured for morphological comparisons. The lumen STR of RECS-3D MERGE was significantly lower than that of 3D MERGE while the wall-lumen CTR of RECS-3D MERGE was significantly higher. There were no significant differences in plaque burden measurements between RECS-3D MERGE and 2D DIR-FSE. For comparison between conventional 3D MERGE and 2D DIR-FSE, there were no significant differences in LA measurement. However, the WA of 3D MERGE was significantly larger. The RECS-3D MERGE sequence achieved more sufficient blood suppression and higher image contrast without prolonging the scan time. These improvements lead to more accurate morphological measurements of carotid atherosclerotic imaging.展开更多
文摘目的:对比三维多回波恢复梯度回波(3D MERGE)、三维可变反转角快速自旋回波(3D SPACE STIR)序列在腰椎间盘突出症(LDH)检查中的应用效果。方法:选择2020年1月~2022年11月收治的135例LDH患者,回顾性分析患者临床和磁共振成像(MRI)资料,所有患者均接受常规MRI扫描及3D MERGE、3D SPACE STIR序列扫描,对比3D MERGE、3D SPACE STIR序列测量神经根直径的一致性,评价两种序列的图像质量参数[信噪比(SNR)、对比噪声比(CNR)]、图像清晰度评分。结果:3D MERGE和3D SPACE STIR序列测量的L3~S1神经根直径比较差异无统计学意义(P>0.05),且两组序列测量的L3、L4、L5和S1直径均显示出较高相关性(r=0.957,0.986,0.975,0.972,P<0.05);3D MERGE序列的SNR及CNR均高于3D SPACE STIR序列,神经根显示分级、图像清晰度评分优于3D SPACE STIR序列,差异有统计学意义(P<0.05)。结论:3D MERGE、3D SPACE STIR序列在LDH神经根直径测量中具有极高一致性,3D MERGE序列较3D SPACE STIR序列能够更清晰显示神经跟的解剖形态,图像质量更好。
文摘This paper presents a principle and a method of col or 3D laser scanning measurement. Based on the fundamental monochrome 3D measureme nt study, color information capture, color texture mapping, coordinate computati on and other techniques are performed to achieve color 3D measurement. The syste m is designed and composed of a line laser light emitter, one color CCD camera, a motor-driven rotary filter, a circuit card and a computer. Two steps in captu ring object’s images in the measurement process: First, the color CCD camera ta kes the color picture of the object to be used for texture mapping in post proce ssing. Secondly, the monochrome data of the object is taken. The laser light emi tter is started; the light plane and the surface of the object intersect to form an undulate line, which forms an image on the CCD sensor. After the optic- electronics transformation, the electronic signals are captured and send to the computer. A new color 3D measurement model was derived, and a rapid calibra ting method to measure the system parameters was proposed--optical plane equat ion calibrating method. A calibrating drone was designed and built. 3D color sca nning system not only provides an object’s individual point information in the 3D coordinate, in the mean time, it provides the color information of each indiv idual point. This paper also advances a multi-frame auto-merging method, i.e. several frames of color 3D digital images measured are merged quickly according to their curvature characteristics and RGB information. Initial matching and fin e tune of the registration are completely performed by the computer; initial mat ching is via user interface in helping computer to find the transformation matri x. The transformation matrix is found according to the geometric characteristics chosen by hand. After the initial transformation matrix is found, fine tune of the registration is preformed to do the optimum adjustment to achieve a complete color textured 3D model. The system can be broadly used in the fields of produc t design, mold manufacture, multimedia, game development, animation, medical eng ineering, antique digitization, etc.
基金The National Natural Science Foundation of China (61261130587,61571332).
文摘This paper deals with the massive point cloud segmentation processing technology on the basis of machine vision, which is the second essential factor for the intelligent data processing of three dimensional conformation in digital photogrammetry. In this paper, multi-model fitting method is used to segment the point cloud according to the spatial distribution and spatial geometric structure of point clouds by fitting the point cloud into different geometric primitives models. Because point cloud usually possesses large amount of 3D points, which are uneven distributed over various complex structures, this paper proposes a point cloud segmentation method based on multi-model fitting. Firstly, the pre-segmentation of point cloud is conducted by using the clustering method based on density distribution. And then the follow fitting and segmentation are carried out by using the multi-model fitting method based on split and merging. For the plane and the arc surface, this paper uses different fitting methods, and finally realizing the indoor dense point cloud segmentation. The experimental results show that this method can achieve the automatic segmentation of the point cloud without setting the number of models in advance. Compared with the existing point cloud segmentation methods, this method has obvious advantages in segmentation effect and time cost, and can achieve higher segmentation accuracy. After processed by method proposed in this paper, the point cloud even with large-scale and complex structures can often be segmented into 3D geometric elements with finer and accurate model parameters, which can give rise to an accurate 3D conformation.
基金supported by the National Natural Science Foundation of China (81760311)Science and Technology Plan Foundation of the Jiangxi Provincial Health and Family Planning Commission (20184009)Chinese Medicine Research Foundation of the Jiangxi Provincial Health and Family Planning Commission (2017A152)
文摘In this study, we quantitatively compared relaxation enhanced compressed sensing(RECS-3D MERGE) with conventional 3D MERGE techniques on blood suppression efficiency, wall-lumen contrast and plaque burden measurement for carotid atherosclerotic imaging in equal scan time. Twelve patients were recruited in the study. RECS-3D MERGE and conventional 3D MERGE were implemented. 2D DIR-FSE was carried out as a reference standard. The lumen signal-to-tissue ratio(STR) was used as the quantitative measure of blood suppression efficiency. The contrast-to-tissue ratio(CTR) was used as the quantitative measure of wall-lumen contrast. Vessel lumen area(LA) and wall area(WA) were measured for morphological comparisons. The lumen STR of RECS-3D MERGE was significantly lower than that of 3D MERGE while the wall-lumen CTR of RECS-3D MERGE was significantly higher. There were no significant differences in plaque burden measurements between RECS-3D MERGE and 2D DIR-FSE. For comparison between conventional 3D MERGE and 2D DIR-FSE, there were no significant differences in LA measurement. However, the WA of 3D MERGE was significantly larger. The RECS-3D MERGE sequence achieved more sufficient blood suppression and higher image contrast without prolonging the scan time. These improvements lead to more accurate morphological measurements of carotid atherosclerotic imaging.
