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31.
Abstract: In this study, an automatic three-dimensional computer-aided detection system for colonic polyps was developed. Computer-aided detection for computed tomography colonography aims at facilitating the detection of colonic polyps. First, the colon regions of whole computed tomography images were carefully segmented to reduce computational burden and prevent false positive detection. In this process, the colon regions were extracted by using a cellular neural network and then the regions of interest were determined. In order to improve the segmentation performance of the study, weights in the cellular neural network were calculated by three heuristic optimization techniques, namely genetic algorithm, differential evaluation and artificial immune system. Afterwards, a three-dimensional polyp template model was constructed to detect polyps on the segmented regions of interest. At the end of the template matching process, the volumes geometrically similar to the template were emhanced. 相似文献
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33.
肝癌是一种常见的恶性肿瘤,近年来发病率呈缓慢上升的趋势,病死率也随之上升。文章利用小波在特征提取和模式识别方面的独特优势,提取了基于小波和灰度共生矩阵的纹理特征,结合遗传算法进行特征选择和优化,用KNN分类器设计出高精确度的肝脏疾病良恶性分类器。采用肝脏CT平扫图像,将肝癌与其他的良性病变进行分类,探讨了小波的不同性质及特征提取方式对分类结果的影响,对小波在肝脏CT图像良恶性分类中的研究有指导意义。 相似文献
34.
Sarve H Lindblad J Borgefors G Johansson CB 《Computer methods and programs in biomedicine》2011,102(1):25-34
Bone-implant integration is measured in several ways. Traditionally and routinely, 2D histological sections of samples, containing bone and the biomaterial, are stained and analyzed using a light microscope. Such histological section provides detailed cellular information about the bone regeneration in the proximity of the implant. However, this information reflects the integration in only a very small fraction, a 10 μm thick slice, of the sample. In this study, we show that feature values quantified on 2D sections are highly dependent on the orientation and the placement of the section, suggesting that a 3D analysis of the whole sample is of importance for a more complete judgment of the bone structure in the proximity of the implant. We propose features describing the 3D data by extending the features traditionally used for 2D-analysis. We present a method for extracting these features from 3D image data and we measure them on five 3D SRμCT image volumes.We also simulate cuts through the image volume positioned at all possible section positions. These simulations show that the measurement variations due to the orientation of the section around the center line of the implant are about 30%. 相似文献
35.
丁红 《数字社区&智能家居》2008,3(12):1697-1699
提出一种用模板匹配来检测CT增强扫描中的小肝癌的算法,该算法先利用改进的区域生长方法提取出完整的肝部以减少模板匹配的计算量,然后简化Y Lee等人的模板匹配方法,从而达到加快计算速度的目的。 相似文献
36.
基于光线跟踪的数字影像重建技术 总被引:4,自引:0,他引:4
本文讨论了CT模拟中的数字图像重建技术,提出了基于光线跟踪的处理方法,并对分辨率、CT值转换和增强技术进行了探讨,给出了在治疗计划系统中的实现。 相似文献
37.
《国际计算机数学杂志》2012,89(5):1040-1056
This paper presents a new technique for computed tomography that is based on moment reconstruction. The proposed technique employs the Fourier and Haar coefficients for spectral and spatial moment-based image analyses, respectively. It provides a new approach to the problem of tomographic image reconstruction, where an X-ray image is obtained from a set of line projections. The experimental evaluation includes reconstructions of standard tomographic images in the presence of blur, caused by uniform linear motions. The results lead to the conclusion that the proposed method is more selective, efficient and robust. Another issue considered is the noise associated with normal transmission. 相似文献
38.
39.
Olli-Pekka Tossavainen Marko Vauhkonen Kyung Youn Kim 《Chemical engineering science》2006,61(23):7717-7729
Sedimentation monitoring is widely used to control and optimize industrial processes. In this paper we propose a novel computational method for sedimentation monitoring using electrical impedance tomography (EIT). EIT measurements consist of electric current and voltage measurements that are made on the surface of the sedimentation tank and therefore they do not interfere with the sedimentation process. The proposed computational method is based on shape estimation and state estimation formulation of the EIT problem. The sedimentation is parameterized by the locations of the phase interfaces and conductivities of the phase layers. Three different evolution models for the state parameters are considered and the state estimates are computed using the extended Kalman filter algorithm. The performance of the method and the models are evaluated using simulated data from a six electrode EIT measurement configuration. From the results a promising performance of the method can be seen. 相似文献
40.
本研究利用Matlab软件的图像处理功能自编程序对人体头颅CT图像进行图像分割、二值化、边缘提取、选取参考点等过程,测量人体头部前额骨、顶骨、枕骨上测量位置的厚度。该方法即可实现对某一头颅CT图像上不同位置的测量,也可实现对大量头颅CT图像上同一位置的测量。其测量结果将为建立人体头颅数据库、临床医学、头部的生物力学造型等领域的研究提供可靠依据。 相似文献