Adaptive Tensor-Based Principal Component Analysis for Low-Dose CT Image Denoising

Computed tomography (CT) has a revolutionized diagnostic radiology but involves large radiation doses that directly impact image quality. In this paper, we propose adaptive tensor-based principal component analysis (AT-PCA) algorithm for low-dose CT image denoising. Pixels in the image are presented by their nearby neighbors, and are modeled as a patch. Adaptive searching windows are calculated to find similar patches as training groups for further processing. Tensor-based PCA is used to obtain transformation matrices, and coefficients are sequentially shrunk by the linear minimum mean square error. Reconstructed patches are obtained, and a denoised image is finally achieved by aggregating all of these patches. The experimental results of the standard test image show that the best results are obtained with two denoising rounds according to six quantitative measures. For the experiment on the clinical images, the proposed AT-PCA method can suppress the noise, enhance the edge, and improve the image quality more effectively than NLM and KSVD denoising methods.     

三种重要单宁植物营养器官中单宁的分布(简报)

余甘子（PhyllanthusembnlicaL．）、杨梅(Myricarubra（Lour．）Sieb．etZucc．X细枝木麻黄（CasaarinacunninghamianaMiq．）是重要的单宁植物。Moseley[1]咱报道木麻黄属茎的次生木质部和次生韧皮部的结构。Metcalf和ChalkP[2]曾对这三种植物所在属的营养器官结构作了概述,但未涉及这三种植物。Sidey[3]曾报道柔毛金合欢（ACaciamollissimaWilld）各器官的组织中单宁的分布。我们观察了上述三种植物根、茎、叶（或同化技）组织中单宁的分布,为研究植物体内单宁的分布提供资料,同时为生产上充分提取单宁提供理论依据．1材料和方…     

毛叶芋兰的生物学特性和栽培技术

药用植物毛叶芋兰一般每年仅从地下块茎或根状茎顶端长出一片新叶,地下部分有真菌共生,地上部生活期短,平均为１６９天。花芽５月中旬出土,６月中旬果熟,花果期约３０天。毛叶芋兰通常生长于以漫射光为主,或短时直射光,土壤潮湿疏松,透水性良好,ｐＨ４．４～６．５的灌木林下。栽培时,应根据毛叶芋兰生境条件选择植地,并注意防止积水和虫害。     

中国兰科一新记录属──指柱兰属

报道了中国兰科植物一个分布新记录的属－指柱兰属和该属一新记录的种－指柱兰。     

女贞和白蜡树的树皮结构及次生韧皮部发育的季节变化

女贞（ＬｉｇｕｓｔｒｕｍｂｕｃｉｄｕｍＡｉｔ）和白蜡树（ＦｒａｘｉｎｕｓｃｈｉｎｅｎｓｉｓＲｏｘｂ）是白蜡虫的两种主要寄主树。树皮由外向内为周皮,皮层,初生韧皮部的纤维束和次生韧皮部．它们的筛管分子具复筛板或单筛板,具Ｐ－蛋白质和筛管淀粉。伴胞为与筛管分等长的一列或单个细胞。筛管寿命在女贞中最长为一年,在白蜡树中则不超过８个月．形成层活动时间在女贞中是３月中下旬到１１月中旬,在白蜡树中是３月中下旬到１１月下旬．两种树木的木质部和韧皮部在３月中旬已开始分化,木质部和韧皮部分化停止的时间在女贞中分别是１１月中旬和１２月下旬;在白蜡树中分别是９月下旬和１１月下旬．两种树木在冬季都有部分分化的筛管分子,白蜡树中的部分分化的筛管分子于秋季形成,翌年３月中旬成熟,同年９—１０月瓦解。女贞枝条冬季平均保留１７０．２μｍ的具功能韧皮部区;而白蜡树在径向仅保留数列细胞宽的具功能韧皮都区越冬．     

药用植物“一粒癀”的初步研究(二)

本文报道民间药用植物“一粒癀”的生态生物学特性及其在福建的自然分布,并对分布局限性的原因进行探讨。     

红金麻——木槿属一个新杂种

<正> 红金麻 新杂种 Hibiscus×hongjinma Y. T. Chang, hybr. nov. H. cannabinus L. ♀× H. radiatus Cav.♂ Hybrida hortensis ( 2n=30+6sat) θ Hibisco cannabino L. ( 2n=32+4sat) et H. ranndiato Cav. (2n=70+2sat) exorta, Habitu illo simil, characteribus ad hoc magis accedit; ab illo differt floribus purpureis, folio prope basin 3—5     

Global Patch Matching (GPM) for freehand 3D ultrasound reconstruction

Background

3D ultrasound volume reconstruction from B-model ultrasound slices can provide more clearly and intuitive structure of tissue and lesion for the clinician.

Methods

This paper proposes a novel Global Path Matching method for the 3D reconstruction of freehand ultrasound images. The proposed method composes of two main steps: bin-filling scheme and hole-filling strategy. For the bin-filling scheme, this study introduces two operators, including the median absolute deviation and the inter-quartile range absolute deviation, to calculate the invariant features of each voxel in the 3D ultrasound volume. And the best contribution range for each voxel is obtained by calculating the Euclidian distance between current voxel and the voxel with the minimum invariant features. Hence, the intensity of the filling vacant voxel can be obtained by weighted combination of the intensity distribution of pixels in the best contribution range. For the hole-filling strategy, three conditions, including the confidence term, the data term and the gradient term, are designed to calculate the weighting coefficient of the matching patch of the vacant voxel. While the matching patch is obtained by finding patches with the best similarity measure that defined by the three conditions in the whole 3D volume data.

Results

Compared with VNN, PNN, DW, FMM, BI and KR methods, the proposed Global Path Matching method can restore the 3D ultrasound volume with minimum difference.

Conclusions

Experimental results on phantom and clinical data sets demonstrate the effectiveness and robustness of the proposed method for the reconstruction of ultrasound volume.

     

福建的药用植物-苦丁茶

本文介绍苦丁茶的用途及其原植物,同时介绍福建苦丁茶资源及利用现况。