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基于分水岭和梯度的蝴蝶兰图像分割方法 被引量:21
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作者 任守纲 马超 +2 位作者 谢忠红 徐焕良 陈发棣 《农业工程学报》 EI CAS CSCD 北大核心 2012年第9期125-129,共5页
利用图像识别技术采集设施蝴蝶兰生长参数,从而对花期进行调控,是提高蝴蝶兰种植效益的重要手段,而如何把蝴蝶兰图像与自然背景图像进行分割与提取,是图像识别的关键。该文利用彩色梯度算法,提取出蝴蝶兰自然图像的梯度图像,利用阈值找... 利用图像识别技术采集设施蝴蝶兰生长参数,从而对花期进行调控,是提高蝴蝶兰种植效益的重要手段,而如何把蝴蝶兰图像与自然背景图像进行分割与提取,是图像识别的关键。该文利用彩色梯度算法,提取出蝴蝶兰自然图像的梯度图像,利用阈值找出梯度图像的显著部分(即图像中的显著边缘),同时利用水域分割方法对源图像进行分割,产生过分割图像,然后利用显著边缘图像对过分割图像进行判断,去除不显著的"水坝"并令其两边水域相融合,从而达到极大的抑制过分割的目的,最后再根据区域合并准则合并相似的区域,得到蝴蝶兰目标物图像。针对20幅蝴蝶兰图像,通过与人工分割的方法进行对比试验,结果表明,该文提出的基于梯度和分水岭的分割算法能够很好地从自然背景中提取出蝴蝶兰图像,分割正确率达到了92.6%。 展开更多
关键词 图像识别 梯度法 融合 水域分割 共性边缘 蝴蝶兰
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EVALUATION OF NEUROPROTECTIVE EFFECTS OF LONG-TERM LOW DOSE HORMONE REPLACEMENT THERAPY ON POSTMENOPAUSAL WO-MEN BRAIN HIPPOCAMPUS USING MAGNETIC RESONANCE SCANNER 被引量:1
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作者 Ling Hu Yun Yue +5 位作者 Ping-ping Zuo Zheng-yu Jin Feng Feng Hui You Ming-li Li Qin-sheng Ge 《Chinese Medical Sciences Journal》 CAS CSCD 2006年第4期214-218,共5页
To investigate the effects of long-term low dose hormone replacement therapy (HRT) on postmenopaosal women in homone level, cognition score, hippocampus volume, and magnetic resonance spectroscopy (MRS) parameters... To investigate the effects of long-term low dose hormone replacement therapy (HRT) on postmenopaosal women in homone level, cognition score, hippocampus volume, and magnetic resonance spectroscopy (MRS) parameters. Methods A total of 182 postmenopausal women aged 50-87 years were chosen at Peking Union Medical College Hospital and assigned to HRT group and control group. The volunteers of HRT group had taken low dose hormone [ estradiol (E2 ) 0. 5-1.0 mg and progesterone 0.5-2.0 mg, once a day ] for 4-33 years. The concentrations of E2, progesterone, and testosterone were measured using enzyme-linked immunosorbent assay (ELISA). The gene types of apolipoprotein E (ApoE) were measured by polymerase chain reaction, and the subjects with susceptible genes ( ApoE ε3/ε4) of Alzheimer's disease (AD) were screened. Their hippocampus volumes and MRS parameters were obtained through magnetic resonance imaging (MRI), and results in two groups were analyzed by statistical method. Results Compared with control group, the concentrations of E2 at each age stage in HRT group were significantly higher (P 〈0. 05) except the 80-89 years old subgroup; yet, there were no statistical differences in the concentrations of progesterone and testosterone between the two groups. There was no obvious difference in ApoE subtypes distribution between the two groups The results of hippocampus MRI for the subjects with susceptible genes ApoE ε3/ε4 (HRT group 14 cases, control group 11 cases) showed that the ratio of bilateral hippocampus volume to whole brain volume in HRT group (0. 406 ± 0.028) was signiticantlyhigher than control gronp (0.369±0.031, P〈0.05). Theresults of ^1H MRS for the subjects with susceptible genes ApoE ε3/ε4 ( HRT group 12 cases, control group 11 cases) showed that the N-acetylaspartate/total creatine at the area of hippocampus in HRT group ( 1.54±0. 08 ) were significantly higher than control group ( 1.45±0. 13, P 〈 0. 05). Conclusions For postmenopausal women, long-term low dose HRT can maintain the physiological concentration of E2 in plasma. Furthermore, the hippocampus MRI performed on those with ApoE ε3/ε3 genes shows that long-term low dose HRT can prevent hippocampus atrophy, which is beneficial to maintain the brain function and prevent AD. 展开更多
关键词 long-term low dose hormone replacement therapy ESTROGEN apolipoprotein E HIPPOCAMPUS magnetic resonance spectroscopy
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