Sum-modified-Laplacian-based Multifocus Image Fusion Method in Sharp Frequency Localized Contourlet Transform Domain

为了克服Contourlet 融合在远离支撑区间上出现的混叠成分，抑制融合图像在奇异处产生伪吉布斯现象，提出改进拉普拉斯能量和的尖锐频率局部化Contourlet ( Sharp Frequency Localized Contourlet Transform-SFLCT)域多聚焦图像融合方法。首先，采用SFLCT 而不是原始的Contourlet 对多聚焦图像进行分解。接着，将多聚焦图像空域融合方法中评价图像清晰度的指标引入到SFLCT 变换域，采用拉普拉斯能量来选择变换域系数。然后，逆SFLCT 重构得到融合结果。最后，采用循环平移(Cycle Spinning)来提高SFLCT 的平移不变性，有效抑制融合图像在奇异处产生伪吉布斯现象。实验结果表明：对于多聚焦图像，所提方法比循环平移小波变换互信息提高5.87%, QAB/F 提高2.70%,比循环平移Contourlet 方法互信息提高1.77%,QAB/F 提高1.29%,视觉效果优于典型的空域分块拉普拉斯能量方法和平移不变小波变换方法 ============ Abstract: In order to suppress pseudo-Gibbs phenomena around singularities of fused image and reduce significant amount of aliasing components which are located far away from the desired support when the original contourlet is employed in image fusion, Sum-modified-Laplacian-based multifocus image fusion method in sharp frequency localized contourlet transform (SFLCT) domain is proposed. First, SFLCT, instead of the original contourlet, is utilized as the multiscale transform to decompose the source multifocus images into subbands. Second, typical measurements for multifocus image fusion in spatial domain are introduced into contourlet domain and Sum-modified-Laplacian (SML), evidenced in this paper with the best capability to distinguish SFLCT coefficients is from the clear parts or blurry parts of images, is employed in SFCLT subbands as measurement to select SFLCT transform coefficients. Third, inverse SFLCT is used to reconstruct fused image. Finally, cycle spinning is applied to compensate for the lack of translation invariance property and suppress pseudo-Gibbs phenomena of fused images. Using the proposed fusion method, experimental results demonstrate that mutual information is improved by 5.87% and transferred edge information QAB/F is improved by 2.70% compared with cycle spinning wavelet method, while mutual information is improved by 1.77% and QAB/F is improved by 1.29% compared with cycle spinning contourlet method. Meanwhile the proposed fusion method outperforms block-based spatial SML method and shift-invariant wavelet method in term of visual appearance.国家自然科学基金(No.60472081),航空基础科学基金(No.05F07001

Sum-modified-Laplacian-based Multifocus Image Fusion Method in Sharp Frequency Localized Contourlet Transform Domain

为了克服Contourlet融合在远离支撑区间上出现的混叠成分，抑制融合图像在奇异处产生伪吉布斯现象，提出改进拉普拉斯能量和的尖锐频率局部化Contourlet ( Sharp Frequency Localized Contourlet Transform-SFLCT)域多聚焦图像融合方法。首先，采用SFLCT而不是原始的Contourlet对多聚焦图像进行分解。接着，将多聚焦图像空域融合方法中评价图像清晰度的指标引入到SFLCT变换域，采用拉普拉斯能量来选择变换域系数。然后，逆SFLCT重构得到融合结果。最后，采用循环平移(Cycle Spinning)来提高SFLCT的平移不变性，有效抑制融合图像在奇异处产生伪吉布斯现象。实验结果表明：对于多聚焦图像，所提方法比循环平移小波变换互信息提高5.87%, QAB/F提高2.70%,比循环平移Contourlet方法互信息提高1.77%, QAB/F提高1.29%,视觉效果优于典型的空域分块拉普拉斯能量方法和平移不变小波变换方法。 In order to suppress pseudo-Gibbs phenomena around singularities of fused image and reduce significant amount of aliasing components which are located far away from the desired support when the original contourlet is employed in image fusion, Sum-modified-Laplacian-based multifocus image fusion method in sharp frequency localized contourlet transform (SFLCT) domain is proposed. First, SFLCT, instead of the original contourlet, is utilized as the multiscale transform to decompose the source multifocus images into subbands. Second, typical measurements for multifocus image fusion in spatial domain are introduced into contourlet domain and Sum-modified-Laplacian (SML), evidenced in this paper with the best capability to distinguish SFLCT coefficients is from the clear parts or blurry parts of images, is employed in SFCLT subbands as measurement to select SFLCT transform coefficients. Third, inverse SFLCT is used to reconstruct fused image. Finally, cycle spinning is applied to compensate for the lack of translation invariance property and suppress pseudo-Gibbs phenomena of fused images. Using the proposed fusion method, experimental results demonstrate that mutual information is improved by 5.87% and transferred edge information QAB/F is improved by 2.70% compared with cycle spinning wavelet method, while mutual information is improved by 1.77% and QAB/F is improved by 1.29% compared with cycle spinning contourlet method. Meanwhile the proposed fusion method outperforms block-based spatial SML method and shift-invariant wavelet method in term of visual appearance.国家自然科学基金(No.60472081),航空基础科学基金(No.05F07001

近70年来中国自然地理与生存环境基础研究的重要进展与展望

自然环境是人类赖以生存和发展的基础,探索自然环境及其各要素(如地貌、气候、水文、土壤等)的特征、演变过程、地域分异规律以及驱动机制是自然地理学的重点研究内容.中国自然地理要素类型丰富且区域差异较大,为开展自然地理研究提供了难得的机遇.文章主要围绕青藏高原隆升与亚洲内陆干旱化及河流发育、高原冰冻圈环境演化、全新世多时间尺度季风与西风气候变化、湖泊与湿地、流域模型与土壤侵蚀、过去人-地关系演化、生物地理及中国三维地带性规律等几个方面,梳理了近70年来中国自然地理与生存环境研究的重大理论进展与重要贡献.在简要交代国际前沿研究进展的基础上,回顾并梳理了中国自然地理学各分支领域的研究脉络,进一步聚焦重大研究成果或具有较大争议、重大影响的学术争鸣问题,归纳目前研究现状,并进行未来工作展望.最后提出在推进生态文明建设的国家需求下,应发挥中国自然地理研究的优势,厘清自然地理要素变化的过程、规律与机制,持续推进中国自然地理研究为国家战略服务,在全球视野下做出具有中国特色的自然地理学理论贡献

Aripiprazole versus other atypical antipsychotics for schizophrenia

BACKGROUND: In most western industrialised countries, second generation (atypical) antipsychotics are recommended as first line drug treatments for people with schizophrenia. In this review we specifically examine how the efficacy and tolerability of one such agent - aripiprazole - differs from that of other comparable second generation antipsychotics. OBJECTIVES: To evaluate the effects of aripiprazole compared with other atypical antipsychotics for people with schizophrenia and schizophrenia-like psychoses. SEARCH METHODS: We searched the Cochrane Schizophrenia Group Trials Register (November 2011), inspected references of all identified studies for further trials, and contacted relevant pharmaceutical companies, drug approval agencies and authors of trials for additional information. SELECTION CRITERIA: We included all randomised clinical trials (RCTs) comparing aripiprazole (oral) with oral and parenteral forms of amisulpride, clozapine, olanzapine, quetiapine, risperidone, sertindole, ziprasidone or zotepine for people with schizophrenia or schizophrenia-like psychoses. DATA COLLECTION AND ANALYSIS: We extracted data independently. For dichotomous data we calculated risk ratios (RR) and their 95% confidence intervals (CI) on an intention-to-treat basis based on a random-effects model. Where possible, we calculated illustrative comparative risks for primary outcomes. For continuous data, we calculated mean differences (MD), again based on a random-effects model. We assessed risk of bias for each included study. MAIN RESULTS: We included 12 trials involving 6389 patients. Aripiprazole was compared to olanzapine, risperidone and ziprasidone. All trials were sponsored by an interested drug manufacturer. The overall number of participants leaving studies early was 30% to 40%, limiting validity (no differences between groups).When compared with olanzapine no differences were apparent for global state (no clinically important change: n = 703, 1 RCT, RR short-term 1.00 95% CI 0.81 to 1.22; n = 317, 1 RCT, RR medium-term 1.08 95% CI 0.95 to 1.22) but mental state tended to favour olanzapine (n = 1360, 3 RCTs, MD total Positive and Negative Syndrome Scale (PANSS) 4.68 95% CI 2.21 to 7.16). There was no significant difference in extrapyramidal symptoms (n = 529, 2 RCTs, RR 0.99 95% CI 0.62 to 1.59) but fewer in the aripiprazole group had increased cholesterol levels (n = 223, 1 RCT, RR 0.32 95% CI 0.19 to 0.54) or weight gain of 7% or more of total body weight (n = 1095, 3 RCTs, RR 0.39 95% CI 0.28 to 0.54).When compared with risperidone, aripiprazole showed no advantage in terms of global state (n = 384, 2 RCTs, RR no important improvement 1.14 95% CI 0.81 to 1.60) or mental state (n = 372, 2 RCTs, MD total PANSS 1.50 95% CI -2.96 to 5.96).One study compared aripiprazole with ziprasidone (n = 247) and both the groups reported similar change in the global state (n = 247, 1 RCT, MD average change in Clinical Global Impression-Severity (CGI-S) score -0.03 95% CI -0.28 to 0.22) and mental state (n = 247, 1 RCT, MD change PANSS -3.00 95% CI -7.29 to 1.29).When compared with any one of several new generation antipsychotic drugs the aripiprazole group showed improvement in global state in energy (n = 523, 1 RCT, RR 0.69 95% CI 0.56 to 0.84), mood (n = 523, 1 RCT, RR 0.77 95% CI 0.65 to 0.92), negative symptoms (n = 523, 1 RCT, RR 0.82 95% CI 0.68 to 0.99), somnolence (n = 523, 1 RCT, RR 0.80 95% CI 0.69 to 0.93) and weight gain (n = 523, 1 RCT, RR 0.84 95% CI 0.76 to 0.94). Significantly more people given aripiprazole reported symptoms of nausea (n = 2881, 3 RCTs, RR 3.13 95% CI 2.12 to 4.61) but weight gain (7% or more of total body weight) was less common in people allocated aripiprazole (n = 330, 1 RCT, RR 0.35 95% CI 0.19 to 0.64). Aripiprazole may have value in aggression but data are limited. This will be the focus of another review. AUTHORS' CONCLUSIONS: Information on all comparisons are of limited quality, are incomplete and problematic to apply clinically. Aripiprazole is an antipsychotic drug with a variant but not absent adverse effect profile. Long-term data are sparse and there is considerable scope for another update of this review as new data emerges from the many Chinese studies as well as from ongoing larger, independent pragmatic trials