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利用光度立体法获取物体深度图的研究
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作者 王新华 傅晓云 《激光与光电子学进展》 CSCD 1995年第A01期189-189,共1页
关键词 光度立体法 物体深度 光源
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成像参数对大深度物体聚焦形貌恢复的影响
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作者 夏晓华 曹雨松 +2 位作者 向浩鸣 袁述皓 葛兆凯 《光学学报》 EI CAS CSCD 北大核心 2024年第8期150-159,共10页
为探究成像参数对大深度物体聚焦形貌恢复精度的影响规律,明确实际应用中聚焦形貌恢复重建精度不满足要求时成像系统的改进措施,在构建聚焦形貌恢复三维重建精度评价指标的基础上,利用正交实验确定成像参数对聚焦形貌恢复精度影响的主... 为探究成像参数对大深度物体聚焦形貌恢复精度的影响规律,明确实际应用中聚焦形貌恢复重建精度不满足要求时成像系统的改进措施,在构建聚焦形貌恢复三维重建精度评价指标的基础上,利用正交实验确定成像参数对聚焦形貌恢复精度影响的主次顺序,重点分析主要和次主要参数对重建精度的影响规律,并揭示最佳成像参数随多聚焦图像采样间距的变化关系。考虑到成像参数的变化实际通过改变系统景深影响聚焦形貌恢复精度,建立了多聚焦图像采样间距与最佳景深之间的经验公式,为系统成像参数的设定提供了理论依据。实验结果表明:焦距和F数是聚焦形貌恢复的主要和次主要影响参数,在给定多聚焦图像采样间距下存在使重建精度最高的最佳焦距和最佳F数,且随着采样间距减小,最佳焦距增大,最佳F数减小;多聚焦图像采样间距与最佳景深之间的经验公式拟合准确率为97.28%,验证准确率为94.76%,可用于最佳景深的计算;采用最佳景深能够显著提升聚焦形貌恢复精度,为大深度物体聚焦形貌恢复精度的提升提供了新途径。 展开更多
关键词 机器视觉 聚焦形貌恢复 成像参数 深度物体 重建精度
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一种改进的GVF Snake模型轮廓检测方法
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作者 姚斌 《科技信息》 2009年第12期77-77,79,共2页
由于深度凹陷物体的GVF力场中存在着滞止点区域,导致直接使用GVF Snake模型不能正确逼近深度凹陷物体的真实轮廓,本文提出了一种基于GVF Snake模型的轮廓检测算法。首先根据滞止点区域的伪轮廓把物体的整个轮廓分成多段,然后分别设定初... 由于深度凹陷物体的GVF力场中存在着滞止点区域,导致直接使用GVF Snake模型不能正确逼近深度凹陷物体的真实轮廓,本文提出了一种基于GVF Snake模型的轮廓检测算法。首先根据滞止点区域的伪轮廓把物体的整个轮廓分成多段,然后分别设定初始轮廓线利用GVF Snake模型获得各段轮廓线,最后把各段轮廓线融合成一个完整轮廓。实验结果表明,新的方法不仅能够提取一次深度凹陷物体的完整轮廓,而且能够成功提取多次深度凹陷物体的完整轮廓。 展开更多
关键词 梯度矢量流 轮廓检测 深度凹陷物体
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Analysis of Object Depth Effects on Accuracy of Dimensional Shape in X and Y Directions Using Single Non-metric Image
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作者 Tarek M.A. ZHU Qing 《Geo-Spatial Information Science》 2007年第4期269-275,共7页
In general, to reconstruct the accurate shape of buildings, we need at least one stereomodel (two photographs) for each building. In most cases, however, only a single non-metric photograph is available, which is us... In general, to reconstruct the accurate shape of buildings, we need at least one stereomodel (two photographs) for each building. In most cases, however, only a single non-metric photograph is available, which is usually obtained either by an amateur, such as a tourist, or from a newspaper or a post card. To evaluate the validity of 3D reconstruction from a single non-metric image, this study analyzes the effects of object depth on the accuracy of dimensional shape in X and Y directions using a single non-metric image by means of simulation technique, as this was considered to be, in most cases, a main source of data acquisition in recording and documenting buildings. 展开更多
关键词 SINGLE non-metric image reconstruction object depth ACCURACY dimensional shape
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Effect of Ploughing Depth on the Growth and Yield of Heracleum candicans:a Threatened Medicinal Herb and a Less-explored Potential Crop of the Himalayan Region 被引量:1
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作者 Hemant K. Badola Jitendra S. Butola 《Journal of Mountain Science》 SCIE CSCD 2005年第2期173-180,共8页
This paper examines the effect of ploughing depths (A -- 60 cm, B -- 45 cm and C -- 30 cm) on the growth and yield of Heracleum candicans Wall (Apiaceae), a threatened medicinal herb of the Himalayan region. This ... This paper examines the effect of ploughing depths (A -- 60 cm, B -- 45 cm and C -- 30 cm) on the growth and yield of Heracleum candicans Wall (Apiaceae), a threatened medicinal herb of the Himalayan region. This less-explored plant is being suggested as a potential crop for the mountain agriculture. The study was carried out in an orchard in Himachal Pradesh, India at 2500 m altitude, for two successive growth years. During the first year, all plants remained in juvenile state; in the second year, nearly 65 % plants produced flowers only under 60cm ploughing depth. Among its morphological traits, plant height, collar diameter and aboveground flesh weight were found to be strongly correlated (P 〈 0.01) with the belowground biomass during the first year (r =0.968, 0.925 and 0.973, respectively) and during the second year (r=0.945, 0.928 and 0.775, respectively). Increase in the ploughing depth was significantly correlated (P〈0.01) with all growth parameters, including the belowground dry weight, marketable portion of the produce. The belowground biomass (commercial yield; 16.28 Qt/hec) at depth A was about 2.6 and 4.7 times higher than those recorded at depths B and C, respectively. The results clearly justify the importance of deep ploughing and this paper strongly recommends it for economically sustainable cropping. 展开更多
关键词 CROP Heracleum candicans medicinal herb morphological traits ploughing depth yield mountain agriculture Patrala
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