摘要
第一人称2D地形草图重建三维模型是具有挑战性的研究,由于缺失一维信息,多数研究都侧重于研究自由设计地形及提高真实感的地面纹理映射方法,却并未涉及更符合普通用户手绘的目的并遵循摄影几何规律的真实空间位置重建,本文提出手绘草图直接生成符合真实空间位置的三维模型生成方法。首先,遵循二维草图既定的形状规律、视觉遮挡关系,根据小孔成像规律构建相对深度关系;然后,通过采样不同深度层的轮廓数据点进行椭圆扩展来建立等高线图,周向采样点的分形插值来计算地形单元;接着通过旋转映射来实现空间地形单元的非刚性变形,从而实现第一人称视角下同一轮廓不同三维模型的构建;最后,加入柏林噪声以添加三维地形细节展示的随机效果。实验结果表明在相同的二维草图透视下,可以构建具有不同真实空间位置的三维地形模型,与三种草图地形建模方法相比,解决了真实空间位置重建的问题。本文提出的方法更符合用户的设计目的,实现任意同一投影草图轮廓的三维地形真实空间重建,得到多层遮挡地形草图的多种真实空间位置布局,并能满足地形特征的展示,弥合了艺术意图与数字建模之间的鸿沟。
It is challenging to reconstruct 3D terrain modelsbased on sketches drawn in the first-person pointofview.Owing to the lack of one-dimensional information,most studies focus on terrain-independent design and texture mapping methods to improve the realism;however,the spatial location is not considered in such methods.To address this limitation,we propose a methodto generate 3D modelsthat conform tothe real space position.First,based on the established shape rules and visual occlusion relation,the relative depth relationship is determined according to the geometric rules derived from photographs;then,a contour map is established by sampling the contour data points of different depth layers for ellipse expansion.Furthermore,the fractal interpolation of circumferential sampling points is performed to calculate terrain units,and the non-rigid deformation of spatial terrain elements is realized via rotation mapping.Finally,Berlin noise is added to improve the random effect of the 3D terrain display.Experimental results show that for the same 2D sketch perspective,3D terrain models corresponding todifferent real spatial locations can be constructed;in this regard,the proposed method is different from the other three methods.Furthermore,it solves the problem of real space location reconstruction.Our method is more suitable for expressing the intended design purpose of users.It realizes the 3D terrain real space reconstruction of any 2D sketch;moreover,it obtains a variety of real space layouts of multi-layer occlusion terrainsin addition to displayingthe terrain features,which bridges the gap between artistic intent and the actual result.
作者
曾升
耿国华
邹林波
周明全
ZENG Sheng;GENG Guo-hua;ZOU Lin-bo;ZHOU Ming-quan(College of Information Science and Technology, Northwest University, Xi’an 710127, China)
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2020年第8期1861-1871,共11页
Optics and Precision Engineering
基金
国家自然科学基金资助项目(No.61672103,No.61731015,No.61673319)
科技部重点研发计划资助项目(No.2017YFB1402100)
陕西省重点产业链资助项目(No.2019ZDLSF07-02,No.2019ZDLGY10-01)
陕西省重点产业创新链资助项目(No.2017ZDCXL-GY-03-01-01)。
关键词
小孔成像
相对深度关系
周向分形插值
旋转映射
pinhole imaging
relative depth relation
circumferential fractal Interpolation
rotation mapping
