Accurate Image Generation and Interactive Image Editing with the A-buffer

The A-buffer suggested by Carpenter [2] is a hidden surface removal method which deals with arbitrary overlapping edges in a pixel. In this paper, we suggest a way of increasing the subpixel resolution by storing the bitmask index rather than the bitmask. This allows much more accurate images to be generated while at the same time, minimising memory usage. It also allows zooming to reveal more information. We also suggest an enhancement to the A-buffer by allowing the creation of dynamic objects. These dynamic objects can then be edited (deleted, moved, etc.) interactively as image modification and assembly is going on. This new buffer forms part of the image composition system we have been working on.     

用于半色调图像的一种层次增强方法

半色调图像的层次分辨率是衡量半色调图像生成算法的一个重要指标。在高质量图像硬拷贝设备上,其产生的半色调图像的层次分辨率必须达到较高的水平,才能保证图像复制的质量。文中提出了一个基于线性像素置换理论的阈值矩阵抖动方法,该方法把一维线性像素置换扩展到了二维的情形,并使其作用于阈值矩阵的生成。这个方法能在提高阈值矩阵的层次分辨率的同时,有效地避免附带产生的斑纹效应。通过计算机模拟显示和硬拷贝设备的实际输出试验,证明了此方法的有效性。     

基于对象复制的协同绘图并发控制算法

全复制模式下的基于对象的实时协同图形编辑系统支持不同地域的设计人员通过网络同步高效地浏览、操作和修改共享文档和文档中的各种对象，包括图形、图象和文本等，其中操作意愿保证及其并发控制成为复杂而又关键的问题之一，其研究具有挑战性．文中讨论了基于图形对象的并发操作的冲突，提出直接依赖和对象状态概念确定操作的候选对象和相容集合，并改进了对象复制算法．基于此，给出了一个有效的并发控制算法。     

基于模型的面部图像生成方法

在人脸部件几何特征及肌肉运动模型的基础上,本文提出了一种二维面部图像的生成方法。该方法采用特征网络模型精确地描述人脸部件,将网络上轮廓特征点的相对位移作为面部图像变形及表情综合的参数,并通过面部整合模型控制各部件之间相互作用关系及人脸轮廓变化。实验证明该方法产生的面部变形图像比较精确,表情效果也很自然。     

一种综合的有噪图象边缘提取方法

有噪图象的边缘提取是一个难点。经典的边缘检测方法由于引入了各种形式的微分运算，从而必然引起对噪声的极度敏感。为此，本文提出了采用分形方法并综合传统方法以解决低信噪比图象的边缘检测问题，并给出了自然场景中的人造物体边缘检测的实例。     

基于多尺度与注意力特征增强的遥感图像描述生成方法

遥感图像描述生成是同时涉及计算机视觉和自然语言处理领域的热门研究话题,其主要工作是对于给定的图像自动地生成一个对该图像的描述语句.文中提出了一种基于多尺度与注意力特征增强的遥感图像描述生成方法,该方法通过软注意力机制实现生成单词与图像特征之间的对齐关系.此外,针对遥感图像分辨率较高、目标尺度变化较大的特点,还提出了一种...     

Bayesian Scheme for Interactive Colourization,Recolourization and Image/Video Editing

We propose a general image and video editing method based on a Bayesian segmentation framework. In the first stage, classes are established from scribbles made by a user on the image. These scribbles can be considered as a multi‐map (multi‐label map) that defines the boundary conditions of a probability measure field to be computed for each pixel. In the second stage, the global minima of a positive definite quadratic cost function with linear constraints, is calculated to find the probability measure field. The components of such a probability measure field express the degree of each pixel belonging to spatially smooth classes. Finally, the computed probabilities (memberships) are used for defining the weights of a linear combination of user provided colours or effects associated to each class. The proposed method allows the application of different operators, selected interactively by the user, over part or the whole image without needing to recompute the memberships. We present applications to colourization, recolourization, editing and photomontage tasks.     

The Buffer Tree: A Technique for Designing Batched External Data Structures

We present a technique for designing external memory data structures that support batched operations I/ O efficiently. We show how the technique can be used to develop external versions of a search tree, a priority queue, and a segment tree, and give examples of how these structures can be used to develop I/ O-efficient algorithms. The developed algorithms are either extremely simple or straightforward generalizations of known internal memory algorithms—given the developed external data structures.     

采用多曲线拟合的柔性体建模仿真方法

提出了一种多曲线拟合的数学建模方法,用于在仿真中快速建立柔性物体受力的形变模型。该方法根据柔性体的形变特性将其外形轮廓分为多个部分;然后使用不同的简单曲线拟合各部分轮廓的形状,并通过改变拟合曲线的参数使得曲线形状改变,以此定量仿真出轮廓的受力形变;最后将曲线拼接起来构成物体的整体形变模型。文中讨论了常见的方体和板块体在挤压、拉伸和扭转这三种非常普遍受力下的形变特性,并使用多曲线拟合方法建立了形变模型。多曲线拟合方法虽然在表现精度上存在一定误差,但建模形式简单、计算速度快,为仿真中表现速度与表达精度的矛盾提供了一种有效的解决手段。     

图象数据读取方法及阈值分割技术

对ＢＭＰ文件格式进行分析,读取图象数据,并对这些数据进行处理,通过阈值分割技术得到图象边缘。