一种流体艺术风格的自适应LIC绘制方法

把LIC算法应用到非真实感绘制中,提出一种自适应流体艺术图的LIC绘制方法.对源图像亮度分量计算切矢量场,然后对其进行增强、平滑处理获得结构矢量场;通过随机扰动源图像获得纹理参考图像;根据结构矢量场和纹理参考图像的局部特征产生可变的LIC积分步长和步数,自适应地处理纹理参考图像;最后对绘制效果进行颜色渲染,生成具有丰富颜色特征的流体艺术图.实验表明,该方法能够较好地模拟诸如梵高画的流体艺术风格,呈现生动、灵活的波动感.     

非真实感铅笔画艺术效果研究

改进了非真实感铅笔画艺术效果的绘制算法,利用图像分割、线积分卷积技术确定线条纹理的方向,模拟得到局部区域铅笔画的笔划纹理。采用轮廓线增强、灰度色调控制最终铅笔画艺术效果的边缘信息和灰度色调。通过色彩传输技术得到具有彩色铅笔画的艺术效果。     

交互式云南绝版套色木刻数字化合成

目的 云南绝版套色木刻是套色木刻的一种特殊艺术形式。绝版套刻是一种极具云南地方特色和艺术价值的中国传统文化,数字模拟合成该艺术形式的目的不仅是为了解决其“绝版”问题,更是对中国传统文化的保留和传承,根据其实际创作过程,提出一种交互式绝版套刻的数字合成方法。方法 本文方法前期采集了大量真实刻痕图像,并从中提取了多种刻痕元素构建了刻痕库。在模拟套印过程中,首先对输入图像进行颜色聚类分层用以模拟不同版次。再通过笔刷绘制刻痕来模拟不同版次刻制操作。然后对每版图像着色来模拟真实绝版套刻的印刷过程。最后利用风格化边缘对合成版画的轮廓进行增强。结果 最终数字合成云南绝版套刻风格化图像,与已有木刻滤镜得到的木刻图像相比更为贴近真实木刻,效果令人满意。结论 本文方法较真实地模拟了云南绝版套色木刻制作过程,填补了NPR(non-photo realistic rendering)在云南绝版套色木刻形式上的空白。     

一种基于笔刷的非真实感绘制算法的研究

非真实感绘制是计算机图形学的一个分支,基于笔刷的非真实感绘制是非真实感绘制的重要内容.给出一种基于笔刷的多重非真实感绘制算法.算法运用源图像灰度图像的颜色梯度法线方向作为笔刷的方向,以颜色空间距离来控制笔刷的绘制.实验结果表明,对于给定的输入图像,该算法能够有效地生成具有油画艺术风格的图像.     

多尺度双通道卷积神经网络下的刺绣模拟

目的 针对现有刺绣模拟算法中针线感不强、针线轨迹方向单一等问题,提出了一种基于多尺度双通道卷积神经网络的刺绣模拟算法。方法 1）搭建多尺度双通道网络,选取一幅刺绣艺术作品作为风格图像,将MSCOCO（microsoft common objects in context）数据集作为训练集,输入网络得到VGG（visual geometry group）网络损失和拉普拉斯损失;2）将总损失值传回到网络,通过梯度下降法更新网络参数,并且重复更新参数直到指定的训练次数完成网络训练;3）选取一幅目标图像作为刺绣模拟的内容图像,输入训练完成的网络,获得具有刺绣艺术风格的结果图像;4）使用掩模图像将得到的结果图像与绣布图像进行图像融合,即完成目标图像的刺绣模拟。结果 本文算法能产生明显的针线感和多方向的针线轨迹,增强了刺绣模拟绘制艺术作品的表现力。结论 本文将输入图像经过多尺度双通道卷积神经网络进行前向传播,并使用VGG19、VGG16和拉普拉斯模块作为损失网络进行刺绣模拟。实验结果表明,与现有卷积神经网络风格模拟算法对比,本文提出的网络能够学习到刺绣艺术风格图像的针线特征,得到的图像贴近真实刺绣艺术作品。     

图像局部纹理特性的静电力触觉渲染

目的 触摸触觉设备感知物体时,需要实现视觉-力触觉同步反馈,其中图像-力触觉反馈难点在于再现更真实的纹理触感的触觉渲染过程。本文提出了一种基于图像局部纹理特征的静电力触觉渲染模型,实现了更加清晰、触感真实的图像纹理的静电力触觉反馈。方法 首先,采用局部傅里叶变换方法强化局部纹理特征,提取傅里叶变换系数分离出表征形状和局部纹理、边缘的频域分量。其次,对局部纹理特征进行力触觉渲染,建立局部纹理特征与驱动信号的映射模型,采用比例模型将局部纹理特征值转化为同等级的静电力表达。最后,根据静电力与驱动信号的心理学模型,由局部纹理特征控制不同驱动信号的输出产生静电力触觉。结果 进行纹理触觉对比感知实验验证算法有效性,62.5%的实验参与者偏爱基于图像局部纹理的触觉渲染算法反馈的纹理触感,本文算法可以模拟多种图像的纹理、边缘的触感。结论 算法在频域分离图像局部纹理、边缘和形状特征,建立纹理-力触觉渲染模型,针对大多数图片可以有效地增强纹理触感,提升触觉再现交互技术的沉浸感。     

苗绣艺术风格针迹模拟研究

摘 要： 非真实感绘制(NPR)也称艺术化渲染,主要用于模拟艺术化的绘制风格。随着图像 处理技术的不断发展,研究者已经对中国特有的中国水墨画、烙画、云南重彩画等艺术作品进 行了模拟,目前对苗族刺绣的数字化模拟研究还不多见。苗族刺绣也称苗绣,经国务院批准列 入我国第一批国家级非物质文化遗产名录,是我国装饰艺术园地里的一朵奇葩。以苗绣为研究 对象,根据真实苗绣艺术作品特点,提出了一种多角度针迹的苗绣艺术风格绘制方法。首先, 针对苗绣图案构图手法夸张、层次分明的特点,将目标图像灰度处理,采用多阈值处理图像的 方法分割出多幅刺绣图像;然后采用形态学方法消除杂散点、填充空洞点并平滑图案边缘,获 得圆润自然、紧凑饱满的特征图案;接着,使用一种基于图像矩阵空间变换和添加纵向纹理的 针迹生成算法使每一幅刺绣图像生成不同角度的苗绣针迹纹理;再用图像线性组合的方法将多 幅苗绣针迹纹理图像合成为纹理图;最后用 Alpha 透明度混合算法将苗绣纹理图和目标图像叠 加,获得苗绣图案设色对比强烈的艺术特征,产生效果图像。实验证明,该方法能够模拟出真 实苗绣艺术作品的多角度针迹纹理效果。     

加权核范数降噪算法在扩散加权图像中的应用

目的 扩散加权成像技术是一种能够检测活体组织内水分子扩散运动的无创方法,其对数据的准确度要求较高且对噪声较为敏感。扩散加权图像的自相似性程度高,纹理细节较多且纹理和结构具有重复出现的特性。而获取图像的过程中受到不可避免的噪声干扰会破坏图像的数据准确度,因此对扩散加权图像进行降噪是十分必要的。方法 根据扩散加权图像的特点,提出将加权核范数降噪算法应用于扩散加权图像的降噪。加权核范数降噪算法由于能够利用图像的自相似性,通过对图像中的相似块进行处理从而实现对图像的降噪,该算法能够保存图像中大量的纹理细节信息。结果 通过模拟数据实验和真实数据实验,将加权核范数降噪算法与传统的扩散加权图像降噪算法如各向异性算法进行比较,结果表明,加权核范数降噪算法相较于其他算法得到的峰值信噪比至少高出20 dB,结构相似性值也至少高出其他算法0.20.5,再将降噪后的图像进行神经纤维跟踪处理,得到的神经纤维平均长度较其他算法至少要长0.20.8且纤维更为平滑。结论 加权核范数降噪算法不仅能够更好地减少扩散加权图像中的噪声,同时也能够最大限度地保存扩散加权图像的纹理细节,降噪效果理想,提高了数据的准确度及有效性。     

基于颜料扩散的水彩画仿真

针对水彩画独特纹理和复杂艺术效果,提出一种新的仿真模拟水彩画的方法,该方法基于颜料的扩散,也是水彩画模拟过程中最重要的一个环节。根据输入原图像所提供的重要信息,运用图像处理的方法,实现了两个最基本的绘制技术（即湿到干和湿到湿的绘制）所表现出的水彩画独有艺术效果,如：边缘暗色化、颜料颗粒扩散、流动图案及平滑光照等,最后加入纸张纹理,使最终产生的非真实感水彩画更加接近于传统水彩画的效果。     

基于多尺度笔刷的分层油画风格化

基于图像的油画风格化绘制是计算机图形学领域非真实感绘制研究的热点之一.为了进一步提高图像油画风格化的质量,提出了一种基于多尺度笔刷的分层图像油画风格化绘制算法.该算法模拟艺术家的油画绘制过程,采用不同尺度的笔刷按照从粗到细的顺序逐层绘制.在每层笔刷绘制中,首先使用增量Voronoi序列采样点和图像切线方向场确定笔刷流线,然后结合笔刷形状与笔刷高度场进行纹理贴图,得到最终的图像油画风格化绘制结果.通过与现有算法比较,文中算法不仅能模拟真实的油画绘制过程,而且生成的油画效果层次感更强,充分体现了图像的结构特征和油画细节.     

Gourd pyrography art simulating based on non-photorealistic rendering

Non-photorealistic rendering (NPR) is a field in computer science which can create effective illustrations and appealing artistic imagery. Some researchers have proposed NPR methods to simulate different artistic illustrations. However, simulating the new art styles remains extremely challenging. National pyrography is a very famous artistic work in China, and few algorithms have been put forward to illustrate this style. Some exist rendering methods can not demonstrate the main characters of the real pyrography, and the rendering speed is time-consuming using texture synthesis technique. This paper proposes a non-photorealistic rendering technique that automatically generates a gourd pyrography style from a 2D photograph. Similar to the existing exemplar-based methods, an input natural image is regarded as the foreground image, and an input gourd image is taken as the background image. To avoid time-consuming methods like texture synthesis or analogy, this paper simulates character of real pyrography through image abstraction and enhancement from the foreground image. The foreground image will be deformed using equilateral triangle mesh to match the gourd image and mapped to this background image. Experimental results demonstrate the effectiveness of our methods in producing gourd pyrography stylistic illustrations. Meanwhile, the proposed method is simple, fast, and easy to implement.     

非真实感绘制技术研究现状与展望

非真实感绘制技术（non-photorealistic rendering, NPR）主要用于模拟艺术风格、表现艺术特质和传达用户情感等,是计算机图形学的重要组成部分,其研究对象逐渐丰富,研究方法不断创新。本文从基于图像建模的绘制方法、基于深度学习的绘制方法、中国特有艺术作品的数字化模拟、非真实感情感特征识别以及非真实感视频场景绘制等5个方面概述目前研究进展,然后从扩展非真实感研究对象、增强视频绘制帧间连贯性、提取艺术风格情感特征以及评价非真实感绘制结果等4个角度讨论需要进一步研究的问题。针对需要深入研究的问题,指出提高算法的通用性和绘制效率,以及提高深度学习网络的泛化性,有助于扩展研究对象,模拟艺术风格的多样性,同时减小视频场景的帧间跳变;对艺术风格作品具有的情感特征、内在机理特征进行模拟,有助于提高绘制结果与艺术风格图像的相似度;结合主观和客观评价模型,可以更准确地对绘制结果进行评价,同时有利于优化网络模型参数,提高绘制效率。非真实感绘制在计算机视觉、文化遗产保护等领域具有重要的应用前景,但其研究对象、绘制算法、绘制效率仍然存在很多亟待解决的问题,随着硬件设备的不断改进,综合运用学科交叉知识、扩展应用领域将进一步推动非真实感绘制技术的发展。     

Cubist style rendering from photographs

The contribution of the paper is a novel nonphotorealistic rendering (NPR) technique, influenced by the style of Cubist art. Specifically, we are motivated by artists such as Picasso and Braque, who produced art work by composing elements of a scene taken from multiple points of view; paradoxically, such compositions convey a sense of motion without assuming temporal dependence between views. Our method accepts a set of two-dimensional images as input and produces a Cubist style painting with minimal user interaction. We use salient features identified within the image set, such as eyes, noses, and mouths, as compositional elements; we believe the use of such features to be a unique contribution to NPR. Before composing features into a final image, we geometrically distort them to produce the more angular forms common in Cubist art. Finally, we render the composition to give a painterly effect, using an automatic algorithm. This paper describes our method, illustrating the application of our algorithm with a gallery of images. We conclude with a critical appraisal and suggest the use of "high-level" features is of interest to NPR.     

Real-time image-based chinese ink painting rendering

Chinese ink painting, also known as ink and wash painting, is a technically demanding art form. Creating Chinese ink paintings usually requires great skill, concentration, and years of training. This paper presents a novel real-time, automatic framework to convert images into Chinese ink painting style. Given an input image, we first construct its saliency map which captures the visual contents in perceptually salient regions. Next, the image is abstracted and its salient edges are calculated with the help of the saliency map. Then, the abstracted image is diffused by a non-physical ink diffusion process. After that, we combine the diffused image and the salient edges to obtain a composition image. Finally, the composition image is decolorized and texture advected to synthesize the resulting image with Chinese ink painting style. The whole pipeline is implemented on the GPU, enabling a real-time performance. We also propose some optional steps (foreground segmentation and image inversion) to improve the rendering quality. Experimental results show that our model is two to three orders of magnitude faster, while producing results comparable the ones obtained with the current image-based Chinese ink painting rendering method.     

3D street art illusions: embedding chalk stylized rendering of 3D objects into a pavement photo

Three dimensional street art illusions have become more popular in recent years. Many of them are drawn on pavement such as streets, sidewalks, and town squares. It is often known as 3D chalk art, where a 2D artwork is drawn on the street, giving the viewer a 3D optical illusion from a certain perspective. This paper supplies chalk stylized renderings for 3D models and synthesizes 3D objects into a realistic photograph. Users can input one photo for the 3D model. First, a camera position is achieved by using a camera calibration algorithm. Second, a chalk stylized rendering was applied to create an artistic image of the 3D models using the same camera position. Then, the non‐photorealistic rendering image is composited into a source photograph using a modified Poisson approach. All of the enhanced pavement texture details are also blended into the object's image. The major contribution of this paper is providing a user to create any interesting and attractive 3D illusionary art without physically drawing pictures on the pavement. Finally, the proposed method is demonstrated using various experimental 3D street art illusion images. Copyright © 2014 John Wiley & Sons, Ltd.     

偏离映射的烙画风格绘制

针对非真实感绘制烙画艺术风格模拟技术中可能存在的背景单一、绘制速度慢以及缺少细节及写意效果等问题,提出一种自动的、基于偏离映射的烙画风格绘制方法。算法采用对烙画的前景和背景图像分别处理再进行融合的方法,首先通过边界扩充、种子点填充、L2距离优化等改进的纹理合成算法,将样本合成为烙画背景图像,扩展了背景题材;其次,采用各向异性滤波平滑前景图像的结构张量场,并沿张量场局部曲线方向进行线积分卷积计算的方法突出了烙画前景写意风格的特点,同时通过图像增强技术增强了局部细节和结构信息。此外,采用改进的Phong光照明模型将前景图像偏离映射到背景图像中。最终的实验结果突出了细节信息和写意效果,增强了艺术表现力,提高了绘制速度,能模拟出真实的烙画艺术效果。     

Stroke Style Analysis for Painterly Rendering

We propose a novel method that automatically analyzes stroke-related artistic styles of paintings.A set of adaptive interfaces are also developed to connect the style analysis with existing painterly rendering systems, so that the specific artistic style of a template painting can be effectively transferred to the input photo with minimal effort.Different from conventional texture-synthesis based rendering techniques that focus mainly on texture features, this work extracts, analyzes and simulates high-level style features expressed by artists’ brush stroke techniques.Through experiments, user studies and comparisons with ground truth, we demonstrate that the proposed style-orientated painting framework can significantly reduce tedious parameter adjustment, and it allows amateur users to efficiently create desired artistic styles simply by specifying a template painting.