分形几何与分形花形的迭代函数系统方法

介绍分形几何生成计算机图形的基本方法 ,在阐述迭代函数系统IFS方法生成分形图形原理的基础上 ,讨论分形图形算法的实现方法、参数C对分形图形的影响及分形理论在纺织品花形设计中的应用     

基于三角函数牛顿迭代图形的提花织物纹样设计

运用牛顿迭代的数学原理,提出一种提花织物纹样的设计方法.该方法运用非线性科学可视化设计手段,对三角函数形式的广义牛顿迭代的分形图形生成原理以及通过参数控制其图形变化,由此产生系列图形的方法进行初步研究.在此基础上利用VC++16.0开发工具,运用计算机图形技术,通过牛顿迭代图形的二次设计,借助电子提花实验,对在提花纹样设计中应用三角函数牛顿迭代图形的方法进行了初步的探讨,从而获得了几点有益的启示.     

IFS分形吸引子的多尺度随机控制

研究迭代函数系统分形吸引子的随机化造型方法,定义一个有限区间上服从均匀分布的随机变量,构造了多尺度随机数序列的生成模型,对仿射变换参数系统进行随机调整,控制IFS吸引子的形状变化.以自然景物的树木生长为研究实例,应用计算机图形技术随机生成形态变化多端的树木.     

基于IFS确定性迭代算法的麦粒分形组织设计法

针对L系统在绘制织物分形组织图方面存在的局限,运用IFS的确定性迭代算法生成规则,结合计算机图形方法,提出了一种分形组织图的纹织效果设计方法。该设计方法以复杂变化组织中的麦粒组织为基础组织,基于IFS生成具有自相似结构的分形组织图,然后选择不同形式的组织为填充组织,从而获得具有特殊纹理效果的分形织物组织图。结合纺织CAD技术,借助电子提花机进行了相应的组织织造实验,对设计形成风格新奇的织物组织的新方法进行了初步的探讨。     

利用L-系统生成分形图

为了模拟大自然中的分形现象,在D0L系统、随机L系统和参数L系统的基础上,利用龟形解释系统,生成了雪花、复叶、树形结构等几种典型的分形图形.利用L-系统生成的图形真实感较强,适合应用于娱乐、教育等领域.     

利用L-系统生成分形图

为了模拟大自然中的分形现象,在D0L系统、随机L系统和参数L系统的基础上,利用龟形解释系统,生成了雪花、复叶、树形结构等几种典型的分形图形.利用L-系统生成的图形真实感较强,适合应用于娱乐、教育等领域.     

应用广义牛顿迭代图形的丝巾纹样设计方法

借助计算机图形技术与数学变换手段生成一类广义牛顿迭代图形,根据此类牛顿迭代图形独有的造型及其所具有的迷幻渐变、科技感强烈等视觉特点,提出丝巾纹样新的设计方法。该方法从丝巾纹样的角度,从灵感源到设计构思,再到牛顿迭代图形元素的选择与解读,以及构图设计方法与过程,具体讨论了以松果造型为灵感源运用广义牛顿迭代图形设计丝巾纹样的方法,从而通过丝巾纹样设计的实例表明,牛顿迭代图形不失为一种独具利用价值的丝巾纹样设计资源,运用该资源设计丝巾纹样的方法是可行的。     

纺织工程中的分形应用研究

在简要介绍分形图形生成方法的基础上,综述了分形在纺织工程中应用的两个方面:一是将分形图形用于纺织图案设计、纺织纹样设计等;二是基于分形理论对织物性能进行分析,包括机织物渗透率分析、织物瑕点检测、织物表面纹理分析等.分形图形的应用为纺织图案设计提供了新的创作思路,分形理论是解决纺织工程复杂问题的有力工具.     

分形图形艺术在服装面料设计中的应用

分形图形艺术是科学和艺术的完美统一.就分形图形艺术的审美价值及其在现代视觉艺术--服装面料设计中的具体应用进行了探讨,以此求得更为完备的分形图形艺术与服装面料设计相结合的理论支持和技术支持,以便将分形图形艺术更准确、更具体地应用到具体的服装面料设计之中.     

基于L系统的3×3平纹分形组织设计应用方法

为探讨分形组织在织物设计中的具体运用途径,根据3×3平纹变化组织点分布简单、均衡与对称等特点,运用L系统的链式语言生成规则与计算机图形方法,生成具有4级自相似结构的分形组织,并在此基础上讨论其分形组织的主要变化形式及其设计应用方法.重点研究通过填充组织的变化,配合分形组织获得一类新型的组织结构,进而探索设计产生新的织物...     

基于逃逸法的分形图像盒的维数计算

计算和分析了复动力系统分形图像的盒维数计算问题,将传统的逃逸时间算法进行推广之后应用于吸引子图像的维数计算,给出了具体的计算实例和比较结果.实验表明,该算法可以提高图像盒维数计算的准确性和可靠度.     

Bilevel thresholding of sliced image of sludge floc

This work examined the feasibility of employing various thresholding algorithms to determining the optimal bilevel thresholding value for estimating the geometric parameters of sludge flocs from the microtome sliced images and from the confocal laser scanning microscope images. Morphological information extracted from images depends on the bilevel thresholding value. According to the evaluation on the luminescence-inverted images and fractal curves (quadric Koch curve and Sierpinski carpet), Otsu's method yields more stable performance than other histogram-based algorithms and is chosen to obtain the porosity. The maximum convex perimeter method, however, can probe the shapes and spatial distribution of the pores among the biomass granules in real sludge flocs. A combined algorithm is recommended for probing the sludge floc structure.     

Fractal texture analysis of bread crumb digital images

A fractal texture analysis technique was applied to bread crumb digital images. Fractal dimensions obtained from several methods (fractional Brownian motion, frequency domain, relative differential box-counting, morphological fractal, mass fractal and random walks methods) were investigated in order to determine their capability to accurately describe the surface roughness of bread crumb images or the visual appearance of bread crumb in meaningful terms. A total of 500 bread crumb images of different porosity and grain quality were analysed. It was found that bread crumb appearance could be effectively quantified by the fractal dimension of its digital image. Correlations of fractal dimensions with mean cell area, standard deviation of cell area and void fraction were variable for the fractal methods. While the mass fractal method measured better crumb heterogeneity, other methods quantified coarseness, cell–cell wall ruggedness and cell wall tortuosity. A vector comprising fractal dimensions would objectively depict crumb grain and would allow comparisons between different bread crumb images.     

Prediction of panellists’ perception of bread crumb appearance using fractal and visual textural features

Ratings of visual characteristics of bread crumb images obtained by panellists were correlated with features obtained by digital fractal and texture analysis and simple thresholding. Trained panellists were asked to rate 168 bread crumb images on fineness, homogeneity and degree of orientation, using continuous line scales. The relative orientation of the main and secondary peaks of the image power spectrum was the only parameter related to the human perception of the degree of crumb orientation. Single fractal dimension terms correlated better with the panellists’ perception of grain fineness and homogeneity than the single crumb features from thresholding. Second-order polynomial models were significantly better (P < 0.01) in most predictors than simple linear models. Grain fineness was better approached by the method of relative differential box-counting fractal dimension (R ² = 0.822) whereas grain homogeneity was highly related to the mass fractal dimension (R ² = 0.820). Multiple linear models to estimate grain fineness with higher predictive capacity included predictors such as fractal dimension, mean intercellular distance and void fraction (R ² > 0.860).     

基于绉织物表面图像分形特征分析的绉效应评价

通过MATLAB对绉织物表面图像进行处理，根据分形理论对绉织物表面图像的起绉纹理进行分析。结果表明，绉织物表面具有最著的分形特征，且绉织物的起绉程度与绉织物表面的视觉风格存在一定的关系，起绉程度大的绉织物其维数大于起绉程度小的织物。     

Enzymatic browning in sliced and puréed avocado: A fractal kinetic study

Modelling of browning is essential to evaluate the effectiveness of the processes applied to obtain fresh-appearance foods and also to determine their shelf life. Computer vision and the fractal kinetic method were used to quantify browning in three avocado cultivars. Samples (avocado slices and purée) were stored at 4 °C and surface images were captured in the tiff format. Browning kinetic was derived from images using the L^∗ mean method and the fractal method. In another experiment, inhibitor kinetic was also quantified, using the polyphenol oxidase activity method (in purée samples) with 0.1%, 0.5% and 1% of sodium bisulfite. In the results for avocado slices, kinetic rate derived by the fractal kinetic method was higher than that obtained with the L^∗ mean method, but the opposite was observed when the avocado was pulping (avocado purée). Kinetic quantified by the fractal method was similarly inhibited by bisulfite, when compared with the L^∗ mean value or PPO activity value methods. In general, the fractal method can be used to record browning kinetic and to discriminate between avocado cultivars, initial structural state of the sample (slice or purée), or in experiments using browning inhibitors.     

Comparative fractal characterization of physical changes of different food products during drying

The development of a relationship between microstructural changes of model food products (carrot and potato cubes) and their physical changes during conventional hot air drying (HAD) using combined fractal and image analysis was performed in this study. Dried carrot and potato sections were examined by light microscopy and the fractal dimension (FD) of the microscopic images was determined using a box counting technique. The apparent physical changes of the samples undergoing HAD were represented in terms of the percentage of shrinkage and rehydration ratio. These apparent changes correlated well with their microstructural changes represented by the normalized changes of fractal dimension (ΔFD/FD₀) of the microstructural images. Although the microstructural changes of the samples undergoing HAD were quite different, the changes of ΔFD/FD₀ of the samples undergoing drying were in the same trend. FD has thus proved to be a good indicator of microstructural changes of products undergoing drying.     

基于分形的棉条建模及其牵伸过程的仿真

为分析计算棉条牵伸力的变化，以提高棉纤维牵伸的质量，依据分形理论的建模思想，将具有相同圆形截面的棉纤维按照分形理论进行排列，构建了新的棉须条模型。基于动态牵伸和静态牵伸的相似性，将该模型进行静态拉伸仿真，得出不同定量的棉条静态牵伸力。结果显示须条静态拉伸力与动态牵伸力的平均误差为5.66%,最大相对误差在12%以内。利用线性拟合求出动态牵伸力与静态牵伸力的关系式，成功预测了不同定量下的牵伸力。此外，得出了在定量为25.60 g/m时，静态牵伸力随牵伸倍数的变化曲线。结果表明仿真牵伸力与动态牵伸力的变化趋势基本一致。建立的分形须条模型有效，也为动态牵伸力的近似预测提供参考。     

Fractal analysis of the retrogradation of rice starch by digital image processing

The surface profiles of retrograded rice starch (RS) samples stored at different times were obtained by horizontal sectioning and scanning electron microscopy (SEM). SEM images showed that the surface topography of the retrograded RS samples possessed fractal characteristics, which was also proven by fractal analysis. The fractal features for analysis were extracted using a new image processing method. The average fractal dimensions of the retrograded RS samples stored for 1, 5, 10, and 15 days were 1.6587, 1.7333, 1.7807, and 1.8340, respectively. The method indicated that the fractal dimension increased as the extent of retrogradation increased. The good correlation between fractal dimensions and the retrogradation enthalpies of the retrograded samples were established using a fitted binomial model (R² = 0.9976). These results show that the fractal dimensions obtained using this new image processing method could effectively quantify the extent of retrogradation.     

基于小波变换的分形特征图像编码

在对图像块进行小波变换的基础上,通过计算各频带的分形维数,形成图像块的分形特征向量,把传统的子块匹配问题转化为分形特征向量意义下的子块匹配问题.实验结果显示,本文提出的方法与Jacquin的全局搜索法相比,尽管解码图像质量略有下降,但编码速度提高了70倍以上.