Parameterized Generation Technology For Random-needle Embroidery Rendering

Random Needle Embroidery is a Chinese modern embroidery art which has been enrolled to the World Intangible Heritage.For the purpose of protection and inheritance of Random Needle Embroidery,we analysis its stitching artistic characteristics,and do several researches on stitch model definition,optimization of stitch model parameters and user customization in this thesis.It is good to support the promotion of Random Needle Embroidery and expands the application of the artistic rendering field.The main achievements of this thesis are as follows:(1)Presenting a parameterized stitch model definition for Random Needle Embroidery:Firstly,a three levels model including single stitch,cross stitch and cross stitch layout is defined in vector space and lighting&crossing shadow effect of stitches is defined in pixel space.Our model can control density,orientation,length and chaos of stitches;Secondly,a construction method is defined from high-level parameters to vector stitch attributes and pixel array,and then the result is generated by mapping image features to model parameters.(2)Presenting an optimizing method for selecting stitch model parameters of Random Needle Embroidery:Firstly,an objective function used to evaluate rendering result is defined.It combines visual information metrics(color&texture)and stitch vector constraints(coverage rate&uniformity)according to the artistic style;Secondly,a modified PSO+SA algorithm is applied to increase the ability of searching the global best parameters.(3)Presenting a user customizable simulation method for Random Needle Embroidery:Firstly,six intuitive high-level visual parameters are defined,which include density,orientation contrast,length contrast,hue contrast,saturation contrast and lightness contrast;Secondly,a 2D topological structure between neighboring stitch is built.It is used to support the process of global layout and local contrast;Thirdly,based on stitch neighborhood graph,several reaction diffusion processes are applied according to the high-level visual parameters and the attributes(orientation,length&color)of all the stitches are controlled by the reaction diffusion processes;Finally,there are two kinds of user customizing manner to verify the result:adjusting high-level visual parameters and drawing guiding sketch.