Study On Generation Technology Of Clustered Dot Screening Threshold Matrix

Dot is an important graphic printing units, Screening is the key technology to form the printed dots. Digital screening based on AM screening holds dominant position in the many screening technology in those years, which key technology is generating screening threshold matrix. As far as known to the writer, there has been systematic study about using digital screening abroad, while domestic research relatively small and focused on theoretical introduction, especially the research about dynamic generation technology of analysis formula dot screening threshold matrix. From analysis of the dot form, AM dot belong to clustered dot. This paper mainly research about dynamic generation technology of analysis formula dot screening threshold matrix in this context.Firstly, identifies the main factors that affecting generate the dot screening threshold matrix in this paper, and based on a variety of grid coordinates to establish generating method and step for a dot function threshold matrix. Secondly, establish a balanced relationship between the relevant factors, and designed generation algorithms of dot threshold matrix and image screening process. Thirdly, generate the screening threshold matrix function though these steps in MATLAB7.0.4, rational tangent transformation to screen line along screen angle direction, collecting pixels, converting space coordinates, converting coordinates within a Cartesian coordinate system, and so on. Finally, develop clustered dot threshold matrix system software based on MATLAB GUI. This paper researches the effect of the actual printing parameters on the dot threshold matrix using the software, and develops the image RIP software based on algorithms and theory of AM screening using the dot threshold matrix.The experimental results showed that the larger order of grid elements are arranged, the greater threshold of grid elements. If maintain constant image resolution, the larger the size of the input image, the greater screening time, the greater computer processing share memory. Changing screen angle will be changes the sizes of grid template which create threshold matrix, when the screen angle is not0degrees or90degrees, Surrounding outlets of the threshold matrix will generate invalid threshold. Screens line and Tonal gradation of the image reproduction is inversely proportional relationship when the resolution of the output device keeps unchanged.In the process of develop clustered dot threshold matrix and its screening system, this paper using MATLAB GUI modules, generated system can be extracted related data of threshold matrix, display three-dimensional map and flat map, reads the image, display image information and design functional, and screening the image. Generation method of threshold matrix and image screening algorithm proposed in this paper can provide the necessary guidance of the RIP theory and algorithms for researchers of digital screening direction, it has a good reference guide value to the practical application of printing and related industries.