Research And Implementation Of Digital Halftone Technology Based On Image Segmentation

After more than 70 years of development,the photocopier equipment has developed from single-functional black and white analog copy to today's multi-functional color digital copy.With the progress of science and technology,the function of the photocopier is becoming more and more perfect,and the quality of photocopying is also improving.At present,the research & development and production technology of China's photocopier equipment are far behind the foreign countries,the photocopier products are heavily dependent on imports,which has inevitably brought great hidden trouble to China's office automation industry and national information security.Therefore,the research and application of the digital halftone technology based on text segmentation in photocopier equipment will greatly improve the output quality and market competitiveness,and have positive significance for improving the level of China's information security.This thesis firstly analyzes the hardware platform and control software of the self-developed photocopier.By not changing the original hardware circuit structure,it presents a design scheme to achieve photocopying image & text segmentation and digital half-tone functional module based on FPGA logic.Secondly,on the basis of studying the classical image & text segmentation algorithm and digital halftone algorithm,this thesis studies and designs the FPGA logic implementation method of graphic segmentation and digital halftone based on the actual requirements.Thirdly,on "the FPGA+ DDR2" development platform,this thesis studies the logic design based on the morphology of the graphic segmentation method,and through scheduling of each sublogic module by Nios?soft core,the separation of graphics and text areas of the copied image is realized;This thesis designs a digital halftone logic module based on error diffusion algorithm and a digital halftone logic module based on Bayer jitter algorithm.According to the storage format of DDR2 copy image,the mapping logic of image and text segmentation region coordinates and DDR2 image/text information storage is designed,and the distribution of image and text object data read by DDR2 to two halftone processing modules is realized.The digital halftone output data of the image and text object is printed or uploaded after splicing by the data combination logic module.Finally,on the selected development platform,the simulation test and verification of each logic function module were carried out,and the system integration and FPGA download were carried out.The function and performance of the image-text segmentation and digital halftone system integrated into FPGA were tested by building a test environment for storing photocopied images transferred from PC to DDR2,The test results show that the system functions are correctly achieved and meets the design requirements.The digital halftone technology based on image and text segmentation proposed in this thesis can improve the quality of halftone output image of the photocopier system,and provide technical support for the digital halftone technology of the color photocopier in the future,which has certain application value.