Theory And Application Of Digital Printing Image Quality Detection And Quality Control Engineering

Printing, which was previously regarded as an ancient industry, actually can be describedas a historic visual information transmission technology. It is issued carrying images or textsand people will get the information by reading. Through dynamically integrating withcomputer and modern communication technology, printing has already developed into awhole digital work flow in which the information flow is processed digitally from input tooutput. Digital printing is the representative technology of this digital context.The application of digital printing has developed rapidly in China. In the recent5years,the rate of new investment increased by more than30%each year. Disproportionally, there isno sign that the high-end industrial digital printer can be supplied by domestic enterprises. Soit is extremely meaningful to do some research about the core technology for further designwork in digital printer development. The ultimate goal of this research is to propose sometheoretical foundations and analysis model in order to provide some theoretical foundationsfor independent development.Digital printing can help synthesize information flow and make full use of productiveresource by employing complete digital and network technology so as to promote theadvanced equipment and technology closer to business. Meanwhile, it can meet therequirements of information service on demand as well by offering short run manufacturing,print on demand and personalized printing. Nowdays print quality has been improvedintegrally with continuous technique development. A customer will not pay for poor qualityproducts even though it is outputted quickly. So the quality control is still a key technique indigital printing. When the whole printing process is concentrated into closed smallerequipments, the quality control must be operated by intellectualized systems. Then the qualityis not an adjusting technology based on measurement any more, but system engineering withfeedback optimization aiming at better perception quality.The theories and methods about digital printed image quality detection and qualitycontrol technology were researched according to different requirements between equipmentdevelopment and quality control respectively in this paper. Firstly the drawbacks of thetraditional quality theory system and its inelasticity in digital printing application wereanalyzed. Based on the analysis the research approach that the integrity of the basic qualitytheory should be optimized first was determined. Then a bidirectional mapping quality modelframework was proposed by modeling the imaging process in digital printing technology in terms of the research object. At last a MTF-based quality feedback enhancement algorithmwas further put forward.The main innovation in this thesis includes the following aspects:1. The relationship between printed image quality and image quality were analyzed bycanvass related quality concepts. This was beneficial to find the theoretical foundation forintroducing image quality principles into print quality research. Thus an optimized digitalquality basic theory framework based on the Engeldrum image quality circle was build up.2. A digital printing quality control engineering theory was proposed. Meanwhile as apreparatory work, a simplified quality analysis model based on impact factor domain wasderived according to the mathematical analysis of imaging process in digital printing. Thenthe bidirectional mapping quality model framework connecting the digital printing system andquality assessment was build up by fusing the simplified model and the up to date researchachievements in quality perception attributes.3. A series of basic printed image quality measurement experiments were carried out toexplore the quality attributes metrics detection approach in digital prints. The survey coversfour aspects, the quality characters of digital prints, the performance of quality attributesdetection instruments, the effects of print medium and storage stability of digital prints. Theseworks accumulated significant experiences for image quality attributes detection application.4. An optimization intention using control system was presented and certified bysimulation experiment. The MTF of the plain output image was measured and the data wasreturned to calibrate the digital image by filtering, convolution and fusing calculation. Theresults show that the output resolution can be efficiently improved.