Research on Line Drawing Extraction of Qijiang Prints Based on Image Processing Technology

China has many traditional print styles, but with the development of digital images, Qijiang prints are unique. It is a skill worth learning to print prints on boards in a way that combines painting and printing. This technology is a key factor in the printing process. Therefore, in today's digital image, the digital quality of line drawings is an important step if we want to carry forward Qijiang prints and make them continue to develop in the digital field. Based on the computer image processing technology, this paper takes the line drawing pattern extraction of Chongqing Qijiang printmaking as the main content, smoothes the image globally on the basis of F0 norm, optimizes and improves the FDoG filter by using the tangential flow field of Gaussian filter and ETF filter, and extracts the line drawing with certain enhancement effect. When the gray value of the local line is less than the gray value of background, the algorithm can still generate a line drafts with accurate positioning and unified style. Based on this algorithm, the line drawings of most works can be extracted, but some broken boards or broken images can also be extracted by computer technology and manual operation, thus basically completing all the tasks of Qijiang printmaking extraction.