טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentGilad-Glickman Danit
SubjectColor Restoration of Scanned Archaeological Artifacts
with Repetitive Patterns
DepartmentDepartment of Electrical Engineering
Supervisors Professor Lihi Zelnik-Manor
Professor Ilan Shimshoni
Full Thesis textFull thesis text - English Version


Abstract

In this work, we address the problem of virtually restoring archaeological artifacts. Virtual restoration is the process of creating a noise-free model of a degraded object, to visualize its original appearance. Our work focuses on restoring the coloring of the object. We considered both 2D and 3D objects, including scans of ancient texts and 3D models of decorated pottery.


Our denoising method exploits typical characteristic of archaeological artifacts, such as repetitive decoration motifs and a limited palette of colors. A special case of such characteristics are ancient texts, where a single color is commonly used, and reoccurring letters constitute as repetitions. Assuming a limited number of colors allows us to use classification of the model's colors, in order to revert the degradation process. Repetitive patterns are used to deduce the original coloring at damaged regions.


Our classification method is based on minimization of an energy function. Similar to previous methods, the energy function contains a data term and a smoothness term. But, in addition to those, we add a correspondence term, which encourages consistent labeling of matching regions. The new term can be considered a generalization of the smoothness term; while the original smoothness term imposes similarity on geometrically close pixels, the suggested correspondence term enforces similarity on semantically close pixels. The energy function is minimized using Graph-Cut algorithm.