An Orbifold Framework for Point Scan
구분 | 박사학위 논문 발표 |
---|---|
일정 | 2025-06-04(수) 11:00~16:00 |
세미나실 | 129동 301호 |
강연자 | 김지원 (수리과학부) |
담당교수 | 국웅 |
기타 |
This dissertation introduces a novel orbifold-based framework that resolves the three main challenges in point scanning system such as phase shifts, mechanical-coupling errors, and optimal frequency selection. Point scan systems, which trace Lissajous or Rosette paths are increasingly used in LiDAR and confocal microscopy.
Scanning paths are modeled as geodesics on a Clifford torus in S3; lifting the dynamics to the *2222 and *22 orbifolds exposes differential geometric tools and fits naturally into a pull-back push-forward structure.
At the heart of the framework is the SO(4) action on the torus. Phase shifts appear
as internal T2 automorphisms and mechanical coupling error correspond to rotations
in the Grassmannian Gr(2,R4). Gauge directions are quotiented out, leaving a base
space for reconstruction.
The orbifold framework induces a general folded error functional, denoted E(g),
defined on SO(4) where g represents a system perturbation. This functional quantifies
internal inconsistencies within the lifted observed image by measuring deviations from
perfect symmetry across fibers generated by g. Crucially, E(g) is proven to be locally
convex along non-gauge directions. That result shows that gradient descent can find
the optimal point and solve the problem.
Furthermore, the theorems established for this SO(4) framework naturally extend to higher-dimensional frameworks, such as multiple frequency components or more complex harmonic distortions.