,
Maike Buchin
,
Zijin Huang
,
André Nusser
,
Sampson Wong
Creative Commons Attribution 4.0 International license
We study the problem of computing the Fréchet distance between two polygonal curves under transformations. First, we consider translations in the Euclidean plane. Given two curves π and σ of total complexity n and a threshold δ ≥ 0, we present an 𝒪̃(n^{7 + 1/3}) time algorithm to determine whether there exists a translation t ∈ ℝ² such that the Fréchet distance between π and σ + t is at most δ. This improves on the previous best result, which is an 𝒪(n⁸) time algorithm.
We then generalize this result to any class of rationally parameterized transformations, which includes translation, rotation, scaling, and arbitrary affine transformations. For a class T of rationally parametrized transformations with k degrees of freedom, we show that one can determine whether there is a transformation τ ∈ T such that the Fréchet distance between π and τ(σ) is at most δ in 𝒪̃(n^{3k+4/3}) time.
@InProceedings{buchin_et_al:LIPIcs.ICALP.2025.36,
author = {Buchin, Kevin and Buchin, Maike and Huang, Zijin and Nusser, Andr\'{e} and Wong, Sampson},
title = {{Faster Fr\'{e}chet Distance Under Transformations}},
booktitle = {52nd International Colloquium on Automata, Languages, and Programming (ICALP 2025)},
pages = {36:1--36:20},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-372-0},
ISSN = {1868-8969},
year = {2025},
volume = {334},
editor = {Censor-Hillel, Keren and Grandoni, Fabrizio and Ouaknine, Jo\"{e}l and Puppis, Gabriele},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICALP.2025.36},
URN = {urn:nbn:de:0030-drops-234137},
doi = {10.4230/LIPIcs.ICALP.2025.36},
annote = {Keywords: Fr\'{e}chet distance, curve similarity, shape matching}
}