Testing Connectedness of Images
We investigate algorithms for testing whether an image is connected. Given a proximity parameter ϵ ∈ ( 0 , 1 ) and query access to a black-and-white image represented by an n × n matrix of Boolean pixel values, a (1-sided error) connectedness tester accepts if the image is connected and rejects with...
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| Veröffentlicht in: | Algorithmica Jg. 86; H. 11; S. 3496 - 3517 |
|---|---|
| Hauptverfasser: | , , , |
| Format: | Journal Article |
| Sprache: | Englisch |
| Veröffentlicht: |
New York
Springer US
01.11.2024
Springer Nature B.V |
| Schlagworte: | |
| ISSN: | 0178-4617, 1432-0541 |
| Online-Zugang: | Volltext |
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| Zusammenfassung: | We investigate algorithms for testing whether an image is connected. Given a proximity parameter
ϵ
∈
(
0
,
1
)
and query access to a black-and-white image represented by an
n
×
n
matrix of Boolean pixel values, a (1-sided error) connectedness tester accepts if the image is connected and rejects with probability at least 2/3 if the image is
ϵ
-far from connected. We show that connectedness can be tested nonadaptively with
O
(
1
ϵ
2
)
queries and adaptively with
O
(
1
ϵ
3
/
2
log
1
ϵ
)
queries. The best connectedness tester to date, by Berman, Raskhodnikova, and Yaroslavtsev (STOC 2014) had query complexity
O
(
1
ϵ
2
log
1
ϵ
)
and was adaptive. We also prove that every nonadaptive, 1-sided error tester for connectedness must make
Ω
(
1
ϵ
log
1
ϵ
)
queries. |
|---|---|
| Bibliographie: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 14 |
| ISSN: | 0178-4617 1432-0541 |
| DOI: | 10.1007/s00453-024-01248-x |