Evaluation of Accuracy of Spatio-Temporal Image Analysis Methods Using Artificial Images and Proposal of a Hybrid Method

Kwonkyu Yu

doi:10.17820/eri.2024.11.3.100

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2024 Vol.11, Issue 3 Preview Page

Original Article

Evaluation of Accuracy of Spatio-Temporal Image Analysis Methods Using Artificial Images and Proposal of a Hybrid Method 인공시공간영상을 이용한 시공간영상분석법의 정확도 평가와 혼합분석법의 제안

30 September 2024. pp. 100-109

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Abstract

There are various methods in surface image velocimetry that can measure the flow velocity of a river surface using footage of a river surface. Among them, spatio-temporal image velocimetry (STIV) is widely used. This paper analyzed advantages and disadvantages of two STIV methods developed by the author, correlation-based STIV (C-STIV) and FFT-based STIV (F-STIV). This study also proposed a new method, hybrid STIV (H-STIV), that could supplement the advantages and disadvantages of the two existing methods by combining them. For the analyses, 20 cases of artificial spatio-temporal images, having image displacement ranging from 0.1 px/fr to 19.0 px/fr, were prepared. As a result, F-STIV was accurate with footage containing small image displacements and C-STIV was more accurate with footage containing large image displacements. For images with medium displacement, the two methods showed similar accuracies. Based on this result, H-STIV was proposed to adopt the result of F-STIV in displacements smaller than 2.0 px/fr (image strip slope 63.4°) and the result of C-STIV in larger displacements. As a result of applying the proposed method to argumentation, it was confirmed that H-STIV could calculate the flow velocity efficiently according to the situation.

Keywords

Artificial image

Flow velocity measurement

Image displacement

Spatio-temporal image velocimetry (STIV)

Spatio-temporal image (STI)

Surface image velocimetry (SIV)

하천표면의 동영상을 이용하여 하천표면유속을 측정하는 표면영상유속계에는 다양한 방법들이 있으며, 그 중 시공간영상(STI)을 이용한 분석법(STIV)이 널리 쓰이고 있다. 본고는 저자들이 개발한 두 가지 방법인 상호상관법기반 시공간영상분석법(C-STIV)과 FFT-기반 시공간영상분석법(F-STIV)의 장단점을 분석하고, 이를 조합하여 두 방법의 장단점을 보완할 수 있는 혼합형 시공간영상분석법(H-STIV)을 제안하였다. 분석을 위해 영상변위 0.1 px/fr부터 19.0 px/fr에 이르는 20종의 인공 시공간영상을 작성하였다. 이 인공시공간영상을 분석한 결과 영상변위가 작은 영역은 F-STIV가 정확하고, 영상변위가 큰 영역은 C-STIV가 정확하며, 중간 정도의 영상변위를 가진 영상들은 두 방법 모두 비슷한 경향을 보였다. 이 결과에 기반하여 2.0 px/fr(줄무늬 기울기 63.4°) 보다 작은 범위에서는 F-STIV의 결과를, 이보다 큰 범위에서는 C-STIV의 결과를 채택하는 H-STIV를 제안하였다. 제안된 방법을 인수천에 적용한 결과, H-STIV가 상황에 맞게 효율적으로 유속을 산정함을 입증하였다.

키워드

인공영상

유속측정

영상변위

시공간영상분석법

시공간영상

표면영상유속계

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Information

Publisher :Korean Society of Ecology and Infrastructure Engineering
Publisher(Ko) :응용생태공학회
Journal Title :Ecology and Resilient Infrastructure
Journal Title(Ko) :응용생태공학회 논문집
Volume : 11
No :3
Pages :100-109
Received Date : 2024-09-20
Revised Date : 2024-09-26
Accepted Date : 2024-09-27
DOI :https://doi.org/10.17820/eri.2024.11.3.100

Ecology and Resilient Infrastructure ISSN:2288-8527(Online) 응용생태공학회 논문집

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