Journal of the Korea Academia-Industrial cooperation Society (한국산학기술학회논문지)

The Korea Academia-Industrial cooperation Society (한국산학기술학회)
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Accuracy Evaluation and Analysis of SLAM for the Advancement of Forest Investigation

산림조사 고도화를 위한 SLAM의 정확도 평가 및 분석

  • Yun, Hee-Cheon (Dept. of Civil Engineering, Chungnam National University) ;
  • Lee, Jong-Sin (Dept. of Construction Engineering Education, Chungnam National University)
  • 윤희천 (충남대학교 토목공학과) ;
  • 이종신 (충남대학교 건설공학교육과)
  • Received : 2018.11.06
  • Accepted : 2018.12.07
  • Published : 2018.12.31
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Abstract

The National Forestry Inventory of Korea has started the 7th (2016 ~ 2020) survey from the first (1972 ~ 1974) National Forest Situation Survey. The diameter at breast height was measured using a diameter tape, and the tree height was measured using a hypsometer in the National Forestry Inventory of Korea from the 1st to recently the 7th surveying. In the case of the diameter tape, however, irregularly shaped trees may cause a large error. In the case of a hypsometer, the height may be measured indirectly in 10 cm increments to the front edge of the tree, so that the accuracy may be lowered. This paper suggests the use of SLAM to improve the accuracy and advance forest investigations. For this purpose, a test bed for the measurement of DBH and tree height was set up, and the scan data was acquired directly using SLAM equipment. The accuracy of DBH and tree height measurements were analyzed. As a result, it was possible to calculate directly the DBH and tree height to 1mm unit, and it showed that the DBH accuracy of 2cm or less and the accuracy of the tree height accuracy of 1.3cm or less are sufficient for practical use. Based on the results, the scan data will be acquired for sample points and analyzed.

우리나라의 국가산림조사는 제1차(1972년~1974년) 전국산림실태조사를 시작으로 현재 제7차(2016년~2020년) 조사가 실시되고 있다. 제1차부터 최근 제7차까지의 진행된 우리나라의 국가산림자원조사에서 흉고직경은 직경테이프를 이용하고, 수고는 측고기를 사용하여 측정하고 있다. 그러나 직경테이프의 경우 불규칙한 형태의 임목에서는 다소 큰 오차가 발생될 수 있고, 측고기의 경우 입목의 정단부까지 높이를 10cm 단위로 간접 측정하고 있어 정확도가 낮아질 수 있다. 이에 본 연구에서는 산림조사의 정확도 향상 및 고도화를 위해 SLAM의 활용 가능성을 제시하고자 하였다. 이를 위해 흉고직경 및 수고 측정을 위한 테스트베드를 설정하고, SLAM장비를 이용하여 스캔데이터를 직접 획득한 후 흉고직경 및 수고 측정 정확도를 분석하였다. 그 결과 흉고직경 및 수고를 1mm 단위까지 직접 산출 가능하였으며, 2cm 이하의 흉고직경 정확도와 1.3cm 이하의 수고 정확도를 나타냄으로써, 실무에서 충분히 활용 가능함을 제시하였다. 향후 본 연구결과를 바탕으로 표본점에 대한 스캔 데이터를 획득하고 분석을 진행할 예정이다.

Keywords

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Fig. 1. Test bed

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Fig. 2. Coordinates and target number about test bed

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Fig. 3. Scan result about test bed

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Fig. 4. Distance calculation between No.1 and No.2 specimen

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Fig. 5. Process of calculating the DBH from the scan result of No.19 specimen

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Fig. 6. Process of calculating the height from the scan result of No.21 pole

Table 1. Distances and error calculated from scan results

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Table 2. Measurement results of DBH using measuring tape

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Table 3. DBH and error calculated from scan results

SHGSCZ_2018_v19n12_734_t0003.png 이미지

Table 4. Measurement results of height using measuring tape

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Table 5. Height and error calculated from scan results

SHGSCZ_2018_v19n12_734_t0005.png 이미지

References

  1. Korea Forest Service, National Forest Inventory [Internet]. Korea Forest Service [cited 2018 October 5], Available From: http://www.forest.go.kr/ (accessed October 5, 2018)
  2. National Assembly of South Korea, Forest Protection Act [Internet], National Law Information Center, c2018[cited 2018 Nov. 15], Available From: http://www.law.go.kr/%EB%B2%95%EB%A0%B9/%EC%82%B0%EB%A6%BC%EB%B3%B4%ED%98%B8%EB%B2%95 (accessed Nov. 15, 2018)
  3. S. H. Kim, J. C. Kim, S. W. Lee, H. G. Jo, S. A. Seo, J. S. Lim, I. B. Jeong, "Guidebook of The 6th National Forest Inventory and Forest Health Monitoring", p.95, Guidebook, Korea Forestry Promotion Institute, 2013. ISBN: 978-89-98575-06-9
  4. C. Liu, Y. Xing, J. Duanmu, X. Tian, "Evaluating Different Methods for Estimating Diameter at Breast Height from Terrestrial Laser Scanning", Remote Sensing, Vol.10, No.4, Article ID 513, pp.1-20, 2018. DOI: https://dx.doi.org/10.3390/rs10040513
  5. Korea Forest Service, Forest Forestry Glossary [Internet]. Korea Forest Service [cited 2018 May 6], Available From: http://www.forest.go.kr/ (accessed May 6, 2018)
  6. J. S. Lee, Construction of Forest Geospatial Information based on SLAM for the Efficient Forest Investigation, Dissertation of Doctors's Degree, Chungnam National Univ., p.142, 2018.