CCDカメラによる撮影画像を用いた樹洞の深さと内部容積の推定方法  [in Japanese] A Method of Estimating the Depth and the Internal Volume of Tree Hollows with CCD Camera Images  [in Japanese]

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Abstract

CCD カメラによって撮影した画像を用いて樹洞内部の深さの値を推定し, 内部容積を算出する方法を考案した。内径の異なる円筒状の模型を使って, 実際の模型の底面積に対する画像に写った底面の面積の比と円筒の内径との関係から, 樹洞内部の深さを推定する回帰式を得た。深さが実測可能な自然林の樹洞を対象にこの回帰式を用いて深さの推定値を算出し, 実測値に比べどの程度の差があるかを検証した。その結果, 19個中16個 (84.2%) が推定値よりも実測値の深さの方が深く, 推定値は実測値を過小評価していた。算出した内部容積についても実測値に比べ推定値は小さい値を示す傾向にあったが, この推定方法は大まかな内部容積の把握には有効であることが示唆された。

We designed a method of estimating the internal volume of a tree hollow based upon its depth that was obtained from the CCD camera image. We made four cylindrical models with different bore diameter hollows. While changing the internal depth, we took internal pictures of the models with a CCD camera. A regression formula to estimate the depth of tree hollows was obtained from the ratio between the area of the bottom in the images to the area of the bottom of actual cylindrical models and their inside diameters. To verify the depth estimated from the regression model, we measured the inside diameter at the entrance and the depth of tree hollows in natural forests. We found that the measured depth in 16 of 19 samples was deeper than the estimate. The internal volume of tree hollows calculated from the estimated depth was also undervaluing, but this method may be useful for estimating the scale of tree hollows.

Journal

  • Journal of the Japanese Forest Society

    Journal of the Japanese Forest Society 91(4), 299-302, 2009-08-01

    Japanese Forestry Society

References:  14

Cited by:  1

Codes

  • NII Article ID (NAID)
    110007356251
  • NII NACSIS-CAT ID (NCID)
    AA12003078
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    13498509
  • NDL Article ID
    10440049
  • NDL Source Classification
    ZR21(科学技術--農林水産--林産)
  • NDL Call No.
    Z18-340
  • Data Source
    CJP  CJPref  NDL  NII-ELS  J-STAGE  JASI 
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