文章基本信息

标题：Detection of forest management operations using bi-temporal aerial photographs
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作者：Pekka Hyvönen ; Jaakko Heinonen ; Arto Haara 等
期刊名称：ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences
印刷版ISSN：2194-9042
电子版ISSN：2194-9050
出版年度：2010
卷号：XXXVIII - Part 7B
页码：309-313
出版社：Copernicus Publications
摘要：The increased need for timely forest information is leading to the continuous updating of stand databases. In continuous updating, stand attributes are estimated in the field following a forest operation (cutting or silvicultural treatment) and stored in databases. To determine the changes caused by forest operations and forest damage, a semi-automatic method was developed based on bi-temporal aerial photographs. The field data consisted of 2 362 forest stands, from which the changes between years 2001 and 2004 were collected from different databases. Stands were divided into three classes according to the type of change. The No-change class (1 890) included stands with no changes other than growth. The Moderate-change class (373) included stands with changes such as thinning, partly operated stand and improvement of young stand. The Considerable-change class (99) included stands with major changes such as clear cutting and severe storm damage. The data were randomly divided into training and test data. The aerial photographs were acquired for the years 2001 and 2004 with almost the same image specifications and the photographs were temporally registrated. As change detection is sensitive to location errors, locational adjustments were made at the stand and segment levels. Linear stepwise discriminant analysis and the non-linear k-nearest neighbour (k-NN) method were tested in classification. The classification results at the stand level were found to be better than at the segment level. Compared to previous studies , the results of this study demonstrate remarkable improvement in the classification accuracy of moderate changes. The results showed that change detection substantially improved when the registration at the stand level was used, especially in the detection of thinned stands.
关键词：Change detection; aerial photograph; segmentation; k-NN; rectification