DIGITALNA ARHIVA ŠUMARSKOG LISTA
prilagođeno pretraživanje po punom tekstu
| ŠUMARSKI LIST 9-10/2014 str. 53 <-- 53 --> PDF |
species spectral signature differs especially in Red-Edge, NIR – 1 and NIR – 2 and in the Green band. The box-and-whiskers plots in Fig. 6 show the spectral variability among and within the five tree species. The difference between deciduous and coniferous species is clearly visible in Red-Edge, NIR – 1 and NIR – 2 and in Green band. Moreover, there were not as many outliers in Red-Edge, NIR – 1 and NIR – 2 bands. 2.4. Object-based image analyses – Analiza snimaka Example-based Feature Extraction was performed in Exelis VIS ENVI 5 software applying support vector machine model (SVM). After a trial and error with various combinations, the optimal parameters of the segmentation were set. In addition to the original 8 bands, Red-Edge normalized difference vegetation index (Red-Edge NDVI) calculated from Red-Edge and Red band, and DMC layer were stacked into a 10-band image for the five tree species supervised classification. In the first step of classification the area on the image was masked by laser scanning height data to include only areas with heights between 15 and 50 m to remove the lower (also ground) vegetation influence and reduce the abundance of data, as suggested by some previous studies (e.g. (Leckie et al., 2003)). In the second step, training samples of the five tree species were included as a reference. Post-classification was performed by calculating a confusion matrix (Tab. 3) in Exelis VIS ENVI Classic software to assess the accuracy of a classification output by comparing |