Rami Piiroinen

Mr. Rami Piiroinen


Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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31 March 2022 in ISPRS Journal of Photogrammetry and Remote Sensing
Verified
Journal Article
Closed access
HZHengwei Zhao
Hengwei Zhao
YZYanfei Zhong
Yanfei Zhong
XWXINYU WANG
XINYU WANG
XHXin Hu
Xin Hu
CLChang Luo
Chang Luo
PPPetri Pellikka
Petri Pellikka

1 December 2018 in Remote Sensing of Environment
Verified
Journal Article
Open access
RPRami Piiroinen
Rami Piiroinen
FFFabian Fassnacht
Fabian Fassnacht
JHJanne Heiskanen
Janne Heiskanen
EMEduardo Maeda
Eduardo Maeda
BMBenjamin Mack
Benjamin Mack
PPPetri Pellikka
Petri Pellikka

23 August 2017 in Remote Sensing
Verified
Journal Article
Open access
PDF file
RPRami Piiroinen
Rami Piiroinen
JHJanne Heiskanen
Janne Heiskanen
EMEduardo Maeda
Eduardo Maeda
Arto ViinikkaArto Viinikka
Arto Viinikka
Petri PellikkaPetri Pellikka
Petri Pellikka
Airborne imaging spectroscopy (IS) and laser scanning (ALS) have been explored widely for tree species classification during the past decades. However, African agroforestry areas, where a few exotic tree species are dominant and many native species occur less frequently, have not yet been studied. Obtaining maps of tree species would provide useful information for the characterization of agroforestry systems and detecting invasive species. Our objective was to study tree species classification in a diverse tropical landscape using IS and ALS data at the tree crown level, with primary interest in the exotic tree species. We performed multiple analyses based on different IS and ALS feature sets, identified important features using feature selection, and evaluated the impact of combining the two data sources. Given that a high number of tree species with limited sample size (499 samples for 31 species) was expected to limit the classification accuracy, we tested different approaches to group the species based on the frequency of their occurrence and Jeffries–Matusita (JM) distance. Surface reflectance at wavelengths between 400–450 nm and 750–800 nm, and height to crown width ratio, were identified as important features. Nonetheless, a selection of minimum noise fraction (MNF) transformed reflectance bands showed superior performance. Support vector machine classifier performed slightly better than the random forest classifier, but the improvement was not statistically significant for the best performing feature set. The highest F1-scores were achieved when each of the species was classified separately against a mixed group of all other species, which makes this approach suitable for invasive species detection. Our results are valuable for organizations working on biodiversity conservation and improving agroforestry practices, as we showed how the non-native Eucalyptus spp., Acacia mearnsii and Grevillea robusta (mean F1-scores 76%, 79% and 89%, respectively) trees can be mapped with good accuracy. We also found a group of six fruit bearing trees using JM distance, which was classified with mean F1-score of 65%. This was a useful finding, as these species could not be classified with acceptable accuracy individually, while they all share common economic and ecological importance.

12 October 2015 in Remote Sensing
Verified
Journal Article
Open access
PDF file
Elfatih Abdel-RahmanElfatih Abdel-Rahman
Elfatih Abdel-Rahman
DMDavid Makori
David Makori
Tobias LandmannTobias Landmann
Tobias Landmann
RPRami Piiroinen
Rami Piiroinen
SGSeif Gasim
Seif Gasim
SRSuresh K. Raina
Suresh K. Raina
Knowledge of the floral cycle and the spatial distribution and abundance of flowering plants is important for bee health studies to understand the relationship between landscape and bee hive productivity and honey flow. The key objective of this study was to show how AISA Eagle hyperspectral data and random forest (RF) can be optimally utilized to produce flowering and spatially explicit land use/land cover (LULC) maps for a study site in Kenya. AISA Eagle imagery was captured at the early flowering period (January 2014) and at the peak flowering season (February 2013). Data on white and yellow flowering trees as well as LULC classes in the study area were collected and used as ground-truth points. We utilized all 64 AISA Eagle bands and also used variable importance in RF to identify the most important bands in both AISA Eagle data sets. The results showed that flowering was most accurately mapped using the AISA Eagle data from the peak flowering period (85.71%–88.15% overall accuracy for the peak flowering season imagery versus 80.82%–83.67% for the early flowering season). The variable optimization (i.e., variable selection) analysis showed that less than half of the AISA bands (n = 26 for the February 2013 data and n = 21 for the January 2014 data) were important to attain relatively reliable classification accuracies. Our study is an important first step towards the development of operational flower mapping routines and for understanding the relationship between flowering and bees’ foraging behavior.