Current issue: 58(5)
Select issue
Silva Fennica 1926-1997
1990-1997
1980-1989
1970-1979
1960-1969
1950-1959
1940-1949
1926-1939
Acta Forestalia Fennica
1992-1999
1984-1991
1974-1983
1968-1973
1953-1968
1933-1952
1913-1932
Articles containing the keyword 'relative error'
Category : Research note
article id 1114,
category
Research note
(2014).
Measurement errors in the use of smartphones as low-cost forestry hypsometers.
Silva Fennica
vol.
48
no.
5
article id 1114.
https://doi.org/10.14214/sf.1114
Highlights:
We analysed two smartphones (HTC Desire and Samsung Galaxy Note) to determine the errors in the height measurements; The calibration included with the Android applications is insufficient; After appropriate calibration, the smartphone errors are similar to other forest hypsometers (Blume Leiss and Vertex).
Abstract |
Full text in HTML
|
Full text in PDF |
Author Info
Various applications currently available for Android allow the estimation of tree heights by using the 3D accelerometer on smartphones. Some make the estimation using the image on the screen, while in others, by pointing with the edges of the terminal. The present study establishes the measurement errors obtained with HTC Desire and Samsung Galaxy Note compared to those from Blume Leiss and Vertex IV. Six series of 12 measurements each were made with each hypsometer (for heights of 6 m, 8 m, 10 m and 12 m). A Kruskall Wallis test is applied to the relative errors to determine whether there are significant differences between the devices. The results indicate that the errors of the uncalibrated smartphones significantly exceed those of traditional forestry apparatus. However, calibration is a very easy procedure that can be done by means of a linear regression line between real angles (obtained with a Digital Angle Finder or with a series of measurements taken independently of the experiment), and the angles of the accelerometer. With this adjustment, the smartphones achieve adequate quality levels although the bias was not totally eliminated. The relative errors when pointing with the edges of the terminal show no significant differences compared to Blume Leiss. Applications that use the screen image give better results (no significant differences were detected with Vertex). There is currently no application that offers calibration of the linear regression slope, which is an essential requirement for ensuring the accuracy of height measurements obtained with smartphones.
-
Villasante,
Agroforestry Departament, Universitat de Lleida, Av. Rovira Roure 177, 25198 Lleida, Spain
http://orcid.org/0000-0002-7549-7424
E-mail:
avillasante@eagrof.udl.cat
- Fernandez, Agroforestry Departament, Universitat de Lleida, Av. Rovira Roure 177, 25198 Lleida, Spain E-mail: cfernandez@eagrof.udl.cat
Click this link to register to Silva Fennica.
If you are a registered user, log in to save your selected articles for later access.
Your selected articles
Silva Fennica ·
Finnish Society of Forest Science
