bise {phenex} | R Documentation |
Best index slope extraction
Description
Reduces noise in NDVI time-series. Second interpretation of bise algorithm.
Usage
bise(x, slidingperiod, growthFactorThreshold, cycleValues)
Arguments
x |
An object of class ‘NDVI’ containing raw NDVI values. |
slidingperiod |
Sliding Period of the BISE-algorithm, default value is 40. |
growthFactorThreshold |
Maximum allowed increase per day as factor, default value is 0.1 (increase of 10 percent). |
cycleValues |
A boolean value determining whether the end of the ndvi timeserie is combined with its beginning or not (default value is true). If false, gaps or low ndvi values at the beginning of timeserie influence the resulting timeserie. |
Details
Knowledge regarding the phenological cycle in temperate climates and its temporal evolution is used to detect and eliminate cloud contaminated observations. As the algorithm is searching forward within daily NDVI observations over 1 year, decreases are only accepted if no higher value is found within a so called sliding period. A period of 40 days proved best for our study area but might have to be modified when study areas in different climates are investigated.
Value
An object of class ‘NDVI’ containing raw and corrected NDVI values.
Author(s)
Daniel Doktor, Maximilian Lange
References
Viovy, N., Arino, O. and Belward, A.S. (1992). The Best Index Slope Extraction (BISE) - a method for reducing noise in NDVI time-series. International Journal of Remote Sensing, 13, 1585-1590.
See Also
Examples
# load data
data(avhrr)
# create NDVI object
ndvi <- new("NDVI", values=avhrr.ndvi/10000, year=as.integer(1995))
# correct values (bise)
ndvi.bise <- bise(ndvi, slidingperiod=40, growthFactorThreshold=0.1)
#plot
plot(ndvi.bise)