Ridler: Analyzing canopy pictures

In Sky: Canopy Openness Analyzer Package

Description

Ridler uses the Ridler and Calvard algorithm (1978) to iterativelly find the threshold for each picture in order to calculate the proportion of sky (canopy openness) in one picture. The function can also display the original picture, the gray-scale picture, and the final picture (once the threshold is applied). This function was inspired by the matlab work of Jose Suau Rodriguez.

Usage

Ridler(Original, pixel, p = TRUE)

Arguments

Original	is the original picture to analyze
pixel	Indicates the number of pixel of the hemispherical picture. If not given, Ridler will use the total number of pixel detected.
p	if p==TRUE, three pictures are displayed: the original, the gray version, and the final version.

Value

the value corresponds to the proportion of sky (canopy openness).

Author(s)

Benedicte Bachelot

References

Ridler, T.W. & Calvard, S. (1978). Picture thresholding an iterative selection method. IEEE transactions on Systems, Man and Cybernetics, 8(8), 630-632.

Examples

data(Original_ex)
Ridler(Original_ex,p = TRUE) 

Example output

Loading required package: EBImage
Only the first frame of the image stack is displayed.
To display all frames use 'all = TRUE'.
Only the first frame of the image stack is displayed.
To display all frames use 'all = TRUE'.
[1] 0.04738765

Sky documentation built on May 2, 2019, 2:50 p.m.