colNarrow {measuRing}

Narrow rings

Description

This function can detect narrow rings in a sequence of tree-ring widths in wood (TRWs). This and other in-package functions are recursively implemented by multiDetect.

Usage

colNarrow(rwidths, marker = 5)

Arguments

rwidths

a dataframe with the ring widths such as that produced by ringWidths.

marker

a number from 1 to 10. Those rings with scaled averages greater than or equal to this argument will be identified as narrow rings.

Details

Each ring is averaged with those rings on either side of it (t-1,t,t+1), and averages are divided by the highest computed average in the sample; such quotients are scaled from 10 (the narrowest possible ring) to one (the broadest ring).

Value

character vector with the columns in gray matrix corresponding to the narrow rings (see ringDetect, multiDetect, andplotSegments).

Author(s)

Wilson Lara, Carlos Sierra, Felipe Bravo

Examples

## (not run) Read one image section in package measuRing:
image1 <- system.file("P105_a.png", package="measuRing")    
## (not run) compute a gray matrix from RGB in the image:
gray <- imageTogray(image = image1,ppi=1000)
## (not run) Columns in gray matrix to be included/excluded:
Toinc <- c(196,202,387,1564) 
Toexc <- c(21,130,197,207,1444,1484)
## (not run) tree-ring widths:
rwidths <- ringWidths(gray,inclu = Toinc,exclu = Toexc,last.yr=2012)
##(not run) narrow rings:
narrows <- colNarrow(rwidths,marker = 8)