Adaptive thresholding

Description

Thresholds an image using a moving rectangular window.

Usage

thresh(x, w=5, h=5, offset=0.01)

Arguments

Details

This function returns the binary image resulting from the comparison between an image and its filtered version with a rectangular window. It is equivalent of doing {f = matrix(1, nc=2*w+1, nr=2*h+1) ; f=f/sum(f) ; x>(filter2(x, f)+offset)} but slightly faster. The function filter2 provides hence more flexibility than thresh.

Value

An Image object or an array, containing the transformed version of x.

Author(s)

Oleg Sklyar, osklyar@ebi.ac.uk, 2005-2007

See Also

filter2

Examples

  x = readImage(system.file('images', 'nuclei.tif', package='EBImage'))
  display(x)
  y = thresh(x, 10, 10, 0.05)
  display(y)

Results

R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)

R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.

R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

> library(EBImage)
> png(filename="/home/ddbj/snapshot/RGM3/R_BC/result/EBImage/thresh.Rd_%03d_medium.png", width=480, height=480)
> ### Name: thresh
> ### Title: Adaptive thresholding
> ### Aliases: thresh
> ### Keywords: manip
> 
> ### ** Examples
> 
>   x = readImage(system.file('images', 'nuclei.tif', package='EBImage'))
>   display(x)
Only the first frame of the image stack is displayed.
To display all frames use 'all = TRUE'.
>   y = thresh(x, 10, 10, 0.05)
>   display(y)
Only the first frame of the image stack is displayed.
To display all frames use 'all = TRUE'.
> 
> 
> 
> 
> 
> dev.off()
null device 
          1 
>