| thresh {EBImage} | R Documentation |
Functions to threshold images and color channels of images.
## S4 method for signature 'Image': thresh(x, w=5, h=5, offset=0.01, ...) ## S4 method for signature 'Image': athresh(x, w=10, h=10, offset=0, ...) ## S4 method for signature 'Image': cthresh(x, threshold=0, ...)
x |
An object of Image. For thresh it must be
in the Grayscale mode. |
w, h |
Thresholding frame width and height in pixel. |
offset |
Threshold offset from the mean value. |
threshold |
Threshold value for channel thresholding (uniform). |
... |
Reserved. |
If thresh and athresh are adaptive thresholind functions.
While athresh can be used on both Grayscale and
TrueColor images, thresh can only be used on
Grayscale images, however it is significantly faster on them.
The value of offset in thresh is on the same scale as data, i.e.
the default value is selected assuming data in the range [0,1]. This
value for athresh should be selected empirically, as this function
uses AdaptiveThreshold of ImageMagick and the scale of this
parameter was not documented; the reasonable values are usually in the orders
of 500, 1000 or avobe (at least to obtain similar thresholding to that of
0.01 with thresh on cytomicroscopic images. ).
A new instance of Image in the same color mode as input.
Oleg Sklyar, osklyar@ebi.ac.uk, 2005-2007
ImageMagick: http://www.imagemagick.org.
Image, Image, distmap, segment,
[,Image-method
## see example(watershed)