| im.object {spatstat} | R Documentation |
A class "im" to represent a two-dimensional pixel image.
An object of this class represents a two-dimensional pixel image. It specifies
If X is an object of type im,
it contains the following elements:
v | matrix of values |
dim | dimensions of matrix v |
xrange | range of x coordinates of image window |
yrange | range of y coordinates of image window |
xstep | width of one pixel |
ystep | height of one pixel |
xcol | vector of x coordinates of centres of pixels |
yrow | vector of y coordinates of centres of pixels |
Users are strongly advised not to manipulate these entries directly.
Objects of class "im"
may be created by the function
im. They are also returned by the functions
Kmeasure and
setcov.
Image objects may be displayed using the methods
plot.im, image.im, persp.im
and contour.im. There are also methods
summary.im for summarising an image,
mean.im for calculating the average pixel value, and
hist.im for plotting a histogram of pixel values.
Values of an image may be looked-up using
lookup.im or using the subset operator [.im.
Calculations involving one or more images (for example,
subtracting one image from another) can often be done
easily using eval.im.
Note that the row index of the matrix v corresponds
to increasing y coordinate, while the column index of m
corresponds to increasing x coordinate. Thus a correct
display of the image would be obtained by transposing, e.g.
image.default(xcol, yrow, t(im)), if you wanted to do it by hand.
The internal representation of images is likely to change in the next release of this package.
Adrian Baddeley adrian@maths.uwa.edu.au http://www.maths.uwa.edu.au/~adrian/ and Rolf Turner rolf@math.unb.ca http://www.math.unb.ca/~rolf
im,
Kmeasure,
setcov,
plot.im,
eval.im,
lookup.im