"im" to represent a two-dimensional pixel image.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.
im,
Kmeasure,
setcov,
plot.im,
eval.im,
lookup.im