Hi Miltinho,
the package name is EBImage, not EPImage, but actually I do not
understand what you want to obtain (what are Haralick texture images?)
and what you also want to achieve finally.
Haralick features (not images) are calculated for each individual
object
in an image (not for an image as a whole) from the corresponding
co-occurrence matrices. There are 13 of them implemented in the
package.
So for each individual object in an image you can get at most 13
values
(or if you really need those - 13 co-occurrence matrices), for n
objects
in an image you can get a matrix of n*13 values, which you can obtain
with 'haralickFeatures' *after* you have segmented and indexed all the
objects. Objects are indexed by positive *integer* numbers instead of
pixel color values with 0 being background, and 1, 2, 3 etc - being
objects - in your example, therefore, io will never be indexing
objects
- as there a very low chance to get 1 and it is impossible to get
anything higher (to have at least one object)! You can correct your
example to generate some random objects, e.g. in the following way:
io<-round(as(ii,"IndexedImage")*5)
> table(io)
io
0 1 2 3 4 5
1020 2060 1940 1949 1964 1067
Then it is also not clear what you want to achieve with nc=3 - this
basically tells the script to reduce the number of colors that encode
image to 3! Have you seen any photographic image made in 3 colors or
shades of gray?
Finally, why do you need the matrices? Sure one can calculate further
statistics on those, not described by Haralick, but well some work was
put into deriving those 13 and already the last 3 have no name as they
do not have much of a meaning - just numbers - so do you want to
derive
new ones? Good luck if so, if not, then you only need those 13 numbers
(calculated on say nc=256, i.e. 256x256 matrices instead of 3x3
matrices, which in amount of information account to less than 13
features).
> hr<-haralickMatrix(io, ii, nc = 3)
> hr
, , 1
[,1] [,2] [,3]
[1,] 1 0 0
[2,] 0 0 0
[3,] 0 0 0
, , 2
[,1] [,2] [,3]
[1,] 1 0 0
[2,] 0 0 0
[3,] 0 0 0
, , 3
Regards,
Oleg
Milton Cezar Ribeiro wrote:
> I Dear all,
>
> I just started to use EPImage package. I am looking for to generate
Haralick texture images from a greyscale image.
>
> I have an greyscale image like the simulated below, and my intention
is to generate a set of texture image, where each pixel of an image is
the estimated texture measure. The output images will be used a
modeling approach as input image.
>
> ii<-as.Image(matrix(runif(10000),nc=100))
> io<-as(ii,"IndexedImage")
> hr<-haralickMatrix(io, ii, nc = 3)
>
> Any suggestion are welcome
>
> Kind regards
>
> Miltinho
> Brazil
>
>
>
> para armazenamento!
>
> [[alternative HTML version deleted]]
>
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--
Dr Oleg Sklyar * EBI-EMBL, Cambridge CB10 1SD, UK * +44-1223-494466
