| Dereferencing a Pointer Array [message #24972] |
Tue, 01 May 2001 10:59 |
Art Burden
Messages: 2
Registered: May 2001
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Junior Member |
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Hi,
I have a structure that contains a pointer array that points to twelve
512-by-512 images. I would like to find the mean image from the twelve
images in a simple and fast way. I understand that I can dereference
the pointer to an image or an individual element in an image by using,
for example
img = (*info.images[0])
and
img_element = (*info.images[0])[240,240]
but I can't figure out a way to dereference the pointers to all 12 pixel
values from a given coordinate in one step. At this stage, I pass the
structure into my averaging subroutine and I create a new array to
store the 12 images. I then fill the array by dereferencing the pointer
to each image in a loop. Finally, I loop through the rows and columns
to get each mean pixel value, as shown below. Can anyone think of a
better (mainly faster) way to do this?
;retrieve array of images
ffim = lonarr(12,512,512)
for num=0,11 do ffim[num,*,*] = *info.images[num]
;calculate mean of images
mean_ff = fltarr(512,512)
for ir = 0,511 do for ic = 0,511 do mean_im[ic,ir] = mean(ffim[*,ic,ir])
I greatly appreciate your help with this,
Art
aburden@mpl.ucsd.edu
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