Can this be done using CALL_FUNCTION?

[edward.s.meinel(at)aero.org]

OK, here's one for the IDL gurus (since I'm only a little guru would
that make me a gu-gu?)...

I am working with spectral images. Unfortunately, IDL is geared toward
multidimensional data in which all of the dimensions are the same type
(i.e. spatial, spectral, frequency...) but it doesn't like to operate on
data with mixed dimensions, such as a multispectral image (unless I'm
missing something really obvious).

Rather than having to rewrite every bloody function/procedure for
spectral imagery, I was hoping it would be possible to write a generic
wrapper function along the lines of:

FUNCTION spatial_function, name, image, other_stuff
im_size = SIZE(image)
CASE im_size[0] OF
   1: BEGIN        ; vector
      data = CALL_FUNCTION(name, image, other_stuff)
      RETURN, data
   END

   2: BEGIN        ; image
      data = CALL_FUNCTION(name, image, other_stuff)
      RETURN, data
   END

   3: BEGIN        ; spectral image
      CASE true OF
         1: BEGIN                ; BIP
            bands  = im_size[1]
            pixels = im_size[2]
            lines  = im_size[3]
            data   = image
            FOR i = 0, bands - 1 DO BEGIN
               dummy = REFORM(image[i, *, *])
               dummy = CALL_FUNCTION(name, dummy, other_stuff)
               data[i, *, *] = dummy
            ENDFOR
         END

         2: BEGIN                ; BIL
            bands  = im_size[2]
            pixels = im_size[1]
            lines  = im_size[3]
            data   = image
            FOR i = 0, bands - 1 DO BEGIN
               dummy = REFORM(image[*, i, *])
               dummy = CALL_FUNCTION(name, dummy, other_stuff)
               data[*, i, *] = dummy
            ENDFOR
         END

         ELSE: BEGIN                ; BSQ
            bands  = im_size[3]
            pixels = im_size[1]
            lines  = im_size[2]
            data   = image
            FOR i = 0, bands - 1 DO BEGIN
               dummy = REFORM(image[*, *, i])
               dummy = CALL_FUNCTION(name, dummy, other_stuff)
               data[*, *, i] = dummy
            ENDFOR
         END
      ENDCASE
      RETURN, data
   END

   ELSE: BEGIN        ; error
      data = DIALOG_MESSAGE('The input array is not an image.')
      RETURN, 0
   END

END

Then I could do things like:

hist = SPATIAL_FUNCTION('histogram', image)
mw = SPATIAL_FUNCTION('median', image, 5)

Is there any hope for me???

Ed Meinel


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