Histogram Equalization in IDL

;####################################################
;                       Histogram Equalization
;                  Author : S.Ganesh Babu
;####################################################

PRO EX12

file = DIALOG_PICKFILE(PATH='E:\Image')
im = READ_IMAGE(file)
sz=SIZE(im,/DIMENSIONS)
nv=SIZE(sz,/DIMENSIONS)

nim=HIST_EQUAL(im)

IF nv EQ 2 THEN BEGIN
WINDOW,0,XSIZE=sz[0],YSIZE=sz[1],TITLE='INPUT IMAGE'
TVSCL,im
WINDOW,1,XSIZE=sz[0],YSIZE=sz[1],TITLE='Histogram Equalization'
TVSCL,nim
ENDIF ELSE BEGIN
WINDOW,0,XSIZE=sz[1],YSIZE=sz[2],TITLE='INPUT IMAGE'
TVSCL,im,TRUE=1
WINDOW,1,XSIZE=sz[1],YSIZE=sz[2],TITLE='Histogram Equalization'
TVSCL,nim,TRUE=1
ENDELSE
END