আইডিএল/নমুনা প্রোগ্রাম

pro center

image=read_bmp('C:\Users\Zilee\IDLWorkspace\Images\20031025_064105.bmp')

rimage=rebin(image,504,508)

x=504

y=508

z=256

p=200

q=p+1

finding x center

for j=p,y-q do begin

 s=0

 for i=0,x-1 do begin

   a=i*long(rimage(i,j))

   s=s+a

 endfor

 d=total(rimage(*,j))

 r=s/d

endfor

xcenter=mean(r)

print, 'xcenter'

print, xcenter

finding y center

for j=p,x-q do begin

 s=0

 for i=0,y-1 do begin

   a=i*long(rimage(j,i))

   s=s+a

 endfor

 d=total(rimage(j,*))

 ry=s/d

endfor

ycenter=mean(ry)

print, 'ycenter'

print, ycenter

shifting image to the calculated center

xshift=xcenter-(x/2-1)

yshift=ycenter-(y/2-1)

simage=shift(rimage,xshift,yshift)

window, 0, xsize=504, ysize=508

tvscl,simage

finding radius of shifted image

xc=round(xcenter)

yc=round(ycenter)

dia1=0

dia2=0

for m=0,500 do begin

 if simage(xc,m) gt 1 then dia1=dia1+1

 if simage(m,yc) gt 1 then dia2=dia2+1

endfor

radius=(dia1+dia2)/4

print, 'radius'

print, radius

image creation using distance function

dimg=dist(x,y)

sdimg=shift(dimg,x/2,y/2)

onion pilling of the Sun

rad=0

img=float(simage)

for i=0,26 do begin

 index=where((sdimg gt rad) and (sdimg le rad+8))

 sd=stddev(img(index))

 avg=mean(img(index))

 nring=where(img le avg+2*sd) or (img ge avg-2*sd)

 ringavg=mean(img(nring))

 ;print,ringavg

 img(index)=ringavg

 rad=rad+z/32

endfor

img(where(img eq 0))=1

window,1,xsize=504,ysize=508

tvscl, img

correcting to get perfect limb darkening

ringimage=(float(simage)/img)

window,2,xsize=504,ysize=508

tvscl, ringimage

end