;+ ; Project : SOHO - CDS ; ; Name : CONNECT ; ; Purpose : Find objects of connected pixels in a binary image ; ; Explanation : Counts the groups of 8-connected pixels in a ; binary image. Object pixels must have value 1, ; zero otherwise. ; ; Use : IDL> connect, array [, nobj, npix, /debug] ; ; Inputs : array - binary image array ; ; Opt. Inputs : None ; ; Outputs : None ; ; Opt. Outputs: nobj - the number of objects found ; npix - the total number of object pixels ; ; Keywords : DEBUG - prints out the details of the pixel runs ; associated with each object and displays ; the array with one pixel in each detected object ; highlighted ; ; Calls : None ; ; Common : None ; ; Restrictions: Uses an intermediate text file 'Connect_run_data', ; user must have privilege to write this file. ; ; Side effects: Sometimes has trouble if objects occur on the edges of the ; array ; ; Category : Image processing ; ; Prev. Hist. : Based on algorithm by Thanisch et al (1984) ; Image and Vision Computing, Vol 2, No 4, Pg 191 ; ; Written : C D Pike, RAL, 28-Jun-00 ; ; Modified : ; ; Version : Version 1, 28-Jun-00 ;- pro prep_image,arr,tr s = size(arr) nx = s(1) ny = s(2) openw,lun,'Connect_run_data',/get_lun tr = 0 for i=0,ny-1 do begin x = arr(*,i) lhs = where(x-shift(x,1) eq 1,cl) rhs = where(x-shift(x,-1) eq 1,cr) n = n_elements(lhs) printf,lun,i+1,cl if cl gt 0 then begin for kk=0,cl-1 do begin printf,lun,lhs(kk),' ',rhs(kk) endfor endif tr = tr + cl endfor free_lun,lun end function touching, ptr1, ptr2 common alldata, run, obj, component, stack, $ oldrhead, newrhead, newrun, oldrun, rear, $ count, objavail, runavail, $ mergecount, prevobj, objhead, objptr, $ lun_data, temp2, temp3 common arrsize, totalcolumns, totalruns if (run(ptr1).lhs le run(ptr2).rhs+1) and $ (run(ptr1).rhs ge run(ptr2).lhs-1) then begin return,1 endif else return,0 end pro getrun, ptr common alldata, run, obj, component, stack, $ oldrhead, newrhead, newrun, oldrun, rear, $ count, objavail, runavail, $ mergecount, prevobj, objhead, objptr, $ lun_data, temp2, temp3 common arrsize, totalcolumns, totalruns ptr = runavail runavail = run(runavail).rnext run(ptr).object = 0 run(ptr).rnext = 0 end pro getobj, ptr common alldata, run, obj, component, stack, $ oldrhead, newrhead, newrun, oldrun, rear, $ count, objavail, runavail, $ mergecount, prevobj, objhead, objptr, $ lun_data, temp2, temp3 common arrsize, totalcolumns, totalruns ptr = objavail objavail = obj(objavail).obnext obj(ptr).first = 0 obj(ptr).last = 0 obj(ptr).newlabel = ptr obj(ptr).obnext = 0 end pro freeobj, ptr common alldata, run, obj, component, stack, $ oldrhead, newrhead, newrun, oldrun, rear, $ count, objavail, runavail, $ mergecount, prevobj, objhead, objptr, $ lun_data, temp2, temp3 common arrsize, totalcolumns, totalruns obj(ptr).obnext = objavail objavail = ptr end pro getscan common alldata, run, obj, component, stack, $ oldrhead, newrhead, newrun, oldrun, rear, $ count, objavail, runavail, $ mergecount, prevobj, objhead, objptr, $ lun_data, temp2, temp3 common arrsize, totalcolumns, totalruns readf,lun_data,n,k newrun = newrhead ;print,'n,k ',n,k for i=1,k do begin getrun, temp run(newrun).rnext = temp newrun = temp readf, lun_data, a,b run(newrun).lhs = a run(newrun).rhs = b run(newrun).scan = n endfor run(newrun).rnext = rear end pro findtouches common alldata, run, obj, component, stack, $ oldrhead, newrhead, newrun, oldrun, rear, $ count, objavail, runavail, $ mergecount, prevobj, objhead, objptr, $ lun_data, temp2, temp3 common arrsize, totalcolumns, totalruns newrun = run(newrhead).rnext mergecount = 0 while run(oldrhead).rnext ne rear do begin oldrun = run(oldrhead).rnext while run(newrun).rhs le run(oldrun).rhs do begin if touching(newrun,oldrun) then begin obj(run(oldrun).object).istouched = 1 run(newrun).object = obj(run(oldrun).object).newlabel endif newrun = run(newrun).rnext endwhile if touching(newrun,oldrun) then begin obj(run(oldrun).object).istouched = 1 run(newrun).object = obj(run(oldrun).object).newlabel if touching(newrun,run(oldrun).rnext) then begin mergecount = mergecount + 1 stack(mergecount,1) = run(oldrun).object stack(mergecount,2) = run(run(oldrun).rnext).object updatelabels, run(oldrun).object, run(run(oldrun).rnext).object endif endif run(oldrhead).rnext = run(oldrun).rnext run(oldrun).rnext = obj(run(oldrun).object).last obj(run(oldrun).object).last = oldrun if obj(run(oldrun).object).first eq 0 then begin obj(run(oldrun).object).first = oldrun endif endwhile end pro findcomponents common alldata, run, obj, component, stack, $ oldrhead, newrhead, newrun, oldrun, rear, $ count, objavail, runavail, $ mergecount, prevobj, objhead, objptr, $ lun_data, temp2, temp3 common arrsize, totalcolumns, totalruns prevobj = objhead while obj(prevobj).obnext ne 0 do begin objptr = obj(prevobj).obnext obj(objptr).left = 0 if obj(objptr).istouched then begin prevobj = objptr obj(objptr).istouched = 0 endif else begin count = count + 1 component(count) = obj(objptr).last obj(prevobj).obnext = obj(objptr).obnext freeobj, objptr endelse endwhile end pro relabel common alldata, run, obj, component, stack, $ oldrhead, newrhead, newrun, oldrun, rear, $ count, objavail, runavail, $ mergecount, prevobj, objhead, objptr, $ lun_data, temp2, temp3 common arrsize, totalcolumns, totalruns for ptr = mergecount, 1, -1 do begin updatelabels, stack(ptr,1), stack(ptr,2) endfor newrun = run(newrhead).rnext while newrun ne rear do begin if run(newrun).object eq 0 then begin getobj, objptr run(newrun).object = objptr obj(objptr).left = run(newrun).lhs obj(objptr).obnext = obj(objhead).obnext obj(objhead).obnext = objptr endif else begin run(newrun).object = obj(run(newrun).object).newlabel if obj(run(newrun).object).left eq 0 then begin obj(run(newrun).object).left = run(newrun).lhs endif endelse newrun = run(newrun).rnext endwhile end pro mergestore common alldata, run, obj, component, stack, $ oldrhead, newrhead, newrun, oldrun, rear, $ count, objavail, runavail, $ mergecount, prevobj, objhead, objptr, $ lun_data, temp2, temp3 common arrsize, totalcolumns, totalruns objptr = obj(objhead).obnext prevobj = objhead while objptr ne 0 do begin obj(objptr).istouched = 0 if objptr eq obj(objptr).newlabel then begin prevobj = objptr endif else begin run(obj(objptr).first).rnext = obj(obj(objptr).newlabel).last obj(obj(objptr).newlabel).last = obj(objptr).last obj(prevobj).obnext = obj(objptr).obnext freeobj,objptr endelse objptr = obj(prevobj).obnext endwhile end pro updatelabels, obj1, obj2 common alldata, run, obj, component, stack, $ oldrhead, newrhead, newrun, oldrun, rear, $ count, objavail, runavail, $ mergecount, prevobj, objhead, objptr, $ lun_data, temp2, temp3 common arrsize, totalcolumns, totalruns if obj(run(obj1).object).left lt obj(run(obj2).object).left then begin obj(obj2).newlabel = obj(obj1).newlabel obj(obj(obj2).newlabel).newlabel = obj(obj1).newlabel endif else begin obj(obj1).newlabel = obj(obj2).newlabel obj(obj(obj1).newlabel).newlabel = obj(obj2).newlabel endelse end pro initialise common alldata, run, obj, component, stack, $ oldrhead, newrhead, newrun, oldrun, rear, $ count, objavail, runavail, $ mergecount, prevobj, objhead, objptr, $ lun_data, temp2, temp3 common arrsize, totalcolumns, totalruns ; ; initialise ; count = 0 objavail = 1 runavail = 1 for i=totalruns+3,1,-1 do begin obj(i).obnext = i+1 run(i).rnext = i+1 endfor getobj, objhead getrun, oldrhead getrun, rear run(rear).lhs = totalcolumns+2 run(rear).rhs = totalcolumns+2 run(oldrhead).rnext = rear getrun, newrhead run(newrhead).rnext = rear end ;****************************** ; main routine ;****************************** pro connect, array, ncray, npix, debug=debug common alldata, run, obj, component, stack, $ oldrhead, newrhead, newrun, oldrun, rear, $ count, objavail, runavail, $ mergecount, prevobj, objhead, objptr, $ lun_data, temp2, temp3 common arrsize, totalcolumns, totalruns s = size(array) totalcolumns = s(1) if max(array) gt 1 or min(array) lt 0 then begin bell print,'Array must only have binary (0/1) values.' return endif prep_image,array,tr totalruns = tr openr,lun_data,'Connect_run_data',/get_lun rec1 = {rec1a, lhs:0, rhs:0, object:0, scan:0, rnext:0} run = replicate(rec1,totalruns+5) rec2 = {rec2a, left:0, first:0, last:0, newlabel:0, obnext:0, istouched:0b} obj = replicate(rec2,totalruns+5) component = intarr(totalruns+1) stack = intarr(totalcolumns+1,3) initialise ; data file records while not eof(lun_data) do begin getscan findtouches findcomponents relabel mergestore run(oldrhead).rnext = run(newrhead).rnext run(newrhead).rnext = rear endwhile ncray = count nn = where(array gt 0,npix) if keyword_set(debug) then begin temp = array for i=1,count do begin print,'Runs in connected component',i kk = component(i) print,run(kk).lhs,run(kk).rhs,run(kk).scan-1 temp(run(kk).lhs,run(kk).scan-1) = 2 while run(kk).rnext gt 0 do begin kk = run(kk).rnext print,run(kk).lhs,run(kk).rhs,run(kk).scan-1 endwhile print,'=========' endfor print,' ' print,'Number of objects: ',ncray print,'Number of affected pixels: ',npix print,' ' plot_image,temp endif free_lun,lun_data end