Image segmentation-Region growth algorithm and IDL implementation

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1. Principle of Regional growth algorithm

Reference: wiki entry area growth algorithm;

From seed point seed, traverse the 4 neighborhood of the seed, and if a neighborhood pixel conforms to the threshold setting, it is scaled as a growth point and inserted into the seed queue as a new growth seed, and the old seed is removed until the seeded column is empty, and the pixel space (a picture) is split. As shown, the red lattice is the initial seed;

　　

2. Example of Regional growth

　　　　　　

3. Code implementation

Note: Development language for IDL,ENVI 4.8 version of the own development language

Regional Growth algorithm class file Regiongrow__define.pro

1FUNCTION Regiongrow::init, Region=region, seeds=seeds2   3Self._region= Ptr_new (/allocate_heap);4* (self._region) =Region ;5   6dims = size (region,/DIMENSIONS);7Self._width= dims[0];8Self._height= dims[1];9   TenSelf._ifront=0L; OneSelf._iback=n_elements (seeds); ASelf._seeds= Ptr_new (/allocate_heap); -* (self._seeds) = Make_array (self._width* Self._height,/long, value=0); -(* (self._seeds) [Indgen (self._iback)] =seeds; the    -Self._hseeds= HASH (seeds, make_array (self)._iback,/byte, value=0)); -    -RETURN,1 +    - END +  A PRO regiongrow::setthreshold, mint, Maxt atSelf._mint=Mint; -Self._maxt=Maxt; - END -  - FUNCTION regiongrow::isgrowable, Value -RETURN, (self._mintLe value && value le self._maxt) in END -  to FUNCTION regiongrow::hasseeds +RETURN, (self._ifrontLT self._iback); - END the  * FUNCTION regiongrow::isnotseed, index $RETURN, (self._hseeds). Haskey (Index) EQ0);Panax Notoginseng END -  the FUNCTION regiongrow::p opseed +Seed = (* (self._seeds)) [Self._ifront]; ASelf._ifront= self._ifront+1; the RETURN, seed; + END -  $ PRO regiongrow::p ushseed, Index $(self.)_hseeds) [Index] =0; -(* (self._seeds)) [Self._iback] =index; -Self._iback= self._iback+1; the END - Wuyi FUNCTION Regiongrow::grow the      -Growimg = Make_array (self._width, self._height,/byte, value=0); WuK =0; -while (self->hasseeds ()) Do BEGIN AboutK = +1; $;Print,"==========================>", K; -Seed = self->popseed (); -i = Floor (seed/self._width); -j = seed-i * self._width; AGrowimg[j,i] =255; +         the        ;;;;; Left -index = seed-1; $IF (J-1GE0) && (Self->isnotseed (index)) && self->isgrowable ((* (self)._region)) [J-1, I]) Then BEGIN theSelf->pushseed, index; the ENDIF the         the        ;;;;; Right -index = seed +1; inIF ((j+1) LT self._width) && (Self->isnotseed (index)) && self->isgrowable ((* (self)._region)) [j+1, I]) Then BEGIN theSelf->pushseed, index; the ENDIF About         the        ;;;;; up theindex = seed + self._width; theIF ((i+1) LT self._height) && (Self->isnotseed (index)) && self->isgrowable ((* (self)._region)) [j,i+1] then BEGIN +Self->pushseed, index; - ENDIF the        Bayi ;;;;;D OWN theindex = seed-self._width; theIF ((I-1) GE0) && (Self->isnotseed (index)) && self->isgrowable ((* (self)._region)) [j,i-1] then BEGIN -Self->pushseed, index; - ENDIF the         the Endwhile the      the RETURN, Growimg -      the END the  the PRO Regiongrow::cleanup94    the* (self._region) = ! NULL; the    thePtr_free, self._seeds;98    AboutDelvar, self._seeds; -Delvar, self._hseeds;101   102 RETURN103 END104  the PRO Regiongrow__define106 107struct = {Regiongrow,_region:P tr_new (),_seeds:P tr_new (),_hseeds: HASH (),_ifront:0L,_iback:0L,_width:0L,_height:0L,_mint:0,_maxt:0}108 RETURN109END

Regional Growth test main function file Region.pro

1 PRO Region2Grayimg = Read_tiff ('D:\ndvi.tif');3 ; help, Grayimg .4Seeds = WHERE (grayimg EQ221);5   6Executer = Obj_new ("Regiongrow", Region=grayimg, seeds=seeds);7Executer.setthreshold,186, the;8St = SYSTIME (1);9result =Executer.grow ();TenET = SYSTIME (1); One Help , result; A   Print,"=====================>time:", (et-St); -; im =IMAGE (result); -    theGR = Make_array (3,2048,1024x768,/byte, value=0); -Fr0, *,*] = result[*,*]; -Fr1, *,*] = result[*,*]; -Fr2, *,*] = result[*,*]; +Write_jpeg,"grow.jpg", GR,/TRUE -END

The results of the split water test are as follows:

　　　　

Image segmentation-Region growth algorithm and IDL implementation