Computers & GeosciencesVol. 18, No. 9, pp. 1213-1253, 19920098-3004/92 $5.00 + 0.00 Printed in Great Britain. All rights reservedCopyright 1992Pergamon Press Ltd COMPRESSIONOFDIGITIZEDMAPIMAGES DAVID A.SOUTHARD TheMITRECorporationE073, 202BurlingtonRoad,Bedford,MA01730-1420, U.S.A. (ReceivedI0February1992; accepted30April1992) Abstract--An efficient way to storeandretrieve digitized chartimages using alossy vector quantization 0/Q)compressiontechniqueispresented.AVQcodebookislocatedusingthefastpairwisenearest neighbor(PNN)clustering algorithm.Ak-dtree datastructureisused for efficient image compression. Some uniquefeatures of this approachare that compressed files use a predictable amountof storage, and canbedecompressedquicklyfordisplayonequipmentrangingfromportablepersonalcomputersto advancedgraphicsworkstations.Themethodalsoappliestopanchromaticandmultispectralsatellite imagery. In this application, digitized chart images with compression ratios of 24: 1 exhibited good quality. Incertainapplications,even highercompressionratiosarefeasible. KeyWords:Digital mapping,Image compression, Vector quantization,Clustering algorithms, k-dtree. INTRODUCTION Thisinvestigationinto image compression techniques wasmot i vat edbytechnicalissuessurroundingthe designof anaut omat edmissionplanningprogram termedtheAirForceMissionSupport System( AF MSS)(Southard, 1992).Thedisplayof digitized navigationalchartsiscentralt othefunctionof this system. TheDefenseMappi ngAgency(DMA), supplies digitizedchartsoncompact diskread-onlymemory (CDROM) media.Thesegeoreferenceddigitalim- agesaretermedEqualArc-secondRasterChart(ARC)DigitizedRasterGraphics( ADRG) (Defense Mappi ngAgency,1989).Itwasestimatedt hat AF MSS wouldneedon-line about 200 gigahytes (GB)ofADRGdata,initsrawform.Imagecompressionis onestrategyt hat willbeusedtoreducethiscostly storagerequirement.Thetechniquesaredescribed andevaluated,andasetofalgorithmst hat meetsthe goalssetbyAFMSSarepresented.AnANSI C sourcecodeforthesealgorithmsisprovided. Applications Themethodsselectedhavebroadapplicabilityto manyaut omat edmapping, charting,andgeodesy systems.Digitizedchartscanreplacepaperchartsin manydisplayapplications.Digitalmapping,remote sensingandanalysis,computer-aideddesignfor civil engineering,architecture,andenvironmentalanaly- sis,global positioning andnavigation,and geographi- cali nformat i onsystems(GIS),aresomeexamples. Digitizedchartimagesareusefulinmilitarymission planningandcommand, control,andcommuni- cations(C 3)systems. Imagecompressiontechniques Compressiontechniquescanbeclassifiedintotwo br oadcategories:lossless,andlossy.Losslessalgor- ithmsincludesuchwell-knowntechniquesasrun- length coding, quadtree coding, Huffman coding, and theLempei-Zivalgorithm,whichisusedbythe UNI Xcompr essutility(Welch,1984).Alossless algorithmreconstructscompresseddat aexactly toits originalstate.Thedegree ofcompression dependson thecontentof thedata.Ontypicalchart images, losslesstechniquescanachieveuptoabout a2 : 1compressionratio(theratiooftheoriginalimagesize tothecompressedimagesize).Tablelshowsthe compressionof selectedchartandsatelliteimages usingrun-length,Huffman, andLempel -Ai zcoding. I nsomesituations,however,thesecodingschemes increasedthesizeof theimages. Lossy algorithmsadmithighercompressionratios. Lossyalgorithmsincludedifferentialpulsecode modul at i on(DPCM), vector quantization(VQ),and thediscretecosinet ransform(DCT),whichisthe centraltechniqueinthepopul arJ PEGandMPEG standards(RabbaniandJones,1991).Lossyalgor- ithmswilldegradetheoriginalimagesomewhat, dependingontheimagecontent,theamount ofcompression,andthepropertiesofthealgorithm.In manysituations,however,somedegradationisper- missible.Thelossmaybevisuallyimperceptible. Theclassificationandcompressiontechniquest hatare presentedare appropriatefor display andanalysis of manytypesof scientificandengineeringimages. Thelossycharacterof thesealgorithms,however, wouldmaketheminappropriateforarchivaldat a storage,orforsituationst hat requirecompleteaccu- racy.IntheseinstancesIosslessalgorithmsmust be employed.For example,DigitalTerrainElevation Dat a(DTED)suppliedbytheDMAforhillyterrain in centralGermanycanbecompressedtoanaverage compressionratioof 1.7usingHuffmancoding,and 3.4 using Lempel-Ziv coding.It would be inappropri- atetousealossytechnique,becausethiswould 1213 1214D.A.SOUTHARD Table1.Compressionratiosforlossless compressionof selected images Lossless compressionmethod ImageSizeRunlengthHuffmanLempel-Ziv ONC5125120.971.060.99 TPC*1000 x10000.981.101.00 TPC500x5000.971.251.27 JOG1024 10241.021.121.12 TLM512x5120.981.111.06 SPOTt2391x22491.011.711.93 SPOT:~2391x22490.981.040.99 Unlessindicated,imageshavebeen spatiallyfilteredandsubsampled. *RawADRGimage. tRawpanchromatic image,withlittle contrast. ~Processedwithcontraststretch,andspatiallyfilteredtoremoveimaging artifacts. compr omi sethecharact erof thedat a. Arelief- shadedi m a g e of thesedat a, however,canbecom- pressed successfully using the met hods described here. V e c t o r q u a n t i z a t i o nVect orquant i zat i onisageneralmet hodt hat is usedextensivelyforappl i cat i onsinspeechcoding,i magecoding, segment at i on, classification,andrec- ogni t i onprobl ems. Therearemanyformsof VQ,as wellashybri dsof VQwithot her techniques(Abut ,1990;Rabbani andJones,1991).SeveralformsofVQ, al ongwithot her compressi onschemes,have beenpr oposedforcompressi ngdi gi t alchart s(Barad andMart i nez, 1989;Jai si mhaandothers, 1989; Lohr enzandothers, 1990;Pot l apal l i andothers, 1989;Pot l apal l i , Barad, andMart i nez, 1989).Inthis work, severalcompet i ngVQal gori t hmsweretested, eval uat i ngt hemwithanemphasi soni magequal i t y andprocessi ng speed,andthe best techniquesforthis appl i cat i onwereapplied.I n VQ, ani mage is di vi ded i nt osmall units,t ermed v e c t o r s . I nthiscontext, thet ermv e c t o r simply refers toann-t upl e; t hereisnogeomet ri ci nt erpret at i on.Thevect orscompri seagr oupof adj acent i mage pixels.Typi cal l y, avect orisasmallrect angul ar gr oupi ngof f r om2to25pixels.Suppose, fora moment , t hat wehaveapredefinedlistof vectors, namedt hec o d e b o o k . Tocompress, t heent ry is deter- mi nedinthecodebookt hat most closelymat ches eachvect orfromthei nput image.Inot her words,eachi magevect orisclassifiedi nt oacat egoryrep- resentedbyacodebookentry. Theindexof each ent r yissavedinthecompressedimage.Todecom- press,eachindexisusedtol ook- upavect orinthe codebookandreassembl etheimage.Vectorquan- t i zat i onhasseveralsalientcharacteristicst hat dis- t i ngui shi t f r omtheot her compressi onal gori t hms,andwhichmakeVQideallysuitedforaut omat ed mappi ngsystems: A s y m m e t r i c . Near l yallthecomput at i onassoci- at edwithcompressi onanddecompressi onfalls on thesideofcompressi on. Imagereconst ruct i onisa fastt abl el ook- upoperat i on. Most ot hercom- pressional gori t hmstendtorequireabout asmuch comput etimefordecompressi onasforcom- pression(cf.Rabbani andJones,1991). E f f i c i e n t . Thecompressi onstagecompri sestwo steps: codebook devel opment ,andthe compressi on itself.Oncethereisacodebookforaclassofimages,suchasforapar t i cul ar t ypeof chart , the codebookcanbereusedtocompressanyi magein t hat class.Al t houghcodebookdevel opment isin- tensive comput at i onal l y,compressi on is simple and quick. P r e d i c t a b l e . Thecompressi onrat i odoesnotchange from i mage toimage.The size ofthe vectors andthelengthof t hecodebookdet ermi net he amount of compression. Thispr oper t ysimpli- fiesdiskspacemanagement onaheavilyl oaded system. F l e x i b l e . Thedecompressi on canbet ai l ored tothe localresources,rangi ngfromaPCwithaSuper- VGAcard, toasupergraphicswor kst at i onwitha hi gh-resol ut i ondisplay. Thesamecompressedfile canbedecompressedforagray-scaledisplay, an 8-bit (256colors) l ook- upt abl edisplay,or a24-bit RGB(16.8mi l l i oncolors)display. Thi sadapt a-bi l i t y requires onl y t hat we modi f y the VQl ook- up t abl easappr opr i at e. Thereisnoneedtocompress theimagedifferentlyforeachsi t uat i on.R a n d o m - a c c e s s . Manyal gori t hmsrequiredecom- pressiontocont i nuefrombeginningtoendina predet ermi nedway.Themet hoddescri bedcan begin atany poi ntinthe compressedimage, andgo inanydirection.F i l t e r i n gDigitizedchart imagesmaycont ai ntwointerest- ing,but undesi rabl e, artifacts.Chart susuallyare pr i nt edusingonl yafewcol orsof ink.Int ermedi at e shadesarereproducedwiththehal f-t onepri nt i ng process,inwhichar r aysof tinydot sof inkreplicate i nt ermedi at etonesof color. Whendigitizedwithan opt i cal scanningprocess, thehal f-t onedareas appears t i p p l e d . Thestipplecanbestbedescribedasa Compressionof digitized mapimages1215 7Y vqntvqoo.pvq,xp@ vq' .p vq,n,,@ Figure1.Overview of vectorquantizationimage compression. salt-and-peppertextureinthebackgroundareas.The cart ographeroriginallyintendedtheseareastol ook likeaconst ant shadeof color. Thesecondartifactisaninteractionof thehalf- tone printingscreens withthe implicit arrayofoptical samples,whichproducesamoir# patterninthese areas.Thiseffectisunderst oodasabeatingof the spatialfrequencyof thepixelarrayagainstthoseofthehalf-tonescreens.Themoir6patterncanbe distinct. I f eitherof theseartifactsarepresent,theimage shouldbefilteredbeforecompression.Byfiltering beforecompression,stippleandmoir6canbeelimi- nated,andthelegibilityof thedecompressedimage increased.Filteringmaybeaccomplishedbyreplac- ingeachpixelbyaweightedaverageofpixelsinits immediatenei ghborhood, asdiscussedbyPratt (1991)orbyGonzalezandWintz(1987).Eight differentfiltersweretested,andthebestresultswere obtainedwithaseparable,piecewisecubicfilterofMitchellandNetravali(1988).Aseparablefilter responsefunctionintwodimensionsisF( x, y) = f (x)f (y), wherexandyrepresentthehorizontaland verticaldistancesfromasamplepoint,measuredin pixelintervalsfromthesamplepoint.Tofilter,the weightedsumofallpixelst hat fallwithinthefilter's radiusiscalculated,wheretheweightsaredeter- minedbythefilterresponsefunction,thenare normalizedbydividingbythesumof theweights. Separablefilterscanbeusedbot hforsubsampling andinterpolatingimages.Because they are calculated usinganalyticalfunctions,eitherintegralornon- integralsamplingfatorscanbeused.Theequation forMitchellandNetravali' sfamilyof cubicfilters is: whereB andCare parameterst hat define aparticular cubicspline.MitchellandNetravalirecommended thevalues(B,C)=(1, !) 3"Overview ofVQcompression Figure1illustratestheimagecompressionpro- cedure.Theimageisconvertedfromthedistribution mediatothelocalfilesystem.Afterfiltering,if needed,arepresentativesubset ofvectors is extracted, andassembledintoatrainingimage.Thecodebook developmentprogram, vqinit,analyzesthetraining imaget odetermineacodebook. Then,theprogram vqeompusesthecodebook tocompressoneormore imagesfromtheclassrepresentedbythetraining image.Asanoptionalseparatestep,vqinitgenerates acolortable,andvqcmapusesthecolortableto color-mapthecodebook. Thedecompressionpro- gram,vqexp(VQ-expand),takesthecodebookand the compressed image,andassemblesan image file. A displayprogram, specifictothelocalenvironment, readstheimage,andforcolor-mappedimages,also readsthecolortable,andwritestheimagetothe comput erdisplay. CODEBOOKDEVELOPMENT Thekey toVQis the methodby which acodebook isobtained.Thecodebookdeterminesthequalityofthereconstructedimage.Thecodebookislocatedby aprocesstermedclustering. Oneormoretraining imagesisanalyzedtolocateacodebookt hat will minimizeadistortionmeasureforthecompressed image.Thetrainingimagesrepresenttheclassofimagest obecompressedwiththecodebook. The 1 ((12-9B -6C) l xl3 +( - 18 +12B +6C) l xl2 +(6 -2B) f ( x) =g ~ ( - B -6C)1xl3 +(6B+30C)lxl2+ ( - 12B-48C)lxl+(8B+24C) ifIxl n o d e . s p l i t . i n d e x =-1; t r e e - > n o d e . s p l i t . l e f t =N U L L ;t r e e - > n o d e . s p i l t . r i g h t =N U L L ;b r e a k ;d e f a u l t :f p r i n t f (s t d e r r ,e x i t (E R R O R 1; }r e t u r n (t r e e 1; /*i n i t i a l i z e s p l l t n o d e * /E r r o r i s n e w n o d e : u n k n o w n n o d e t y p e \ n " ); / *. . . . . . . . . . . . . . . . . . . . . . * //*n e w c l u s t e r */ / * . . . . . . . . . . . . . . . . . . . . . . * /* n e w c l u s t e r (/*a l l o c a t e a n d I n l t an e w c l u s t e r * /l o n g h u m , /*n u m b e r o f v e c t o r s a c c u m u l a t e d */ l o n g e r r , /*t o t a l e r r o r I n c l u s t e r */ s h o r t * v e c t o r )/*p o i n t e r t o b l o c k o f s i z e c l u s t e r _ s l z e * /C l u s t e r *c;/*p o i n t e r t o n e w c l u s t e r * /c=( C l u s t e r *)m y a l l o c (s l z e o f ( C l u s t e r ) ) ;c - > n =h u m ;c - > e r r o r = e r r ;c - > a r r a y = ( s h o r t *)m y a l l o c (c l u s t e r _ s l z e *s l z e o f (s h o r t )1; m e m c p y (c - > a r r a y , v e c t o r , c l u s t e r _ s l z e *s i z e o f (s h o r t )1; n _ c l u s t e r s + + ;r e t u r n (c1; / *. . . . . . . . . . . . . . . . . . . . . . * //*m a t c h */ I *. . . . . . . . . . . . . . . . . . . . . . * I# d e f i n e N O T _ F O U N D (-11 l o n g m a t c h ( K D T r e es h o r t{r e g i s t e rr e g i s t e r* t r e e ,* v e c t o r ) /*s e a r c h b u c k e t f o r m a t c h l n g c l u s t e r * //*p o i n t e r t o b u c k e t n o d e * //*p o i n t e r t o v e c t o r t o m a t c h */ i; J ;/*o u t e r l o o p c o u n t e r : c l u s t e r i n d e x */ /*i n n e r l o o p c o u n t e r : v e c t o r e l e m e n t i n d e x */ f o r (I=0;inode.bucket.count;i + + ) {f o r (J=0;J n o d e . b u c k e t . c l u s t e r [ i] - > a r r a y [ J] v e c t o r [ J])b r e a k ;) i f (J= = c l u s t e r _ s l z e )r e t u r n (i); )r e t u r n ( N O T _ F O U N D ); I = / *. . . . . . . . . . . . . . . . . . . . . . * // * s p l i t * // * . . . . . . . . . . . . . . . . . . . . . . * /Compressionof digitizedmapimages1231 K D T r e e{* s p l i t ( K D T r e e * t r e e ) /*s p l i t ab u c k e t i n t o t w o p i e c e s */ r e g i s t e r i;/*l o o p v a r i a b l e */ r e g i s t e r il;/*l e f t b r a n c h c l u s t e r c o u n t e r */ r e g i s t e r Jr;/*r i g h t b r a n c h c l u s t e r c o u n t e r */ l o n g m a x i n d e x ; /*m a x r a n g e o r d i n a t e i n d e x * /l o n g m a x r a n g e ; /*m a x o r d i n a t e r a n g e */ K D T r e e * n e w t r e e ; /*n e w t r e e n o d e */ l o n g r a n g e ; /*c u r r e n t o r d i n a t e r a n g e * /l o n g t h r e s h o l d ; /*s p l i t t h r e s h o l d */ / *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * //*F i n d t h e o r d i n a t e w i t h t h e g r e a t e s t v a r i a n c e * //, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ,/ m a x i n d e x =0; m a x r a n g e =t r e e - > n o d e . b u c k e t . m a x [ 0]-t r e e - > n o d e . b u c k e t . m i n [ 0]; f o r (i=1;i n o d e . b u c k e t . m a x [ i]-t r e e - > n o d e . b u c k e t . m l n [ i]; i f (r a n g e >m a x r a n g e ) {m a x i n d e x =i; m a x r a n g e =r a n g e ;})1". . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * //*I f c l u s t e r s a r e i d e n t i c a l , c o n d e n s e i n t o o n e */ /*c l u s t e r a n d r e t u r n i m m e d i a t e l y */ l *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " 1i f ( m a x r a n g e = = 0) {f o r (i=1;i n o d e . b u c k e t . c o u n t ;i + + ) {t r e e - > n o d e . b u c k e t . c l u s t e r [ 0] - > n + =t r e e - > n o d e . b u c k e t . c l u s t e r [ i]->n; t r e e - > n o d e . b u c k e t . c l u s t e r [ 0] - > e r r o r + =t r e e - > n o d e . b u c k e t . c l u s t e r [ i] - > e r r o r ;f r e e c l u s t e r (t r e e - > n o d e . b u c k e t . c l u s t e r [ i]); )t r e e - > n o d e . b u c k e t . c o u n t =I; r e t u r n (t r e e ); )/ *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * //*O t h e r w i s e , a l l o c a t e an e w s p l i t n o d e , * //*a n d t w o n e w b u c k e t n o d e s , i n i t i a l i z e * // *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * /t h r e s h o l d =(t r e e - > n o d e . b u c k e t . m a x [ m a x i n d e x ]+ t r e e - > n o d e . b u c k e t . m i n [ m a x i n d e x ])/2; n e w t r e e =n e w n o d e (S P L I T ); n e w t r e e - > n o d e . s p l l t . l n d e x =m a x l n d e x ;n e w t r e e - > n o d e . s p l i t . t h r e s h =t h r e s h o l d ;n e w t r e e - > n o d e . s p l i t . l e f t =n e w n o d e (B U C K E T ); n e w t r e e - > n o d e . s p l l t . r i g h t =n e w n o d e (B U C K E T ); / *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * //*P a r t i t i o n s e x i s t i n g c l u s t e r s t o l e f t o r r i g h t */ /*b r a n c h e s a c c o r d i n g t o t h r e s h o l d t e s t . */ / *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * /i l =i r =0; f o r (i=0;i n o d e . b u c k e t . c o u n t ;i + + ) {i f (t r e e - > n o d e . b u c k e t . c l u s t e r [ i] - > a r r a y [ m a x i n d e x ]> t h r e s h o l d ) {n e w t r e e - > n o d e . s p l i t . r l g h t - > n o d e . b u c k e t . c l u s t e r [ J r + + ]= n e w c l u s t e r ( t r e e - > n o d e . b u c k e t . c l u s t e r [ i]->n, t r e e - > n o d e . b u c k e t . c l u s t e r [ i] - > e r r o r ,t r e e - > n o d e . b u c k e t . c l u s t e r [ i] - > a r r a y ); )e l s e{n e w t r e e - > n o d e . s p l i t . l e f t - > n o d e . b u c k e t . c l u s t e r [ i f + + ]= n e w c l u s t e r ( t r e e - > n o d e . b u c k e t . c l u s t e r [ i]->n, 1232D,A.S O U T H A R Dt r e e - > n o d e . b u c k e t . c l u s t e r [ i] - > e r r o r ,t r e e - > n o d e . b u c k e t . c l u s t e r [ i] - > a r r a y ); }}n e w t r e e - > n o d e . s p l i t . l e f t - > n o d e . b u c k e t . c o u n t =il; n e w t r e e - > n o d e . s p l l t . r l g h t - > n o d e . b u c k e t . c o u n t =Jr; / * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * /I*R e s e t t h e m a x / m l n a r r a y s f o r b o t h b u c k e t s * // * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * /s e t m a x m i n ( n e w t r e e - > n o d e . s p l i t . l e f t ); s e t m a x m i n ( n e w t r e e - > n o d e . s p l i t . r i g h t ); I *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * I/*D e - a l l o c a t e b u c k e t n o d e , a n d */ /*r e t u r n n e w s p l i t n o d e . */ I *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , if r e e n o d e (t r e e ); r e t u r n ( n e w t r e e ); / *. . . . . . . . . . . . . . . . . . . . . . * //*a p p e n d */ / *. . . . . . . . . . . . . . . . . . . . . . * /v o i d a p p e n d ( K D T r e el o n gl o n gs h o r t{ * t r e e ,n u m ,err, * v e c t o r ) r e g i s t e r i;/*n e w c l u s t e r i n d e x */ i=t r e e - > n o d e . b u c k e t . c o u n t + + ;t r e e - > n o d e . b u c k e t . c l u s t e r [ i]=n e w c l u s t e r ( n u m , err,v e c t o r ); i f (i= = 0)/*b u c k e t w a s e m p t y */ ( )e l s e( /*a p p e n d o n e c l u s t e r t o b u c k e t */ /*p o i n t e r t o b u c k e t n o d e */ /*n u m b e r o f v e c t o r s r e p r e s e n t e d */ /*m a x s q u a r e d e r r o r f o r c l u s t e r */ /*v e c t o r t o b e a p p e n d e d */ s e t m a x m i n (t r e e );I*i n i t i a l i z e m a x l m l n a r r a y s *I /*u p d a t e m a x / m l n a r r a y s */ u p d m a x m i n (t r e e - > n o d e . b u c k e t . m a x , t r e e - > n o d e . b u c k e t . m i n ,v e c t o r ); / *. . . . . . . . . . . . . . . . . . . . . . * //*s e t m a x m i n */ / * . . . . . . . . . . . . . . . . . . . . . . * /v o i d s e t m a x m l n (I*s e t t h e m a x / m l n a r r a y s i n ab u c k e t *I K D T r e e * t r e e )/*p o i n t e r t o B u c k e t t y p e t r e e n o d e */ { r e g i s t e r i;/*l o o p c o u n t e r o v e r c l u s t e r s i n b u c k e t */ i f (t r e e - > n o d e . b u c k e t . c o u n t >0) { m e m c p y (t r e e - > n o d e . b u c k e t . m a x ,t r e e - > n o d e . b u c k e t . c l u s t e r [ 0] - > a r r a y ,c l u s t e r _ s i z e *s l z e o f (s h o r t )); m e m c p y (t r e e - > n o d e . b u c k e t . m i n ,t r e e - > n o d e . b u c k e t . c l u s t e r [ 0] - > a r r a y ,c l u s t e r _ s i z e *s l z e o f ( s h o r t )); f o r (i=i;i n o d e . b u c k e t . c o u n t ;i + + ) { u p d m a x m i n (t r e e - > n o d e . b u c k e t . m a x ,t r e e - > n o d e . b u c k e t . m i n ,t r e e - > n o d e . b u c k e t . c l u s t e r [ i] - > a r r a y ); ) / *. . . . . . . . . . . . . . . . . . . . . . * //*u p d m a x m l n */ I *. . . . . . . . . . . . . . . . . . . . . . * Iv o i d u p d m a x m l n ( s h o r t * m a x ,s h o r t * m i n ,s h o r t * v e c t o r ) /*u p d a t e t h e m a x / m i n a r r a y s i n ab u c k e t */ /*a r r a y o f m a x v a l u e s */ /*a r r a y o f m i n v a l u e s */ /*n e w c l u s t e r v e c t o r */ Compressionof digitizedmapimages1233 r e g i s t e r i ; / * l o o p i n g c o u n t e r * /f o r (i=0;ic o d e b o o k _ l e n ) ( t r e e =b a l a n c e (t r e e ); c a n d i d a t e s =( C a n d i d a t e *)m y a l l o c (nb u c k e t s * s i z e o f ( C a n d i d a t e ) ) ;nc a n d l d a t e s =f i n d _ c a n d i d a t e s (t r e e , c a n d i d a t e s )- c a n d i d a t e s ;q s o r t (c a n d i d a t e s , n _ c a n d l d a t e s , s i z e o f (C a n d i d a t e ), c o m p a r e _ c a n d l d a t e s ); n _ c a n d i d a t e s =n _ c l u s t e r s -c o d e b o o k _ l e n n o d e . s p l l t . r l g h t ;i f (t l - , t y p e = = B U C K E T & & t l - > n o d e . b u c k e t . c o u n t n o d e . b u c k e t . c l u s t e r [ i]; t r =i n s e r t (t r , c - > n , c - , e r r o r , c - > a r r a y ); ) t r e e - > n o d e . s p l l t . r l g h t =N U L L ;f r e e n o d e (t r e e ); t r e e =t r ;) e l s e i f (t r - > t y p e = = B U C K E T & & t r - > n o d e . b u c k e t . c o u n t n , c - > e r r o r , c - > a r r a y ); } t r e e - > n o d e . s p i l t . l e f t =N U L L ;f r e e n o d e (t r e e ); t r e e =tl; /*r e c u r s i v e d e s c e n t o f t r e e */ tree->node.spilt.left t r e e - > n o d e . s p l l t . r l g h t} } r e t u r n (t r e e ); =b a l a n c e (tl); =b a l a n c e (t r ); / *. . . . . . . . . . . . . . . . . . . . . . * //*f r e e n o d e */ I* . . . . . . . . . . . . . . . . . . . . . .*i v o i d f r e e n o d e (/*f r e e m e m o r y a l l o c a t e d f o r K D T r e e */ K D T r e e * t r e e )/*p o i n e r tot r e e */ { r e g i s t e r i;/*l o o p i n g c o u n t e r */ i f (t r e e ]=N U L L )s w i t c h (t r e e - > t y p e ) { c a s e B U C K E T :f o r (i=0;i n o d e . b u c k e t . c o u n t ;i + + ) { f r e e c l u s t e r (t r e e - > n o d e . b u c k e t . c l u s t e r [ i]); ) f r e e (t r e e - > n o d e . b u c k e t . c l u s t e r ); f r e e (t r e e - > n o d e . b u c k e t . m a x ); f r e e (t r e e - > n o d e . b u c k e t . m l n ); ' f r e e (tree); n _ b u c k e t s - - ;b r e a k ;c a s e S P L I T :f r e e n o d e (t r e e - > n o d e . s p l i t . l e f t ); f r e e n o d e (t r e e - > n o d e . s p i l t . r i g h t ); f r e e (t r e e ); b r e a k ;d e f a u l t :f p r l n t f (s t d e r r , ' E r r o r i n f r e e n o d e : u n k n o w n n o d e t y p e \ n " ); e x i t ( E R R O R ); ) / *. . . . . . . . . . . . . . . . . . . . . . * //*f r e e c l u s t e r * /i, . . . . . . . . . . . . . . . . . . . . . .,i v o i d f r e e c l u s t e r ( C l u s t e r * c l u s t e r ) { f r e e (c l u s t e r - > a r r a y ); f r e e (c l u s t e r ); n _ c l u s t e r s - - ;) / *. . . . . . . . . . . . . . . . . . . . . . * //*f i n d _ c a n d l d a t e s */ /* . . . . . . . . . . . . . . . . . . . . . .* /C a n d i d a t e * f l n d c a n d l d a t e s ( K D T r e e * t r e e ,C a n d i d a t e * c a n d ) { /*f r e e ac l u s t e r a r r a y * //*p o i n t e r t o c l u s t e r */ /*f i n d c a n d i d a t e c l u s t e r p a i r s */ /*t r e e t o s e a r c h */ /*p o i n t e r i n t o c a n d i d a t e a r r a y */ i f (t r e e = = N U L L ) ( f p r i n t f (s t d e r r , ' E r r o r i n f l n d _ c a n d i d a t e s : n u l l t r e e p o l n t e r \ n " ); e x i t ( E R R O R ); ) s w i t c h (t r e e - > t y p e ) { c a s e S P L I T :c a n d =f l n d _ c a n d l d a t e s (t r e e - > n o d e . s p i l t . l e f t , c a n d ); c a n d =f l n d _ c a n d i d a t e s (t r e e - > n o d e . s p i l t . r i g h t , c a n d ); b r e a k ;c a s e B U C K E T :i f (t r e e - > n o d e . b u c k e t . c o u n t >i) { c a n d - > p t r =t r e e ;Compressionof digitized mapimages 1235 c a n d - > e r r =c a n d i d a t e (t r e e , & c a n d - > n o l , & c a n d - > n o 2 ); c a n d + + ;)b r e a k ;d e f a u l t :f p r l n t f (s t d e r r , " E r r o r i n f l n d _ c a n d l d a t e s : u n k n o w n t r e e t y p e \ n " ); e x i t (E R R O R ); )r e t u r n (c a n d );I*r e t u r n p o i n t e r t o n e x t e m p t y s l o t * //*c a n d i d a t e */ / * . . . . . . . . . . . . . . . . . . . . . . * /l o n g c a n d i d a t e (/*f i n d i n d e x o f c a n d i d a t e f o r b u c k e t * /K D T r e e * t r e e , /*b u c k e t n o d e o f t r e e * /l o n g * m i n i , /*i n d e x o f f i r s t i n c a n d i d a t e p a i r * /l o n g * m l n J )/*i n d e x o f s e c o n d i n c a n d i d a t e p a i r * I{r e g i s t e r C l u s t e r **c;/*c l u s t e r p o i n t e r a r r a y * /r e g i s t e r i;/*l o o p i n g i n d e x * /r e g i s t e r J;/*l o o p i n g i n d e x * /r e g i s t e r i;/*l o o p i n g l i m i t * /r e g i s t e r 11;/*l o o p i n g l i m i t -1* /l o n g m l n e r r ; /*m i n i m u m e r r o r e n c o u n t e r e d * /l o n g e r r o r ; /*c u r r e n t e r r o r */ c=t r e e - > n o d e . b u c k e t . c l u s t e r ; /*p o i n t e r t o c l u s t e r */ 1=t r e e - > n o d e . b u c k e t . c o u n t ; /*l e n g t h o f c l u s t e r */ i i =1-I;/*l e n g t h m i n u s o n e */ m l n e r r =L O N G _ M A X ; /*ag i a n t n u m b e r * /f o r (i=0;i# i n c l u d e < l i m l t s . h ># i n c l u d e < m a t h . h >/*s t a n d a r d I/Of u n c t i o n d e f i n i t i o n s */ /*c o n t a i n s MAX_INT,etc.*I /*m a t h f u n c t i o n s l o g (),etc.*/ / *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * //*M A N I F E S T C O N S T A N T S */ / *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * /# d e f i n e B I T S 8 # d e f i n e B U C K E T S I Z E 8 # d e f i n e E R R O R (-i) # d e f i n e F A L S E 0 # d e f l n e M I N A R G S 3 # d e f i n e N O R M A L 0 # d e f i n e T R U E (]FALSE) I*n u m b e r ofb i t s p e r b y t e */ I*n u m b e r o f v e c t o r s p e r b u c k e t */ /*e r r o r r e t u r n code*/ /*logicalF A L S E */ /*mln.n u m b e r ofa r g u m e n t s r e q u i r e d */ /*normalr e t u r n code*/ /*logicalT R U E */ / *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * //*D A T A S T R U C T U R E S */ /*V e c t o r Q u a n t i z a t l o n C o d e b o o k */ I *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * It y p e d e f u n s i g n e d c h a r uchar;I*ensureu n s i g n e d for p o r t a b i l i t y *I t y p e d e f s t r u c tl o n g index; u c h a r *vector; }Code; /*s t r u c t u r e d e f i n i n g asinglecode*/ /*i n d e x ofthec o d e */ /*p o i n t e r tocodev e c t o r */ t y p e d e f s t r u c t{ l o n g num; C o d e *book; C o d e B o o k ;/*s t r u c t u r e d e f i n i n g ab o o k ofc o d e s */ /*n u m b e r ofcodev e c t o r s inc o d e b o o k */ /*p o i n t e r toac o l l e c t i o n ofC o d e s */ # d e f i n e CODE(J) # d e f i n e V A L U E ( J , I )( c o d e b o o k . b o o k [ J ] . v e c t o r )(CODE(J)[I]) / *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * //*S t r u c t u r e s forK - d treeu s e d inP N N s e a r c h a l g o r i t h m */ /, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*i t y p e d e f e n u m { BUCKET,S P L I T ) t y p e d e f s t r u c t s p i l t _ n o d e{ l o n g disc; l o n g part; s t r u c t k d _ n o d e *left; s t r u c t k d _ n o d e *right; )Split; t y p e d e f s t r u c t k d _ D o d e{ No d e T y p e type; u n i o n{ Splitsplit; c o d e B o o k bucket; }node; NodeType; /*s t r u c t u r e ford e c i s i o n n o d e s */ /*i n d e x ofd i s c r i m i n a t o r c o o r d i n a t e */ /*p a r t i t i o n v a l u e ford i s c r i m i n a t o r */ /*for v e c t o r s t h r e s h o l d */ /*s t r u c t u r e forK - D treen o d e s */ /*oneoftwot y p e s */ /*d e c i s i o n n o d e *I /*d a t a n o d e *I }KDTree; / * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * //*F U N C T I O N P R O T O T Y P E S */ / * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * /l o n g b o b ( u c h a r *); Compressionof digitized mapimages 1239 K D T r e el o n gint l o n gl o n gv o i dl o n gK D T r e eK D T r e eC o d eC o d e B o o kl o n gC o d e B o o kC o d e B o o kl o n g*build__tree( C o d e B o o k ); b w b ( u c h a r *); c m p r ( C o d e *,C o d e *); d i s c r i m ( C o d e B o o k ); d l s t ( long,u c h a r *,u c h a r *); get__args( int,char**); m e d i a n o f ( long,C o d e B o o k ); * n e w b u c k e t ( C o d e B o o k ); * n e w s p l l t ( long,long,K D T r e e *,K D T r e e *); * m a t c h ( u c h a r *,K D T r e e *); r d _ c o d e s ( F I L E *); s e a r c h ( u c h a r *,K D T r e e *); s p l i t _ l e f t ( long,C o d e B o o k ); s p l i t _ r l g h t ( long,C o d e B o o k ); s p r e a d o f ( long,C o d e B o o k ); / *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . r . . . . . . . . . . . . . . . . . . * //*G L O B A L D A T A */ / *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * /l o n gl o n gF I L Eu c h a rC o d el o n gl o n gl o n gl o n gl o n gu c h a rl o n gb l o c k _ h e i g h t ; I*h e i g h t ofv e c t o r b l o c k */ b l o c k _ w l d t h ; /*w i d t h ofv e c t o r b l o c k */ *codef;/*c o d e b o o k inputfiles t r e a m */ *lower;/*lowerb o u n d s fors e a r c h */ *matched;/*p o i n t e r tom a t c h e d c o d e */ nearest;/ * i n t e r i m n e a r e s t c o d e m a t c h i n d e x */ n_cols;/*n u m b e r ofc o l u m n s ininputi m a g e */ n_rows;/*n u m b e r ofrowsininputimage*/ p i x e l _ d e p t h ; /*sizeofp i x e l */ serno;/*c o d e b o o k serialn u m b e r */ *upper;/*u p p e r b o u n d s fors e a r c h */ v e c t o r slze;/*sizeofcodev e c t o r */ / *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * // *P R O G R A M * / I *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * Im a i n ( ( /*VQc o m p r e s s i o n */ intargc,/*a r g u m e n t count*/ c h a r *argv[])/*a r g u m e n t v e c t o r *I C o d e B o o k codebook;/*thec o d e b o o k */ l o n g code_width;/*w i d t h inb y t e s ofav e c t o r b l o c k */ u c h a r *cvq;/*(uchar)c o m p r e s s e d r o w b u f f e r */ r e g i s t e r l o n g i;/*v e c t o r b l o c k r o w i n d e x */ u c h a r **image;/*rowsofinputimage*/ r e g i s t e r l o n g J;/*v e c t o r b l o c k c o l u m n i n d e x */ r e g i s t e r l o n g k;/*p i x e l b y t e (depth)i n d e x */ r e g i s t e r l o n g I;/*p l x e l b y t e (depth)i n d e x */ l o n g n_bytes;/*b y t e s ininputimager o w */ r e g i s t e r u c h a r *pl;/*p o i n t e r intoi m a g e b u f f e r */ r e g i s t e r u c h a r *pv;/*p o i n t e r intov e c t o r b u f f e r */ r e g i s t e r short*pvq;/*p o i n t e r intoc o m p r e s s e d r o w b u f f e r */ s h o r t *svq;/*(short)c o m p r e s s e d r o w b u f f e r */ K D T r e e *tree;/*thek - d s e a r c h tree*/ u c h a r *v;/*v e c t o r b u f f e r */ l o n g x;/*ximagei n d e x */ l o n g xsize;/*xsizeofc o m p r e s s e d image*/ l o n g y;/*yimagei n d e x */ l o n g yslze;/*ysizeofc o m p r e s s e d image*/ l o n g zsize;/*zsize(depth)ofC o m p r e s s e d i m a g e */ / *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * //*getc o m p r e s s i o n p a r a m e t e r s */ I * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * Ig e t _ a r g s ( a r g c , a r g v );/*c o m m a n d - l l n e a r g u m e n t s */ c o d e b o o k = r d _ c o d e s ( c o d e f );/*c o d e b o o k */ t r e e =b u i l d _ t r e e ( c o d e b o o k );/*m a k e as e a r c h tree*/ / * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * //*c a l c u l a t e d e r i v e d p a r a m e t e r s */ I *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * Ix s l z e =n _ c o l s /b l o c k _ w l d t h ; /*c o m p r e s s e d c o l u m n s */ y s l z e =n _ r o w s /block__height;/*c o m p r e s s e d rows*/ zsize=( log( ( d o u b l e ) c o d e b o o k . n u m )/l o g (2.0)+BITS-1)/BITS; /*b y t e s p e r c o d e */ n _ b y t e s =p l x e l _ d e p t h *n_cols;/*sizeofi m a g e r o w b u f f e r */ c o d e _ w l d t h =p l x e l _ d e p t h *b l o c k _ w l d t h ; /*b y t e w i d t h ofab l o c k */ I *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * I/*w r i t e o u t p u t fileh e a d e r i n f o */ / * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * /1240D. A. S o u T ~c h a rf w r l t e ( & e e r n o , s i z e o f (l o n g ),i,s t d o u t );/*s e r i a l n u m b e r * /f w r l t e ( & x s l z e , s l z e o f (l o n g ),I,s t d o u t );/*n u m b e r o f c o l u m n s * /f w r l t e ( & y s l z e , s l z e o f (l o n g ),1,s t d o u t );/*n u m b e r o f r o w s * /f w r i t e (& z s l z e , s l z e o f (l o n g ),1,s t d o u t );/*b y t e s p e r c o d e */ / * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * /I*a l l o c a t e b u f f e r m e m o r y *I I *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * Iv=( u c h a r *)m a l l o c ( v e c t o r _ s i z e *s l z e o f ( u c h a r ) ) ;u p p e r =( u c h a r *)m a l l o c ( v e c t o r _ s l z e *s l z e o f ( u c h a r ) ) ;l o w e r =( u c h a r *)m a l l o c ( v e c t o r _ s l z e *s l z e o f ( u c h a r ) ) ;8 v q =( s h o r t *)m a l l o c ( x s i z e *s i z e o f ( s h o r t ) ) ;c v q =( u c h a r *)m a l l o c ( x s l z e *s l z e o f ( u c h a r ) ) ;i m a g e =( u c h a r **)m a l l o c ( b l o c k _ h e l g h t *s l z e o f ( u c h a r *)); f o r (i=0;i v e c t o r [ k e y ]); /*f i n d i n d e x o f m e d i a n v a l u e */ I*d i s c r i m i n a t o r c o o r d i n a t e i n d e x */ /*p o i n t e r t o c o d e b o o k * //*i n d e x o f m e d i a n */ k e y =d;I*s o r t o n k e y i n d e x e d b y d i s c r i m . *I q s o r t (c o d e b o o k . b o o k , c o d e b o o k . n u m , s l z e o f ( C o d e ),c m p r ); m=c o d e b o o k . n u m /2+i;/*n o m i n a l i n d e x o f m e d i a n */ w h i l e ( m>0& & V A L U E ( m,d)= = V A L U E ( m-I,d)) {m - - ; /*d e c r e m e n t w h i l e v a l u e s a r e e q u a l */ )r e t u r n ( m-1);/*-i=n o s p l i t p o s s i b l e */ / *. . . . . . . . . . . . . . . . . . . . . . * //*n e w s p l l t */ I *. . . . . . . . . . . . . . . . . . . . . . * IK D T r e e * n e w s p l l t ( l o n g d, l o n g p, K D T r e e * l e f t ,K D T r e e * r i g h t ) {K D T r e e * t r e e ;t r e et r e e - > t y p et r e e - > n o d e . s p l i t . d l s ct r e e - > n o d e . s p i l t . p a r tt r e e - > n o d e . s p i l t . l e f tt r e e - > n o d e . s p l l t . r l g h tr e t u r n (t r e e ); /*r e t u r n s n o n - t e r m i n a l k - d t r e e n o d e */ /*d i s c r i m i n a t o r i n d e x */ /*p a r t i t i o n v a l u e f o r d i s c r i m i n a t o r */ /*l e f t s u b - t r e e */ /*r i g h t s u b - t r e e * //*p o i n t e r t o n e w k - d t r e e n o d e */ =( K D T r e e *)m a l l o c (8 i z e o f (* t r e e )); =S P L I T ;=d; =p; =l e f t ;=r i g h t ;/ *. . . . . . . . . . . . . . . . . . . . . . * //*s p i l t _ l e f t */ / *. . . . . . . . . . . . . . . . . . . . . . * /C o d e B o o k s p i l t _ l e f t (/*r e t u r n l e f t p a r t i t i o n */ l o n g pl,/*i n d e x o f p a r t i t i o n * /1244D. A. SOUTHAgD C o d e B o o k c o d e b o o k )/*c o d e b o o k */ C o d e B o o k l e f t ; /*t h e l e f t p a r t i t i o n */ l e f t . n u m =p i +i; l e f t . b o o k =c o d e b o o k . b o o k ;r e t u r n (l e f t ); /*n u m b e r o f c o d e s */ /*p o i n t e r t o c o d e s * //*s p l l t r l g h t */ / *. . . . . . . . . . . . . . . . . . . . . . * /C o d e B o o k s p i l t _ r i g h t ( l o n g pl, C o d e B o o k c o d e b o o k ) {C o d e B o o k r i g h t ;/*r e t u r n r i g h t p a r t i t i o n */ /*i n d e x o f p a r t i t i o n */ /*c o d e b o o k */ /*t h e r i g h t p a r t i t i o n */ r l g h t . n u m =c o d e b o o k . n u m -p l -I; r l g h t . b o o k =c o d e b o o k . b o o k +p i +I; r e t u r n (r i g h t ); /*n u m b e r o f c o d e s * //*p o i n t e r t o c o d e s */ / *. . . . . . . . . . . . . . . . . . . . . . * //*s e a r c h */ / *. . . . . . . . . . . . . . . . . . . . . . * /l o n g s e a r c h ( u c h a r v e c t o r [ ] ,K D T r e e * t r e e ) {i f (t r e e - > t y p e = = B U C K E T ) {)e l s e{/*r e c u r s l v e s e a r c h t h r u k - d tree*/ /*v e c t o r t o b e m a t c h e d */ /*t r e e t o b e t r a v e r s e d * //*c h e c k a l l c o d e s i n b u c k e t */ r e g i s t e r C o d e *c;/* r e g i s t e r i;/* r e g i s t e r J;/* r e g i s t e r m a t c h e s ; / *r e g i s t e r sum;/* c o d e p o i n t e r */ c o d e l o o p i n d e x */ c o o r d i n a t e l o o p i n d e x * /l o g i c a l p r e d i c a t e */ p a r t i a l d i s t a n c e s u m */ c=t r e e - > n o d e . b u c k e t . b o o k ;f o r (i=0;i n o d e . b u c k e t . n u m ;i++,c + + ) {s u m =d i s t (0,v e c t o r , c - > v e c t o r ); f o r (J=1; ( m a t c h e s =s u m n o d e . s p l i t . d l s c ;p=t r e e - > n o d e . s p i l t . p a r t ;i f ( v e c t o r [ d]< = p) {/*g e t d i s c r i m i n a t o r i n d e x */ /*g e t p a r t i t i o n v a l u e */ /*s e a r c h l e f t s u b t r e e */ t e m p =u p p e r [ d]; u p p e r [ d]=p; /*s a v e u p p e r b o u n d */ /*n e w u p p e r b o u n d */ d o n e =s e a r c h ( v e c t o r , t r e e - > n o d e . s p l i t . l e f t ); i f ( d o n e )r e t u r n d o n e ;u p p e r [ d]=t e m p ;t e m p =l o w e r [ d]; l o w e r [ d]=p; /*r e s t o r e u p p e r b o u n d */ /*s a v e l o w e r b o u n d * //*n e w l o w e r b o u n d * /i f ( b o b ( v e c t o r ))/*b o u n d s o v e r l a p b a l l ? */ {d o n e =s e a r c h ( v e c t o r , t r e e - > n o d e . s p l i t . r l g h t ); i f ( d o n e )r e t u r n d o n e ;)Compressionof digitizedmapimages1245 } e l s e{ l o w e r [ d]=t e m p ;t e m p =l o w e r [ d]; l o w e r [ d]=p; d o n e =s e a r c h ( v e c t o r ,i f ( d o n e )r e t u r n d o n e ;l o w e r [ d]=t e m p ;t e m p =u p p e r [ d]; u p p e r [ d]=p; i f ( b o b ( v e c t o r )) { /*r e s t o r e l o w e r b o u n d */ /*s e a r c h r i g h t s u b t r e e */ /*s a v e l o w e r b o u n d */ /*n e w l o w e r b o u n d * /t r e e - > n o d e . s p l i t . r i g h t ); /*r e s t o r e l o w e r b o u n d */ /*s a v e u p p e r b o u n d */ /*n e w u p p e r b o u n d */ /*b o u n d s o v e r l a p b a l l ? * /d o n e =s e a r c h ( v e c t o r , t r e e - > n o d e . s p i l t . l e f t ); i f ( d o n e )r e t u r n d o n e ;) u p p e r [ d]=t e m p ; /*r e s t o r e u p p e r b o u n d */ } ) r e t u r n ( b w b ( v e c t o r )); / *. . . . . . . . . . . . . . . . . . . . . . * //*m a t c h * //* . . . . . . . . . . . . . . . . . . . . . .*/ v e c t o r [ ] ,* t r e e ) i; C o d e * m a t c h ( u c h a rK D T r e e{ r e g i s t e rm a t c h e d =N U L L ;n e a r e s t =I N T _ M A X ;f o r (i=0;iProgram L~ting F I L E : v q e x p . cP U R P O S E : D e c o m p r e s s ( e x p a n d ) V Q c o m p r e s s e d i m a g e f i l e s .U S A G E : v q e x p < c o d e b o o k > [ i n p u t . v q ] [ o u t p u t . i m a g e ]A R G U M E N T S :c o d e b o o k : n a m e o f c o d e b o o k file,c r e a t e d b y v q i n i ti n p u t . v q = n a m e o f V Q - c o m p r e s s e d i m a g e f i l e ( s t d i n )[o u t p u t . i m a g e :n a m e o f d e c o m p r e s s e d i m a g e f i l e ( s t d o u t )L A N G U A G E : A N S I C,M I P S Cc o m p i l e r v e r s i o nA U T H O R = D a v i d A.S o u t h a r d , T h e M I T R E C o r p o r a t i o nC R E A T E D : 12N o v 1 9 9 1N O T E S / W A R N I N G S :/*s t a n d a r d I / O l i b r a r y d e f i n i n t i o n s */ /*M A N I F E S T C O N S T A N T S */ /* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . */ # d e f i n e E R R O R (-i)/*e r r o r r e t u r n s t a t u s c o d e * /# d e f i n e M I N A R G S 1/*v a l i d m i n i m u m n u m b e r o f a r g u m e n t s */ # d e f i n e N O R M A L 0/*n o r m a l r e t u r n s t a t u s c o d e */ I* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . *I /*F U N C T I O N P R O T O T P Y E S */ I* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . *I t y p e d e f u n s i g n e d c h a r u c h a r ; /*e n s u r e u n s l g n e d f o r p o r t a b i l i t y */ v o i d g e t _ a r g s (i n t , c h a r **); u c h a r * r d _ c o d e s (F I L E *); Compressionof digitizedmapimages1247 / *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * !/*G L O B A L V A R I A B L E S */ ! *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1l o n g c o d e b o o k _ l e n g t h ; /*n u m b e r ofcodesinc o d e b o o k *! F I L E *coder;/*filep o i n t e r forthec o d e b o o k */ l o n g b l o c k _ h e i g h t ; !*v e c t o r b l o c k h e i g h t *! l o n g b l o c k _ w l d t h ; !*v e c t o r b l o c k w i d t h *! l o n g p i x e l _ d e p t h ; /*b y t e s p e r pixel*/ l o n g serial;/*serialn u m b e r ofc o d e b o o k */ l *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " 1/*P R O G R A M */ ! *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * !1"V Q d e c o m p r e s s i o n */ intargc,/*argumentcount*! c h a r * * a r g v )!*argumentlist*/ u c h a r "*codebook;/*c o d e b o o k ford e c o m p r e s s i o n *! l o n g c o d e _ w l d t h ; /*w i d t h ofonev e c t o r r o w */ l o n g c o d e 81ze;/*numberofb y t e s inav e c t o r */ r e g i s t e r i;/*v e c t o r b l o c k r o w i n d e x *! u c h a r **image;/*a r r a y ofp o i n t e r s toi m a g e rows*/ r e g i s t e r J;/*v e c t o r b l o c k c o l u m n i n d e x */ r e g i s t e r k;/*v e c t o r b l o c k b y t e i n d e x */ r e g i s t e r i;/*i n d e x intoimagerows*/ l o n g n_cols;!*n u m b e r ofcolsine x p a n d e d i m a g e */ r e g i s t e r u c h a r *pi;!*p o i n t e r intoani m a g e r o w */ r e g i s t e r u c h a r *pv;!*p o i n t e r intoacodev e c t o r */ l o n g serno;/*c o m p r e s s e d images e r i a l n u m b e r */ short*svq;/*(short)a r r a y ofc o d e s b u f f e r *! u c h a r *cvq;/*(uchar)a r r a y ofc o d e s b u f f e r */ l o n g x;!*c o m p r e s s e d imagec o l u m n i n d e x */ l o n g xslze;/*n u m b e r ofcolsinc o m p r e s s e d image*/ l o n g y;/*c o m p r e s s e d imager o w i n d e x */ l o n g ysize;/*numberofrowsinc o m p r e s s e d i m a g e */ l o n g zsize;!*n u m b e r ofb y t e s p e r c o d e i n d e x */ m a i n ( {/ *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * //*R e a d a r g u m e n t s a n d c o d e b o o k s */ / *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * !g e t _ a r g s ( argc,a r g v );/*c o m m a n d - l l n e a r g u m e n t s */ c o d e b o o k =rd__codes( c o d e f );/*getc o d e b o o k fromfile*/ 1 ". . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * l/*R e a d c o m p r e s s e d imageh e a d e r info*! / *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * !f r e a d ( &serno,s i z e o f ( l o n g ),i,stdin);/*serialn u m b e r *! f r e a d ( &xsize,s l z e o f ( l o n g ),1,stdin);/*n u m b e r ofc o l u m n s */ f r e a d ( &yslze,s i z e o f ( l o n g ),1,s t d l n );!*n u m b e r ofrows*! f r e a d ( &zsize,s i z e o f ( l o n g ),1,stdin);!*b y t e s p e r code*! if( s e r n o I=serial)/*v e r i f y serialn u m b e r s */ { f p r i n t f ( stderr, %s:c o d e b o o k i n c o n s i s t e n t w i t h c o m p r e s s e d imagelkn', argv[0]); exit( E R R O R ); ) l *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * l!*A l l o c a t e b u f f e r m e m o r y "1 l *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * ln _ c o l s =x s i z e *block_.width;/*bytesa c r o s s c o l u m n */ c o d e _ w l d t h =b l o c k _ w l d t h *p i x e 1 _ d e p t h ; /*b y t e s a c r o s s b l o c k */ c o d e _ s l z e =c o d e _ w l d t h *b l o c k _ h e i g h t ; !*b y t e s e n t i r e b l o c k */ i m a g e =(uchar**)m a l l o c (b l o c k _ h e l g h t *sizeof(uchar*)); for( i=0;i