michael crichton.congo-第15节

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egetation　that　obscured　her　vision　of　the　ground。　…
　The　study　of　vegetation　was　mon　in　temperate　regions；　where　the　foliage　underwent　seasonal　changes。　But　the　equatorial　rain　forest　was　unchanging：　winter　or　summer；　the　foliage　remained　the　same。　Ross　turned　her　attention　to　another　aspect；　the　differences　in　vegetation　albedo。
　Albedo　was　technically　defined　as　the　ratio　of　electromagnetic　energy　reflected　by　a　surface　to　the　amount　of　energy　incident　upon　it。　In　terms　of　the　visible　spectrum；　it　was　a　measure　of　how　〃shiny〃　a　surface　was。　A　river　had　a　high　albedo；　since　water　reflected　most　of　the　sunlight　striking　it。　Vegetation　absorbed　light；　and　therefore　had　a　low　albedo。　Starting　in　1977；　ERTS　developed　puter　programs　which　measured　albedo　precisely；　making　very　fine　distinctions。
　Ross　asked　herself　the　question：　If　there　was　a　lost　city；　what　signature　might　appear　in　the　vegetation？　There　was　an　obvious　answer：　late　secondary　jungle。
　The　untouched　or　virgin　rain　forest　was　called　primary　jungle。　Primary　jungle　was　what　most　people　thought　of　when　they　thought　of　rain　forests：　huge　hardwood　trees；　mahogany　and　teak　and　ebony；　and　underneath　a　lower　layer　of　ferns　and　palms；　clinging　to　the　ground。　Primary　jungle　was　dark　and　forbidding；　but　actually　easy　to　move　through。　However；　if　the　primary　jungle　was　cleared　by　man　and　later　abandoned；　an　entirely　different　secondary　growth　took　over。　The　dominant　plants　were　softwoods　and　fast…growing　trees；　bamboo　and　thorny　tearing　vines；　which　formed　a　dense　and　impenetrable　barrier。
　But　Ross　was　not　concerned　about　any　aspect　of　the　jungle　except　its　albedo。　Because　the　secondary　plants　were　different；　secondary　jungle　had　a　different　albedo　from　primary　jungle。　And　it　could　be　graded　by　age：　unlike　the　hardwood　trees　of　primary　jungle；　which　lived　hundreds　of　years；　the　softwoods　of　secondary　jungle　lived　only　twenty　years　or　so。　Thus　as　time　went　on；　the　secondary　jungle　was　replaced　by　another　form　of　secondary　jungle；　and　later　by　still　another　form。
　By　checking　regions　where　late　secondary　jungle　was　generally　found…such　as　the　banks　of　large　rivers；　where　innumerable　human　settlements　had　been　cleared　and　abandoned…Ross　confirmed　that　the　ERTS　puters　could；　indeed；　measure　the　necessary　small　differences　in　reflectivity。
　She　then　instructed　the　ERTS　scanners　to　search　for　albedo　differences　of　。03　or　less；　with　a　unit　signature　size　of　a　hundred　meters　or　less；　across　the　fifty　thousand　square　kilometers　of　rain　forest　on　the　western　slopes　of　the　Virunga　volcanoes。　This　job　would　occupy　a　team　of　fifty　human　aerial　photographic　analysts　for　thirty…one　years。　The　puter　scanned　129；000　satellite　and　aerial　photographs　in　under　nine　hours。
　And　found　her　city。
　In　May；　1979；　Ross　had　a　puter　image　showing　a　very　old　secondary　jungle　pattern　laid　out　in　a　geometric；　gridlike　form。　The　pattern　was　located　2　degrees　north　of　the　equator；　longitude　3　degrees；　on　the　western　slopes　of　the　active　volcano　Mukenko。　The　puter　estimated　the　age　of　the　secondary　jungle　at　five　hundred　to　eight　hundred　years。
　〃So　you　sent　an　expedition　in？〃　Elliot　said。
　Ross　nodded。　〃Three　weeks　ago；　led　by　a　South　African　named　Kruger。　The　expedition　confirmed　the　placer　diamond　deposits；　went　on　to　search　for　the　origin；　and　found　the　ruins　of　the　city。；；
　〃And　then　what　happened？〃　Elliot　asked。
　
　He　ran　the　videotape　a　second　time。
　Onscreen　he　saw　black…and…white　images　of　the　camp；　destroyed；　smoldering。　Several　dead　bodies　with　crushed　skulls　were　visible。　As　they　watched；　a　shadow　moved　over　the　dead　bodies；　and　the　camera　zoomed　back　to　show　the　outline　of　the　lumbering　shadow。　Elliot　agreed　that　it　looked　like　the　shadow　of　a　gorilla；　but　he　insisted；　〃Gorillas　couldn't　do　this。　Gorillas　are　peaceful；　vegetarian　animals。〃
　They　watched　as　the　tape　ran　to　the　end。　And　then　they　reviewed　her　final　puter…reconstituted　image；　which　clearly　showed　the　head　of　a　male　gorilla。
　〃That's　ground　truth；〃　Ross　said。
　Elliot　was　not　so　sure。　He　reran　the　last　three　seconds　of　videotape　a　final　time；　staring　at　the　gorilla　head。　The　image　was　fleeting；　leaving　a　ghostly　trail；　but　something　was　wrong　with　it。　He　couldn't　quite　identify　what。　Certainly　this　was　atypical　gorilla　behavior；　but　there　was　something　else。　…
　He　pushed　the　freeze…frame　button　and　stared　at　the　frozen　image。　The　face　and　the　fur　were　both　gray：　unquestionably　gray。
　〃Can　we　increase　contrast？〃　he　asked　Ross。　〃This　image　is　washed　out。〃
　〃I　don't　know；〃　Ross　said；　touching　the　controls。　〃I　think　this　is　a　pretty　good　image。〃　She　was　unable　to　darken　it。
　〃It's　very　gray；〃　he　said。　〃Gorillas　are　much　darker。〃
　〃Well；　this　contrast　range　is　correct　for　video。〃
　Elliot　was　sure　this　creature　was　too　light　to　be　a　mountain　gorilla。　Either　they　were　seeing　a　new　race　of　animal；　or　a　new　species。　A　new　species　of　great　ape；　gray　in　color；　aggressive　in　behavior；　discovered　in　the　eastern　Congo。
　He　had　e　on　this　expedition　to　verify　Amy's　dreams…a　fascinating　psychological　insight…but　now　the　stakes　were　suddenly　much　higher。
　Ross　said；　〃You　don't　think　this　is　a　gorilla？〃
　〃There　are　ways　to　test　it；〃　he　said。　He　stared　at　the　screen；　frowning；　as　the　plane　flew　onward　in　the　night。
　
　2。B…8　Problems
　
　〃YOU　WANT　ME　TO　WHAT'？〃　TOM　SEAMANS　SAID；　cradling　the　phone　in　his　shoulder　and　rolling　over　to　look　at　his　bedside　clock。　It　was　3　A。M。
　〃Go　to　the　zoo；〃　Elliot　repeated。　His　voice　sounded　garbled；　as　if　ing　from　under　water。
　〃Peter；　where　are　you　calling　from？〃
　〃We're　somewhere　over　the　Atlantic　now；〃　Elliot　said。　〃On　our　way　to　Africa。〃
　〃Is　everything　all　right？〃
　〃Everything　is　fine；〃　Elliot　said。　〃But　I　want　you　to　go　to　the　zoo　first　thing　in　the　morning。〃
　〃And　do　what？〃
　〃Videotape　the　gorillas。　Try　to　get　them　in　movement。　That's　very　important　for　the　discriminant　function；　that　they　be　moving。〃
　〃I'd　better　write　this　down；〃　Seamans　said。　Seamans　handled　the　puter　programming　for　the　Project　Amy　staff；　and　he　was　accustomed　to　unusual　requests；　but　not　in　the　middle　of　the　night。　〃What　discriminant　function？〃
　〃While　you're　at　it；　run　any　films　we　have　in　the　library　of　gorillas…any　gorillas；　wild　or　in　zoos　or　whatever。　The　more　specimens　the　better；　so　long　as　they're　moving。　And　for　a　baseline；　you'd　better　use　chimps。　Anything　we　have　on　chimps。　Transfer　it　to　tape　and　put　it　through　the　function。〃
　〃What　function？〃　Seamans　yawned。
　〃The　function　you're　going　to　write；〃　Elliot　said。　〃I　want　a　multiple　variable　discriminant　function　based　on　total　imagery〃
　〃You　mean　a　pattern…recognition　function？〃　Seamans　had　written　pattern…recognition　functions　for　Amy's　language　use；　enabling　them　to　monitor　her　signing　around　the　clock。　Sea…mans　was　proud　of　that　program；　in　its　own　way；　it　was　highly　inventive。
　〃However　you　structure　it；〃　Elliot　said。　〃I　just　want　a　function　that'll　discriminate　gorillas　from　other　primates　like　chimps。　A　species…differentiating　function。〃
　〃Are　you　kidding？〃　Seamans　said。　〃That's　a　B…8　problem。〃　In　the　developing　field　of　pattern…recognition　puter　programs；　so…called　B…8　problems　were　the　most　difficult；　whole　teams　of　researchers　had　devoted　years　to　trying　to　teach　puters　the　difference　between　〃B〃　and　〃8'　'…precisely　because　the　difference　was　so　obvious。　But　what　was　obvious　to　the　human　eye　was　not　obvious　to　the　puter　scanner。　The　scanner　had　to　be　told；　and　the　specific　instructions　turned　out　to　be　far　more　difficult　than　anyone　anticipated；　particularly　for　handwritten　characters。
　Now　Elliot　wanted　a　program　that　would　distinguish　between　similar　visual　images　of　gorillas　and　chimps。　Seamans　could　not　help　asking；　〃Why？　It's　pretty　obvious。　A　gorilla　is　a　gorilla；　and　a　chimp　is　a　chimp。〃
　〃Just　do　it；〃　Elliot　said。
　〃Can　I　use　size？〃　On　the　basis　of　size　alone；　gorillas　and　chimps　could　be　accurately　distinguished。　But　visual　functions　could　not　determine　size　unless　the　distance　from　the　recording　instrument　to　the　subject　image　was　known；　as　well　as　the　focal　length　of　the　recording　lens。
　〃No；　you　can't　use　size；〃　Elliot　said。　〃Element　morphology　only。〃
　Seamans　sighed。　〃Thanks　a　lot。　What　resolution？〃
　〃I　need　ninety…five…percent　confidence　limits　on　species　assignment；　to　be　based　on　less　than　three　seconds　of　black…and…white　scan　imagery。〃
　Seamans　frowned。　Obviously；　Elliot　had　three　seconds　of　videotape　imagery　of　some　animal　and　he　was　not　sure　whether　it　was　a　gorilla　or　not。　Elliot　had　seen　enough　gorillas　over　the　years　to　know　the　difference：　gorillas　and　chimps　were　utterly　different　animals　in　size；　appearance；　movement；　and　behavior。　They　were　as　different　as　intelligent　oceanic　mammals…say；　porpoises　and　whales。　In　making　such　discriminations；　the　human　eye　was　far　superior　to　any　puter　program　that　could　be　devised。　Yet　Elliot　apparently　did　not　trust　his　eye。　What　was　he　thinking　of？
　〃I'll　try；〃　Seamans　said；　〃but　it's　going　to　take　a　while。　You　don't　write　that　kind　of　program　overnight。〃
　〃I　need　it　overnight；　Tom；〃　Elliot　said。　〃I'll　call　you　back　in　twenty…four　hours。〃
　
　
　
　
　3。 Inside　the　Coffin
　
　IN　ONE　CORNER　OF　THE　747　LIVING　MODUL