摘要：Human observers do not accurately perceive acceleration of neither motion in frontal plane nor motion in depth.Recent studies simulated motion in depth by changing only relative size of the object.The purpose of this study was to investigate the influence of various levels of representation of depth on perception of accelerated motion (object approach) in depth.Additionally to using the changing size cue,we used three sources of depth information: object texture,ground texture,and motion vector tilt.We discovered that the chosen sources of information had significant effects on the perception of accelerated motion in depth.When only looming was present in the viewing scene,observers perceived decelerated motion in depth as constant.The result could be interpreted in terms of the foreshortening of perceived depth.The main effects of the three sources of depth information were similar: they did not improve sensitivity for motion acceleration,but with their presence motion had to be more accelerated (less decelerated) to be perceived as linear.Object texture was the least influential source of information,whereas motion vector tilt was the most influential.When motion vector was tilted for 15°,approach had to be accelerated in order to be perceived as linear.We argue that the latter effect was due to the frontal-plane motion vector when height in visual field was present,which in turn relates to the findings that motion in frontal plane has to be accelerated in order to be perceived as constant.We also found that object texture consistently decreased the effects of ground texture and motion vector tilt.The obtained interactions among the three sources of information indicate that these sources integrate as proposed by the modified weak fusion model.
其他摘要：Ljudje nenatančno zaznavamo pospešenost gibanja v čelni ravnini in v globini.Dosedanje raziskave zaznavanja pospešenega gibanja v globini so gibanje v globini simulirale zgolj z večanjem ali manjšanjem relativne velikosti predmeta.Namen raziskave je bil zato preučiti vpliv prikaza globine na zaznavanje pospešenosti gibanja (približevanja predmeta) v globini.Poleg spreminjanja relativne velikosti predmeta smo v dražljajski prikaz vključili še tri globinske vire informacij: teksturo predmeta,teksturo podlage in nagib vektorja gibanja predmeta (ali 0° ali 15°).Ugotovili smo,da izbrani viri informacij pomembno vplivajo na zaznavanje pospešenosti gibanja v globini.V primeru,ko je bilo gibanje v globini simulirano le z optičnim širjenjem,je moralo biti gibanje upočasnjeno,da so ga opazovalci zaznali kot enakomernega.Rezultat smo poskušali pojasniti s skrčenjem zaznane globine.Učinki vseh uporabljenih globinskih virov informacij so bili istosmerni: čeprav niso izboljšali globalne občutljivosti za spreminjanje hitrosti gibanja,pa je moralo biti za zaznavo enakomernega približevanja gibanje bolj pospešeno (oz.manj upočasnjeno) v primeru prisotnosti virov informacij kot v primeru njihove odsotnosti.Tekstura predmeta je predstavljala najmanj vpliven vir informacij,nagib vektorja gibanja predmeta pa najvplivnejšega.Ko je nagib vektorja gibanja znašal 15°,je moralo biti gibanje pospešeno,da so ga opazovalci zaznali kot enakomernega.Premik točke subjektivne linearnosti s področja negativne na področje pozitivne pospešenosti smo poskušali razložiti s tem,da z nagibom vektorja gibanja za 15° gibanje predmeta dobi še eno dimenzijo,in sicer komponento gibanja v čelni ravnini,za katerega pa velja,da mora biti pospešeno,da je zaznano kot enakomerno.Viri informacij so interaktivno vplivali na zaznavanje pospešenosti gibanja v globini,pri čemer način sovplivanja nakazuje možnost,da so se viri kombinirali v skladu z modelom modificiranega šibkega zlitja.
