?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=The+intensity+JND+comes+from+Poisson+neural+noise%3A+Implications+for+image+coding&rft.creator=Allen%2C+Jont&rft.subject=Psychophysics&rft.description=While+the+problems+of+image+coding+and+audio+coding+have+frequently%0Abeen+assumed+to+have+similarities%2C+specific+sets+of+relationships%0Ahave+remained+vague.+One+area+where+there+should+be+a+meaningful%0Acomparison+is+with+central+masking+noise+estimates%2C+which%0Adefine+the+codec's+quantizer+step+size.%0AIn+the+past+few+years%2C+progress+has+been+made+on+this+problem+%0Ain+the+auditory+domain+(Allen+and+Neely%2C+J.+Acoust.+Soc.+Am.%2C%0A%7B%5Cbf+102%7D%2C+1997%2C+3628-46%3B+Allen%2C+1999%2C+Wiley+Encyclopedia+of%0AElectrical+and+Electronics+Engineering%2C+Vol.+17%2C+p.+422-437%2C%0AEd.+Webster%2C+J.G.%2C+John+Wiley+%5C%26+Sons%2C+Inc%2C+NY).%0AIt+is+possible+that+some+useful+insights+might+now+be+obtained%0Aby+comparing+the+auditory+and+visual+cases.%0AIn+the+auditory+case+it+has+been+shown%2C+directly+from+psychophysical%0Adata%2C+that+below+about+5+sones%0A(a+measure+of+loudness%2C+a+unit+of+psychological+intensity)%2C%0Athe+loudness+JND+is+proportional+to+the+square+root+of+the+loudness%0A%24%5CDL(%5CL)+%5Cpropto+%5Csqrt%7B%5CL(I)%7D%24.%0AThis+is+true+for+both+wideband+noise+and+tones%2C+having%0Aa+frequency+of+250+Hz+or+greater.%0AAllen+and+Neely+interpret+this+to+mean+that+the+internal+noise+is%0APoisson%2C+as+would+be+expected+from+neural+point+process+noise.%0AIt+follows+directly+that+the+Ekman+fraction+(the+relative+loudness+JND)%2C%0Adecreases+as+one+over+the+square+root+of+the+loudness%2C+namely%0A%24%5CDL%2F%5CL+%5Cpropto+1%2F%5Csqrt%7B%5CL%7D%24.%0AAbove+%24%7B%5CL%7D+%3D+5%24+sones%2C+the+relative+loudness+JND%0A%24%5CDL%2F%5CL+%5Capprox+0.03%24+(i.e.%2C+Ekman+law).%0AIt+would+be+very+interesting+to+know+if+this+same%0Arelationship+holds+for+the+visual+case+between+brightness+%24%5CB(I)%24%0Aand+the+brightness+JND+%24%5CDB(I)%24.+This+might+be+tested+by+measuring%0Aboth+the+brightness+JND++and+the+brightness+as+a+function+of%0Aintensity%2C+and+transforming+the+intensity+JND+into+a+brightness+JND%2C+namely%0A%5C%5B%0A%5CDB(I)+%3D+%5CB(I%2B+%5CDI)+-+%5CB(I)%0A++++++++%5Capprox+%5CDI+%5Cfrac%7Bd%5CB%7D%7BdI%7D.%0A%5C%5D%0AIf+the+Poisson+nature+of+the+loudness+relation+(below+5+sones)%0Ais+a+general+result+of+central+neural+noise%2C+as+is+anticipated%2C%0Athen+one+would+expect+that+it+would+also+hold+in+vision%2C%0Anamely+that+%24%5CDB(%5CB)+%5Cpropto+%5Csqrt%7B%5CB(I)%7D%24.%0A%25The+history+of+this+problem+is+fascinating%2C+starting+with+Weber+and+Fechner.%0AIt+is+well+documented+that+the+exponent+in+the+S.S.+Stevens'+power%0Alaw+is+the+same+for+loudness+and+brightness+(Stevens%2C+1961)%0A++++++++%5Cnocite%7BStevens61a%7D%0A(i.e.%2C+both+brightness+%24%5CB(I)%24+and+loudness+%24%5CL(I)%24+are+proportional+to%0A%24I%5E%7B0.3%7D%24).++Furthermore%2C+the+brightness+JND+data+are+more+like%0ARiesz's+near+miss+data+than+recent+2AFC+studies+of+JND+measures%0A%5Ccite%7BHecht34%2CGescheider97%7D.++++++++++++++++++++++&rft.contributor=Rogowiz%2C+B.E.&rft.contributor=Pappas%2C+T.N.&rft.date=2000&rft.type=Conference+Paper&rft.type=NonPeerReviewed&rft.format=application%2Fpdf&rft.identifier=http%3A%2F%2Fcogprints.org%2F1513%2F3%2FVision.pdf&rft.identifier=++Allen%2C+Jont++(2000)+The+intensity+JND+comes+from+Poisson+neural+noise%3A+Implications+for+image+coding.++%5BConference+Paper%5D+++++&rft.relation=http%3A%2F%2Fcogprints.org%2F1513%2F