Table Of Content‘The Pieturephone® System:
Service Standards
Ry T. ¥. CRATER
‘temp seve Sree 35,1070
We dist Gn thie paper ths jundamonis rauiroments of visual
telephone nereice, Phase lo ta abet igacal configuration of he sation
tquipmest. The picture standards ave chosen fo provide the visual edjunet
tun grantor cout tha i neceary to ecure most of he poeibleeancement
Of svat conerstin. Truntminion stndarde are ctalihad ih the
hjeive of Kinin to an cca range the erence én quality bbe
‘he image as weed at th originating sntion and ax cenied over the
angst conection pol sn ta netcorE,
svn sumakunsnst mgctanwron sux Piturephond® saan
‘Thy peevioue paper’ sorbed Pltwrephons service ae pxiwstxly
‘sige for factro-inee wonveracion. Put very simply, we £10 i>-
{este in isproving teleshone coumuniention by raking th possible
for the tea parties to see ss Nell cx hear each other. The zotion of
secing what Is going on at some distant point by meane of elestriesl
figneletransuiled over ites i¢ as eld ge the telephone itself The
fanly work on tolovision was in Suet divested toward a wire pizt-to-
vine vial eerie
“Alihengh television developed ae a broadest evo, ie ought into
being mot ofthe tedhnology nectsary Lo make veual telephone
ie techvvally feasible. Eoenorll, Eenever, the techniques deel
‘oped for television are in temy neice inapproprinis for 8 faceion
leo wervte. The eubecrber's station muse be eouons with «camera,
f secdiver ani veioe equipmen:, workaged for erent dursbliy and
fofely, and manufaciured intially n relatively mode: quanttien; thi
fuagedts an equipment eos several Limes thet of s home (levsinn xe-
tuiver, The sabstiber nessa private tro-wey channel to the newest
[Brucling machine, but short -vtangeenble syetems used for television
teray aze coal, cypsally for the ital rea of vary light develop
28 tren met, sverEoe Tremto4s soumAdy rDMUANY 10)
of the serve, Finally, long-distance television transmission todas,
teqsiring umully an entire mirownve radio channel and attentive
suintenance, is prohibitively eagtly fore facoto-fce service to
schieve wide public aeeeptance,
“The ky aspect ofthe design and implementation of n Pictutophone
stam therefore pivot around questions of eort. Sueseding papers
this isu wll deseribe the means chosen jn each part ofthe system,
to asinine iia ud maatenanceooste wile meeting standart of
service. We have sel thao slaniceta vo chat the quality wil be 20
Inter Un is really needed, pestieslurls ip ube move eoalsensitive
sepa. Ts doing hs we have tne 3 entre that she standards eboeen
ane fully adsouate for ntoer-o-taeesorvige Ia the foreeeesbe fot
sine it may be extremely eo! upgrace ther Iter. Inthe begine
sg dhe usefulness of Pcturephone servie wil be Hind by its eos
‘venigally Iwill be Tinted yi Fnuloquney relat co something
Uke. The ehoie of the standards will detrmine the lena of ils era
1a he Experimental Basi jar the Standards
‘The subjective favors invalvad in wstcblising video sardanls wre
sufliiendy complex that © comprehensive theory is go: wraable
‘Thor Thy weigiting of esonomie naa tevbmiont futons code nk ewery
step lo require eab'eetive teeing ue well Moreover, a wet of sendin
Ste tentatively eteblshed, mumbo ied under relic conditions,
lo vet the overall efeetivonox und utility of the servi tiey dein
Tis consequently the cuthor's privleze to report on the resus of a
series of studiee, test programs end frei, extending over period of a
Uocade and a helf, ead supported by tho wforea of dozens of people
In what follows se attempr ta abeteact sn outline ina logis! sequence
Bf the seas forthe eae il ilenrelated choles thet male up the
Standards
rit nor pao fa mange ees 49 coer so tho Laatumy for 6
ewripion of Uke test ot tre alded 9, einee mare of tho ore ut
[Bell Luboratarics oa vieua ‘lophone atandancs aaa not yet bean pub-
Tishod Ae w pevialexbetinte, may be heute review here bretly
the mujor study and tee: programs which have conuibuted to these
seandarde
"The work may be sonidered to have startad in 1054 with an invent
sation by W. F. Kock, F.. Besker, 1. T. Miller and others of the
posetbiies of « visual adjurel eoustting of a serice of suupshots of
the distant party, procond. nthe rato, in one seaiantion, of ane every
ao wcone* Althoug thie epproech was not pursued beverd the
semviee wcaswal 231
democrat ofits tvinival fase, the work exile ves intree,
‘a che notion of a visusl adjune to lelepbony. In 1986 A. D. Hall
sith J.D, Gabbe, 11, Cravi, al later M. W. Baldwin, ry J.B. Abate,
the author and other, bran a engineering stad ofthe rao and
tubjecive fects involved, wil te ojcetive of extabishing ruiro-
tents for ten eytameat, At abort she eame time WT. Wintring-
hsm with B. L, Bievberges, Rol. Mller ux€ ler R. ©. Breimaed,
H.W. Moursa, EI. Brown ord ethers, bogan expesimenta with meted
of efiien digi! encoding of th ven sgpel. This group wha Investix
tied standavis in oxder to charuelerie the signal which might be
tncoded, Theie wor has oatinuad to fasuence tau al each step
Hy 1060 an iste] erviee definition was availabe, ealing Zor x
O5-Aile vidio signal which eaulé be trapeniteed wd switched at
acceptable eos, A wierion ine’rament exvelopment us iiss by =
iroup under th dveeion of L &. Metesam, The rsulingistrumers*
eferred to ae che MT Pistorepkone station ee, was installed in a2
Sestation sritehed meowork as ai exh at tho New York Werl@
Tair in 1984" Visitors chosen by sundom-rarpling procedure were
fives as opportinity ta male eels between booths of who exhibit, and
{hei esetions wo she raperieneo, in respoet tothe wltyof the service
fn the apiropriatencm of varios feamees of ta act design, were
Uleitd by moons of @ quemtionmrin, Obwrvationa wer alzo mado of
fhe learning pravéss a visitors used the wawiomenl, io decarmine
‘phether any Kurian-enginering isprovements were indioated
Ts 1965 Mod Tse were instlled in 28 Bell Laboruvies aces at
Murray ill and Iilose!, New Jersey, with switeSing and traneth=
sion equosnesh of prelimainccy design ws wilh ‘elametzy opaipmest
fa record the duzation of enrh phase of every ea ana all aperetions oF
Clcuricul sorta, stinnsees ve aleo wet to determine scbjec:
tive reactions, A ceparate tral wea roudusied ab oes of tae Union
Cacbide Coeporstion in Nev Yorke and Chicago during Ue sme yer,
in whieh 86 stations were inal and stasis of both local und
inert gale were recorded®
‘On the busis of nasute of there tial and of eontinning laborstory
experients we vsanonie studies, staomds for an improved station
so Teferre: ta ne Mod IL, ere caabliched in 1688, This olaton el,
Cleseibed in anatier paper inthis fsuo} was “ete trial inthe
Festingbou-s Cunporatins's ofiees im New York City art Pitsburg
in 1009. Tt is glen In cegulaeexperzintal operation is he Marea
Til-Holusdl neewors, now expauded to include ofes of tho American
‘Telephone nal Telogeaph sn Weslen Pleeteie Companies in New
288 num nox ersrm TromNccAC ovat, vuMuLAuY LL
‘York City, With modientons resulting iv part fom ese test, the
‘Mod TK bine boenexployed in wormneril serve sinea July 1, 1970,
hon Plewphone serlee was illite In the Golder Triangle area
of Pittsburgh, Penneylvani.
1 Basie Piture Ropuiements
In ew of the High cost of television transmieson, it would be
prodigal ta provide the picture at broadcast tclovieon etandards. The
prospect of using fewer ecanning lines and Jes bandwith is very
tractive, With good maintenance of station equipement and of wire
‘ranamission systema, picture quality ena be kept eles to the design
objective: much of the pombe quuity of broudeatt ‘levsion ic lot
in tha vacia breadonst path ard iz poor maiatenanco of the bom
television resiver, The neduetion of bandideh which is possible is
[nnited by a boil-in bumen resistance to very fuazy images and to
itnages whic Meker, Aa willbe oan, a isnt bandvideh ef several
Inundrod Iiloherte i found to be necessary
‘A. lange reduolion of bandwidth ie posible if the display of the
tnotge in entinan motion is abarvdened Inthe views adjunde exper
iments carried on. in te yeais 14RK Carongh 1956 hy TW. F. Kosk,
F-K. Beaker, . Le Mille nd hrm the poke elements were fac
tilted ovar a separate telephone cies and sored at the reeiring
tnd uns the enapebot was complete, and then displayed while infor-
ration wsa sccuulated Zor the next image. This adjunct permitted
Jngpetion of lhe other panty, but the disointed rerio of facil images,
fagh one displayed wile ite susceeor wae mao, did aot provide the
fnhanorment of tolephone coxzcreation which cecurs wth fll motion
portrays.
"We have eboeen to give the xystem snficent bandh ta provide
full motion eapatility, adeqvaie, for example, for lip reuding, and
resolution suficient for a life-like image ofthe fue,
“Moat of the vievel exhancercnt of telephone communication n
qites 8 monochrome image only; tho elemonts of it are amiles,
fhowns, averted glance, brond ariny,expreetone of shock, dimey,
amazement, or sympathy. There ere however additonal vues in the
fabaralness of en image timated In solo. ‘Thess kava aot been
Aleemed snficont to justify delaying the cerice util pret of east
of the color station instriment ean be reeolved, They do avgint the
fonsideration of trensmission etpavty in the light of the needs of
future compatible color system,
samviee vennuano m0
18 Banie Operetional Objectives
Since Plctwophone servioe ie to he an extension of telephone
service, imum operite in typlea! ‘elepkone environments, To avoid
‘upienion of equipment, visu] (cleprone and ordinary” elephone
tals should be snade feom the exme station ing:runon!. To simply
Speration ws yuueh as possible, the station address for Dictwrephone
tervice should be the ste as for tlephone cervive, except fora prefix
ta indicate that eal e Uo include tho vieua adjunct.
‘On the other Ind, the user wil aot wnt to give up other speci
telephone servits which he may aleady ve. This requires that the
‘pnique equipment forthe visual adjunct bo sompatible with any of
fhe mazy types of Toush-Tone® telobone sation instruments nox
in ase in the Hell System,
‘Telephone vervne whould not in any was be diminished when the
‘ional chonnel ie edded, and there iv one respect in whieh it shoul
be expanded. It je apyanpriate 2o mupply Handeftee speakerphone
aandio with Piclurophove serve because the hanleet becomes a bacrier
in the epticel peth and detsacta from the feeling of presence. The
hendaot, of ose, remains avail for use when privacy i impor
taut ror nin in distarbing, Te wptakerpbone, on tho thor hana,
is evailable fer talephone culls ux well
‘In ure, the mbeoriber sould he able co make ete w lephone or
1 vice tceplione call to another Pclutephone cation, ora telephone
fall to any telepione stetun, sing in avy case the sume telephone
fnatrarcent If he elests to nike «sina esl, the video channel
provided ab the beginning and is avaluble dhroughout; this moskee ft
possible forthe syzem to eeleet a nvailale video chanel and check
{ensure that Tt end the called silmeriber line are funetioning before
Taking the eouneetion, It will ol be possible to summon the video
fsjunct midway tarough 4 veleyone all ar drop ie midway through
8 video cll Sie any telephone Tine may became a Pzturepona line
fimey have telephoos-only extensions; visual asi may be orginatod
for received on thes, altbough the piptre Will not be sees
‘We bave discusvod only the use of the service for facetowtace
convertion, Ibs no suitable for the transition of graphio infor
Iation, mah es pencil akatekey, dinyroms, piotors and some printed
Inaterial. The video igplay ad ronan channel are ideal fr inter=
ction vith « eompneer. Te nebwork of broadband cheanele will be
‘veil for the (enstsiason uf dala at very bigh epesds. These appli
‘one re deve im other papers in his ise. The standards, how=
240 cw a, sonOmAE ZECCA JOEREAL, SEOMUARY tL
‘ever, ane bite on the fase-e-fsee application, and only euch minor
rmotientions ve loon permite om bekell of other applietions as
‘will not signiiounty oct the eost of the fuceto-aee use
"Ven elementary considerations lead to 2 concept of a steion
Jntrament which oun be added tothe arising telephone st, to operate
fe simply and with as litle dismption of the normal talephove eave
ony posible, No tne transaction eapacity ned be provided
‘han ie novessary to achive the enhancement wich vision adds to
Ingesto-fage conversation, withont visas) strain, nervous strsin or
Aisentrt
Tn seltng standart obi fly equ viel images at nn'-
sum net vigeo parameters sch a notaber of asanning fine, reaD-
Iusion and the wows bi dep wf pein imypsitnont of ane kind
ave of primey insportanee because thes dlermine che cole of ana
‘Thesp roquitemeasa tous: be evatoatod in vere of 8
‘specie sttion eoagurwtie, wih :xctiularrespeet to viewing
distance, niore sis, and plccure aspect -vo,
“To omits with th dishes of etandarde, we therfore lok next
ot the station consgertion. Given tke ici requizement that the
feipmest be desigeed dor uee e: the eos> quartre provided by «
‘iesk a lable ere ave some ooratints that met bo eccommedatad
4. Imani the Pincer
‘or the partis te the conversetion to enjoy a normal visual ex-
‘change, they should each rezesinrelisbly ip view of the other, and
Ley shuld e able 1 “ook each other in the eye." The frst of these
rode mighé be sini by m camera atvanged lo follow the user 50
fs to ke him contend fn the Geld of view. Tha present consid
fred unltraeive on technes}, ecsnomie, esthetic aul paychologeal
rounds. Some resins is thane dasiraie tw ey the ser sey
‘iow. The eotond ideally muines that the camens he Tasstd in fest
tere the sere is, st seul he bridge of she nove ofthe ia
oth of there aeuls ace nite wel iste yy putting the came:
Loshind a halesilvered miror whith sofre the icege of the display
tue so t ean be reon by dhe user." "The resull s wo Sx inthe atic!
‘ath Lo Ue sso 9o that fe apzeaze to be et the ferent ef hort tune
Bol, Tn onder to see the entive image, the ase aay wha the eamera
senvice staxonsos an
fold, Eye contact is also ver good, A achematio diagram of exe»
ion sot ie show in Big. 2; inatranat ong chit prinaple wee
‘onsiructod and tested at Bell Laborctorios ia 1965 by T, 1» Filen-
berger.
‘This errangement makes it quite Aion: for thers in the evom to
see the image, While the resting privacy is an advantage in some
abe, ib nn soutee ul fran len the nore Wante ta Sntroduce
‘second pereaa to che diane party, o* when be wents to demonstte
Tie sevice to others, ‘The rit ala reqives an ierease in bul,
For these zeneone the super wonfigaalon sown in Fi 2 is pe
sed for general wee, The viewer 10's direst atthe sereen and the
camers it leeated at 2= emall ix angle from tie strom ne poeile
‘The eve contact sequivenent.remaiza t saster tv emensoning the
inctiuwent Wis quelion iy Giused fare in the paper on tbe
ation set bx tha sue. The eventual devrlopment of a station eat
Cringe sit tie! path iy mo moans role ont By the stands
tre bave chosen, smi sash a sl would lave aunties advantagie for
Tne wae sh wns to rsohe he cistracions of Su enzeooment.
1 The Caner Pt of Vine
Sone} mata te re eline af the wen semen Ss the euestion
of the felt of view. Sige che major vimun sls in conveation are
Tc: expreesian and movements of sho her aes, isthe aaie
nin bundwidts ould bo required Zor an image of “he head oaly
With the epensoxce, she consciows clfortzesunce ofthe user 7 stey
jn eo couetraiaed a postion wouls male zim que tmeomfortae
Fapviments enncaeed by 1. D. Gabbe cad others Sn 1866 and tere
after nial by RT. Rilmbeger and athere aboot the sare “ime
242 nu saat avoTHME TeoMSTEAL JUN, PERROARY 972
ig. 2Salon st wi 9 ia
ickly established the decizbility of the Hesd-end-shoulders view
‘the epenapreen eonfiziation. TH pee a
rocomnry dares of fioetor of mation, but alo allows the distant
party to see come of the surouring envirormest, hows additonal
‘isu signals such ne rnd and arm motions and chrogs, and provides
fn entetionllypleseing pcre. xperever withthe REod I set at the
[New York World's Heir in 1064 contre! the adventeges of the
Dead-asd-ahouHre view.
"The eubtentelearinge in trezamiasion aoe might juny the ead-
‘only yietora in the early years of the service when eos are para
Imouat, Ke the long tems, bomerer, the provision of the head-on
thoulders view ia considered necesary Ur neste the full adequecy
ff Une verve foe norte! Saeeto-Eace eemvorstion,
Piao Siz and Fiewing Distance
‘The ratio of viewing dieanee ta str seis closely seated Wu the
smi of scanning lines a ta whe horivall reso}ntoa, and in fuok
‘o many slker pela quality etendards, This ie beesuse the wer
santa re ene enugh to axe lo: th wis! pene dca buf
hong away to be unditanbed by the Hine sirueline and otber visual
‘Molde tot waning proce, La eho wewatelepaone appliction
‘icing distanoe tanés to be the nope. vacieble,eaving picture
sie an scaisng stalarda to be ekosca in the Tih of the coe! of
bendvidth in tien con,
Since Pichsrephone servige muse opersie in the mlatively aml
paces in which Uie telephone i ured, the avelwble viewing distanoe
is limited. Toru eek wi ordinary size a dietnce greater than about
09 eset is nvlowand. Ton tale too mush for many telephone
Sitnations, On te olier hand, shocter viewing ditanoes tendo
‘degrade the image cbainod by Ue camera, waich sust be located as
har the deplay a0 proctieble, Shor eamers ranges tend to increaso
the eye eontact angle und to inlrvuee distortion efets duo to per-
smuyton seasasroe 28
sprolve, A short exter range who cepeives the user of leeway for
‘oml forward and Bockward waverente. Ase: whu Jae
forward U3 mctr Zona &xertn]ronge of 0.9 meter may’ lil rent
fan aeeepable pirury, bu. the es nf moring from 08 meler (0 03
rues Hound to be inst goles
‘A longer comers. rege also reduces she height which the eamers
sus be nested, and therelury lua Wo ove encpact eat Sie tbe
head ie to anpecr near the rertar of the picure, the camers mast
citer be lownsed ae se level of Le hezd or be ited upwend. Tting
‘Te enmore tende to bring ovevhesd “iphts izve the pictur, ad if
nated to extremes, aler walls ard haokesses appear to be easing
Tbeeemand ane produoce a divelel view of tho faeo. ‘he further
any ‘ho camern the owt Hin opted and ell eranin within
given Ullwagle bation
Bowausb of these fasts, uted hy experiance with the Mod
ec 9 sieing distinc of DDB welch (4 inehes) has been ebue, to
place che fartoment ae far sway a povsile while kemning fon the
Hes oe lable sh which the nse esi:ticg. This shade has bean no-
tsined Uheoach Ue sevcsal Lleof the bro secon ect mass
"Ths chai of plete sine is eomewant more complicated. A pri-
rouy Tne i Uae stability af a compact cubseniber's et. Llowever,
we user's eatherie or pryrtoloen’regotion ia that. the eture se
teen at the cesign sieving divsncr iv "00 aca"L” be may tend to
bomapennete by moving forwar’, In experirenle sl Bll Taho-asnoe
1058, BLL, Eienbenge: sound thar nt-a viewing Sitanve of aly DOE
‘note, © itane nf aboct 0013 equnne ulin (2) spare inches) see
rejeoal by lest aubenta ia favor ef Lexger pit
‘An upper Tit a Ube aizo ie fnposed by cho Froth fhm dee
ko use for ether aetvities, It appotcs however Ubi eset prefers
fase tenet piknne sige more thon deve pee might, MrT
Sewer Toul ovefused pictuse asghie manga fom O18 reer (55
Inevee) Un 0.0 meter {02 inebos) at wiswing cistacoes frou O88
moles (26 father) lp LOT meter (22 inbea}. Le tome welt. S25-line
piesa and the hugh, prelesences obtaizad ace there're bascd on
fethetie preferences rer hen verter wsiiity, ln feet of psturee
fish Ueokad bardvicth aden Pell Labnsatories, 1D. Gabbe ard
0 Handi and that it 245-lne pictus o£ 0 S8-aneter (Sine
fight, cubjeets cussion 4 1nevae vieming ditanes fo eos, wale
rrith a O.-meter (3) neh) plete oF the same pamber of Bags, the
Tater Siganee es etcely valifaclry,
(Optimizing the yilare at minirmam bandwidth Jeade ¢o a sila
2A mre a, svar mmrmoat rout, ssacaRT er
are hight, The piss highs sha Be ehazen ta ake the crane-
{hid iforasina Cally available yen WHR neal vision
“The viewer ums to approach the ire uni La seaming erature
socomes alent ebtraee they there ik vo aevantage in Woring
loge, Lf the distance av wet this Exper U9 eter (BN ince]
che eptcaom viewing range wi. eoinsie ith te vues esmera range
twill be duowe in Seclion TEL tasb this Les ton pote hight of
aboue 118 mete: (3 the
‘The choiog of sitive Heigl wanna’ he ertvey divoreed fro te
vhuivo of aml alia. Suutes oF yrefeenel sepectsatio for a howl
fedbshenlders view, based spa ening cho pews, were nie in
omalete geese a 8:4 asporsvarin Coca thei) Dein fone
vote ebay and lol 1:1 ia mall, Phe Moe L wanna el the
Bef tao, will a OM -noley (As med) by OAGemeter (3/4 eh
intute, Prins uf thie myinnct ak tne New York Woel’a Tair
1885, ot the Uaioe Cacbide Corporation ja New York and Chiengo in
1D6R, ad al Rll Labotures hens in Meee El end Hosea,
Now ervey, i 1906 nal Tier, eld len.on to he vscr's problem
of etuyimg within the earora feld of vier. A whoive of the 4:3 cepect
‘cio of entertsinment television wo wolves problem quite oa
lovely, fs ae handwicch world sn be revel Iy «ae nto 16/9
fare given meathacon al koe acta weer image,
‘These factors were compromized inthe Mod II ear by the choice w:
the 1151 ast rat; te “rare Semone ennistne, with eet erate
opis apr ao tor viewing, yier adeqaeTradom far
thence gn Je ceonoriea of andih. Ax the eame tie, she picture
ght way vead eon UI voter ta the (18 eter mentioned
ior, Thi sere Ul ili ube ne aun. lo tease
the inereaee it the contsitation of sha digp'ay anba tule, from 47
sere Lo 0 gore, wed praitiol nshuetinn uf the exe amet
sagle, The Weskindhouee and Bell Lekoratorioe Win revalte with tke
[Nod LU design indies tat theee dimensions are enticely entifueory
2 Au and Controle
Tom sido hyo val, He Potnens Vacéae a woby we
ubeteteion.coveca‘ing impovtane pene of the Fee, Sy c0 ourene
a hae, iat wi pe stan the arpa
dbjene to be caplayee. For thin reruns torophone and spescer are
fons ceantil for every sation, ‘Tho lade mz: ele he vale
able for tse ocentons magn criracy ot background noize tales the
orakeroue areangerient undeseadte.
