‘The Station ‘The Picturephone® System: 2C Video Telephone Station Set By W. B. CAGLE, K. K. STOKES, and R, 4. WRIGHT (Manet serie Ooi 1 20) This exile describe the sution sa desimal jor use sn cnmmercial Pcturephons® terion. Coded te A Video Tetephone Staion, it enette of three nw pions of appraise 14 Diogiy Unt te 1A Service {ask andthe 784 Cond Lit We dies tains of Be eetrical and phywial dean. ‘The station sie that park of Use Pstucehens eystean with which the customer internet dccetly ni the peeing? hae fr his rou tions to the rervien, The vet would provide the video camorn ond Tislny nelions, handietvee andio feelicee, and the noeeecry ou tomer eontrolt in an atrsecive, exsy-to-use, ard oonuien! form. he fundamen design sequizemente for the 20 Video Telephone Station, commonly known aa the Mod IL Picturephone Sct, evolved from laboratory and fel atudiea ae diaccwed in other papery in chit jvc" From these another studies, che following general obotives sere formate: (i) Tho Piarephone station equipment should initially be designed. for desl-top location and should ork in eojanetion with ‘any standard 1-button Tousk-Tone® telephone. (is) The ost shoud ineonporste & built-in speakerphone with ox, ‘rr, and vou controls. (68 he eamars and digplay should utilize a L-MIIs video signal containing 261 vibe scanning ines in w bwo-l-one inerineo, 30 frames pr ewoond format (is) Pho camera should be physically vtered sbove the display (ue whit abi piv se pltune ith a TT by 10 aspoot 272 wen auc everns aueuniest sommeay, yumMUANY 177 (0) The user il sit sbont 0. mets in font of the set and should be eble to openste the major costola from this postion (oi) There ehomld be eoatzols for changing the display brightness, vinwing the outgoing pioture wd shutting off tho camern for ideo privsey (oi) The ext should contain simple mean Jor customer eontel of the camera fld of iow for si, elevation and azimuth. (vii) The cemera should sxtomusticlly sompensate for 8 wile range of ambient umsination covering the levels to be encountered in ofees (s) The set should ntiie Toeal 110 V se power snd talephone service sould not be impaired during power flare, (2) A convenient menus for trxuaaitting gaphion| material should be inecrpoenid, ‘The resulting station equipment devine to mecé these objeslives tovnists of a diplay nit end eontel ‘nie which, tepother with a ndard, Towsk-Tote tlentons, arm lovato! on’ the user's desk, ‘These unit interface with the netnerkedirowgh a aervio uait whieh fa be rnmotelp located vith m cable ran of 25 mecere meximunn length "3 GHD Canto nit ie sleo required for speakerphone operation. "This unit i eonnseted nto the Picturepkono elation equisment st the cerviee Unit, ‘The SSD Com‘rol Unis hue more reelved signa Incnelingeapabil3y than the 349 used with 2ho A Speakerphone ‘The 14 Digplay Unit (Fig. 1) conta tho carom and display tuber and aoiosited tronemstier and zeeeivar electronic, the Tou! teak, and tae cane sounder for dietinetive Piclaephure ea! elert= Inge While designed primazily for face-to-face communication, it includes « buil-in espablty for showing grephies plage on the dak in front. of the set. The digplay unit design is discussed in det] in Beolion T ofthe paper ‘The T2A Couto] Unit (Fi. 2) eontsins the user controls and the microphone for apexkerphuvi opertion, The 0S, OPP And VOIR oo trols aze for handé-iree uudio operation on telephone und Picture- phone ells. Tho ieropbone en be muted for audio privacy by held- Ing tho guucr bution depreeed. ‘The ve-seur and Duvacy switches provide for checking the trunsmittd pictare and for shutting of the famera for video privacy. A distinctive horizontal bar pattam is ‘sanmitied when the mevuey aviteh i operated, The zoos and FRRLOR= controle allow the usc to adjust the run = 28 cameru's eld of view, The meomr contr permits adjustment of tho dlzpury brightnae for bot sulfonive povfermanee, The decga ofthe tontco! unt is deseribed in Sesion TT Tho 1A ferric Usb (Tig. 3) cotaine the station power supply, fuparvisory ene conical ln, and the videw Tne /logp terninatin, protcodon end caninvenancecleleonies, All inlaller austenite nd options are foeted in the servive wil to srspify istallian and tinlenaree, ‘The esrviee rt desvn is eseribed in Seetion TY. 2 Cova Fare 1.3 Lens Cosiderione ‘The display’ un i derk-topinstraazen designs to accommodate the height of percent ofthe Amsinas male and fmplo ad popt~ ition when seated, For eonvenivne of desk use und oer reasons, a ‘D-om viewing disanoa has bean evabliched A eurvoy of subjects ising Se Med T Pietiephove act slow that users seldom remain at t xed viewing distant, Et move from « nesrpasition ef €0 ex» to «distant postion oF 140 om, mth an averaye distance of 82 em, This cerabliched ni objest feel distr of 92 em for the camert fang nd porn te display wn 0 Ie posiionedheyord cho eon taal working ree ofa ek ZZ Fg. 81 Sere Lt Carer en. An aperture stop of #28 mue solecles as 4 compromise between i of field eoalderation and the ad I lens. The rirulking rons plas diemetar of 1.65 em ie wh ating vraphies, oye comtect angle, zost az size cbjevcves. Above an il inion of four fishers, an ancemsaie Sin pongsessively elses 276 vn svermae TaCuNCAL JOURNAL, FEBGOARY 171 sad thereby inerouee the deplh of fil until the 60> to 160-em range fof weer metion ited above ix acoommedated with an Muinstion 0! 422 oot-iembert, Wor biguor light levels the irs epntioues to stop flown tntil a maximam design allaninalion of 420 foot-luaberte is ‘eacled. Te sange of illiination over waieh the sot works exeneds the ge of igh levels recommend 95 the Thuniaating Bogineeing Society! for offceapplietion, "The lees cortinuoualy riewa the maximom object field. Zooming is sccomplished teetrially by reducing the zaser size on the cemers get to evan a portion of the wide cagle Gold. Smiley, austment Of fhe eflestive dolia! aie Zor unere oF different heights 3s oblainut ‘without moving the Tees by digplucing Vie resiuoed raster vetially over the fll ge ld bw “Boeeuse of the melhod used Sor height adjustment, the maximum objost eld height Js determined by the rang of customer brights Referring to Hig. 4, the 99 peroatle large mic cole upright mes ‘ures 489 om frou the deck to the top of hia heed, while the 1 per- eae smell roman easted relied mesured 204 cr from das to thin? This range of 484 em is supplemented with vordienl mangins to fame the eubjeste aul allow for vavatina in doek-to.chair height dif- ferences, yelling a desir! verdes! ald eight of €07 en, ‘Po scecme todata thie object fll igh st a 92-cm viewing dirtzave with at 11 to 1D aapect rai, a wide augle Ione was required with m 52° diagonal (ck'ng angle (7 verti! ‘aleng engl). ‘An invert lle lens wae designe! to reset the radial varia ig. Horna fetrersierione for ube placement seunen sur Fy tion in relaive Illumination typically exporicved jn x Tans due to oct Joes! The sx-lerent less hae a paras] tracsmisson factor of ppeiniintely 80 perecnt with rvletive lsmination at the wide engle alive falling to wppcusinniely 52 percent. In adiion, the modulation Uuansiae function (MTP) was shapes diferent from that of « cone entional pholographie lens to. maximize the signal for frequencles Telos MTB, At no poi does the MTF fall below 75 percent. Wish 1 focal length of 16.15 mam wad a maueification ratio of 1/57, the lene paducer am image of 167-tn diameter, which i equal to the diagonal of the LlG-em by LOG isa Tormal on the camera tare aa Tue Placement ‘Tho exer is oested 38.4 om above the desk wn tad upwards for che cootzel s0y to intercept the center of the desired ebject fel (42 em nbove dec height) ct che desi viewing distance of 62 ex. ‘The plseemen: ie a compromise besween uuduc xt hugh ad exe sive eattera tlt which would itzodce perspective dictction aod the eaolem of intervepting eeling tik. "Phe disolay tobe is ploeed dizecly beneath the eamera Zo min~ inize uw eye cont angle, Revause the user views Pe dipley rether tan te comers, che cranemited picture stoma the fxation poits of the oyer dieplecod downward. Mouauremente? show thst tbe loee of 7 contect in more difeuk to pacesivo on tke vertical exis taan on ‘he Aovionsa. ‘The los of eye eantach on ke vertical sx ia peresp ‘ible at about 3° end objestionable at 12°. Fortunately, the center of inceres in a display tubo—the place wheze the majeity of people refer te paction their ayes in the pickme—areurs 1D peteent shove ‘the tubs canter. Tbe seperation between ta camera and the dipley enter of intrest ie 08 om, ea dederaniaed by the tube snes, At 8 Swing distance of 2 en, thi ella inne wy mac ane wf 8", ‘hich perceptible but eceptable. "The Plturephone sereen dgplays abot 250 Tnes, To obtain satis: Iactory subjective pielare quality ab the prefered viewing distace the display tbe height wor st at 127 em, Tho 11 to 10 width-to- eight aspect rtio reslled in x Meemcoide diaplay. At « viewing distance of B2 ex, the evi display semuins within the ental 10° fee. of bot perception? (16 em wide) nnd permite total viewing ‘without eye motion. This eof guration provides comfortable head inclination for viewing Tora seated peron, the types ine of lat is 15° below he hoxzontal 278s sds MRAM TERMI AULA, MIMD 5° about that Ting” Therefore, the vl the comfortable hen it Aisplay sabe sould be paged euch Unt tay top odge is below the hoviontal eyo Level for the emall woman snd tho bottom edge ie kt than 30° Dolow th: uvizontal for the tall man, Within this 28.9¢m range, the dnp soran placement 2erlting ‘tom tho aforementioned tonaideretions achieved ceneprabis downward angles of O° for the fall woman sul 25.7 for the large man, “A simple. vsor-mounted min on the front of tho eaers provider a eapublity for traneitting graphs, When the vitor ie minnnally Ttte as shown in Pig th lene atomacosly refocus co ce plane ig Orage vi nope