BSTJ 50: 2. February 1971: The Picturephone System: The Station: 2C Video Telephone Station Set. (Cagle, W.B.; Strokes, R.R.; Wright, B.A.)

26.7 MB·English

‘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