US1851072A - Apparatus and method for electrical transmission of pictures - Google Patents

Description

March 29, 1932. e. s. VERNAM ET AL APPARATUS AND METHOD FOR ELECTRICAL TRANSMISSION OF PICTURES Filed Dec. 15, 1925 2 Sheets-Sheet l g N [N VEN TORS g 61.5: vmm zffin mma B y 21?. P611 7 A TTORNEY 19215 2 Sheets-Sheet 2 Mar h 29, 9 2- e. s. VERNAM ET AL APPARATUS AND METHOD FOR ELECTRICAL TRANSMISSION OF PICTURES Filed Dec. 15

IN VEN TOR MUM;

A TTORNEY of area'and transmitting code combinations,

" lying portion of the film 12 falls on the pho- Patented Mar. 29; 1932 GILBERT s. vER1vAM, or RIvnREnGE, EwfJnRs-Ei. ANIIYEDWAYRD nl wa'rsoiv, or

. V 'ranorriuoiv r, AND DONALD B. PERRY,

F .YoNKERs, new YORK, 3ASSIGNORS-TO AMERIGA'N TELEPHONE AND TELEGRAPHflOMPANKJA CORPORATION OF,- -Y ORK Q APPARATUS AND METHOD non E wmm mwsmssma onrrcrngans Q Application filed December 15 1923. erial No. 1,007.. I

' The principal object of our invention isto providea new and improved method and suitable apparatus for transmitting pictures "ma distance by electrical impulses. An-

nuniberof elements in thesequence. These 1 other object 'of'our invention is to provide corresponding to the degree of shade of the successive elements. Anotherobject of our invention has relationj to transmitting asingle, code combination for a sequence of elementsof like shade, the combination indicating both" the degree of that shade and the and various other objectsand advantages of our invention will become apparent on consideration of the specific example of the practice of the invention which wehave chosen to disclose in the following specification and illustrate in the accompanying drawings. It will be u'nde'rstood that the inventionis, de-

fined'in the appended c-laimsand that the following specification relates to the particularexample'here presentedto illustrate the invention. I I I Referring to the drawings, Figure -1' is a diagram showing the, transmitting apparatus, Fig.2 is a plan showing the code as punched in a section of tape and Fig; 3 is a diagram showing the receivingv apparatus. The picture to be transmitted is in the form of a semi-transparent film 12 which is wrapped aboutthe glass drum, 10; thisis rotated on its axis ,and'meanwhile traversed relatively slowly along its axis so that the portion 'of the film 12 adjacent to the opening in the screen 13 describes a helical course of adjacent turnson' the film 12. The light from, the source 14 shining through. the'opening in the screen 13 and through the undertoelectric cell 15. The current in the circuit of the cell 15 is accordingly varied in corjr'es'pondence with the varying degree of shade in the'spot of the film 12 adjacent to the opening in the screen 13. This varying current relays A; B and C are in the output circuit of the amplifier 16. The adjustments'are I such thatgfor a part ofthe-liln'1f12corre-v spending to" White none of the're'lays or -(J will pick-up;v for light grey only 'will :pickup, as shown in Fig. 1; for dark'grefy 'A and B will pickup but notG andfor black all three relays A, B and(} will pick up. The cams '18 and 19: rotate once for each,

unit or element of the picture film 12 lying under the opening of the scree'nll3.

is punchedwith a code cornbinationjwhen the shade changesjto indicate the preceding shade and to ind1cate the'-*'nu1nber of picture e1e ments' in sequence having that same'sh'ade.

The'co'de employed is the usual'fi've unit code I shade. As shown in Fig. 2, this number of units permits countinga number of-elements up" to seven inclusive,-and as will be pointed out presently, if a sequence of seven elements of like shade is encountered in the picture .to be transmitted, the countis made to seven and then the apparatus is cleared ready to repeat. Suppose that a'singl'e'whit'e' unit inthe 'pic'-.

ture film 12 is to be transmitted." Aglance elements in the sequence "havlng' the same atFig. 2 shows that-the corresponding code I impression in the-tape comprises-i holes punched in the first and thirdfpo'sitions; the punch in the first position meaning a single unit and the punchin the third position meaning the white shade. As already statdyfor the white shade the current in the output circuit of the-amplifier 16 will be so low that none'of the marginal re lays A, B and C will be operate'd'an'd their armatures will all be ontheir back' contaots at the left. f 5 With thearmatureof relay A onits back contact, relay a will been'er ized so 'that'whe'n cam 19 closes contact'25 a circuit-will bemade "through the back'contact of relay "0;: upper front contact of relay a' 'back contact of relay a to the perforatorrelay 20, whichwill cause the latter to lock up and energizethe punch magnet 21-. 'This will punch the tape f28 v The tape 28 '(shown'both in F igs. ,1 and upper winding of relay a and causesit to operate. 'Also, the operation of-thepunch magnet 21 breaks the locking circuits for relavs b" and and releases them if they or either of them had previously been locked up also the operation of the punch magnet21 releases any of the counting relays 1a, 1b, 2a, etc., that may have been locked up previously.

The operation of the punch magnet 21 also breaks the locking circuit for the perforator relay 20, which opens and thereby releases the punch magnet. The release of the punch magnet then closes a circuit from battery 23.

through the lower back contact of relay 0 and the lower winding and front contact of relay a to energize selector magnet 3 and also lock up relay (1.

Y The cam 19 continues to rotate and closes the contact at 24, the counting contact. This closes a circuit from battery,rthrough the upper back contact of relay 0, the back contact of relay 1b and the winding of relay in, which operates accordingly. This connects battery 23 through the armature of 1b and the armature of 1a to the winding of 16, but lb-does not operate at this time because it is already shunted by the low resistance path just traced through the contacts at 24-, 0 and 1b. 7

Also, the operation of relay 1a closes the circuit for selecting magnet 1 and causes it to per When the counting contact 24 opens, this opens the shuntaround relay 1]), which operates and transfers the counting circuit -(throughthe upper back contact of relay 0) so that now, instead of connecting to 1a and 16 it connectsto 2a and 2b.

We have already assumed that only a sin gle element of white shade is to be transmit tedso that accordingly the shade will now change, Assume that it changes to light grey. Marginal relay A willbe energized and relay a will be released. When the cam 119;.makes the contact 25, a circuit is closed from ground, through the contact 25, back contact of relay 0, back contact ofa, front contact-of'a to the perforator relay 20. This operates as described before and the punch magnet. 21 operates as described before, and selector magnets 1 and 3 having been previously energized, holes are punched at the first and third positions, as shown in Fig. 2. The operation of the punch magnet 21 releases the countingrelays by breaking their circuit at the contact adjacent to battery 23 and the system is ready to start overagain. I e

Let us go back and suppose that instead rater relay will not operate because its of a single white element in the film 12 there were five such elements in succession. Then, when the punch contact 25 closes, instead of getting the, result last described,,.the perfocircuit will be open at the back contact of relay us. However, the counting contact-24 will close a circuit from battery, through the upper back contact of relay 0'," front contact of relay 16, back contact of relay 2b, through the winding of counting relay 2a, which will opera-tent once. By the operation of 2a, battery 23 will be applied through the windof r'elay'2b, and as soon as the contact 24 opens, opening the shunt around 26, battery '23 will become effective and operate 2?) as well as 2a..

On the next revolution of the cams 18 and 19 corresponding to the next element of the picture film 12, counting relays 3a and 3685 will be operated and locked up in similar manner. Thenon the next rotation of the camslS and 19 for another element of film 12, relays la and 46 will be operated in like manner. It will be noticedthat relay 4a has its winding in series with a winding of relay -10 so'that relay 10 operates simultaneously with 40 and 4c locks up by currentifrom the battery Also 10 closes a direct circuit from battery through the selecting magnet 4:. i 7

When 7 the counting contact at 24 opens after the fourth count, relay 46 operates by reason of the opening of the shunt around it. The operation of 1b breaks the circuit from T00 battery 23 to the relays 1a, 1b, 2a, 2b, 3a and 3b and allows them torelease. Then, when 2hrcleases it breaks atits rightehand front contact the circuit for 4a and 4b and they release, but 4-0 remains locked up.

' On the fifth revolution of the- cams 18 and 19 corresponding to the fifth successive element of white shade in the film 12, relays 1a and 1?) are operated again successively upon the closure andsubsequentopening of the contact 24, causing selecting magnet 1 to be operated. After the fifth revolution the shade changes in the film 12, operatingone or more of the relays-A, B and C and thus, as described heretofore, establishing a circuit for the perforator relay 20 and allowing the punch magnet 21 to operate and punch holes at positions 1, 3' and l, indicating a sequence of five white elements shown in Fig. 2. The operation of the punch magnet 21 clears 12 0 the counting relays by breaking the circuit from battery 23, as previously described. Tfa'sha'de recurs more than seven times in succession a punch will be made on the seventh count andthe count will be begun I again for another series. -WVe have already seen that on the fourth count the relay 410 locks up; on the fifth count 1a and 1b are operated; on the sixth count relays 2axand 2b are op- 3 erated and'on the seventh count relays 3a and on the right a circuit from battery, through theiupper winding of perforator relay 20, in'- ner leftcontact of relay 40, back contact of relay 4a, rightfront contact of relay 3b, and this circuit is completedat 25 to operate the pertorator relay'20 and the punch magnet 21. The Operation of the punch magnet 21 in the tape. QThese five contacts controlcirpunches holes in the second andv fourth positions to indicate seven'elements of likeshade andother holes (or a blank) in other positions to indicate the degree of shade also the 'operation'of the punch 1nagnet2l clears out the counting relays, as described heretofore,- ready to begin over again. 7 A contact 26 at the transmitting drum 10 is closed through battery 27 at the edge of the film '12. The circuitthus" established through the winding of relay c-je nergizes the latter and closes the upper front contact of relayc so that when the punching contact is made at 25 the circuit is closed for the perforator relay 20, thereby causing the punch magnet 21 to punch whatever combination happens to be set up at that time, that is when the edge of the film 12 is reached by the contact 26. The operation of the punch magnet 21 clears out the counting relays. 'as has been described and causes theirelay c to be picked up and locked up by current from the battery 23.. This condition .continues until the'other edge of the film 12 reaches the'contact 26 and breaks it;"duringthis time both thecircuit for'periorator relay 20 and the counting circuits are held open at'the upper backcontacts of relays 0 and c. 7

But at the other edge of the picture when the contact 26 is broken, relay 0 releases and the circuit for perforator-relay 20 is established through the upper back contact of relay a and a frontcontact of relay 0, which remains, locked up. "The circuits ofselector magnets 3 and 5 are both openat the lower back contact of'relay 0 at this time, and when the contact 25 is closed and theperforatorre lay'20 operates, causing the punch magnet 21 to operate, the blank combination will occur on the tape, which is the code for carriage return and line feed. T'ThlS will be explained -further in connection with the discussion of the receiving apparatus that is'to follow.

The cam 18 closes briefly for'each element of the picture, shunting out the marginal re-' lays A, B and C; this allows them to operate always on the same point on their magnetiza- I time to elapseafter the contact T opens for ficient time, to release and operate again before the next punching-operation.

The tape produced at the sending end'according to the code of Fig. 2 is put through a tran-smitterand thereby at the receiving end This received tape is-passed through the tape transmitter 34, 34 of'F1g.

3, which is of a type used iii-printing telegraphy; The drawing is meant to indicate symbolically that the contacts numbered from .1 to 5 adjacent to 34 are closed to thebattery 35,for'each hole in the co-rrespondingposition cuits to the respective relays 11,22, 33,44and 55," of which 11, 22 and 44; are count selecting lays.

relays and 33 and 55 are shade selecting re-s Theperforatedt'ape 28 at'the receiving end passes from theperi'orator 51 to the tape transmitter 34: me loop under the member 52 so arranged that when the tape 28' is pulled up it will cause the circuit of magnet 53 to open andstop the operation of the receiving printer; I

The'printingis done on a page in a page printing receiver inwhich the printer select-- mg magnets 110, 220,330, 440 and 550 areemployedJ The magnet 110 is unnecessary for picture printing, and the remaining four magnets mentioned operate according to the -following code:

Prin ter selecting magnets operated Characters printed a other Printer perations t .330 Space or blank V y l None Small dot Y i 5501 a Medium dot 330,440,550 Large dot 44:0 Carriage return f 220 Line feed This particular code arrangement is shown as one suited for use in connection with certain ordinary printing telegraph machines" now widely used.

34, in" readiness so that one step will bringit' through the windings of the clear-out relay 31 and the tape transmitter magnet 32 to-battery. -Upon the closure of this circuit the clear-out relay 31' and the tape transmitter magnet 32 are operated, and they release when the circuit opens at T; v

The cam 38 is designedto allow a suflicient the tape transmitter magnet 32: to release and for the transmitter contacts'at 34toe'n'ergize the respective relays with which they are connected beforethe contact S closes at 38.

7 If relay 33 of the two shade selectingree lays is energized, then when contact S closes r 1 The tape-is'ins'erted in the tape transmitter to thefirst code combination of the picture.

fi io battery .36 will be connected through printer h selecting magnet 330. This will'cause-the printerato record a space or blank 'as indi- 2 to a new signal combination. The actuation cated in the foregoing table.

; been set up in the tape transmitter.

If relay 55, but not 33, is energized, the contact closure at S will connect the battery to printer selecting magnet 550 anda medium dot-will be printed. If relays 33 and 55 are both energized, then contact'closure at S will apply battery to magnets 330, 440 and 550 in parallel and a large neither relay 33 pulse will be sent dot will be printed, If

through the printer selecting magnets, and a small dot will be printed.

For an example to explain the action of the counting relays 11, 22 and 44, let it be assumed that the code combination 1, 2, 5 has A reference to Fig. 2 shows that this corresponds to a sequence of two medium dots. The transmitter contactsat 34, numbered 1, 2 and 5, will be closed to the battery 35, and there fore the relays 11,22 and 55 will be energized. When the cam 38 closes contact S, printer selecting magnet 550 will be energized thus preparing the printer for recording a medium dot. At the same time the relay 11a will be'energized by the closure of the contact S through a circuit from battery .36 through the back contact of relay 115. Accordingly the relay 11a will connect battery 39 to the lower end of the winding of relay 11?), but relay 11?) will not operate until contact S opens, because meanwhile relay 11b is shunted through said contact S. When relay 115 does operate, it transfers the counting circuit 37 to the armature of relay 22b and thence to the winding of relay 22a.

As the cam 38 continues to rotate, contact T will be closed and will connect ground through the front contacts of relays 11 and 11a to the armatures of relays 22, 220; and 33a, but as these are all opened, the transmit ter magnet will not'be energized. When contact S closes on the next revolution, the printer selecting magnet 550 will be energized again to cause the printer to record another medium dot, and relays 22a and 225 will be energized in succession in the manner heretofore described for 11a and 116. Then when contact T is again closed by the further rotation of the cam 38, ground will be connected through T and the, front con tacts of relays 11, 11a and 22a and the back contact of relay 44 to the windings of the clear-out relay 31 and the tape transmitter magnet 32. The tape will now step ahead of the clear-out relay 31 establishes a direct circuit from ground through the contact T andfront contact of relay 31, through said relay 31 andthe tape transmitter magnet .32;

i this insures that the tape transmitter 34 will receive a full length impulse. The opening of the back contact of relay 31 removes battery 39 from the counting relays and releases them. In what goesv before, we have traced the nor 55 is energized, no imoperation for the code combination 1, 2 and 5 corresponding to a sequence of two medium dots as shown in Fig. 2. v 1 and 2 determine the count and 5 determines the shade. As-

suming that the shade is the same, other set- 770 tings of the count selecting relays 11, 22 and 44 will cause the selected shade character to be recorded a different number of times as follows:

If relay 11 is energized alone, the tape feed circuit controlled at T will be closed through the front contacts of relays 11 and 11a and back contactsof relays 22 and 44 after a single contact closure at S. If relays 11 and 22 are both operated, the said tape feed circuit controlled at T will remain open until contact 5 has operated twice as in the case previously followed through in detail. If relay 22 alone is operated, contact S must operate three times so as to energize relays 11a22a and 33a and then close the tape feed circuit controlled at T through the back contact of relay 11, front contacts of relays 33a and 22a and back contact of relay 44.

If relay 44 alone is operated, four revolutions of the cam 38 must take place which will operate all four of the pairs of counting relays. Therenpon, with the operation of the relay 44a, the repeat relay 41 will operate and lock by current from battery 39. Relay 44b releases all the counting relays to the left thereof, and relay 33b then'releases 44aand 44?) so that after four operations of contact S the repeat relay 41 is the only relay remaining energized of the counting group. The ape feed circuit controlled by T is now closed through back contacts of relays 11, 11a and 22 and the upper front contact of repeat relay 41. If relays 11 and 44 are both energized, the tape feed circuit controlled by T will be held open until the repeat relay-41 pulls up on the fourth revolution as described above and until'relay 11a is energized again by the fifth operation of contact S. The tape feed circuits from T for this case of five characters, and also for the cases of six or seven characters, are the same, respectively, as for counts of 1, 2or 3 as described heretofore, except that in each case the tape feed circuit extends through the front contact of the relay 41 instead ofthe back contact of relay 44.

The foregoing description covers the operations of printing from one to'seven like characters from the respective code combinations of the tape. The carriage return and line feed operations which are determined when no holes are punched in the tapewill now be described. In this case when the contact T opens, the tape transmitter contacts at 34 will all be held away from connection with battery 35, and all five selecting relays 11, 22, 33, 44 and 55- will remain deenergized. Then when contact S closes, a'circuit will be established from battery-36, through back contacts of relays44, 22, '11 and 22b to printer select ing magnet 440, which, in accordance withthe foregoing table controls the carriage return operation of the printer. Relays 11a and 11b 7 22a and 226 will beenergized. Then whencontact S closes the third time, an impulse will be sent through printer selecting magnet 220, instead of 440 (due to the energization of relay 225). This causes the printer to feed the paper one line in accordance with the last entry in the foregoing table, and at the same time relays 33a and 38?). areenergized. When contact T closes, the tape transmitter magnet 32 will be energized over a circuit from T, through back contact ofrelay 11, front con.- tacts of 33a and 22a, back contact of relay 44, winding of relay 31 and tapetransmitter 1 magnet 32 to battery.

Thus it will be seen that, with the tape' reproduced at the receivingstation in accordance with the code of Fig. 2, the code combinations control the receiving printer to printa space or a dot of varying size and to repeat each such space or dot any number of times from one up to seven, and automatically to perform the operations of carriage return and line feed. T

We claim: 7 1. In a picture transmitting system, means to explore successive elements of the picture a V v I CODdItIlOll of said tape. forcontrollmg the.

and to automatically transmit code currents corresponding both to the number of elements in a sequence. of like shade and to the shade of the elements of, such sequence, means for varying sald code currents in accordance with the numberof elements in a sequence,

. and means to receive such currents and reproduce the pictureaccordingly.

2. In a picture transmitting system,'means to automatically explore successive elements of the picture and to punch code combinations in a tape corresponding both to the number of elements in a sequence of like shade and the shade of said sequence, said code combinations varying in accordance with thenumber of elements in a sequence and means to reproduce a similar tape at the receiving end and therefrom picture accordingly.

8. In a picture transmitting system,means to automatically produce a tape punched with code combinations to represent the number of picture elements in a sequence of eleto reproduce the ments of like shade and to represent that shade, said code combinations varying in accorda'nce with the number of elements in a sequence, means to impress a character of correspondlng shade at a correspondlng posltion on a picture receiving surface, and means pulses in a'sequence off like strengthtosaid relays, means operable on change of strength to repeat .tha t same-character'insuccessive;

in.v successive impulses 'to v recordjthe number of impulses inthe countedsequence and the degreeof strength of those impulses and pic-.,

ture reproducing means responsive to the" cor pul e V.

5; In picture transl nission system,"marginal relays,'a circuit therefor, means to auto;

matically send sequences of current-impulses to'said relays,gcounting relays, meanstoop-f V 852 I erate the countingrelays fora sequence of impulses of equal-strength through themar-g ginal' relays, means-to record the count af d also tojrecord the number and N degreej of strength vo f the impulses whenthe degreeof strength of those impulses changes through the marginal relays and picture ,re'; ducing meansgresponsive to -,the recorded,

' impulses. i V

6. In a picture transmission system,

combination of atape perforator, meansforv operating said perforator m accordance with receivedfcurrent corresponding characteristics, a' tape transmitterto jbe op' erated bythe tape from said perforaton'pi c: ture receiving apparatus controlled by saidtransmitter, and means depending upon the speed of said, receiving 7 apparatus.

' 7., In a picture transmiss onsystem, a "105,

perforator, means for operating said perforator n. accordance with received currents r sia e' ns Pic re iqhar t s esaa,

said tape, picture receiving apparatus controlled byrsaid transmitter, a stopv forsaid apparatus, magnet and a a, control circuit for said stop, and aswitch for said circuit governed by said tape. 7 e I 8. In a plcture transmitting system, means to explore success ve elements of the plcture,

tape transmitter governed in its operation means to count the number of like elements in a sequence, means to make a record of said count, said record varying in accordance both with the numberof elements in a sequence and with their shade, means to transmit code currents corresponding to said record, and means to receive such currents and reproduce the picture accordingly.

9. In a picture transmitting system, means to automatically produce a code record with code combinations in accordance with both the number of picture elements in a sequence of elements of like shade and in accordance with that shade, means to impress a corresponding degree of shade at a ing surface, and means to repeat that same impression in successive positions on that surface the number of times corresponding to the number embodied in the code.

' 10. The method of transmitting a picture Which consists in analyzing it into sequences of elements of "like shade, automatically transmitting a-code combination of currents for each sequence, each combination varyingin accordance With the number of elementsin the sequence and theshade of those elements, and reproducing the-picture from these currents.

11. The method of transmitting a picture which consists in analyzing itinto sequences of elements of the same shade, for each sequence of a difie'rent number of elements automatically transmitting a corresponding code combination, and for each such code combmation received printing a sequence of characters of the'corresponding number and shade on a receiving surface.

12; In combination, a picture having groupsot elemental areas the size of each group determined by the number of successivearea's with the same degree of shade, means for testing and counting the number of elements in a group, and meansresponsive to said count for making asingle code record indicating the number of elemental areas counted and their degree of shade.

13. The method of transmitting a picture, Which consists in exploring its elements successively for degree of shade, counting the elements of like shade in sequence, recording a code combination for the number of the sequence and the shade when the shade changes, and reproducing the picture from this record.

In testimony whereof We have signed our names to this specification this 13th day of December, 1923;

. V GILBERT S. VERNAML EDWARD F. WATSON.

DONALD B. PERRY corresponding position on a picture receiv-

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