CA1055147A - Picture transmission systems - Google Patents
Picture transmission systemsInfo
- Publication number
- CA1055147A CA1055147A CA219,536A CA219536A CA1055147A CA 1055147 A CA1055147 A CA 1055147A CA 219536 A CA219536 A CA 219536A CA 1055147 A CA1055147 A CA 1055147A
- Authority
- CA
- Canada
- Prior art keywords
- arrangement
- shift register
- channel
- original image
- bubble
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/02—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes by tracing or scanning a light beam on a screen
- G09G3/025—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes by tracing or scanning a light beam on a screen with scanning or deflecting the beams in two directions or dimensions
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/09—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on magneto-optical elements, e.g. exhibiting Faraday effect
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/001—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
- H04N3/10—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical
- H04N3/30—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical otherwise than with constant velocity or otherwise than in pattern formed by unidirectional, straight, substantially horizontal or vertical lines
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N7/00—Television systems
- H04N7/002—Special television systems not provided for by H04N7/007 - H04N7/18
- H04N7/005—Special television systems not provided for by H04N7/007 - H04N7/18 using at least one opto-electrical conversion device
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Computer Hardware Design (AREA)
- Signal Processing (AREA)
- Multimedia (AREA)
- Nonlinear Science (AREA)
- Power Engineering (AREA)
- Optics & Photonics (AREA)
- Compression Of Band Width Or Redundancy In Fax (AREA)
- Thin Magnetic Films (AREA)
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
Abstract
ABSTRACT:
A picture transmission system has boustrophedral scanning of the original picture at the transmitter, A-D
conversion of the video signal to serial binary form, and display of the picture at the receiver by illumination of the pattern formed by the serial binary information fed into a single magnetic bubble shift register channel whose path corresponds to the complete scan pattern in the trans-mitter.
A picture transmission system has boustrophedral scanning of the original picture at the transmitter, A-D
conversion of the video signal to serial binary form, and display of the picture at the receiver by illumination of the pattern formed by the serial binary information fed into a single magnetic bubble shift register channel whose path corresponds to the complete scan pattern in the trans-mitter.
Description
21.1.75 1055~47 "Improvements in and relatin~ to picture transmission syste~-! This invention relates to picture transmission ¦ systems and to display units for use in the recei~ers ¦ of such systems~
~ The object o~ the invention is to utilise the 5 I magneto-optic properties of a magnetic bubble domain device iIl a lo-~-cost display unit capable of showing picture information transmitted over a communication channel, for example a low bandwidth telephone or mobile radio channel.
According to the invention there i~ provid-ed a picture transmission system in which a transrr.it-ter includes means adapted to scan a picture in a .
boustrophedral pattern to produce an analogue video signal, in which a receiver connectable to the trans-mitter by a co3~nunication channel includes a displ~y unit, said display unit including a visible light source, polarising and analysing means 9 and a body - capable of supporting maglletic bubble domains which has a tran~parent display area and a bubble shift register channel on`the display area whose path cor-.
responds to the complote boustrophedral scan pattern at the transmitter, and in which an analoguo-to-digital convcrt,or at the transrnitter or recoiver is , ~ i adaptod to produce, from the analogue video signal, , .
'~`'~'' ` ' ' _ z' _ ~}~r~ 32~
~1.1.75 sorial binary information to bo fed into the bubble shift rogister channel.
According to the invention there is also pro-vided a display unit suitab~e for use in the abo~
picture tr~rlslnission system, said display unit includ-ing a visible li~ht source, polarising and analysing means, and a body capable of supporting magnetic bubble dolnains which has a transparent display area and a bubble shift register channel on the display area ,whose path corresponds to'the complete boustrophedral scan pattern at the transmitter.
- The invention will now be described in more detail with reference to the accompanying drawings, "-in which:
Figure 1 shows a schematic outline in pers-pective ~iew of a display ~lit, and Figure 2 shows a block schematic circuit dia-gram of a picture transmission system including the ' display unit of Figure 1.
Referring now to Figure 1, the display unit includes a visible light source in the form of a lamp 1, a pair of cross¢d optical polarising elements com-prising a polariser Z and an analyser 3, and a body 4 capable of supporting magnetic bubble domains which has a transparent display aroa between the polarising elom~nts alld a single bubblo shirt register chanllel 5 whofie path on the display area rollows a boustrophedral , ;~ , ~ 3 , `` PH13 3~ c~
21. 1.75 (left to right to left) pattern. A coil 6 is also shown for providing a bubbl~ supporting magnetic bias field normal to the body 4.
The bubbles 7 present in the shift register 5 each have a direction of magnetisation opppsite to that o~ the surroundin~ material and so effect an op-posite Earaday rotation on the light from the polariser
~ The object o~ the invention is to utilise the 5 I magneto-optic properties of a magnetic bubble domain device iIl a lo-~-cost display unit capable of showing picture information transmitted over a communication channel, for example a low bandwidth telephone or mobile radio channel.
According to the invention there i~ provid-ed a picture transmission system in which a transrr.it-ter includes means adapted to scan a picture in a .
boustrophedral pattern to produce an analogue video signal, in which a receiver connectable to the trans-mitter by a co3~nunication channel includes a displ~y unit, said display unit including a visible light source, polarising and analysing means 9 and a body - capable of supporting maglletic bubble domains which has a tran~parent display area and a bubble shift register channel on`the display area whose path cor-.
responds to the complote boustrophedral scan pattern at the transmitter, and in which an analoguo-to-digital convcrt,or at the transrnitter or recoiver is , ~ i adaptod to produce, from the analogue video signal, , .
'~`'~'' ` ' ' _ z' _ ~}~r~ 32~
~1.1.75 sorial binary information to bo fed into the bubble shift rogister channel.
According to the invention there is also pro-vided a display unit suitab~e for use in the abo~
picture tr~rlslnission system, said display unit includ-ing a visible li~ht source, polarising and analysing means, and a body capable of supporting magnetic bubble dolnains which has a transparent display area and a bubble shift register channel on the display area ,whose path corresponds to'the complete boustrophedral scan pattern at the transmitter.
- The invention will now be described in more detail with reference to the accompanying drawings, "-in which:
Figure 1 shows a schematic outline in pers-pective ~iew of a display ~lit, and Figure 2 shows a block schematic circuit dia-gram of a picture transmission system including the ' display unit of Figure 1.
Referring now to Figure 1, the display unit includes a visible light source in the form of a lamp 1, a pair of cross¢d optical polarising elements com-prising a polariser Z and an analyser 3, and a body 4 capable of supporting magnetic bubble domains which has a transparent display aroa between the polarising elom~nts alld a single bubblo shirt register chanllel 5 whofie path on the display area rollows a boustrophedral , ;~ , ~ 3 , `` PH13 3~ c~
21. 1.75 (left to right to left) pattern. A coil 6 is also shown for providing a bubbl~ supporting magnetic bias field normal to the body 4.
The bubbles 7 present in the shift register 5 each have a direction of magnetisation opppsite to that o~ the surroundin~ material and so effect an op-posite Earaday rotation on the light from the polariser
2 which gives a corresponding difference in the in~en-` sity of light transmitted by the analyser 3. An ex~ple of a suitable materlal for the body l~ is the monocrystal-line bismuth substituted garnet Bio 8Sm2 2Ga1 QFe4 012-~` This material has a magneto-optic figure Or merit of - 5~dB corresponding to a ratio of Faraday rotation per cnl./ Absorption coefficient, ~/C~ = 22 degrees J5 at 560 nm. If operated between crossed polarising ele-~j ments so that there is zero light transmission with this material saturation magnetised in one direction, then a light transmission of 19% can be achieved when the magnetisation of the maberial is reversed; this ~ figure being uncorrected for polarisation and reflec-tion losses. Experimental contrast ratios of 50 to 1 have been observed. The body 4 can be a plate cut ~ -from a crystal, polished to the desired thickness, ~, and supported e.g. on a gla~s plate. An alternative is for the body 4 to bo a layer epitaxially grown on !' a transpar~nt non-magnetic crystal substratc, e.g.
rare-¢arth ~alliu~n garnet, hicil acts as a a-~pport.
., .
~, """
, . ~
p}~l3 32~'l09 -21.1.75 lOS5~ ~7 Propagation of bubbles alon~ the shift regis-ter channel 5 can be achieved by drivc means, kno~ per se, which create magnetic field gradients at selected . ¦ points on a surface of the body 4. For example, the I drive means can comprise current-carryin~ conductors ¦ which also define the channel 5 or external means for ¦ producing magnetic fields in conjunction with the channol 5 being defined by a magnetic overlay pattern on the body 4. The magnetic over].ays can be produced directly by deposition of ma~netic material, or by modifying the surface magnetic properties of the body 4 usin~ ion implantation or etchil~g so as to maintain the transparency of the body 4. An example is the so-call0d ~angel fish~ overlay pattern which requires 15. only an oscillating bias magnetic field for propa-gation. The shift register drive means will be adapt-ed to be controlled by clock pulses. A bubble genera-tor will be provided adapted to feed bubbles into the . .:
. channel 5 in response to picture information in serial binary form and under the control of the clock pulses, . and a bubble annihilator will be provided at the out-, . . put end of the channel 5. The shift register drive means can also be adapted to bo turned on and off by marker pul~es before and after the serial binary pic-turo information, and in this case there is no need to provide ~ub~lc dotection means, i On~ of tll~ factors which influcnce the con-, .
, ' ' .
_ 5 _ ~ .
'" .: ",. ' ' . , ' ', ' " ' ' ' ,' . ', ' ',' ". ' ;: ~, ' ' .' ' ' ' " ` . :' - ' , , ' Pll~ O~
21.1.75 trast ratio of thc display and hence its optical effi-ciency is the ratio of the bubble si7.e to the bubblo spacing. That is to say that large bubbles close to-gether will give a high contrast ratio. For a given body 4, the bubble size is determined by the bias mag-notic field, and the bubble spacing is determined by tho structure of the shift register channel 5 which will require a certain bias magnetic field. It may be found that a bias field which is suitably low for la~e`bubble size is lower than that required by a particular structure of the channel 5 giving small bubble spacing. A possible solution to this problem would be to use a high bias field for propagation of - bubbles through ~he ~hift register, followed by re-duction of the bias field to expand the bubbles when a stationary pattern of bubbles which is to be d~ 9-played has been formed.
:~ -It should be pointed out that the display has the advantage of possessing memory, that is to say that once a particular pattern of bubbles has been formed by propagation through the shift register chan-nel 5, it can be viewed indefirlitely as long as the magnetic bias field is present to support the bubbles.
Thus permanent magnetic means could be provided, instead ; 25 of the coil 6 shown in Figure 1,~to provide the bias field and thus be sufficient alone to maintain a par-ticular bubble pattorn. The permanont magnetic means , .
~ _ 6 , . . . .
. _ .
'' P~B 32~JO'J
' 21.1.7i5 migllt, for exan~ple, be in the form of a layer of perma-nent magnetic matcrial on the body 4. -As described above, the display unit is j adapted to be f0d via an input to the single shift I register channel 5 with information in serial binar~;
¦ form, and this is the form in which information can be ¦ easily transmitted over a communication channcl, ~or , examp]e a low band-~idth telephone or mobile radio ¦ channel. The present state of the art of magnetic - bubble shift registers is that such shift registers having a capacity Or 104 bits with an operating speed of 10 ~z are attainable, and this performance is -, sufficient for, a display unit having a single shift - -register channel as described above to be provided ~ -in'a receiver at one end Or a low bandwidth telephone - ' or mobile radio channel. For example, a still picture having 10 elements could be fed into the shift re-gister from a 3 KHz bandwidth t,elephone channel in approximately three seconds,'an alpha-numeric message 20 , of 100 characters and 50 elements per character could be fed into the shift register from a 5 ~Iz bandwidth radio channel in one second, and an alpha-numeric , message of 12 chari~cters and 50 elements per charac-.: .
,` ter could be fed into the shift register from a 1.2 ' 25 -- KHz bandwidth radio channel in half a seoond. In all '' these oxarnples the capacity of the shift register relative to the bandwidth Or tho ColNnUniOatiOn ~, ' , , _ 7 . .
.. ' , , . , . , , ',' , ,; ,. .
,: , , , , , ,, , , , , : . , PHB. 32,409.
channel is such that the bubble pattern for a ocmplete still picture is built up in the shift register during a time longer than the integration time of the eye.
If required, illumination control means can be pro-vided in the display unit whereby the display area is not illuminated during operation of the shift register.
It will be appreciated that if the bandwidth of the ocmmunication channel used is sufficiently large, then information can be received at such a speed as to enable the display unit to show mDving pictures.
An example of the size of the display area of the body 4 shown in Figure 1 is 2 mm square. ~his area would accommodate a shift register of capacity 104 bits æranged as 100 lines with 100 elements per line, in which the elements, i.e. bubbles, are 10 /u diameter with 20 /u centre-to~centre spacing. As another example, an æea 10 mm square would acocmmDdate a shift register also of 104 bits capacity but with bubbles of 50 /u dia~e~Pr. m ese display areas oould be directly viewed with a magnification of x 10 prcduced by a lens æ ranged`between the analyser 3 and the viewer. In the tw~ examples just given, this wculd produce picture of 2 cm square and 10 cm respectively. me display unit giving a 2 cm square pichlre could be ocmpact enough to be :, .... . .
PHB 32'tog 21.1.75 l()S51~7 incorporated in a hand-held portable radio receiver.
One possible variation of the viewin~ ar-~ rangcment of the display unit shown in ~iguro 1 is to ¦ havo the analyser 3 on tho same side of the body 4 as ¦ the polariser 2, ~ritll a mirror behind thc channel 5 ¦ so that the picture is seen by reflection rather than ¦ transmission. In this case it may be possible to com-bine the polariser 2 and the analyser 3 in a single polariser which is traversed by both the incident ` 10 and the reflected light. It is to be noted that for ; a given magneto-optic effect, half the thickness of the body 4 is required when used in the reflection mode compared with the thickness required when used - in the transmission mode.
- Referring now to Figure 2, a complete picture transmission system is sho~n includlng the display unit of Figure 1. At the transmitter there is a te-levision camera 10 constituting means to scan a pic-ture, an analogue-to-digital converter 11 connected between the output of the television camera 10 and a data transmitter 12 adapted to be coupled to a com-munication channel 13, and a clock unit 14 for con-trolling tho camera, converter~ and data transmitter.
The camera 10 is adapted to scan a picture in a bouskrophedral (left to right to lcft) pattern, i.o. in general t~rms the scan is triangular rather than ~awtooth. In more prrcisc terJns, the complete - . . _ Pll~.~ 3.~0 21.1.~5 boustrophedral scan pattcrn of the camera 10 and the boustrophedral path of the bubble shift register chan-nel in the display Ullit sllould correspond as closely as possib].e. Tl~c analoguc video signal output 101 of the camera lO is converted by the ana].ogue-to-digitsl con~erter 11 into seri.al binary information 111 which is ~ed to the data transmitter 12. The clock unit 14 provides synchronisation pulses 141 to conl:rol the scan of t~le camera 10, cloclc pulses 142 to control the converter 11, marker pulses 143 ~hich are trans-mitted by the data transmitter 12 at the beginning and at the end of the binary information 111 derived from each complete scan of the camera iO, and clo'ck pulses 144 to control the data transmitter 12.
At the receiver there is a data receiver 15 adapted to be coupled to th~ col~unication channel 13, a unit 16 to extract from the rcceived data 151 the serial binary picture information 161, the clock pulses 162 and the marker pulses 163, and a gating ~ -unit 17 which in response to the inputs 161, 162 and 163 provides clocked serial binary information 171 to the bubble generator of the display unit 18 and ~ -also pulses 172 (i.e. clock pulses preceded and followed by marker pulses) to th~ shift register drive means of the display unit 18.
One possiblc variation of the above-describ-ed system is to trarlsmit only rrame s.ynchronisation PHB 32,409 pulses at the beginning of each picture, instead of marker pulses at the beginning and end of each picture.
However, this would require the display unit to have a bubble detector at the output of the shift register which would respond to the passage of the frame synchron;sation pulses to determine when the bubble pattern for a complete picture is in the shift re-gister.
If required, the analogue-to-digital conver-ter 11 can include means for coding the serial binary information so as to enable the display unit 18 to show a grey scale picture. For example, the serial binary information can be coded to produce a pattern of bubbles in the shift register whose spacing is modulated so as to effectively produce a grey scale picture.
The picture transmission system described above with reference to Figure 2 is particularly suitable for inclusion in an existing communication -system in which a transmitter and a receiver are adapted for communicating digital information. How-ever, by having the analogue-to-digital converter at the receiver end this picture transmission system could be made better suited for inclusion in an exist-ing communication system in which a transmitter and a receiver are adapted for communicating analogue infor-mation.
.
rare-¢arth ~alliu~n garnet, hicil acts as a a-~pport.
., .
~, """
, . ~
p}~l3 32~'l09 -21.1.75 lOS5~ ~7 Propagation of bubbles alon~ the shift regis-ter channel 5 can be achieved by drivc means, kno~ per se, which create magnetic field gradients at selected . ¦ points on a surface of the body 4. For example, the I drive means can comprise current-carryin~ conductors ¦ which also define the channel 5 or external means for ¦ producing magnetic fields in conjunction with the channol 5 being defined by a magnetic overlay pattern on the body 4. The magnetic over].ays can be produced directly by deposition of ma~netic material, or by modifying the surface magnetic properties of the body 4 usin~ ion implantation or etchil~g so as to maintain the transparency of the body 4. An example is the so-call0d ~angel fish~ overlay pattern which requires 15. only an oscillating bias magnetic field for propa-gation. The shift register drive means will be adapt-ed to be controlled by clock pulses. A bubble genera-tor will be provided adapted to feed bubbles into the . .:
. channel 5 in response to picture information in serial binary form and under the control of the clock pulses, . and a bubble annihilator will be provided at the out-, . . put end of the channel 5. The shift register drive means can also be adapted to bo turned on and off by marker pul~es before and after the serial binary pic-turo information, and in this case there is no need to provide ~ub~lc dotection means, i On~ of tll~ factors which influcnce the con-, .
, ' ' .
_ 5 _ ~ .
'" .: ",. ' ' . , ' ', ' " ' ' ' ,' . ', ' ',' ". ' ;: ~, ' ' .' ' ' ' " ` . :' - ' , , ' Pll~ O~
21.1.75 trast ratio of thc display and hence its optical effi-ciency is the ratio of the bubble si7.e to the bubblo spacing. That is to say that large bubbles close to-gether will give a high contrast ratio. For a given body 4, the bubble size is determined by the bias mag-notic field, and the bubble spacing is determined by tho structure of the shift register channel 5 which will require a certain bias magnetic field. It may be found that a bias field which is suitably low for la~e`bubble size is lower than that required by a particular structure of the channel 5 giving small bubble spacing. A possible solution to this problem would be to use a high bias field for propagation of - bubbles through ~he ~hift register, followed by re-duction of the bias field to expand the bubbles when a stationary pattern of bubbles which is to be d~ 9-played has been formed.
:~ -It should be pointed out that the display has the advantage of possessing memory, that is to say that once a particular pattern of bubbles has been formed by propagation through the shift register chan-nel 5, it can be viewed indefirlitely as long as the magnetic bias field is present to support the bubbles.
Thus permanent magnetic means could be provided, instead ; 25 of the coil 6 shown in Figure 1,~to provide the bias field and thus be sufficient alone to maintain a par-ticular bubble pattorn. The permanont magnetic means , .
~ _ 6 , . . . .
. _ .
'' P~B 32~JO'J
' 21.1.7i5 migllt, for exan~ple, be in the form of a layer of perma-nent magnetic matcrial on the body 4. -As described above, the display unit is j adapted to be f0d via an input to the single shift I register channel 5 with information in serial binar~;
¦ form, and this is the form in which information can be ¦ easily transmitted over a communication channcl, ~or , examp]e a low band-~idth telephone or mobile radio ¦ channel. The present state of the art of magnetic - bubble shift registers is that such shift registers having a capacity Or 104 bits with an operating speed of 10 ~z are attainable, and this performance is -, sufficient for, a display unit having a single shift - -register channel as described above to be provided ~ -in'a receiver at one end Or a low bandwidth telephone - ' or mobile radio channel. For example, a still picture having 10 elements could be fed into the shift re-gister from a 3 KHz bandwidth t,elephone channel in approximately three seconds,'an alpha-numeric message 20 , of 100 characters and 50 elements per character could be fed into the shift register from a 5 ~Iz bandwidth radio channel in one second, and an alpha-numeric , message of 12 chari~cters and 50 elements per charac-.: .
,` ter could be fed into the shift register from a 1.2 ' 25 -- KHz bandwidth radio channel in half a seoond. In all '' these oxarnples the capacity of the shift register relative to the bandwidth Or tho ColNnUniOatiOn ~, ' , , _ 7 . .
.. ' , , . , . , , ',' , ,; ,. .
,: , , , , , ,, , , , , : . , PHB. 32,409.
channel is such that the bubble pattern for a ocmplete still picture is built up in the shift register during a time longer than the integration time of the eye.
If required, illumination control means can be pro-vided in the display unit whereby the display area is not illuminated during operation of the shift register.
It will be appreciated that if the bandwidth of the ocmmunication channel used is sufficiently large, then information can be received at such a speed as to enable the display unit to show mDving pictures.
An example of the size of the display area of the body 4 shown in Figure 1 is 2 mm square. ~his area would accommodate a shift register of capacity 104 bits æranged as 100 lines with 100 elements per line, in which the elements, i.e. bubbles, are 10 /u diameter with 20 /u centre-to~centre spacing. As another example, an æea 10 mm square would acocmmDdate a shift register also of 104 bits capacity but with bubbles of 50 /u dia~e~Pr. m ese display areas oould be directly viewed with a magnification of x 10 prcduced by a lens æ ranged`between the analyser 3 and the viewer. In the tw~ examples just given, this wculd produce picture of 2 cm square and 10 cm respectively. me display unit giving a 2 cm square pichlre could be ocmpact enough to be :, .... . .
PHB 32'tog 21.1.75 l()S51~7 incorporated in a hand-held portable radio receiver.
One possible variation of the viewin~ ar-~ rangcment of the display unit shown in ~iguro 1 is to ¦ havo the analyser 3 on tho same side of the body 4 as ¦ the polariser 2, ~ritll a mirror behind thc channel 5 ¦ so that the picture is seen by reflection rather than ¦ transmission. In this case it may be possible to com-bine the polariser 2 and the analyser 3 in a single polariser which is traversed by both the incident ` 10 and the reflected light. It is to be noted that for ; a given magneto-optic effect, half the thickness of the body 4 is required when used in the reflection mode compared with the thickness required when used - in the transmission mode.
- Referring now to Figure 2, a complete picture transmission system is sho~n includlng the display unit of Figure 1. At the transmitter there is a te-levision camera 10 constituting means to scan a pic-ture, an analogue-to-digital converter 11 connected between the output of the television camera 10 and a data transmitter 12 adapted to be coupled to a com-munication channel 13, and a clock unit 14 for con-trolling tho camera, converter~ and data transmitter.
The camera 10 is adapted to scan a picture in a bouskrophedral (left to right to lcft) pattern, i.o. in general t~rms the scan is triangular rather than ~awtooth. In more prrcisc terJns, the complete - . . _ Pll~.~ 3.~0 21.1.~5 boustrophedral scan pattcrn of the camera 10 and the boustrophedral path of the bubble shift register chan-nel in the display Ullit sllould correspond as closely as possib].e. Tl~c analoguc video signal output 101 of the camera lO is converted by the ana].ogue-to-digitsl con~erter 11 into seri.al binary information 111 which is ~ed to the data transmitter 12. The clock unit 14 provides synchronisation pulses 141 to conl:rol the scan of t~le camera 10, cloclc pulses 142 to control the converter 11, marker pulses 143 ~hich are trans-mitted by the data transmitter 12 at the beginning and at the end of the binary information 111 derived from each complete scan of the camera iO, and clo'ck pulses 144 to control the data transmitter 12.
At the receiver there is a data receiver 15 adapted to be coupled to th~ col~unication channel 13, a unit 16 to extract from the rcceived data 151 the serial binary picture information 161, the clock pulses 162 and the marker pulses 163, and a gating ~ -unit 17 which in response to the inputs 161, 162 and 163 provides clocked serial binary information 171 to the bubble generator of the display unit 18 and ~ -also pulses 172 (i.e. clock pulses preceded and followed by marker pulses) to th~ shift register drive means of the display unit 18.
One possiblc variation of the above-describ-ed system is to trarlsmit only rrame s.ynchronisation PHB 32,409 pulses at the beginning of each picture, instead of marker pulses at the beginning and end of each picture.
However, this would require the display unit to have a bubble detector at the output of the shift register which would respond to the passage of the frame synchron;sation pulses to determine when the bubble pattern for a complete picture is in the shift re-gister.
If required, the analogue-to-digital conver-ter 11 can include means for coding the serial binary information so as to enable the display unit 18 to show a grey scale picture. For example, the serial binary information can be coded to produce a pattern of bubbles in the shift register whose spacing is modulated so as to effectively produce a grey scale picture.
The picture transmission system described above with reference to Figure 2 is particularly suitable for inclusion in an existing communication -system in which a transmitter and a receiver are adapted for communicating digital information. How-ever, by having the analogue-to-digital converter at the receiver end this picture transmission system could be made better suited for inclusion in an exist-ing communication system in which a transmitter and a receiver are adapted for communicating analogue infor-mation.
.
Claims (12)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A picture transmission system comprising:
means for scanning an original image of arbitrary shape in a boustrophedral pattern;
means for digitally transmitting said scanned image along a communication channel;
means for receiving said scanned image from said communication channel; and means for displaying said original image com-prising a source for emitting a beam of radiation; a magne-tic material supporting a single magnetic bubble domain shift register channel covering the entire display area of said boustrophedral scan, said channel connected to said receiving means and located in the path of said beam pro-ducing a modulated beam displaying said original image from an image encoded signal applied thereto from said receiving means; and screen means in the path of said radiation beam for providing a visual display of said original image.
means for scanning an original image of arbitrary shape in a boustrophedral pattern;
means for digitally transmitting said scanned image along a communication channel;
means for receiving said scanned image from said communication channel; and means for displaying said original image com-prising a source for emitting a beam of radiation; a magne-tic material supporting a single magnetic bubble domain shift register channel covering the entire display area of said boustrophedral scan, said channel connected to said receiving means and located in the path of said beam pro-ducing a modulated beam displaying said original image from an image encoded signal applied thereto from said receiving means; and screen means in the path of said radiation beam for providing a visual display of said original image.
2. The arrangement as defined in claim 1, further comprising first polarizing means situated between said source and said magnetic material for polarizing said radiation beam.
3. The arrangement as defined in claim 2, wherein said screen means comprises second polarizing means.
4. The arrangement as defined in claim 1, wherein said magnetic material comprises a transparent channel bubble shift register in the form of a boustrophedral pattern.
5. The arrangement as defined in claim 4, wherein said producing means comprises gating means for providing clocked serial binary information to said shift register.
6. The arrangement as defined in claim 1, wherein said source is a visible light source.
7. The arrangement as defined in claim 6, wherein said visible light source is a lamp.
8. The arrangement as defined in claim 4, wherein said scanning means comprises a camera for scanning a scene and having an analog output, analog-to-digital con-version means having an input connected to said analog out-put of said camera, and a digital output for producing said encoded signal.
9. The arrangement as defined in claim 4, further comprising a communication channel for transferring said encoded signal from said scanning means to said displaying means.
10. The arrangement as defined in claim 8, wherein said representing means produced a sequence of bubbles in said shift register wherein the spacing between bubbles is modulated by said encoded signal for producing a grey scale picture on said screen means.
11. The arrangement as defined in claim 1 further comprising permanent magnetic means for providing a bubble-supporting magnetic bias field substantially normal to said magnetic material.
12. A picture transmission system comprising:
means for scanning an original image of arbitrary shape in a boustrophedral pattern;
means for digitally transmitting said scanned image along a communication channel having a predetermined bandwidth;
means for displaying said original image com-prising a source for emitting a beam of radiation; a magnetic material supporting a single transparent magnetic bubble domain shift register channel covering the entire display area in the form of a boustrophedral pattern, the bit-storage of said shift register having sufficient bit-storage capacity relative to the bandwidth of said commun-ication channel so that a still picture bubble pattern is developed in said shift register during a time longer than the integration time of the eye of a viewer, said channel connected to said communication channel and located in the path of said beam producing a modulated beam displaying said original image from an image encoded signal applied thereto from said communication channel; and screen means in the path of said radiation beam for providing a display of said original image.
means for scanning an original image of arbitrary shape in a boustrophedral pattern;
means for digitally transmitting said scanned image along a communication channel having a predetermined bandwidth;
means for displaying said original image com-prising a source for emitting a beam of radiation; a magnetic material supporting a single transparent magnetic bubble domain shift register channel covering the entire display area in the form of a boustrophedral pattern, the bit-storage of said shift register having sufficient bit-storage capacity relative to the bandwidth of said commun-ication channel so that a still picture bubble pattern is developed in said shift register during a time longer than the integration time of the eye of a viewer, said channel connected to said communication channel and located in the path of said beam producing a modulated beam displaying said original image from an image encoded signal applied thereto from said communication channel; and screen means in the path of said radiation beam for providing a display of said original image.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB647774A GB1420887A (en) | 1974-02-13 | 1974-02-13 | Picture transmission systems |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1055147A true CA1055147A (en) | 1979-05-22 |
Family
ID=9815204
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA219,536A Expired CA1055147A (en) | 1974-02-13 | 1975-02-06 | Picture transmission systems |
Country Status (4)
| Country | Link |
|---|---|
| CA (1) | CA1055147A (en) |
| DE (1) | DE2505953A1 (en) |
| FR (1) | FR2260907A1 (en) |
| GB (1) | GB1420887A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0246339B1 (en) * | 1986-05-17 | 1990-08-16 | Deutsche ITT Industries GmbH | Digital circuitry system for a (colour) television receiver with a cathode ray tube |
-
1974
- 1974-02-13 GB GB647774A patent/GB1420887A/en not_active Expired
-
1975
- 1975-02-06 CA CA219,536A patent/CA1055147A/en not_active Expired
- 1975-02-13 FR FR7504503A patent/FR2260907A1/fr not_active Withdrawn
- 1975-02-13 DE DE19752505953 patent/DE2505953A1/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| FR2260907A1 (en) | 1975-09-05 |
| GB1420887A (en) | 1976-01-14 |
| AU7819875A (en) | 1976-08-19 |
| DE2505953A1 (en) | 1975-08-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3849592A (en) | Graphic data redundancy reduction for text and half-tone optical facsimile system | |
| EP0751683A2 (en) | Image processing apparatus, image display apparatus and image sensing apparatus | |
| GB1049449A (en) | System of videophonic telecommunication | |
| TW350186B (en) | TV set receiver with character data function | |
| MY110244A (en) | Wide screen television. | |
| US3928719A (en) | Image display system | |
| US3803353A (en) | Optical-to-electrical signal transducer method and apparatus | |
| CA1057390A (en) | Method and apparatus for time compression of facsimile transmissions | |
| US3488435A (en) | Time-division multiplex system wherein a vidicon is used for frame storage of video signals | |
| CA1268248C (en) | Television picture display device | |
| CA1055147A (en) | Picture transmission systems | |
| US4123783A (en) | Magnetic bubble display systems | |
| US3815107A (en) | Cylindrical magnetic domain display system | |
| US3239606A (en) | Image transmission system employing simultaneous scanning of adjacent paths with sequential transmission of resultant scan signals | |
| GB1373894A (en) | Colour television system which utilizes liquid crystal filters | |
| CN1149859C (en) | Optical synchronous time division stereo TV system | |
| US3912861A (en) | Method and apparatus for time compression of facsimile transmissions | |
| US4531152A (en) | Television system and method | |
| US1808137A (en) | Electrooptical system | |
| US4833540A (en) | Image processing apparatus | |
| US2202541A (en) | Television and like system | |
| US3461223A (en) | Image translation system employing optical fibers | |
| ATE110911T1 (en) | TELEVISION TRANSMISSION SYSTEM COMPATIBLE WITH TRADITIONAL TELEVISION STANDARDS. | |
| SU1631753A1 (en) | Stereo television system | |
| US3712954A (en) | Large screen television systems |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |
Effective date: 19960522 |