FR2589300A1 - DEVICE FOR TRANSFORMING A REPRESENTATION OF A COLOR IMAGE INTO AN ELECTRICAL SIGNAL, AND INVERSE - Google Patents

Abstract

THE INVENTION RELATES TO A DEVICE FOR TRANSFORMING A REPRESENTATION OF A COLOR IMAGE INTO AN ELECTRICAL SIGNAL, and vice versa. IT INCLUDES A MEANS OF PRESENTATION OF THE IMAGE IN AN IMAGE PLAN, A SCANNING DEVICE 7 HAS AT LEAST ONE ELEMENT 9 CREATING AN ELECTRIC SIGNAL REPRESENTATIVE OF THE LUMINANCE OF THE SCANNED REGION OF THE IMAGE, AND A MOVE 10 WHICH MOVES ITEM 9 ABOVE THE IMAGE PLAN FOLLOWING A DIAGRAM INCLUDING A NUMBER OF SCAN LINES. MEANS ARE PROVIDED FOR PLACING COLORED FILTERS IN FRONT OF THE ELEMENT IN ORDER TO PRODUCE COLOR SEPARATION IN THE IMAGE. FIXING MEANS CARRY THE MOVEMENT MEANS, WHICH MOVES THE COLORED FILTERS AS WELL AS THE SCAN ELEMENT IN CONSTANT POSITIONAL CONCORDANCE WITH THE SUCCESSIVE SCAN LINES PRODUCED BY THE MOVEMENT OF THE SCAN ELEMENT.

Description

The present invention relates to a device

  to transform a representation of an image into a

  their in an electrical signal, and vice versa.

  When transmitting an image at a long distance, the image to be transmitted is scanned, image element by image element, with a predetermined resolution, by means of a device which can transform the luminance picture elements into a modulated electrical signal. When transmitting and receiving color images, the preferred method is to separate the colored image into several colors. By means of colored filters, the respective colors of the image are separated in turn and each is allowed to produce an electrical signal. The receiver

  receives the respective signals and is brought to reproduce direct-

  each of the predetermined colors in turn, one after

the other.

  The scanning is therefore carried out in a single

  number of operations that there are colors chosen for the separation

  ration. This makes possible the existence of equipment which, apart from color separation and color reproduction,

  is generally not more complicated than the apparatus which is necessary

  to transmit black and white images. The signal for each color even has the same characteristics as black and white image signals and can be used

  the same transmission channels, for example telephone lines

picnics.

  Even in contexts other than transmission-

  Long-distance vision of color images, devices have been discovered that transform the representation of a color image into an electrical signal. We have discovered, for example, an equipment which looks very much like a transmitter and a receiver for long distance transmission, but which is used locally in electrotyping or other supports.

  or as a basis for them. There are devices

  reils which produce electrotypes or stencils by means of an electrical signal which is produced on the basis of an image in a device which is can be regarded as an image transmitter. It is also possible to create an image signal to obtain a non-permanent image representation on a display means. Such an image representation can be used

  for long distance transmission or locally for in-

  training, checking or preparation. As is well known, such an image representation can be obtained using a television camera providing a signal to a monitor screen. However, for such a signal, the ability

  of transmission lines as simple as telephone lines

  nics is not enough and in many cases it is best to create and transmit the signal using a low frequency,

  after which the signal is recorded in a memory. We trans-

  then forms the signal into a high frequency signal which is applied to a control screen. To create the transmitted signal, it

  an image transmitter designed for this purpose is required.

  When separating colors, it is

  rant to use different colored filters in front of the dispo-

  scanning tool, which moves across the image.

  Color filters must in this case be the same size as the image area chosen for scanning. This leads to relatively bulky color filters and, since they have to be manufactured with great precision, the cost can become considerable. In addition, wherever there is non-uniformity on the surface of the color filter, a signal will be produced which will give an incorrect representation of

the image.

  The object of the invention is to propose a provision

  compact sitive allowing the separation of the colors at the same time as the creation and the reproduction of signals, which device leads to a lower cost for the color filters than it was the case with the systems of the prior art and which, in a large eliminates the risk of incorrect signals appearing due to the presence of non-uniformities in the

colored filters.

  Another object of the invention is to provide a color separation device which makes it possible to create a color image signal using a continuous process which can be controlled in different ways to take account of the

different intended uses.

  The following description, intended as an illustration

  tration of the invention, aims to give a better understanding of its characteristics and advantages; it is based on the accompanying drawings, among which: FIG. 1 schematically shows the image transmitter; FIG. 2 shows, on an enlarged scale, a first embodiment of a scanning device which is

  used in the image transmitter and which is designed according to the invention

tion; and

  FIG. 3 shows a second embodiment

tion of the scanning device.

  As shown in FIG. 1, an image transmitter comprises on and in a housing I a lighting device 2, an image holder 3 which is designed according to the invention, a mirror 5, an optical objective 6, a device scanner 7 with an image window 8 and a row scanner 9 as well as a motor 10, an elongated support 11 on which the mirror 5, the lens 6 and the scanner 7 are mounted at the same time as a mirror 12 which is rotatably mounted by means of a hinge 13. In addition to the lighting device 2, on the outside of the case, a projection window 14, a button panel 15 are provided,

  an electronic unit 16 and an electronic display device

pic 17.

  The lighting device 2 is hinged

  and can be lifted. Under Him is a circular opening

  cover 18 into which a circular base 4 can be inserted on the image holder 3 (see FIG. 1). In addition, the image holder 3 has an image window 19 which, when the image holder with its base is placed in the opening 18 and the lighting device 2 is in the lowered position, is located on the light path from the lighting device 2. The light path continues downward towards the mirror 5, where the light is reflected by the mirror through the lens 6 to reach the scanning device 7. As shown in Figure 1, we can however deflect the light path

  towards the projection window 14 by lifting the middle

laugh 12.

  When using the image transmitter, the image which is inserted in the image holder 3 is projected by light

  coming from the lighting device 2, via the mirror 5 and the object

  tif 6, on the image window 8 of the scanning device 7. There,

  it is scanned the number of times which is determined by The se-

  color matching by means of row sweeper 9, with the aim of creating an electrical signal. This signal can be sent to a receiver or can be used

  any other way for the purpose of reproducing the Image.

  A first simplified embodiment of the device

  scan positive 7 shown in Figure 1 is shown at a

  on a larger scale and in more detail in Figure 2.

  Said row sweeper 9 comprises a body of longitudinal orientation which can move the guides Lcng 20 using said motor 10. The motor 10 and the guides 20 are mounted by a frame 21 provided with an opening 22 in which the sweeper

  row 9 can move and that usually represents the over-

  face of the image. The image to be scanned is the result of a projection made inside the opening 22 of the true film image L located in the holder, age 3. The projection

  occurs when light from the lighting device

  rage 2 passes through mirror 5 and into objective 6, as above

  as described. The image is therefore projected in such a way that the focal plane is located in the opening 22 at the level of a row scanning element 23 located on the row scanner. This row scanning element is consisting of a row of light-sensitive elements which, thanks to an electronic control, can be made to emit successive electrical signals along the row of elements, so that a line of the image is scanned . As the row scanner moves along the guides 20, the image is scanned line after line until it has been scanned in its entirety. The result of all of this is a modulated electrical signal

  which represents all the image elements of the image whose resolution

  lution is determined by the size and separation of the elements

  light sensitive elements along the row sweeper 9, as well as the speed with which the row sweeper moves relative to the scanning speed along the row sweeper, in other words, by the density of

scan lines.

  Each light-sensitive element emits a signal, the amplitude of which simply depends on the intensity of the incident light which arrives on the element, without indication of color. For technical reasons, the sensitivity to the light intensity of the different colors varies, and it also varies in relation to the perception by the human eye of the luminance of the different colors, but these conditions cannot be used to create a signal that indicates

also the color.

  As mentioned in the introduction, we must, on the contrary, separate the image in different colors using colored filters and scan the image successively,

  color after color. A minimum of three colors is required.

  saire; all colors and shades of color can be produced by mixing three colors if these three colors are appropriately placed in relation to each other on the color circle. Separation in more than three colors also takes place. In color printing, it's common to do a separate black print,

  which corresponds to a black and white signal. Such a print-

  sion is called four-color printing. Color filters are used for color separation and, in order not to distort the color perception in the case where the image is seen in the image window 14 via the mirror 12, it is preferable to place the filters colored in the vicinity of the scanning device 7. According to the invention, each of the colored filters consists of a narrow plate 25, which, as can be seen in FIG. 2, fits into

  mounting strips 26 located on the row sweeper 9.

  The plates 25 of the color filters, when they are mounted in order on the row scanner, will therefore follow the latter during scanning. Each plate of a colored filter must simply have the same width as the elements

  sensitive to light in plane 23, which corresponds to

  lays in principle to the single width of a line. For handling reasons, however, it is appropriate for the plate to be somewhat wider. Not only does this facilitate handling, but less precision is required for mounting the plate. The length should naturally be

  the same as that of the row of light sensitive elements.

  It is possible to combine the desired color filters in a switching device so that it is then not necessary for the filters to be handled separately as in the case of mounting strips 26 as presented. In this case, one possibility consists in providing on the plate of the color filter several zones respectively having one of said colors. By pushing the plate into the different positions of the strips 26, the different zones can be placed in front of the

  row of light sensitive elements. According to another possibility

  bility, we can design a switching device which would be,

  for example, a device of the "revolver" type.

  The form of the invention shown in Figure 2 represents the simplest embodiment, where we remove

25893 00

  and we insert, one after the other, by hand, the filters

  colored. Said other form, containing a switching device

  tion, which can be automatic, represents a mode of realization

  more highly developed. An even more highly developed form is shown in Figure 3 and will be described below. As shown in Figure 3, the scanning device 7 (the designations used for Figures 1 and 2

  are also used in Figure 3 to designate the par-

  common ties) includes row sweeper 9, which is movable

  along its guides 20. A second guide means 30 is all-

  times provided in front of the scanner 9, i.e. on the side o

  the light beam coming from the projection device falls.

  On a carriage 31, the guide means 30 carries a plate 32, which rests parallel to the light-sensitive elements of the row sweeper 9. Inserted into openings 33, the plate 32 carries a number of colored filters 34. Here, seven colored filters are shown. As has been mentioned,

  a minimum of three filters is required to produce the separation

  color ration. In this case, the device has been made more universal by the use of three filters intended for the separation of positive images and three filters intended for the separation of negative images, in addition to which an opening 33 is reserved for creation. of a black and white signal. This one is intended

  black-and-white images and black-and-white printing

  chromia. In addition, the device contains a drive device 35, 36 for the carriage 31, so that it can be moved in a reciprocating movement along the guide means 30. Said guide means 30 contains a screw, 5 which meshes with a thread (not shown) mounted on the carriage 31 and which is driven by the action of a second

  motor 36, which is contained in the drive device.

  The driving devices used to move the row sweeper 9 along the guides 20 and the cutter separating carriage 31 with the filters 34 along the guide means 30 are arranged so as to form a coordinated training sequence. specific. This is achieved by means of a rotation control of the motors 10 and 36. Like this

  is well known, there are commonly electric motors

  triques, usually stepper type motors, which can be driven according to complex rotation schemes, ordinarily

  under the control of a computer. Such an engine is available

  nible for the present scanning device and must, in the embodiment considered, at least be designed to allow coordinated control of the two carriage devices. The means of implementation are well known to those skilled in the art and

  call for no further description.

  However, we will explain below the sequence

  control. Two forms of command sequences are possible.

  According to a first form, the image is scanned in its entirety the number of complete sequences which corresponds to the number of colors into which the image must be separated. In this case, the control sequence is such that Plate 32 follows row sweeper 9 as it moves over the

  image area along with a 34 color filter

  Tie light sensitive elements of the row sweeper directly in front of and so as to follow them throughout the sequence. During the next movement of the row sweeper 9 above the image surface, to ensure consistency with the following color, the plate 32 is moved in the same way, at the same time as

  the row sweeper, but this time with a certain spreader

  so that the next color filter 34 in turn follows

  the row sweeper, placed directly in front of its elements

  sensitive to your light. The resulting signal sequence is therefore divided into a number of sub-sequences which each represent the complete representation of the entire image corresponding in turn to one of the different

separation colors.

  In the case of the other type of sequence of com-

  Mande, the row sweeper 9 starts by sweeping a single line or, according to another possibility, a small rump of

258 9,300

  lines above the image surface for representation

  tation of a color, so that the corresponding color filter 34 is placed directly in front of the row scanner. The color separation plate therefore moves so that the following color filter 34 is placed directly in front of the row scanner 9, which then scans the same line or the same group of lines which was scanned previously in relation to the first color . In this way, the same image segment, preferably a single line, is successively scanned the same number of times that there are colors following

  which image must be separated by successive displacements

  color filters relative to the row sweeper.

  When all the colors have been represented, the row sweeper moves and scans the next line according to the same diagram. The resulting signal will therefore consist of subsequences representing a small segment of the image, for example a scanning line. Each subsection is itself divided according to the number of scan sequences to be used to represent all the colors of

separation.

  With regard to this last control sequence, the drive devices must be designed in such a way that the drive device relating to the row sweeper, using the motor 10, maintains the row sweeper at the different scanning positions. while

  that the drive device associated with the separation device

  tion of color, using motor 10, moves the color filters

  res in front of row scanner 9 so that all the colors sought are scanned. Then, the motor 10 moves the sweeper

  row notch and motor 36 applies its effects to displacement

  cementing of the color separation device in a new initial position adjusted to the new position of the row sweeper in order to carry out a new displacement of filters aimed

  when scanning the next color sequence.

  As already mentioned, means

  are planned to realize seven different separation possibilities

  annuities: three colored filters for positive images,

  three color filters for negative images, and the possibility

  ability to form a black and white signal. The device allows

  both move the color separation cart is designed

  so as to allow the four different scanning possibilities

following annuities:

  1. A color separation according to three layers

  their of a positive colorful image. In this case, the drive moves the color separation carriage with the three colored filters for positive images in turn.

  turn forward of the row sweeper.

  2. Color separation allowing to create three color signals and a black and white signal for a positive color image, for example in order to produce

  four color process electrotypes.

  3. Separation in three colors for an image

colored negative.

  4. Separation into four colors for an image

colored negative.

  For the apparatus which has been presented and described, the control means associated with the coordinated movement of the row sweeper and the color filter plate must be designed - so as to switch when a change is made for separation during the four different relationships mentioned above. In case 1, the filters which are intended for

  color separation of positive images are displaced

  these alternately in front of the row sweeper; in case 2, the position associated with the black and white signal is also incorporated in the sequence of displacements; in case 3, the three color filters used for the color separation of negative images are moved; and, in case 4, in addition to these last filters, it is even incorporated the position allowing to create the

black and white signal.

  When using equipment including the

  scanning device as shown in Figure 2, the posi-

  starting position of the row sweeper 9 is located at an edge of the opening 22. When a suitable image 4 has been chosen 11 and inserted into the image holder 3, the latter is placed below the device 2 and is aligned using the projection window 14 until the desired settings have been obtained. The mirror 12 is then lowered so that the image is projected into the opening 22 so that the focal plane is

  in plane 23 light sensitive elements.

  The order in which the colors are represented

  in the scanning signal is determined so that a repro-

  Image duction in the receiver can be accomplished in coordination with scanning in the transmitter. For the first scan, the filter corresponding to the first chosen color is inserted into the bands 26 (FIG. 2) and the scan sequence is executed. The color filter plate 25 is then replaced for the next scan, and the next scan is performed. We repeat the sequence until all the colors have been

  shown, namely, as mentioned, three colors at most.

  The manner in which the embodiment shown in Figure 3 can be used has been made clear

  above by means of the description of how Les

  drive units for row sweeper and dispo-

  color separation sitive are arranged for sequences

  of specific commands. The scan following the command sequence

  Mande described first is mainly identical to that described above for the first embodiment. The only difference is that the color filters exchange device is represented as an automatic device allowing to change the color filters while the image is scanned.

  the number of complete streaks necessary for the separation

  color ration. At the receiving end, the signal processing does not differ from that revealed in the first embodiment. The entire surface of the image is built up in several stages, so that the colors are added

  kez to each other to create the complete colored image.

  In the automatic embodiment of the app

  This can be conveniently switched between the different

  possibilities described for the command sequence and the

choice of filters.

  If we take the other command sequence, where the construction of the image is done segment by segment while all the colors are represented, another reception process is required. Even at reception, we are therefore now in the case where each segment, preferably a single line, will be produced separately, the various colors being added in turn.

  turn to create a complete segment. Then we go to the cons-

  truction of the following segment or the following line until, after reproduction of the final segment, the reproduction of

  the image is completed in the receiver.

  The shape of the scan sequence that is chosen also determines the type of receiver to be used. For

  the first type of scan sequence, you can basically use

  a receiver for black and white, the addition of color

  can be performed after receipt. However, it is likely

  blable that a modified black and white receiver will be used where the only significant change would be the matching of successive completed signals using different colors. As far as matching on a light-sensitive material using a light beam is concerned, this can easily be done using a color filter changer. For reception according to the second scanning sequence, the receiver must be designed so that it follows the same control cycle, which requires more significant changes when compared to a black and white receiver. On the other hand, this sequence of

  command allows greater accuracy in reproduction.

  Very good accuracy can easily be obtained

  operation of representations in different sizes for the various lines, since all the colors are recorded

  line after line. The use of the first sequence of com-

  However, this leads to greater difficulties or to what

  identifies obtaining such a position agreement, since the disoo-

  scanning and breeding devices must be moved oe

  synchronously several times over the entire surface of the image.

  The embodiment described last, as shown in the

258 9300

  figure 3, where the control section described last is used, therefore represents the most highly developed technique

  and, for some applications, the most functionally advanced

  tagger. According to the invention, each of the color filters consists simply of a narrow plate, the length of which corresponds to the height of the projected image. Since the plate of the color filter moves at the same time as the row scanner, these light-sensitive elements do not move along the surface of the color filter. It is sufficient that a narrow central part of the plate is perfectly correct with regard to the refraction of light and color. There is therefore no risk of the row sweeper passing over soiled parts, which could be the case if it were necessary to use, according to the method of the prior art, a plate which is larger relative to the fixed plate. of

row sweeper.

  In addition, the possibility of obtaining very high precision in the reproduction of images is realized by using the most developed embodiment, as shown in FIG. 3, at the same time as the last control sequence described. In addition to the advantages previously indicated, the reduction in the size of the surface of the color filter constitutes a

  additional and equally interesting advantage of the invention.

  The form of the invention which one chooses depends on the requirements of the system in which one will use the device of the invention. If the received signal is to be used to produce printing means, for example a certain number of electrons

  types or stencils that have undergone separation

  their, we emit three or four complete and separate signals in color. In such a case, we can even use the most

  simple, with manual change of the colored filter plates.

  However, the operation would gain much speed and would reduce the possibility of errors with the use of the automatic device. In case you have to produce a color image

  photographic directly in the receiving device,

  improves accuracy by better identifying separate images in color

  their if we apply said second command sequence operated

  rant a successive construction of the image, row by row, for all colors. In such a case, the automatic device must be used. This is also the case if it is necessary to create a signal for presentation on a display means via a memory. On a display device of the cathode ray tube type, the colors are constructed at the same time, so that the last control sequence is the most suitable. As mentioned in the introduction, the invention can also be applied to other scanning devices.

  as image transmitters. In such a case, it is adapted to the device.

  reil considered and we can even foresee a different structure

  of that shown while remaining within the limits of the invention.

  For example, the row scanner described which has a row of light-sensitive elements along a scanning line could be replaced by a point scanner where a scanning point moves along a scanning line after which it moves up to to the next scan line and, there, performs the same line scan. The fact of using such a method does not modify the device according to the invention, since the color filter could even then be oriented longitudinally along a line. In the embodiment of the device making it possible to automatically change the color filters, as shown in

  FIG. 3, two separate drive devices, respectively

  for the row sweeper and for the filters have been

  described, which devices drive these elements of a-

  coordinated way according to a predetermined scheme. It is all-

  possible to arrange the device so that only one

  positive drive is provided, the colored filters being then connected to this drive device so that they can be moved relative to it. This means that,

  when scanning is carried out using a colored filter

  particular, said filter is fixedly connected to the drive device of the row sweeper, while, When the color filter must be changed, a special changing device performs a relative movement between the mounting device of the color filters and the sweeper The same scanning patterns can be obtained in this way as when using the separate drive devices. Of course, those skilled in the art will be able

  to imagine, from the device whose description comes

  to be given for illustrative purposes only and in no way limited

  tative, various variants and modifications not departing from

framework of the invention.

RE V E N D I C A T I 0 N S

  1. Device for transforming a representation

  sensing a color image into an electrical signal and vice versa, comprising a station (22) intended for the presentation of the image in an image plane, a scanning device (7) provided with at least one element (9) light sensitive adapted to create an electrical signal which represents the luminance of the image in the scanned region, a moving means (10, 20; 30, 36) for moving the element (9) above the plane of the image according to a diagram consisting of a number of scanning lines covering the plane of the image, so that, in the region of the scanning element (9), means (26, 32) are provided for placing interchangeable colored filters (25, 34) in front of the element in order to produce a separation of the colors of the image so that several electrical signals can be formed which represent the image, each of being associated with a particular color that has been separated from the image using

  of the color filter, characterized in that each of the color filters

  res (25, 34) is substantially smaller than the plane of the image and is of a size designed to cover, in general, one or more of said scanning lines, and in that fixing means (26, 32) are carried by the displacement means (10,; 30, 36), which move the color filters at the same time as the scanning element (9) in constant positional agreement

  with the successive scan lines produced by the displacement

of the scanning element.

  2. Device according to claim 1, characterized

  in that the means for fixing the colored filters (25) comprise

  take supporting elements (26) which are arranged on a unit intended to support the scanning element (9) and are

  arranged to apply the colored filters in accordance

  positional dance with the Element scan line

  sweep which is placed within the area of said unit.

  3. Device according to claim 2, characterized in that the fixing means (26) of the color filters {25) are arranged so as to fix a single filter and are arranged

  so as to allow manual change of the color filters.

  4. Device according to claim 1, characterized in that the fixing means (32) of the color filters (34) are arranged so as to fix several color filters and to interchange these color filters in turn by moving the fixing means by relative to the scan line of the element

scan (9).

  5. Device according to claim 4, characterized in that a control means is provided for spreading the paths

  for displacement of the scanning element (9) and of the fixing means

  tion (32) of the color filters with respect to each other during the scanning process according to a predetermined scheme, so that the color filters (34), during the scanning process, are brought in and in turn kept in positional agreement with the successively produced scan lines

* above the image plane.

  6. Device according to claim 5, characterized in that the control means is arranged so as to maintain a first color filter (34) in positional agreement with the scan line during a complete scan of the image for creation of a first full color separation signal and then maintaining the next color filter in positional agreement with the scan line during a full scan

  - the image for the creation of the color separation signal

  following them until all the separation signals from

  intended colors have been created.

  7. Device according to claim 5 or 6, charac-

  in that the control means are arranged so as to

  maintain a first colored filter (34) in position-matching

  with the scan line while scanning a single line or a limited number of lines comprising only a limited image segment and then maintaining the second color filter in positional agreement with the scan line in view from scanning the same image segment as the previous one to all the color separation signals relating to said image segment have been created, after which the process is repeated for the second image segment until all The image segments by which the image is divided have been scanned relative to

  to all the colors in which it is planned to separate the image.

  8. Device according to claim 5, characterized in that the scanning element consists of a row sweeper (9) which, by means of the displacement means (20),

  is intended to be moved in its transverse direction to-

  above the plane of the image, and in that the means for fixing the color filters (34) comprise a plate (32) provided with a

  number of openings (33) in which the filters colo-

  res are inserted, the plate being intended to move at the same time as the row sweeper and to change position relative thereto, so that the different color filters carried by the plate can be changed and placed directly

  in front of the row sweeper (9).

  9. Device according to claim 8, characterized in that the row sweeper (9) and the fixing means (32)

  colored filters (34) each have means for moving

  cement (10, 20; 30, 36) adapted to move the row sweeper and the fixing means under the direction of the control means in a manner which is coordinated and which is adapted with

  the scanning and color separation process.

  10. Device according to claim 8, characterized in that the row sweeper and the fixing means (32) of the colored filters (34) have common displacement means and, in addition, an exchange device making it possible to change the position of the color filters (34) relative to the sweeper

row (9).