FR2500190A1 - SYSTEM FOR DETECTION AND TRANSMISSION OF INFORMATION PROVIDED BY MECHANICAL OR ELECTROMECHANICAL COUNTERS - Google Patents

Abstract

THE MOBILE DISPLAY ELEMENTS 1, 2, 3 OF MECHANICAL OR ELECTROMECHANICAL METERS ARE EQUIPPED WITH CHARACTERS OR INDICATIONS 30 CODES ACCORDING TO A BAR CODE, EACH CHARACTER 30 CONSISTING OF A PREDETERMINED NUMBER OF NON-REFLECTING LINES AND REFLECTING SPACES OF VARIOUS AND PREDETERMINED WIDTHS, THE SPACES BETWEEN CHARACTERS ALL NOT REFLECTING AND EACH CHARACTER CODE BEGINNING AND ENDING WITH A REFLECTIVE SPACE. THE MOBILE ELEMENTS 1, 2, 3 ARE ARRANGED IN A BOX 7 PRESENTING A VIEWING WINDOW 70, SUCH AS FOR EACH MOBILE ELEMENT THE CHARACTERS CODED CAN SUCCESSIVELY COME INTO A PREDETERMINED POSITION BEHIND THE VIEWING WINDOW 70. OPTICAL DETECTION MEANS 8 ARE PROVIDED TO ENSURE A SCAN READING OF THE CHARACTERS CODED 30 APPEARING AT A TIME GIVEN IN THE VIEWING WINDOW 70 AND TO TRANSFORM THE SUCCESSION OF NON-REFLECTIVE LINES AND REFLECTIVE SPACES DETECTED SIGNALED INTO A SUCCESSION OF ELECTRICAL SIGNALS.

Description

Information detection and transmission system

  supplied by mechanical or electromechanical counters

  picnics. The present invention relates to a system for detecting and transmitting information

  supplied from mechanical type indicator means

  nique or electromechanical such as mechanical or electromechanical counters with mobile display elements, constituted for example by wheels, discs

or ribbons.

  The use of totalizing meters of mechanical or electromechanical type is very widespread to carry out, for example, measurements of energy consumption or of distance traveled. However, taking into account the data provided by these meters requires a

  manual reading which can lead to errors and neces-

  site, for the further processing of the data collected, the use of a mechanical keyboard, which will convert the data into digital signals capable

  to be processed by a calculator or a computer.

  With a numeric keypad, which remains relatively expensive

  high handling errors are not uncommon, so the traditional handling system

  account of information provided by meteors

  caniques does not appear fully satisfactory.

  The present invention aims precisely to remedy the aforementioned drawbacks and to enable the meter reading to be carried out in a simple, safe and rapid manner in order to allow direct recording of the information read and processing by digital means. These objects are achieved thanks to the fact that, according to the invention, the mobile display elements of the meters are equipped with characters or indications coded according to a bar code, each character being

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  composed of a predetermined number of non-reflected lines

  alternating widths and reflective spaces

  diverse and predetermined, the spaces between characters

  res being all non-reflecting and each coded character starting and ending with a reflecting space, the mobile elements are arranged in a frame having a viewing window, in such a way

  that for each mobile element the characters or indi-

  coded cations can come successively almost outcropping in a predetermined position behind

  said viewing window and detection means

  optical optics are provided to ensure reading by

  scanning of said characters or coded information appears

  falling at a given time in said window of vi-

  sualisation and transform the succession of non-reflective lines and detected reflective spaces into

a series of electrical signals.

  According to a possible embodiment, the optical detection means are mounted on a support

  sliding in at least one solid guide rail

  daire said frame to maintain the detection means at a predetermined distance from the window

  display during a reading sequence.

  According to one possible embodiment, coded information is also inserted behind the viewing window in a predetermined position next to the mobile display elements, on a support.

fixed or removable.

  Furthermore, the support of the means of

  tection is advantageously fitted with cleaning elements

  such as brushes on a front face set

  contact with the viewing window of the frame.

  The optical detection means can also comprise reading authorization means which cooperate with the frame so as to authorize a reading only when the sliding support is engaged in the

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guide rail.

  The optical detection means are re-

  read by means of an interface circuit and of data transmission means to a calculation unit ensuring the decoding of the information detected by the optical detection means and converted into signals

binary logic.

  The scanning movement of the viewing window by the optical detection means at determined instants can be controlled automatically from the computing unit by means of control circuits for driving the support of the

  optical detection means, or be carried out manually-

  is lying. The optical detection means can comprise a light emitting element such as a light-emitting diode, a focusing element for focusing the light emitted in a predetermined plane,

  a photodetector sensitive to reflected light

  chie by said predetermined plane, and electric circuits

  to activate a level 1 logic signal when the photodetector element is itself excited and

  a level O logic signal when the photo-

detector is not energized.

  The electronic circuits associated with the e-

  the photodetector may further include a

  inverter circuit to emit a logic signal of ni-

  calf 1 when the photodetector element is not excited

  tee and a level O logic signal when the element

photodetector is excited.

  We already know the use of bar codes to make labels bearing, for example, data relating to a product. Such labels

  are coded on the products they concern

  and can be read using optical scanners.

  However, this only allows the entry of static data.

  ticks determined once and for all and not varying

  not in time. According to the invention, data entry

  dynamic, that is to say, indications

  bles to vary over time is made possible by optical reading means thanks to a simple and inexpensive arrangement which can be easily adapted to preexisting meters. According to the invention, it suffices in fact that coded indications are affixed to the mobile elements of the meters, without the

  structure of these is changed, and that the indicators

  coded positions to locate can be placed according to

  a reading reference surface defined by a fe-

  to be visualized. An optical detector can then be positioned relative to the reading window to scan the reading reference surface.

  on which the information to be noted appears.

  The use of type barcodes

  classic according to which characters are represented

  ted by a series of dark lines and light spaces

  alternate and having at least two different widths

  However, they cannot be applied as such to the coding of dynamic data. We know that,

  according to these classic codes, it is necessary to have

  use reflective white margins at both ends

  with a coded message, and also with clear spaces

  reflective between two different coded characters.

  Such a characteristic proves prohibitive in the case of a combination of characters intended to be easily modified. Indeed, in the case where for example

  adjacent coded characters are carried by the tran-

  Che adjacent coding wheels united within a counter, there must be a discontinuity

  between two adjacent encoder wheels, because this

  these exhibit independent movements one of

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  the other. This discontinuity, which corresponds to an ab-

  sence of reflection plan during a reading of the characters

  coded tères of the different wheels using a sensor

  optical sensor, necessarily results in a dark mark which, with the usual codes, constitutes a parasitic detection disturbing the detection of the spacings between different characters. According to the invention, because

  the inversion of the usual codes which leads to the

  setting margins and spaces between characters

  which are dark in color, i.e. not reflected

  the discontinuities between mobile coding elements

  adjacent geos do not lead to the detection of information

  parasitic conditions. We also know that bar codes allow large tolerances for

  spacing between characters. The existence

  this of discontinuities between adjacent coding elements

  and the different widths of different discontinuit-

  tees are not obstacles to a reliable detection of a series of coded information supported by

moving parts.

  The invention thus generally relates to a method for detecting and transforming into electrical signals, information supplied from

  mechanical or electromechanical indicating means

  such as mechanical or electromechanical counters

  mobile display elements, characterized by

  what it consists in providing mobile elements with

  bar counters, characters or indications coded according to a barcode, each character being composed of a predetermined number of non-reflecting lines

  and alternating reflective spaces of various widths

  sound and predetermined, the spaces between characters all being non-reflective and each coded character starting and ending with a reflective space to dispose the mobile display elements of the counters in relative positions such that the characters or coded indications of each mobile element can successively come to the surface in a position

  predetermined behind a reference surface of my-

  deny allowing their location; to carry out at determined instants an optical reading by scanning of the coded characters or information appearing at the level of said reference surface, and to develop from the captured light signals, electrical signals

  whose parameters depend on the type of element

  tect according to its reflective character or not.

  According to this method, the electrical signals produced from the captured light signals are binary logic signals in which one of the states or levels corresponds to the detection of a reflecting space and the other state or level corresponds to the detection of a

non-reflective line.

  The embodiments of the invention thus essentially comprise a mechanical or electromechanical counter with mobile display elements such as wheels, discs or ribbons, characterized in that the mobile display elements are provided with characters.

  or indications coded according to a bar code, each card

  being made up of a predetermined number of non-reflecting lines and alternating reflecting spaces of various and predetermined widths, in that the

  spaces between coded characters are all not reflected-

  sants, as well as the uncoded marginal parts of each movable display element and in that each

  coded character begins and ends with a space-

  bending. Other features and benefits of

  the invention will emerge more clearly from the description which

  follows specific examples of embodiment of the invention, with reference to the appended drawing, in which

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  - Figure 1 is a perspective view

  mobile elements for coding a counter according to the

  vention, - Figure 2 is a perspective view of a frame and a reading member cooperating with the frame in which are installed the mobile coding elements such as those of Figure 1,

  - Figures 3 and 4, are schematic views-

  matics respectively from the front and in section of a reading member usable in the context of the invention, - Figure 5 shows an example of a coded message that can be detected with the system according to the invention, - Figure 6 is a table showing an example of bar code applicable to the present invention, - Figure 7 is an example of a detection circuit that can be associated with a reading device, - Figure 8 is a sectional view along line VIII-VIII of Figure 2, and,

  - Figures 9 to 12 are flowcharts-

  mes of an example of a decoding program and taking into account coded information noted by a system

according to the invention.

  We see in Figures 1 and 2 the basic elements for the implementation of a detection system according to the invention. In particular, Figure 1 shows the schematic representation of three

  1,2,3 coding wheels belonging to a counter and above

  capable of being rotated by a mechanical

  conventional me, not shown, for example of the type with gears or cogs such as element 13 (FIG. 8),

  in order to allow the display and the statement of information

  tions, in particular of numerical quantities, representative

of evolving parameters.

  The display at all times of information

  tion can be done according to a line of re-

  fixed reference, for example at the tangent x'x (fig 1) to the coding wheels 1,2,3. In this case, according to the conventional methods of reading information, for each coding wheel 1,2,3 that of the boxes, 20,30 which is located on said reference line

  x'x and note the indication in this box.

  Thus in the example of FIG. 1, the boxes 10, 20, 30 of the wheels 1,2, 3 which are located at the level of the

  line x'x allow the number "137" to be noted.

  The invention overcomes such manual reading of the indications provided by

  counter encoder wheels without changing any-any

  negates the very mechanism of the wheel drive co-

  deuses, that is to say by keeping unchanged the

  seems to be the mechanical structure of the meter, as well as the arrangement of meters or possibly manual positioning means associated with the meter to control the movement of the moving parts of the meter

  continuously or discontinuously depending on a pro-

  fixed term. Thus, as can be seen in FIG. 1, the arrangement of the coding wheels 1,2,3 as well as their dimensioning can remain quite

  made classics. On the other hand, the coded wheel area

  its on which are the information to be read

  worm, i.e. the slice in the case of the example in Figure 1 (but in the case of a disc counter

  mobile for example, this area could also be cons-

  titled by a crown on the front face of the disc) is modified to bring to the level of each box not

  no longer just the symbolic representation of a figure

  fre, character or sign, but a representation of this

  number, character or sign, coded according to a bar code-

  res in a manner which will be explained later.

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  Naturally, a small portion 11, 21, 31 of the boxes

  , 20.30 can be reserved for the figuration of the

  "clear" duction of the barcode which occupies itself

  most of the area of each space 10,20,30.

  In general, each coded character 109 has (Fig 5) a predetermined number of dark lines

  that is to say non-reflective, which will still be called

  the black bars 101,103 and clear intervals that is

  ie reflective which will also be called white spaces 104,105. Black bars and white spaces

  are always alternated so as to allow detection

  tion of the transitions between these various elements. By ail-

  their, the black bars and the white spaces are redi-

  left in series of elements of various widths. For example, the black bars may include a series of thin bars 103 and a series of thick bars 101. Similarly, the white spaces may include a

  series of narrow spaces 105 and a series of wide spaces

  ges 104. Different codes are naturally usable and the black bars and white spaces could for example be divided each into three series of elements having three different widths. Some codes

  have special advantages, however,

  flexibility, reliability and precision. An example of such type

  of code will be explained later with reference to the fig-

  res 5 and 6. For all usable bar codes

  in the context of the invention, it is however essential

  sable to provide spaces between characters that are non-reflective, that is to say of the "black bar" type and to use character encoding such that in the coded representation, each character begins and ends with a clear reflective space , that is to say a "blank", whatever the length of this "blank". In this way, the discontinuities at the edges of the coding wheels 1,2,3 and in particular between

  two encoder wheels 1 and 2 or 2 and 3 (Fig 1) do not

  do not have incorrect detection of the information displayed

  at the location line x'x, since these dis-

  continuities simply translate into a black bar

  re, which, according to the invention, is the normal type of transition element between characters. To facilitate detection, each coded box 10,20,30, which is limited on each side by a white space, does not end in the immediate vicinity of the edge of the coding wheel

  1,2,3 but at a short distance from it

  this one, the remaining marginal space that extends up to

  the edge being constituted by a dark strip 12, 22, 32.

  the beginning and end of a coded character on each wheel

  coders are then defined with very high precision.

if we.

  As can be seen in FIG. 1, we have arranged in the plane tangent to the coding wheels 1,2,

  3 along the line x'x, on either side of the wheels co-

  1,2,3, surfaces 4 and 5 which bear in the vicinity

  line x'x of static coded indications, 42 and 50, 52 respectively. These indications are

  necessary during an optical reading of the message

  checked in coded form by the coding wheels 1,2,3 to give for example information of beginning and end

  of reading. In this way, the collection of information af-

  plugged in by the encoder wheels in the area defined by

  line x'x can be detected and saved automatically

  matically by simply scanning said area using a detector, which precisely avoids errors due to readings by an operator or handling

keyboard.

  FIG. 2 makes it possible to explain the manner in which the reading of information takes place on a counter whose coding wheels have been provided with boxes coded according to a bar code, as shown in FIG. 1 1 1. A frame 7 having a viewing window 70 is arranged around the assembly constituted by the wheels

  1,2,3 coders carrying dynamically coded information

  ques, that is to say likely to vary over time and surfaces 4, 5 carrying static coded information. The window 70 is formed along the axis x'x

  in Figure 1 so that the indications co-

  dees are exposed behind said window 70. The height of window 70 corresponds substantially to the height of boxes 10, 20, 30 of the coded characters. The window 70 is preferably set back relative to the front face of the frame 7 so as to form a slide 71 serving

  guiding a read head 8 constituting a set

  ble for detecting coded information.

  The read head, shown diagrammatically

  only in Figures 2 to 4, includes a boot 80

  extending by a projecting front part 81 for-

  mant nose intended to slide in the slide 71. An opening 82 in the projecting part 81 delimits the reading area of the head 8. Coatings forming

  brush 83, for example made of polytetrafluoroethylene,

  vant to play an antistatic role are advantageously made on the front face of the projecting part

  81, on each side of the opening 82, so as to avoid

  ter errors due to parasitic particles, for example dust placed on the window 70 and

  superimposed on the traces of coded information. The fe-

  nitre 70 in fact preferably comprises a transparent window 74 constituting a physical separation between the coding wheels 1,2,3 which are exposed behind

  this window and the nose 81 of the read head 8. The

  seems to detect 8 which allows an optical reading,

  works on a principle which is itself classic and com-

  essentially takes (Fig 4) a light emitting element 84 such as a working light emitting diode

  in a defined range of corresponding wavelengths

  for example in visible or infrared light,

  optical elements arranged in the vicinity of the opening

  82 to concentrate the light emitted in a reference plane located in front of the opening 82, an element

  photosensitive detection 85, sensitive to light

  re emitted by element 84 and reflected by said plane

  reference, electronic circuits 86 for milking

  ment of the signal emitted by the detector 85 and a cable 96 for connection to an information processing assembly

  digital read head 8.

  When the read head 8 is positioned

  born in the slide 71 of frame 7, the lightning field-

  the light emitting element 84 is located immediately

  behind the window 70, at the level of the coded information 40, 50 of the fixed suffixes 4, 5 or of those 10, 30 of the mobile surfaces which are situated in the vicinity of the axis x'x. Naturally, information coded 60

  can also be affixed to removable surfaces

  bles 6 for example of badges-, interposed between the coding wheels 1,2,3 and the fixed surfaces 4, 5. The code of

  information 60 must in all cases remain compatible

  ble with that of the information in boxes 10, 20, 30,, 50 and in particular the lateral margins 62 not

  of the surface 6 should remain dark. The TRA-

  clear duction 61 of coded information 60 can by

  example appear in a part of badge 6 which emer-

* ge at the top of the frame 7. During the scanning of the surface of the window 70 by the read head 8, the detector element 85 alternately detects dark and light areas according to whether the window 82 of the

  read head is facing an unreflected bar

  chissant or facing a reflecting space at the level of the reference plane illuminated by the photoemissive element 84 and located immediately behind the window 70. The detector 85 then delivers an analog signal which is then processed to provide a level 1 logic signal when a clear space is detected and level 0

  when a black bar is detected.

  Figure 7 shows an example of a cir-

  cooked associated with the photoemissive element 84 and the detector

  photosensitive 85. In this FIG. 7, the elements

  referenced 87 to 95 correspond to the elements of the

  cooked 86 of FIG. 4. The other elements playing similar functions bear the same references on the

different figures.

  Light emitting diode 84 is polar

  connected by a resistor 87 and connected to the potential for

  ference by means of a manual switch 98 which, in the position shown in FIG. 7 activates two micro-switches 97 which are arranged on one of the faces of the support 80 which comes into contact with the front face 73 of the frame 7 when the nose 81 of the read head 8 is engaged in the slide 71. These microswitches 97, when they are put into service by the manual switch 98, make it possible to authorize the supply of the diode 84 , and therefore a reading, only if the nose 81 of the reading head 8 is suitably

  engaged in the slide 71 for guiding the frame 7.

  The photodetector 85 is connected to the

  entry of an amplifier stage comprising an amplifier

  differential sensor 89 and an associated resistor 88. The output of the amplifier stage is itself connected to the non-inverting input of an operational amplifier 94 via a resistor 92. The non-input

  itself is connected to ground by a con-

  densifier 93 while resistors 90 and 91 connect the inverting input of amplifier 94 respectively to ground and to the output of amplifier 94 for

  constitute a follower stage at the exit of which is delimited

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  vré a signal whose level depends on the excitation of the detector 85, that is to say on the presence of an element

  reflecting or not reflecting in the focal plane received

  vant the light of the element 84 and returning it to the detector 85.

  An inverter circuit comprising an amplifier

  operational ficitor 95 associated with resistors 95 'and

  "can be selectively put into service by the

  mutator 99 at the output of the follower stage to deliver an output signal which if it is shaped, constitutes

  -a logic signal having a level 1 when the-

  vertex 82 of the read head 8 passed in front of a dark bar and a level 0 when the aperture 82

  walked past a clear, reflective space.

  The inverter circuit 95 put into service by

  switch 99 allows data to be compatible

  data supplied at the output of the read head 8 on line 96 with those supplied from similar bar codes but in which the role of the white elements and of the black elements is reversed, that is to say according to which the spaces between characters are white, as is the case when reading

exclusively static data.

  During a reading sequence during the

  which read head 8 scans the entire surface of

  the viewing window 70 by a recti-

  sliding line along the slide 71, in a given direction not inverted during the same reading sequence, the head 8 provides information signals

  which are applied by link 96 to an information circuit

  terface 201 and transmitted to a computing unit 203 which

  decodes the digital signals represented

  coded information detected by the head of

  reading 8. The calculation unit 203 can comprise a half

  croprocessor and display means, arranged at the

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  in the immediate vicinity of the interface circuit 201 or, on the contrary, being located remotely, the link 202 between the circuit

  interface baking 201 and the computing unit 203 being able to

  then understand in a conventional way means of

HF reception-reception for example.

  The system according to the invention is suitable for

  particularly good at automating the collection of information present at a given time behind the viewing window 70. Indeed, the support 80 of

  the read head 8 can easily be driven in motion

  lie automatically along the slide 71 by drive means 205 controlled by circuits 204 which themselves receive the necessary orders issued

  from the calculation unit 203, to cause sequences

  these reading at times determined according

a pre-established program.

  It will be noted that the coded message 110 read at each

  that reading sequence can be very complete since static information such as indications

  start and end of message 107, 108 can be called

  placed directly at the two lateral ends of the viewing window 70, for example by gluing

  on the internal face of the window 74, elements 4.5

  taking boxes 40.50 associated with black margins 42.52. This static information can also be

  additional identifying information such as

  only indications on the location of the counter, the type of operation carried out, the name of the operator or holder, the type of quantity measured or the type

  unit of measure. This information can be intro-

  picks for example by means of badges 6 in openings

  tures 72 of the frame 7 so that the indications

  coded worn on the badge are positioned im-

  immediately behind the viewing window 70.

  Dynamic information 10,20,30 carried by

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  mobile encoder elements thus appear each time

  instant behind window 70, next to the other information

  static mations to give the instantaneous state of para-

  meters to watch. Note that the elements of comp-

  1,2,3, may include not only

  permanently connected to drive devices

  automatically in motion by means of various sensors adapted to the processes to be monitored, but also mobile elements periodically updated by manual positioning means, these mobile counter elements then constituting a reliable and inexpensive non-volatile memory, the information of which are read automatically during a reading sequence and

  complete the information provided by the other ele-

  coding elements. The invention thus lends itself to the constitution of

  tion within the same frame 7, of an assembly which can be modular which integrates into a series of elements

  aligned, both elements 1,2,3 carrying information

  variable or adjustable in time, that removable or fixed elements 4,5,6 carrying information invariable in time, without it appearing between two adjacent elements of discontinuity likely

  affect the detection or decoding of the message.

  In addition, the various elements 1 to 6 carrying coded information can all keep

  a classic structure and simply be provided with

  bowls carrying coded signs and characters and

  read by photo-printing. According to a variant, the

  coded indications can also be carried out

  straight on moving elements 1 to 3 by etching

chemical for example.

  The shape of the frame 7 can be varied depending on the applications envisaged. However, a

  high efficiency is obtained when beti 7 presents

  te around window 70 & both upper ledges

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  laughing and lower 71 forming guide slide of the nose 81 of the read head 8, and lateral end stops 75, 76 limiting the stroke of the head 8. In addition, the dimensioning of the nose 81 of the head 8 and runners 71 is preferably made so that the front face of the part of the support 80 outside the nose 81 comes to bear against the front face of the frame 7 so that the flexible brushes 83 do not exert

  only limited pressure on window 70.

  Figures 5 and 6 show an example of a bar code that can be used in the context of

  the present invention. According to this code, which allows to re-

  present at the same time the set of ten figures from 0 to 9, a set of 26 letters and at least four other signs or characters, each coded element 109 comprises a series of five white spaces and four alternating black bars. Each series of five white spaces comprises three narrow white spaces 105 and two wide white spaces 104 (the width of which can be approximately twice that of the narrow white spaces 105). Each set of four black bars includes three narrow black bars 103 and a wide black bar 101 (the width of which can also be approximately double that

  narrow black bars 103). Preferably, the lar-

  gor of narrow black bars 103 is equal to that of narrow white spaces 105 and the width of the bars

  wide black 101 is also equal to that of the spa-

  these wide whites 104. In this way, it is possible

  ble to make a code like the one shown on the

  table in fig. 6. Note that according to this code,

  no character is its own symmetric, and all characters have a characteristic sequence of alternately white and black lines. This code is indeed applicable to a system according to the invention to the extent

  o spaces 106 between characters, which can present

2 5 0 01 9 0

  ter variable lengths, are dark, as well as

margins 102.

  The structure of a code message is shown

  felt in FIG. 5. A first character identifying

  message start and end cation, which may be the symbol of the asterisk, is placed at the head of the message 107, followed by a set 110 of coded characters 109 which, in this case, consist of the information

  encoder wheel dynamics (or other moving elements

  the) of the counter whose information is to be read,

  possibly associated with other statistical information

  intended to supplement the result of the ef-

  carried out. The present invention generally makes it possible to very significantly extend the field of application of bar codes, since the system of

  recommended detection allows taking into account not only-

  static data affixed once and for all on a package for example, but also the socket

  taking into account dynamic data variable over time.

  The message appearing in the display window 70 can be read by scanning from left to right or from right to left using

  the presence of the start and end character of the messa-

  ge, which is not its own symmetric and of the fact that

  any other character itself has a symmetry.

  Furthermore, the scanning speed is not critical and can vary widely since a bar code can allow independent decoding of

  said speed over a wide range of speed values

  reading. Thus, reading speed ranges from 1 to 40 are perfectly tolerable so that manual actuation of the read head 8 to perform a reading sequence is perfectly

possible.

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  Finally, the detection system described previously

  previously allows computer processing of information

  coding mations recorded by the detector set

  tion 8 insofar as optical detection based on the presence or absence of reflection for light

  emitted in the viewing area by the read head

  ture, is of the all or nothing type. As we said before

  In addition, the processing of information can be adapted

  tee directly to the code used or on the contrary be common to two similar codes opposite to each other (that is to say in which the role of the black bars

  and white spaces are inverted) if a reverse circuit

  it is also included in the detection unit 8.

  The decoding of a message is carried out according to

  classical techniques in several stages structured

  layers, which in particular involve recognizing the type of character trait and the

  type of sentence formed by the association of characters.

  For the recognition of the type of coding stroke, it is checked in particular, when the color type has been registered, if the duration is between minimum and maximum durations, in order to identify the strokes

  short, long lines and spaces between characters

  res which are of variable length. The compulsory work-study program

  of white and black elements and the relationships existing

  the widths of the short and long lines also make it possible to carry out control tests at the end of character detection, by adding all of the durations of the different lines of a character and dividing by the total number of elementary units of stroke (that is to say the duration of a short stroke in the case of the code taken as an example with reference to the table in FIG. 6). Recognition of a character recognized as such is then easily done by comparison

  with the elements of a table saved in memory.

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  As for the recognition of a global message, it is

  facilitated by the presence of identifying characters

  start and end message as described

  you higher. Thus, in the case where the character of iden-

  tification of start and end of message is the asterisk

  that, whose structure read from right to left corresponds to

  pond to that of the letter P, it suffices to examine, when detecting a first character, whether it is an asterisk or a P. In the first case, the reading of the message will be normal. In the second case the reading will also take place, but the reading of the characters

  in the table will be reversed. Likewise if at the end of the messa-

  ge the last character read is a P and not an asterisk

  that, the entire sentence will be returned.

  Figures 9 to 12 show the organi-

  grams of an example program suitable for reading and decoding information coded according to the code example described with reference to FIGS. 5 and 6. Thus, in FIG. 9 we see the flowchart of a subroutine

  Bar length reading LLGB. This subpro-

  gram stores in CPT the length of the bar being

  reading. The method used is counting and

  this is stopped by the detection of a transition from

them on the coded message.

  Figures 10 and 11 show the organ-

  nigram of a character reading subroutine.

  Figure 10 corresponds to the first part of this sub-

  program which concerns the reading of the different bars

  res constituting a character and the T-shaped arrangement (IDX) of the successive lengths of the nine bars, white or black, detected. The subroutine in FIG. 10 notably uses the LLGB subroutine for reading the length of a bar and delivers error messages if the detected lengths exceed certain predetermined ranges. Thus, the error message Xl can occur

2500 1 90

  read "this is not an inter character space", the mes-

  sage error X2 can read "the inter character space

  re is too small or too large "and the error message

  X3 can read "bar too small or too large".

  The second part of the character reading subroutine, represented on the flowchart

  in Fig 11, relates to character decoding and

takes five steps.

  In the first step (I), it is carried out

  killed the sum of the lengths of the dark and light spaces (i.e. black and white bars). According to

  code used in the example considered, the sum S com-

  takes two large light spaces, three small light spaces, one large dark space and three small light spaces. Knowing that the dark and light spaces are

  of the same size and that large spaces G are the double

  ble of small spaces P, the size of a small space P

is worth S / 12.

  During the second step (II), we seek to recognize a large space G from a small space P and we use for this a limit L such that L = 3 p 3 S 3 S 2 4 12 x2 '8

  The third step (III) allows to find

  see in a word B the arrangement in binary form of the nine bars making up the character to be decoded. We take

  as convention that a "1" corresponds to a large bar-

re and an "O" at a small bar.

  The fourth step (IV) implements a CAR table in which we find the transcoding of bar codes in the ASCII code for example. Since the CAR table can contain a greater number of characters (ar for example 512) than those actually used in a bar code (for example 40), the characters in the

  unassigned table are affected by an indeter sign-

mination "?".

  The fifth step (v) displays

  an X4 error message if an unknown character is de-

  tecté. Figure 12 shows the flowchart of a sentence reading routine. Each sentence is surrounded by asterisks "". According to the code taken as an example, an asterisk read from right to left corresponds to the code of a "P". So when the first

  read character is an asterisk, it is a sign of a

  normal reading head wiring from left to right

  you. In this case, the message must also end with an asterisk. If on the other hand the first character read is a "P", it is the sign of a right scroll

  to the left. So each character will then have to

  even be returned and the full sentence will also be returned. The detection of a first character which is neither "-" nor "P" leads to an error message X5

indicating that there is an anomaly.

  The system according to the invention is susceptible to

  ble to receive many applications. At ti-

  As an example, it is possible to associate means of

  bar coding and reading such codes at comp-

  car owners in order to facilitate the management of a car fleet by carrying out a simple statement of data on each vehicle and by delocalizing the most

  large number of operations at the level of each vehicle.

  In the vehicle, it is enough to add to existing meters (mileage measurement,

  counting of number of passengers, operating time-

  ment, etc. provided on their movable affi-

  chage of marks coded according to a bar code; a frame

  likely to define a viewing window

  putting at a given time to read by scanning all the information provided by the meters, as well as static additional information

2500 1 90

  but removable by the affixing of coded indications on simple badges. A time reference can be obtained simply, for example using a regularly rotating micromotor whose number of revolutions is counted by means of a counter provided with coded display elements. Other meters provided with coded display elements and also housed in the same frame can also be used for the periodic and normal display by a user, of data such as consumption of products for example. All the information collected using a detector 8 can then be transmitted to and processed by a unit

  computation such as the unit 203 of figure 7.

  Of course, various modifications and additions can be made by those skilled in the art without departing from the scope of the invention. So a head of

  reading 8 of the type described with reference to the

  sin and having a projecting part 80 coming from

  castrating in grooves of the frame 7 to facilitate its positioning is well suited for operation in the form of reading with automatic scanning. In

  the case of manual scan readings, a readout

  A more classic electro-optical type of pencil is also suitable, since the area of

  reading is well defined by window 70.

Claims (12)

  1. Detection and transformation process   mation in electrical signals, of information supplied from mechanical or electromechanical type indicating means, such as mechanical or electromechanical counters with movable display elements, this is provided by providing   mobile display elements for counters,   characters or indications coded according to a bar code, each character being composed of a predetermined number of non-reflecting lines and alternating reflecting spaces of various and predetermined widths, the spaces between characters being all non-reflecting and each coded character beginning and ending ending with a reflective space; arranging the mobile display elements of the counters in relative positions   such as the characters or coded indications of each mo-   bile can come successively outcrop in a positcinA   predetermined behind a reference surface of my-   deny allowing their location; to perform at determined times an optical reading by scanning the characters or coded information appearing at said level   reference surface, and to be developed from the   captured light signals, electrical signals including   parameters depend on the type of element detected   Whether or not it is reflective.   2. Method according to claim 1, characterized in that the electrical signals produced from the received light signals are signals   binary logic with one of the corresponding states or levels   lays upon the detection of a reflective space and the   be state or level corresponds to the detection of a line not reflective.   3. Detection and transmission system   information provided from indicated means   mechanical or electromechanical type, such as 2 5 0 0 1 9 0   mechanical or electromechanical counters with movable display elements (1,2,3), characterized in that the movable display elements (1,2,3) of the counters are equipped with characters or indications (10, 20.30) coded according to a barcode, each character (10,20,30) being composed of a predetermined number of   non-reflecting lines (101,103) and reflected spaces   alternating widths (104,105) of various and predetermined widths, the spaces (106) between characters being   all non-reflective and each coded character begins   erasing and ending with a reflecting space, (104,   ) in that the movable elements (1,2,3) are available   located in a frame (7) having a viewing window   sation (70), such that for each modifying element   bile the characters or coded indications may come   successively almost flush in a predefined position   terminated behind said viewing window (70) and in that optical detection means (8) are   designed to ensure a scanning reading of said characters   res or coded information (10,20,30) -appearing at a given time in said viewing window (70) and transforming the succession of non-reflective lines and detected reflective spaces into a series of electrical signals.   4. System according to claim 3, characterized in that the optical detection means (8) are mounted on a support (80,81) sliding in at least one guide slide (71) integral with said frame (7) to maintain the detection means at a   predetermined distance from the viewing window   sualisation (70) during a reading sequence.   5. System according to claim 3, or   claim 4, characterized in that information   further coded (40,50,60) are inserted behind   the viewing window (70) in a pre- 2 5 0 0 1 90   determined alongside the mobile display elements (1,   2,3), on a fixed or removable support (4,5,6).   6. System according to any one of the re-   vendications 3 to 5, characterized in that the support (81) of the detection means is equipped with cleaning elements (83) such as brushes, on the front face placed   in contact with the window (70) for viewing the tank ti (7).   7. System according to any one of the re-   vendications 3 to 6, characterized in that the optical detection means (8) comprise a light emitting element (84) such as a light emitting diode, a focusing element for focusing the light emitted in a predetermined plane, a photodetector element   (85) sensitive to the light reflected by said pre-plane   determined, and electronic circuits (86) for transmitting   be a level 1 logic signal when the pho-   the detector is itself excited and a logic signal of level O when the photodetector element is not excited.   8. System according to claim 7, ca-   characterized in that the electronic circuits (86) have   associated with the photodetector element (85) further comprises an inverter circuit (95) for emitting a level 1 logic signal when the photodetector element   is not energized and a level O logic signal when   that the photodetector element is excited.   9. System according to any one of   Claims 4 to 8, characterized in that the means   optical detection (8) further comprises reading authorization means (97) which cooperate with the frame (7) to authorize a reading only when the sliding support (80,81) is engaged in the slide guide (71).   10. System according to any one of 2500 1 90   claims 3 to 9, characterized in that the means   optical detection (8) are connected by means of   re of an interface circuit (201) and of means of trans-   data mission (202) to a computing unit (203) ensuring the decoding of the information detected by the   optical detection means (8) and converted into binary logic generals.   11. System according to claim 10, characterized in that the scanning movement of the   viewing window (70) by the detection means   optical tion (8) at determined times is controlled   automatically from the calculation unit (203) by the   means control circuit (204)   (205) support drive (80) detection means optical tion (8).   12. System according to any one of   claims 3 to 11, applied to the surveillance of   operation of motor vehicles, characterized   in that the mechanical or electro-indicating means   mechanicals include distance indication and fuel consumption indication meters.   i3. Mechanical or electromechanical counter   with movable display elements (1,2,3) such as   wheels, discs or ribbons, characterized in that the elements   mobile display elements (1,2,3) are provided with   tères or indications coded according to a barcode, barcode,   that character being composed of a predetermined number of non-reflecting lines (101, 103) and of reflecting spaces (104, 105) alternating of various and predetermined widths, in that the spaces (106) between coded characters are all non-reflecting, of same as uncoded marginal parts (102, 12,22,32)   of each movable display element and in that each   that coded character begins and ends with a space reflective (104,105).