Support and capsule for preparing a beverage by centrifugation, system and method for preparing a beverage by centrifugation

Abstract

The invention relates to a code support adapted to be associated with or part of a capsule intended for delivering a beverage in a beverage producing device by centrifugation of the capsule. The support comprises a code formed by at least a first sequence of symbols and a second sequence of symbols. The code is represented on the support so that each symbol is sequentially readable by a reading arrangement of an external reading device while the capsule is driven in rotation along an axis of rotation (Z). The first sequence comprises at least one first preamble sequence of symbols, and at least one first data sequence of symbols. The second sequence comprises at least one second preamble sequence of symbols and at least one second data sequence of symbols. The first preamble sequence is distinct from the second preamble sequence.

Claims

1. A code support configured to be associated with or part of a capsule configured to deliver a beverage in a beverage producing device by centrifugation of the capsule, the code support comprising: a code comprising a first sequence of symbols, the code represented on the code support so that each symbol of the first sequence is sequentially readable by a reading arrangement of an external reading device while the capsule is driven in rotation about an axis of rotation, the first sequence comprising at least one first data sequence comprising at least two sub-sequences of symbols, and each one of the at least two sub-sequences comprising at least one error-checking symbol for a validity check of the symbols of the corresponding sub-sequence.

2. The code support of claim 1, wherein each of the at least two sub-sequences of symbols within the first sequence is used to code distinct information related to the capsule.

3. The code support of claim 1, wherein the code further comprises a second sequence of symbols, the second sequence comprising at least one second data sequence identical to the at least one first data sequence of the first sequence.

4. A capsule configured to deliver a beverage in a beverage producing device by centrifugation, the capsule comprising: a code support associated with or as part of the capsule, the code support comprising a code comprising a first sequence of symbols, the code represented on the code support so that each symbol of the first sequence is sequentially readable by a reading arrangement of an external reading device while the capsule is driven in rotation about an axis of rotation, the first sequence comprising at least one first data sequence comprising at least two sub-sequences of symbols, and each one of the at least two sub-sequences comprising at least one error-checking symbol for a validity check of the symbols of the corresponding sub-sequence.

5. The capsule of claim 4, wherein each of the at least two sub-sequences of symbols within the first sequence is used to code distinct information related to the capsule.

6. The capsule of claim 4, wherein the code further comprises a second sequence of symbols, the second sequence comprising at least one second data sequence identical to the at least one first data sequence of the first sequence.

7. A system configured to prepare a beverage from a capsule, the system comprising: a code support configured to be associated with or part of the capsule, the code support comprising a code comprising a first sequence of symbols, the code represented on the code support so that each symbol of the first sequence is sequentially readable by a reading arrangement of an external reading device while the capsule rotates about an axis of rotation, the first sequence comprising at least one first data sequence comprising at least two sub-sequences of symbols, and each one of the at least two sub-sequences comprising at least one error-checking symbol for a validity check of the symbols of the corresponding sub-sequence; and a beverage preparation device configured to deliver the beverage from the capsule by centrifugation, the beverage preparation device comprising a capsule holder configured to hold the capsule, a rotational driver configured to drive the capsule holder and the capsule in rotation along the axis of rotation, and the reading arrangement configured to decode the code represented on the code support by reading separately each symbol of the code while driving the rotational driver so that the capsule performs at least one complete revolution and by checking the validity of the read symbols and determining a value for each sub-sequence of the first sequence using the at least one error-checking symbol of each of the at least two sub-sequences of the first sequence.

8. The system of claim 7, wherein each of the at least two sub-sequences of symbols within the first sequence is used to code distinct information related to the capsule.

9. The system of claim 7, further comprising a second sequence of symbols, the second sequence comprising at least one second data sequence identical to the at least one first data sequence of the first sequence.

10. The system of claim 9, wherein the beverage preparation device is configured to compare the at least one first data sequence to the at least one second data sequence.

11. The system of claim 9, wherein the first sequence comprises a first preamble sequence of symbols comprising a plurality of first preamble sub-sequences.

12. The system of claim 11, wherein the second sequence comprises a second preamble sequence of symbols comprising a plurality of second preamble sub-sequences.

13. The system of claim 12, wherein the plurality of first preamble sub-sequences are distributed according to a first pattern in the first sequence, the plurality of second preamble sub-sequences are distributed according to a second pattern in the second sequence, and the first pattern and the second pattern are identical.

14. The system of claim 7, wherein the code comprises at least 100 symbols.

15. The system of claim 7, wherein the code is arranged along an entire circumference of the code support.

16. A system for preparing a beverage from a capsule comprising a support comprising a code comprising a first sequence of symbols and a second sequence of symbols, the code being represented on the support so that each symbol is sequentially readable by a reading arrangement of an external reading device while the capsule rotates along an axis of rotation, the first sequence comprising at least one first preamble sequence of symbols and at least one first data sequence of symbols, the second sequence comprising at least one second preamble sequence of symbols and at least one second data sequence of symbols, and the at least one first preamble sequence being distinct from the at least one second preamble sequence, the system comprising: a beverage preparation device comprising a capsule holder for holding the capsule, a rotational driver for driving the capsule holder and capsule in rotation along the axis of rotation, and the reading arrangement configured to decode the code represented on the code support by reading separately each symbol of the code, while driving the rotational driver so that the capsule performs at least one complete revolution; by searching, in the read symbols, the at least one first preamble sequence and the at least one second preamble sequence; and by identifying a position of the first sequence and the second sequence, accordingly.

17. A method of storing information related to a capsule on a code support that is adapted to be associated with or part of the capsule configured to deliver a beverage in a beverage producing device by centrifugation of the capsule, the method comprising: forming on the code support a code comprising a first sequence of symbols and a second sequence of symbols, the code represented on the code support so that each symbol is sequentially readable by a reading arrangement of an external reading device while the capsule is driven in rotation along an axis of rotation, the first sequence of symbols comprising a first preamble sequence of symbols and a first data sequence of symbols, the second sequence of symbols comprising a second preamble sequence of symbols and a second data sequence of symbols, the first preamble sequence being distinct from the second preamble sequence; encoding first data with the first data sequence of symbols; arranging the first preamble sequence of symbols for determining that the first data sequence of symbols is part of the first sequence of symbols; encoding second data with the second data sequence of symbols; and arranging the second preamble sequence of symbols for determining that the second data sequence of symbols is part of the second sequence of symbols.

18. The method according to claim 17, wherein the forming of the code on the code support comprises printing or embossing.

19. The method according to claim 17, comprising encoding error-detecting or error-correcting information in the code.

20. The method according to claim 17, comprising encoding the same information in the first data sequence of symbols relative to the second data sequence of symbols.

21. The method according to claim 17, comprising forming the first preamble sequence of symbols by distributing a plurality of first preamble sub-sequences according to a first pattern among the first sequence of symbols, and forming the second preamble sequence of symbols by distributing a plurality of second preamble sub-sequences according to a second pattern among the second sequence of symbols.

22. The method according to claim 21, wherein the first pattern and the second pattern are identical.

23. The method according to claim 17, comprising setting the first preamble sequence of symbols and the second preamble sequence of symbols to minimize the number of equal bits in series in the code.

24. The method according to claim 17, wherein the code comprises at least 100 symbols.

25. The method according to claim 17, comprising arranging the code along at least an eighth of a circumference of the capsule.

26. The method according to claim 17, comprising arranging the code along an entire circumference of the capsule.

27. The method according to claim 17, wherein the first preamble sequence is distinct from the second preamble sequence.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The present invention will be better understood thanks to the detailed description which follows and the accompanying drawings, which are given as non-limiting examples of embodiments of the invention, namely:

(2) FIG. 1 illustrates the basic principle of the centrifugal extraction,

(3) FIG. 2a, 2b illustrate an embodiment of the centrifugal cell with a capsule holder;

(4) FIG. 3a, 3b, 3c illustrate an embodiment of a set of capsules according to the invention;

(5) FIG. 4 illustrates an embodiment of a code support according to the invention;

(6) FIG. 5 illustrates an alternate position of the sequence on the capsule, in particular, when placed on the underside of the rim of the capsule, and the capsule fitted into a capsule holder of the extraction device,

(7) FIG. 6 illustrate a graphical representation of an example of the results of a NEB filter on a code with a common preamble used by all the sequence of the code;

(8) FIG. 7 illustrate a graphical representation of an example of the results of a NEB filter on a code according to an embodiment of the invention.

(9) FIG. 8 shows a graphical representation of the number of equal bits in series for a code according to an embodiment of the invention.

DETAILED DESCRIPTION

(10) FIG. 1 illustrates an example of a beverage preparation system 1 as described in WO2010/026053 for which the capsule of the invention can be used.

(11) The centrifugal unit 2 comprises a centrifugal cell 3 for exerting centrifugal forces on the beverage ingredient and liquid inside the capsule. The cell 3 may comprise a capsule holder and a capsule received therein. The centrifugal unit is connected to driving means 5 such as a rotary motor. The centrifugal unit comprises a collecting part and an outlet 35. A receptacle 48 can be disposed below the outlet to collect the extracted beverage. The system further comprises liquid supply means such as a water reservoir 6 and a fluid circuit 4. Heating means 31 may also be provided in the reservoir or along the fluid circuit. The liquid supply means may further comprise a pump 7 connected to the reservoir. A flow restriction means 19 is provided to create a restriction to the flow of the centrifuged liquid which leaves the capsule. The system may further comprise a flow meter such as a flow-metering turbine 8 for providing a control of the flow rate of water supplied in the cell 3. The counter 11 can be connected to the flow-metering turbine 8 to enable an analysis of the generated impulse data 10. The analysed data is then transferred to the processor 12. Accordingly, the exact actual flow rate of the liquid within the fluid circuit 4 can be calculated in real-time. A user interface 13 may be provided to allow the user to input information that is transmitted to the control unit 9. Further characteristics of the system can be found in WO2010/026053.

(12) FIGS. 3a, 3b and 3c relate to an embodiment of a set of capsules 2A, 2B, 2C. The capsules preferably comprise a body 22, a rim 23 and an upper wall member respectively a lid 24. The lid 24 may be a perforable membrane or an aperture wall. Thereby the lid 24 and the body 22 enclose an enclosure respectively ingredients compartment 26. As shown in the figures, the lid 24 is preferably connected onto an inner annular portion R of the rim 23 that is preferably between 1 to 5 mm.

(13) The rim is not necessarily horizontal as illustrated. It can be slightly bended. The rim 23 of the capsules preferably extends outwardly in a direction essentially perpendicular (as illustrated) or slightly inclined (if bended as aforementioned) relative to the axis of rotation Z of the capsule. Thereby, the axis of rotation Z represents the axis of rotation during centrifugation of the capsule in the brewing device, and in particular is sensibly identical to the axis of rotation Z of the capsule holder 32 during centrifugation of the capsule in the brewing device.

(14) It should be understood that the shown embodiment is just an exemplary embodiment and that the capsules in particular the capsule body 22 can take various different embodiments.

(15) The body 22 of the respective capsule has a single convex portion 25a, 25b, 25c of variable depth, respectively, d1, d2, d3. Thereby, the portion 25a, 25b, 25c may as well be a truncated or a partially cylindrical portion.

(16) Hence, the capsules 2A, 2B, 2C preferably comprise different volumes but, preferably, a same insertion diameter D. The capsule of FIG. 3a shows a small volume capsule 2A whereas the capsule of FIGS. 3b and 3c show a larger volume capsule 2B respectively 2C. The insertion diameter D is hereby determined at the line of intersection between the lower surface of the rim 23 and the upper portion of the body 22. However, it could be another referencing diameter of the capsule in the device.

(17) The small volume capsule 2A preferably contains an amount of extraction ingredient, e.g., ground coffee, smaller than the amount for the large volume capsules 2B, 2C. Hence, the small capsule 2A is intended for delivery of a short coffee of between 10 ml and 60 ml with an amount of ground coffee comprised between 4 and 8 grams. The larger capsules 2B is intended for delivery of a medium-size coffee, e.g., between 60 and 120 ml and the largest capsule is intended for delivery of a long-size coffee, e.g., between 120 and 500 ml. Furthermore, the medium-size coffee capsule 2B can contain an amount of ground coffee comprised between 6 and 15 grams and the long-size coffee capsule 2C can contain an amount of ground coffee between 8 and 30 grams.

(18) In addition, the capsules in the set according to the invention may contain different blends of roast and ground coffee or coffees of different origins and/or having different roasting and/or grinding characteristics.

(19) The capsule is designed for rotating around the axis Z. This axis Z crosses perpendicularly the center of the lid which has the form of a disk. This axis Z exits at the center of the bottom of the body. This axis Z will help to define the notion of circumference which is a circular path located on the capsule and having the axis Z as reference axis. This circumference can be on the lid, e.g. lid or on the body part such as on the flange-like rim. The lid may be impervious to liquid before insertion in the device or it may be pervious to liquid by means of small openings or pores provided in the center and/or periphery of the lid.

(20) Hereafter, the lower surface of the rim 23 refers to the section of the rim 23 that is located outside the enclosure formed by the body and the lid, and is visible when the capsule is oriented on the side where its body is visible.

(21) Further characteristics of the capsules or the set capsules can be found in documents WO 2011/0069830, WO 2010/0066705, or W02011/0092301.

(22) An embodiment of the centrifugal cell 3 with a capsule holder 32 is illustrated by FIGS. 2a and 2b. The capsule holder 32 forms in general a cylindrical or conical wide shaped cavity provided with an upper opening for inserting the capsule and a lower bottom closing the receptacle. The opening has a diameter slightly larger than the one of the body 22 of the capsule. The outline of the opening fits to the outline of the rim 23 of the capsule configured to lean on the edge of the opening when the capsule is inserted. As a consequence, the rim 23 of the capsule rests at least partially on a receiving part 34 of the capsule holder 32. The lower bottom is provided with a cylindrical shaft 33 attached perpendicularly to the center of the external face of the bottom. The capsule holder 32 rotates around the central axis Z of the shaft 33.

(23) An optical reading arrangement 100 is also represented in FIGS. 2a and 2b. The optical reading arrangement 100 is configured to deliver an output signal comprising information related to a level of reflectivity of a surface of the lower surface of the rim 23 of a capsule leaning on the receiving part 34 of the capsule holder 32. The optical reading arrangement is configured to perform optical measurements of the surface of the lower surface of the rim 23 through the capsule holder 32, more particularly through a lateral wall of the cylindrical or conical wide shaped capsule holder 32. Alternatively, the output signal may contain differential information, for instance differences of reflectivity over time, or contrast information. The output signal may be analog, for example a voltage signal varying with the information measured over the time. The output signal may be digital, for example a binary signal comprising numerical data of the information measured over the time.

(24) In the embodiment of FIGS. 2a and 2b, the reading arrangement 100 comprises a light emitter 103 for emitting a source light beam 105a and a light receiver 102 for receiving a reflected light beam 105b.

(25) Typically the light emitter 103 is a light-emitting diode or a laser diode, emitting an infrared light, and more particularly a light with a wavelength of 850 nm. Typically, the light receiver 103 is a photodiode, adapted to convert a received light beam into a current or voltage signal.

(26) The reading arrangement 100 comprises also processing means 106 including a printed circuit board embedding a processor, sensor signal amplifier, signal filters and circuitry for coupling said processing means 106 to the light emitter 103, the light receiver 102 and to the control unit 9 of the machine.

(27) The light emitter 103, the light receiver 102, and the processing means 106 are maintained in a fixed position by a support 101, rigidly fixed relatively to the machine frame. The reading arrangement 100 stays into its position during an extraction process and is not driven into rotation, contrary to the capsule holder 32.

(28) In particular, the light emitter 103 is disposed so as the source light beam 105a is generally oriented along a line L crossing at a fixed point F the plane P comprising the receiving part 34 of the capsule holder 32, said plane P having a normal line N passing through the point F. The fixed point F determines an absolute position in space where the source light beams 105a is intended to hit a reflective surface: the position of the fixed point F remains unchanged when the capsule holder is rotated. The reading arrangement may comprise focusing means 104, using for example holes, lenses and/or prisms, to make the source light beam 105 converging more efficiently to the fixed point F of the lower surface of the lid of a capsule positioned into the capsule holder 32. In particular, the source light beam 105 may be focused so as to illuminate a disc centered sensibly on the fixed point F and having a diameter d.

(29) The reading arrangement 100 is configured so as the angle OE between the line L and the normal line N is comprised between 2 and 10, and in particular between 4 and 5 as shown in FIG. 2a. As a consequence, when a reflecting surface is disposed at the point F, the reflected light beam 105b is generally oriented along a line L, crossing the fixed point F, the angle OR between the line L and the normal line N being comprised between 2 and 10, and in particular between 4 and 5 as shown in FIG. 2a. The light receiver 102 is disposed on the support 101 so as to gather at least partially the reflected light beam 105b, generally oriented along the line L. The focusing means 104 may also be arranged to make the reflected light beam 105b concentrating more efficiently to the receiver 102. In the embodiment illustrated in FIG. 2a, 2b, the point F, the line L and the line L are co-planar. In another embodiment, the point F, the line L and the line L are not co-planar: for instance, the plane passing through the point F and the line F and the plane passing through the point F and the line L are positioned at an angle of sensibly 90, eliminating direct reflection and allowing a more robust reading system with less noise.

(30) The capsule holder 32 is adapted to allow the partial transmission of the source light beam 105a along the line L up to the point F. For instance, the lateral wall forming the cylindrical or conical wide shaped cavity of the capsule holder is configured to be non-opaque to infra-red lights. Said lateral wall can be made of a plastic based material which is translucent to infrared having entry surfaces allowing infra-red light to enter.

(31) As a consequence, when a capsule is positioned in the capsule holder 32, the light beam 105a hits the bottom part of the rim of said capsule at point F, before forming the reflected light beam 105b. In this embodiment, the reflected light beam 105b passes through the wall of the capsule holder up to the receiver 102.

(32) The section of the lower surface of the rim 23 of a capsule positioned into the capsule holder 32, illuminated at the point F by the source light beam 105, changes over the time, only when the capsule holder 32 is driven into rotation. So, a complete revolution of the capsule holder 32 is required for the source light beam 105 to illuminate the entire annular section of the lower surface of the rim.

(33) The output signal may be computed or generated by measuring over the time the intensity of the reflected light beam, and possibly, by comparing its intensity to those of the source light beam. The output signal may be computed or generated by determining the variation over the time of the intensity of the reflected light beam.

(34) The capsule according to the invention comprises at least one optically readable code support. The code support can be, in the present part of the flange-like rim. Symbols are represented on the optical code support.

(35) The symbols are arranged in at least one sequence, said sequence coding a set of information related to the capsule. Each symbol is used to encode a specific value.

(36) In particular, the set of information of at least one of the sequences may comprise information for recognizing a type associated to the capsule, and/or one or a combination of items of the following list: information related to parameters for preparing a beverage with the capsule, such as the optimal rotational speeds, temperatures of the water entering the capsule, temperatures of the collector of the beverage outside the capsule, flow rates of the water entering the capsule, sequence of operations during the preparation process, etc; information for retrieving locally and/or remotely parameters for preparing a beverage with the capsule, for example an identifier allowing the recognition of a type for the capsule; information related to the manufacturing of the capsule, such a production batch identifier, a date of production, a recommended date of consumption, an expiration date, etc; information for retrieving locally and/or remotely information related to the manufacturing of the capsule.

(37) The symbols are distributed sensibly on at least th of the circumference of the annular support, preferably, on the entire circumference of the annular support. The code may comprise successive arch-shaped segments. The symbols may also comprise successive segments which are individually rectilinear but extend along at least a part of the circumference.

(38) The sequence is preferably repeated along the circumference in order to ensure a reliable reading. The sequence is repeated at least twice on the circumference. Preferably, the sequence is repeated three to six times on the circumference. Repetition of the sequence means that the same sequence is duplicated and the successive sequences are positioned in series along the circumference so that upon a 360-degree rotation of the capsule, the same sequence can be detected or read more than one time.

(39) Referring to FIG. 4, an embodiment 60a of a code support is illustrated. The code support 60a occupies a defined width H.sub.s of the rim 23 of the capsule. The rim 23 of the capsule can comprise essentially an inner annular portion forming the support 60a and an outer (non-coded) curled portion. However, it can be that the full width of the rim is occupied by the support 60a, in particular, if the lower surface of the rim can be made substantially flat. This location is particularly advantageous since they offer both a large area for the symbols 64 to be disposed and is less prone to damages caused by the processing module and in particular by the pyramidal plate, and to ingredients projections. As a consequence, the amount of coded information and the reliability of the readings are both improved. In this embodiment, the code support 60a comprises 160 of the symbols 64, and each symbol 64 codes 1 bit of information. The symbols 64 being contiguous, and each symbol 64 has an arc-linear length .sub.S of 2.25 and may be arranged along a circle having a radius R.sub.S.

(40) Referring to FIG. 5, an embodiment 60b of a code support is illustrated in planar view. The code support 60b is adapted to be associated with or be part of a capsule, so as to be driven in rotation when the capsule is rotated around its axis Z by the centrifugal unit 2. The receiving section of the capsule is the lower surface of the rim 23 of the capsule. As illustrated on FIG. 5, the code support may be a ring having a circumferential part on which the at least one sequence of the symbols 64 is represented, so as the user can position it on the circumference of the capsule before introducing it into the brewing unit of the beverage machine. Consequently, a capsule without embedded means for storing information can be modified by mounting such a support so as to add such information. When the support is a separate part, it may be simply added on the capsule without additional fixing means, the user ensuring that the support is correctly positioned when entering the brewing unit, or the forms and the dimensions of the support preventing it from moving relatively to the capsule once mounted. The code support 60b 3-013, may also comprise additional fixing means for rigidly fixing said element to the receiving section of the capsule, like glue or mechanical means, to help the support staying fixed relatively to the capsule once mounted. As also mentioned, the code support 60b may also be a part of the rim itself such as integrated to the structure of the capsule.

(41) Each symbol 64 is adapted to be measured by the reading arrangement 100 when the capsule is positioned into the capsule holder and when said symbol is aligned with the source light beam 105a at point F. More particularly, each different symbol 64 presents a level of reflectivity of the source light beam 105a varying with the value of said symbol. Each symbol 64 has different reflective and/or absorbing properties of the source light beam 105a.

(42) Since the reading arrangement 100 is adapted to measure only the characteristics of the illuminated section of the coding support, the capsule has to be rotated by the driving means until the source light beam has illuminated all the symbols 64 comprised in the code. Typically, the speed for reading the code can be comprised between 0.1 and 2000 rpm.

EXAMPLE 1

Unsuitable Code Preamble for Optical Code Support Having at Least Two Sequences, Read in Rotation

(43) An example of a sequence of 15 binary symbols is shown in the following table 1:

(44) TABLE-US-00001 TABLE 1 S1 P1 F11 F12 F13 1 0 1 0 1 0 0 0 1 0 0 1 0 1 0

(45) The sequence S1 of table 1 begins with a 6-bits long preamble. The preamble P1 corresponds to a known reserved sequence of bits, in this example 10101010. Then, the sequence comprises three blocks F11, F12, F13 of data. Each block of data begins with a 2-bits long value, and ends with an odd parity check bit. In table 2, an example of a reading of a code comprising the sequence S1 followed by a sequence S2, is shown:

(46) TABLE-US-00002 TABLE 2 S1 P1 F11 F12 F13 X X 1 0 1 0 0 0 1 0 0 1 0 1 0 S2 S1 P1 F11 F12 F13 P1 1 0 1 0 1 0 0 0 1 0 0 1 0 1 0 1 0

(47) The reading starts at the third bits of the first sequence S1, after the beginning of the preamble P1. To read all the symbols of every sequence, at least one complete rotation of the optical code support is then needed.

(48) Having gathered all the symbols, it is necessary to rebuild each sequence, and in particular by determining the position of the preambles. A matched filtering method can be used to perform this task. For instance, in the following example, a Number of Equal Bits (NEB) filter has been applied to the read bits, using the preamble P1 as matching pattern 101010. This filtering method consists in summing, for each window of consecutive bits of the read bits, said window having the same length as the matching pattern, the number of bits that are in common with the bits of the matching pattern. For a six bits long preamble P1, the maximum of the NEB filter is 6, when the read bits of the window matched those of the preamble P1. The result can be further improved by calculating a contrast between the results of the NEB filter, for instance, by calculating the difference between the result of the NEB filter at a given position of the window, and the result of the NEB filter at the following position of the window. The higher the contrast, the better.

(49) TABLE-US-00003 TABLE 3 S1 S2 P1 F11 F12 F13 P1 F11 F12 F13 X X 1 0 1 0 0 0 1 0 0 1 0 1 0 1 0 1 0 1 0 0 0 1 0 0 1 0 1 0 Matched filter NEB Window 5 1 0 1 0 1 0 X X X X X X X X X X X X X X X X X X X X X X 1 X 0 1 0 0 0 1 X X X X X X X X X X X X X X X X X X X X X 5 X X 1 0 1 0 1 0 X X X X X X X X X X X X X X X X X X X X 2 X X X 0 0 0 1 0 0 X X X X X X X X X X X X X X X X X X X 3 X X X X 1 0 1 0 0 1 X X X X X X X X X X X X X X X X X X 3 X X X X X 0 1 0 0 1 0 X X X X X X X X X X X X X X X X X 2 X X X X X X 1 0 0 1 0 1 X X X X X X X X X X X X X X X X 5 X X X X X X X 0 0 1 0 1 0 X X X X X X X X X X X X X X X 0 X X X X X X X X 0 1 0 1 0 1 X X X X X X X X X X X X X X 6 X X X X X X X X X 1 0 1 0 1 0 X X X X X X X X X X X X X 0 X X X X X X X X X X 0 1 0 1 0 1 X X X X X X X X X X X X 6 X X X X X X X X X X X 1 0 1 0 1 0 X X X X X X X X X X X 0 X X X X X X X X X X X X 0 1 0 1 0 1 X X X X X X X X X X 6 X X X X X X X X X X X X X 1 0 1 0 1 0 X X X X X X X X X 1 X X X X X X X X X X X X X X 0 1 0 1 0 0 X X X X X X X X 5 X X X X X X X X X X X X X X X 1 0 1 0 0 1 X X X X X X X

(50) In this non-working example, the maximum 6 for the NEB filter is found for 6 bits sequences starting at bit 10, bit 12 and bit 14. However, only the 6 bits sequence starting at bit 14 corresponds actually at the preamble P1 of the second period. Even a contrast calculation does not allow solving this problem, since the contrast is higher for the 6 bits sequences starting at bit 10 and bit 12. As a consequence, such preamble P1 is not suitable, in particular since it does not allow determining with confidence the effective position of said preamble, in the sequences. The FIG. 6 shows an example of the results of a NEB filter on such a code structure.

EXAMPLE 2

Code Preamble for Optical Code Support Having Four Sequences, Read in Rotation

(51) A suitable preamble P is shown hereafter. The preamble P is spread over the sequences represented on the optical code support. For instance, the preamble P comprises a first 6-bits long sequence P.sub.A=101010, a second 6-bits long sequence P.sub.B=010101, a third 6-bits long sequence P.sub.c=011001, and a fourth third 6-bits long sequence P.sub.D=100110.

(52) A first sequence Si begins with the first sequence P.sub.A, then, a first block D1 comprising three data block F11, F12, F13 with parity check bits. The second sequence S2 begins with the second sequence P.sub.B, then, a second block D2 comprising three data block F21, F22, F23 with parity check bits. The third sequence S3 begins with the third sequence P.sub.C, then, a third block D3 comprising the three data blocks F11, F12, F13 with parity check bits. The fourth sequence S4 begins with the fourth sequence P.sub.D, then, a fourth block D4 comprising the three data blocks F21, F22, F23 with their parity check bit. Then on the code support are represented the following sequences: P.sub.A-F11-F12-F13-P.sub.B-F21-F22-F23-P.sub.C-F11-F12-F13-P.sub.D-F21-F22-F23. The first block D1, respectively the second block D2, the third block D3, the fourth D4 comprise a number n1, respectively n2, n3 and n4, of bits.

(53) To read all the symbols of every sequence, at least one complete rotation of the optical code support is then needed.

(54) The position of the first block D1, the second block D2, the third block D3, and the fourth block D4 are determined by looking for the pattern P.sub.A-X1-P.sub.B-X2-P.sub.C-X3-P.sub.D-X4 in the sequence of bits read by the optical reader, where X1 stands for any sequence of n1 bits, X2 stands for any sequence of n2 bits, X3 stands for any sequence of n3 bits, X4 stands for any sequence of n4 bits. Hence, not only the sequence of bits corresponding to those of the preamble are searched, but the relative positions of P.sub.A, P.sub.B, P.sub.C, P.sub.D are taken into consideration, allowing a more robust and reliable identification of the start of each data blocks.

(55) For example, a Number of Equal Bits (NEB) filter can be applied to the read bits, using the following matching pattern:

(56) 101010xxxxxxxxx010101xxxxxxxxx011001xxxxxxxxx100110xxxxxxxxx, where x corresponds to any bit, and with n1=n2=n3=n4=9 bits.

(57) The filter is applied to read bits, shifting the start position of the rolling filtering window from the first bit read to the last bit read. The position of the window corresponding to the maximum value of the NEB filter is likely to correspond to the start of the first sequence Si. The FIG. 7 shows an example of the results of a NEB filter on such a code structure.

(58) It is also possible to calculate the contrast between the value of the NEB filter for each position of the window relatively to the value of the NEB filter at the following position of the window: the position of the window corresponding to the maximum value of the NEB contrast is then likely to correspond to the start of the first sequence Si.

EXAMPLE 3

Code Preamble for Optical Code Support Having Four Sequences, Read in Rotation

(59) A suitable preamble P is shown hereafter. The preamble P is spread over the sequences represented on the optical code support. For instance, the preamble P comprises a first 6-bits long sequence P.sub.A=101010, a second 6-bits long sequence P.sub.B=010101, a third 6-bits long sequence P.sub.C=011001, and a fourth third 6-bits long sequence P.sub.D=100110.

(60) The first sequence P.sub.A comprises three sub-sequence P.sub.A1=10, P.sub.A2=10, P.sub.A3=10. The second sequence P.sub.B comprises three sub-sequence P.sub.B1=01, P.sub.B2=01, P.sub.B3=01. The third sequence Pc comprises three sub-sequence P.sub.C1=01, P.sub.C2=10, P.sub.C3=01. The fourth sequence P.sub.D comprises three sub-sequence P.sub.D1=10, P.sub.D2=01, P.sub.D3=10.

(61) A first sequence S1 is formed by the sub-sequence P.sub.A1 then, a data block F1 with a parity check bit, the sub-sequence P.sub.A2, then, a data block F2 with a parity check bit, the sub-sequence P.sub.A3, then a data block F3 with a parity check bit. A second sequence S2 is formed by the sub-sequence P.sub.B1, then, the data block F1 with a parity check bit, the sub-sequence P.sub.B2, then, the data block F2 with a parity check bit, the sub-sequence P.sub.B3, then data block F3 with a parity check bit. A third sequence S3 is formed by the sub-sequence P.sub.C2, then, the data block F1 with a parity check bit, the sub-sequence P.sub.C2, then, the data block F2 with a parity check bit, the sub-sequence P.sub.C3, then data block F3 with a parity check bit. A fourth sequence S4 is formed by the sub-sequence P.sub.D1, then, the data block F1 with a parity check bit, the sub-sequence P.sub.D2, then, the data block F2 with a parity check bit, the sub-sequence PD3, then data block F3 with a parity check bit. Then on the code support are represented the following sequences:

(62) P.sub.A1-F1-P.sub.A2-F2-P.sub.A3-F3-P.sub.B1-F1-P.sub.B2-F2-P.sub.B3-F3-P.sub.C1-F1-P.sub.C2-F2-P.sub.C3-F3-P.sub.D1-F1-P.sub.D2-F2-P.sub.D3-F3

(63) The data block F1, respectively the data block F2, the data block F3, the data D4 comprise a number n1, respectively n2, n3 and n4, of bits.

(64) To read all the symbols of every sequence, at least one complete rotation of the optical code support is then needed.

(65) The position of the data block F1, the second block F2, the third block F3 in each sequences Si, S2, S3, S4 are determined by looking for the pattern:

(66) P.sub.A1-X1-P.sub.A2-X2-P.sub.A3-X3-P.sub.B1-X1-P.sub.B2-X2-P.sub.B3-X3-P.sub.C1-X1-P.sub.C2-X2-P.sub.C3-X3-P.sub.D1-X1-P.sub.D2-X2-P.sub.D3-X3

(67) in the sequence of bits read by the optical reader, where X1 stands for any sequence of n1 bits, X2 stands for any sequence of n2 bits, X3 stands for any sequence of n3 bits.

(68) Hence, not only the sequence of bits corresponding to those of the preamble are searched, but the relative positions of each sub-sequence of P.sub.A, P.sub.B, P.sub.C, P.sub.D are taken into consideration, allowing a more robust and reliable identification of the start of each data blocks. Moreover, by splitting and spreading the preambles into smaller sub-sequences, it is possible to optimize the information coding by minimizing the number of equal bits in series (EBS). FIG. 8 shows the number of equal bits in series for such a code structure.

(69) For example, a Number of Equal Bits (NEB) filter can be applied to the read bits, using the following matching pattern:

(70) 10xxx10xxx10xxx01xxx01xxx01xxx01xxx10xxx01xxx10xxx01xxx10xxx

(71) where x corresponds to any bit, and with n1=n2=n3=3 bits.

(72) The filter is applied to read bits, shifting the start position of the rolling filtering window from the first bit read to the last bit read. The position of the window corresponding to the maximum value of the NEB filter is likely to correspond to the start of the first sequence S1.

(73) It is also possible to calculate the contrast between the value of the NEB filter for each position of the window relatively to the value of the NEB filter at the following position of the window: the position of the window corresponding to the maximum value of the NEB contrast is then likely to correspond to the start of the first sequence S1.