Patent Publication Number: US-8540141-B2

Title: Encoding method for encoding medical items

Description:
CLAIM OF PRIORITY 
     The present application is a continuation of U.S. patent application Ser. No. 13/021,372 filed on Feb. 4, 2011, which is a continuation of PCT/EP2009/060046, filed Aug. 3, 2009, which claims the priority filing benefit of European Application No. 08161756.5, filed Aug. 4, 2008, each of which are hereby incorporated herein by reference in their respective entireties. 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     The invention relates to an encoding method for generating at least one coding on an item, and to a corresponding decoding method and encoding and decoding devices. Such methods and devices can be used, in particular, in the field of medical disposable items in order to provide such disposable items with a code rapidly and reliably. In particular, but not exclusively, such devices and methods can be used in the field of medical diagnostics, for example for encoding test elements in the form of test tapes or test strips, for detecting at least one analyte in a body fluid. Accordingly, the invention also relates to medical disposable items encoded in this way. 
     BACKGROUND 
     In medical diagnostics, in particular, numerous disposable items are known, which have to be encoded rapidly, reliably and cost-effectively. Thus, by way of example, the examination of blood samples or other samples of body fluid, for example interstitial fluid, in clinical diagnostics enables early and reliable identification of pathological states and also targeted and astute monitoring of body states. Medical diagnostics generally presupposes that a sample of blood of interstitial fluid is obtained from the patient to be examined. For this purpose, the skin is usually perforated, for example at the finger pad or the ear lobe, with the aid of a sterile, pointed or sharp lancet in order thus to obtain a small amount of blood for analysis. 
     Self-monitoring of blood sugar levels is a method of diabetes control that is nowadays applied worldwide. Blood sugar devices in the prior art generally have an analysis instrument which interacts with at least one test element. The sample to be analyzed is applied to a test field of the test element and reacts in the test field with one or more reagents, if appropriate, which are generally chosen in a manner specific to the analyte to be detected. This reaction can be detected, for example optically and/or electrochemically. 
     In principle, the invention described below can be applied, for example, to all types of test elements in accordance with the prior art. Thus, the test element can comprise, for example, one or more of the following test elements: a test strip, in particular an individual test strip with an individual analysis zone or a plurality of analysis zones; a test tape; a test wheel with a plurality of analysis zones arranged circumferentially; a test wheel with a plurality of analysis zones arranged on its surface, in particular analysis zones arranged in a cake-slice shape; a foldable test element with a plurality of analysis zones (fan folding). In this case, by way of example, it is possible to use test elements in which the sample is applied directly to the analysis zone, for example by direct dropping, dabbing or the like. This direct application can be effected in the form of “top dosing”, for example, in which the analysis zone is arranged for example on a planar surface of the test element and the sample is applied to it from above. Alternatively or additionally, however, so-called “edge dosing” could also be considered, in which the sample is applied to an end or side face of the test element. In the case of edge dosing, by way of example, the sample can be applied directly to the analysis zones, or the sample can be transported from the application location to the analysis zone, for example by means of capillary forces. Further embodiments are conceivable. There is also a multiplicity of possibilities regarding the type of detection of the analyte. Thus, by way of example, electrochemical detection can be effected. Alternatively or additionally, optical detection can be effected. In the latter case, by way of example, direct optical detection can be effected by light being radiated in. Alternatively or additionally, the incident light or the light emerging from the analysis zone can also be transported by means of one or more optical waveguides. Various other embodiments are conceivable. 
     When such medical or diagnostic consumable materials such as test elements and/or lancets, for example, are used, a number of technical problems arise in practice, however, which in many cases have to be overcome by complex apparatus solutions. Thus, one difficulty consists in the fact that different test elements which can be used in an analysis system can have differences among one another. Thus, by way of example, differences can arise with regard to the manufacturer and/or the production method, with regard to the detection reagents used, with regard to the analyte to be detected, with regard to the analysis method and/or analysis system to be used, with regard to the conditions under which the analysis is intended to be carried out, with regard to the parameters and/or the algorithms for the evaluation of measurements, with regard to the batch numbers, with regard to batch-specific special features, with regard to the manufacturing method, with regard to the number of analysis zones on a test element or the like. In the case of lancets or other types of medical disposable items, too, such item-specific information components can arise, in particular information components with regard to the manufacturer, the type of lancet, the lancet systems to be used or the like. In the following application, such information components are generally encompassed by the expression “item-specific information components”, wherein such item-specific information components generally relate to information components concerning the medical disposable items, which can differ from item to item or even within an item (for example from analysis zone to analysis zone in the case of test elements having a plurality of analysis zones). 
     In many cases it is necessary, therefore, to correspondingly encode a medical disposable item or a group of medical disposable items, for example medical disposable items accommodated in a magazine, in order, as soon as this is necessary, to be able to provide these item-specific information components accordingly. One important exemplary application consists in automatic reading-in of item-specific information components by an analysis instrument which is intended to use medical disposable items such as, for example, test strips, test tapes or lancets. 
     Since manual inputting and read-out of such item-specific information components are generally unreasonable or inconvenient for the patient, various methods and systems in which item-specific information components can be read in automatically are known from the prior art. Thus, by way of example, systems are known in which firstly a calibration test element has to be introduced into the analysis system. Systems are also known in which a separate evaluation code is provided on individual test elements, which code is read by a separate read-out unit. For examples of methods and systems for coding item-specific information components, see US 2007/0273928 A1 and U.S. Pat. No. 5,281,395, the disclosures of which are hereby incorporated herein by reference in their entireties. 
     In addition to such code systems for individual test strips, different types of codings themselves for encoding test tapes are also known. For example, it is known to provide a coding region on a test tape at the beginning of the test tape, the coding region comprising at least one information component. The coding region can be read for example by the detector which is also used for the optical measurement. Strip bar codes or bar codes in the form of two-dimensional black-white test fields may be used for encoding purposes, for example. Such one- or two-dimensional bar codes are known in various embodiments and in accordance with various standards. The bar codes can be detected, for example, in the form of black-white identification by means of different gray-scale values. Examples of different codings are described in U.S. Pat. No. 5,077,010 and DE 101 23 406 A1, the disclosures of which are hereby incorporated herein by reference in their entireties. 
     The problem of conventional bar codes is, however, that generally they have to comprise not just a simple serial number, rather many item-specific information components have a more extensive storage depth. Thus, by way of example, extensive information components generally have to be provided for test strips or test tapes in order to enable correct and reliable evaluation of these test elements. 
     It is therefore known also to use, in addition to simple black-white information components, halftones or gray-scale values themselves as information carrier. Thus, by way of example, an encoding system is known in which data in an image are encrypted by using halftone settings. E.g., see WO 03/086759 A1, the disclosure of which is hereby incorporated herein by reference in its entirety. However, these known methods are comparatively complex and in many cases require an implementation that is costly in respect of resources. Such complexity and outlay often cannot be realized in the field of medical diagnostics, in which, in particular, simple and cost-effective handheld instruments often have to be provided. 
     It is therefore an object of the present invention to specify a method and a device which are suitable for the encoding and decoding of medical disposable items and which can be realized simply and cost-effectively, in conjunction with a sufficiently large amount of storable or encodable information. 
     SUMMARY 
     This object and others that will be appreciated by a person of ordinary skill in the art have been achieved according to the embodiments of the present invention disclosed herein. Embodiments of the present invention include an encoding method and a corresponding decoding method, as well as an encoding device and a corresponding decoding device which at least substantially achieve said object and which are presented in the claims. 
     With regard to the embodiments described herein, the described aspects generally correspond to one another; that is to say, for example, embodiments of proposed encoding methods correspond to proposed embodiments of decoding methods, and the associated devices described herein generally correspond to the respectively associated methods, such that, with regard to possible configurations of one subject, reference may respectively be made to the description of the associated corresponding subjects. By way of example, for the possible configurations of an embodiment of an encoding device described below, reference may be made to possible configurations of an encoding method described below, and vice versa. 
     The proposed encoding method serves for generating at least one coding on an item, in particular a medical disposable item, for example a medical disposable item in accordance with the description above. However, other items, too, can naturally be encoded by means of the proposed encoding method. 
     The coding comprises at least one information component in encoded form. Said at least one information component can comprise, for example, at least one batch information component concerning a particular item. However, other types of information components, too, can be contained in the at least one information component. 
     The proposed encoding method comprises steps a) to c) described below, which can, but not necessarily, be carried out in the order presented. Furthermore, additional method steps, not mentioned, can also be carried out. 
     a) The at least one information component is converted into a code, wherein the code comprises a plurality of value pairs composed of a gray-scale value and a degree of filling. 
     This conversion can be effected by means of a corresponding encoder, for example. This conversion is effected for example in a manner similar to that in which a conventional information component is converted into a binary code or a code according to the decimal system. Thus, by way of example, it is possible to utilize an assignment specification by means of which this conversion takes place. Examples of such conversion or reconversion are described in greater detail below. 
     b) The code generated in this way is converted into an optical information component, in particular a two-dimensional optical information component. This optical information component has at least one field filled with at least one gray-scale value up to an associated degree of filling in accordance with the plurality of value pairs composed of gray-scale value and degree of filling. 
     By way of example, if a first value pair of the code provided at one field comprises the fact that a gray-scale value of level  2  is intended to be present up to a degree of filling of  75 %, then the at least one field is correspondingly filled with said gray-scale value. A corresponding procedure is adopted with all gray-scale values or all pairs composed of gray-scale value and degree of filling. 
     A field should accordingly be understood to mean an area filled with a respective uniform gray-scale value. In this case, a field can have, in principle, any desired geometrical form, for example the form of a rectangle, square, polygon, a round form. In this case, a field can also be composed of a plurality of partial fields, which can be configured as contiguous or else non-contiguous. In this case, different fields need not necessarily have an identical size, rather fields having different sizes can be present. A field can, but need not necessarily, optionally additionally be provided with a recognizable boundary, for example at least one border. 
     c) The optical information component is applied to the item. 
     By way of example, conventional techniques can be used for this application process, in particular printing techniques, including for example screen printing techniques, offset printing techniques, inkjet printing techniques, laser printing techniques or similar printing techniques. Writing techniques or other techniques such as are usually utilized for applying optical information components to items can also be used. Furthermore, for this application process it is also possible to use techniques in which the item itself is correspondingly modified in order to have the optical information component, for example by the introduction of corresponding depressions into an item which represent the optical information component or the like. 
     Corresponding to the proposed encoding method, an encoding device for generating the at least one coding on an item is further proposed, which can be used, in particular, using the encoding method in one of the configurations described above or described further below. This encoding device comprises at least one code generating device designed to convert the at least one information component into a code comprising a plurality of value pairs generally composed of a gray-scale value and a degree of filling. Furthermore, the encoding device comprises at least one conversion device, wherein the conversion device is designed to convert the code into an optical information component. Finally, the encoding device comprises at least one application device designed to apply the optical information component to the item. 
     The code generating device and/or the conversion device can comprise, for example, at least one data processing device. Said data processing device can comprise, for example, at least one personal computer and/or at least one microcomputer and can be designed correspondingly in terms of program technology to perform the code generation and/or the conversion of the code into the optical information component. As described above, the code generating device and/or the conversion device can furthermore comprise at least one encoder which can also be wholly or partly identical to the data processing device in respect of components. In the encoder and/or the data processing device, corresponding specifications for generating the gray-scale value pairs can be saved or stored in some other form. 
     The encoding method and the encoding device can be developed in various ways in accordance with the embodiments of the present invention. 
     The form of the coding and/or of the two-dimensional optical information components is of secondary importance, in principle. By way of example, the coding and/or the two-dimensional optical information component can have a rectangular geometrical shape since rectangular image sensors are also used in many cases. In principle, however, other geometrical forms are also possible, for example lines, circles, ovals, triangular or differently shaped polygonal forms or the like. Alternatively or additionally, by way of example, random and/or irregular forms can also be provided. The at least one field of the optical information component can comprise a plurality of partial fields, for example. A dedicated field can be provided for each gray-scale value. Thus, by way of example, each field can be assigned to a specific gray-scale value and be filled with the latter up to the associated degree of filling. Conversely, however, an assignment to the degree of filling can also be effected, such that, by way of example, a specific field is provided for each degree of filling, which is then filled with the associated gray-scale value. In addition to these examples, a multiplicity of other types of fields or optical information components are also possible, for example any desired patterns. If fields are used, then they can, as explained above, for example in turn have, in principle, any desired form, for example a rectangular, linear, round, polygonal or other form. A plurality of fields can be arranged in matrix form, for example, and form the optical information component in this way. 
     A gray-level coding or gray-scale value coding should in this case generally be understood to mean a coding which also utilizes gray-scale values or gray levels (these terms are generally and hereinafter used synonymously), i.e. different brightness levels of one or more colors, as information carriers. In principle, however, the term gray level or gray-scale value should in this case be interpreted broadly and, for example, also encompasses different brightness levels in the case of detectors for color identification. 
     Depending on the resolution, in this case gray levels can be effected between black (where in the case of a chromatic color “black” should correspondingly be understood to mean the darkest level) and white (where in the case of a chromatic color “white” should correspondingly be understood to mean the lightest level). In one embodiment, the coding can be effected in discrete steps with at least one intermediate level, possibly a plurality of intermediate levels, between these black and white limit values. By way of example, it is possible to use a gray-level coding in gray-level steps with a constant, predefined spacing from black to white. Thus, in the first method step a) presented above, a discrete number of possible gray-scale values can be predefined, which can, for example, be numbered consecutively, for example gray-scale value level  1 , gray-scale value level  2 , etc. This facilitates the evaluation since these gray-scale values can be sought in a targeted manner. By way of example, during the evaluation of the optical information component, it is possible to predefine a range within which the gray-scale values are assigned to a specific gray-scale value level. This threshold value method can easily be automated by means of a corresponding gray-scale value identification. 
     Analogously, a discrete number of possible degrees of filling can also be provided. This also facilitates the evaluation. Thus, by way of example, degrees of filling of 0%, 25%, 50%, 75% and 100% can be predefined as discrete possible degrees of filling. However, a different apportioning is also possible, in principle. 
     The proposed encoding method can be implemented, in particular, by means of a corresponding computer program. Thus, by way of example, method steps a) and b) presented above can be implemented by means of a computer program with program code when the program is executed on a computer, where the latter can analogously also comprise a computer network. Alongside the computer program, a computer program stored on a machine-readable carrier is correspondingly also proposed. 
     Alongside the above-described encoding methods and the encoding device, a decoding method and a decoding device are correspondingly proposed. This decoding method serves for decoding at least one encoded information component on an item, in particular on a medical disposable item, in particular by means of an encoding method according to one or more of the embodiments described above. Accordingly, for numerous details of the decoding method, reference may be made to the above description. 
     The proposed decoding method comprises the following steps: 
     i) at least one optical information component applied on the item, such as a two-dimensional optical information item is detected, wherein the optical information component comprises at least one field filled with at least one gray-scale value up to an associated degree of filling; 
     ii) the optical information component is converted into a code by means of a histogram analysis, wherein the code comprises a plurality of pairs composed of a gray-scale value and a degree of filling, in accordance with the histogram analysis; and 
     iii) the code is converted into the information component. 
     The decoding method described can therefore be a reversal of the encoding method described above. The conversion of the code into the information component or the conversion of the optical information component into the plurality of pairs composed of gray-scale value and degree of filling can, in particular, again be effected by means of an encoder or decoder and/or by means of a correspondingly designed data processing device, for example the data processing device described above. Accordingly, this decoding in accordance with steps ii) and iii) can be configured wholly or partly once again in terms of program technology. Accordingly, a computer program with program code for carrying out method steps ii) and iii) of the decoding method in accordance with the above description when the program is executed on a computer is furthermore proposed. This computer program can also be stored on a machine-readable carrier. 
     In this case, a “histogram” analysis should be understood to mean any analysis which evaluates a frequency distribution. This evaluation can be effected in graphical form, for example, although this need not necessarily be the case. Generally, therefore, a histogram analysis within the meaning of the present invention should be understood as an analysis which assigns corresponding degrees of filling to gray-scale values, or vice versa, depending on the occurrence in the optical information component evaluated. In this case, the type of analysis is of secondary relevance, in principle, as long as the result represents an assignment of gray-scale values to degrees of filling, or vice versa. Thus, by way of example, a gray-scale value/degree of filling evaluation can be performed directly, or else a spatially resolved image information component can firstly be obtained and is then further converted into gray-scale values and degrees of filling. For an example of the use of histograms to aid analysis of optical data, see EP 1 843 148 A1, the disclosure of which is hereby incorporated herein by reference in its entirety. 
     Corresponding to the proposed decoding method, a decoding device is furthermore proposed, which can be designed for carrying out the decoding method, for example. The decoding device comprises at least one detection device for detecting the at least one optical information component applied on the item. Furthermore, the decoding device comprises at least one evaluation device designed to convert the optical information component into a code by means of a histogram analysis, wherein the code comprises a plurality of pairs composed of a gray-scale value and a degree of filling, corresponding to the histogram analysis. Furthermore, the decoding device comprises at least one decryption device for converting the code into the information component. For further details and possible configurations, reference may once again be made to the above description of the decoding method and also to the descriptions of the encoding device and of the encoding method. 
     The decoding device can comprise, in particular, at least one analysis system for detecting at least one analyte in a sample, in particular a body fluid. The analysis system can be designed, in particular, to use at least one test element and/or at least one lancet for this detection. 
     If a test element is used, then this test element can comprise, in particular, at least one test field which enables, for example, an electrochemical and/or an optical measurement of the analyte, i.e. a quantitative and/or qualitative detection of the analyte. Such test elements are known in numerous embodiments from the prior art. 
     In one embodiment in which an optical detection method is used, that is to say the test element comprises an optical test field, the analysis system may use, for evaluating the optical information component, that is to say as detection device or as part of the latter, the same optical detector which is also used for evaluating the optical test field. In this way, it is possible to save additional components for the detection device. For the decoding and the optical detection of the analyte using the same detector, it is possible to utilize synergistic effects since wholly or in part for example the same hardware components and/or moreover at least in part the same software components can be used. 
     By way of example, said at least one optical detector can comprise a spatially resolved optical detector. By way of example, a CMOS and/or CCD chip can be employed in this case. 
     The decoding device can generally also comprise the at least one item, in particular the at least one medical disposable item, on which the optical information component is applied. This has been described above using the example of the analysis system which can comprise, as medical disposable item, for example, a test element in the form of a test strip and/or a test tape, and/or a lancet, which are correspondingly provided with the optical information component. By way of example, the optical information component can comprise, in encoded form, batch information components concerning the medical disposable item. 
     If an image sensor which can resolve two-dimensional image information components, in particular a CCD chip and/or a CMOS chip, is used for detecting the optical information component, then the evaluation device of the decoding device can be integrated wholly or partly in a corresponding data processing device, as has been described above. Alternatively or additionally, however, the evaluation device can also be integrated wholly or partly in the image sensor itself, for example in the CCD chip and/or the CMOS chip. Consequently, by way of example, a partial evaluation of the optical information component for decoding purposes can already be effected in the image sensor. A corresponding histogram analysis can also be integrated in the image sensor, for example. 
     Alongside the decoding device, a medical disposable item is furthermore described, comprising at least one coding which has been generated by means of an encoding method according to one or more of the embodiments described above. As explained above, the medical disposable item can comprise, for example, a test element, in particular a test tape and/or a test strip, for detecting at least one analyte in a sample, such as a body fluid. Alternatively or additionally, other disposable items may also be encompassed, for example a lancet for producing a sample of a body fluid or the like. 
     The coding in the form of the at least one optical information component can in this case comprise, in particular, as explained above, at least one item-specific information component concerning the medical disposable item in accordance with the above description. 
     The coding or the optical information component can be applied, in principle, on any desired location of the medical disposable item. Thus, the coding or the optical information component can be applied, for example, on the medical disposable item itself. Alternatively or additionally, the coding or the optical information component can also be applied on a packaging of the medical disposable item, such that in this case the packaging conceptually replaces the medical disposable article and is intended to be covered by this term within the scope of the present invention. A packaging can comprise one or a plurality of medical disposable items. If use is made of a test strip and/or a test tape suitable for analyzing at least one body fluid and having at least one corresponding test field, then it is particularly preferred to apply the coding in the form of the optical information component on a carrier on which the at least one test field is also applied. By way of example, said carrier can be a carrier comprising a paper material, a plastics material, a laminate material or a ceramic material. 
     If a plurality of test fields are arranged on the test element, then a plurality of codings can also be provided for said plurality of test fields and/or a group of the test fields. By way of example, a test tape can be configured in such a way that it comprises alternately test fields and codings in the form of optical information components. In this way, by way of example, information components concerning the number of test fields still remaining, or the like can also be concomitantly encompassed in an encoded manner. 
     The invention is to be explained in more detail by the following figures and examples. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following detailed description of the embodiments of the present invention can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which: 
         FIG. 1  shows a perspective illustration of an exemplary embodiment of a conventional analysis system as an example of a decoding device. 
         FIG. 2  shows a schematic construction of the analysis system in accordance with  FIG. 1 . 
         FIG. 3  shows a schematic construction of a test tape according to the invention for use in an analysis system in accordance with  FIGS. 1 and 2 . 
         FIG. 4  shows an exemplary embodiment of an analysis system with a test strip. 
         FIG. 5  shows an exemplary embodiment of a test strip for use in an analysis system in accordance with  FIG. 4 . 
         FIG. 6  shows an exemplary embodiment of a coding according to the present invention. 
         FIG. 7  shows an exemplary embodiment of a histogram analysis of the coding in accordance with  FIG. 6 . 
         FIG. 8  shows an exemplary embodiment of a gray-level coding of the number  262144 . 
         FIG. 9  shows the number  262144  illustrated by a commercially available strip bar code. 
         FIG. 10  shows a schematic flow diagram of an exemplary embodiment of an encoding method according to the present invention. 
         FIG. 11  shows a schematic flowchart of an exemplary embodiment of a decoding method according to the present invention. 
     
    
    
     In order that the present invention may be more readily understood, reference is made to the following detailed descriptions and examples, which are intended to illustrate the present invention, but not limit the scope thereof. 
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION 
     The following descriptions of the embodiments are merely exemplary in nature and are in no way intended to limit the present invention or its application or uses. 
       FIG. 1  shows, in a perspective illustration, an excerpt from a commercially available analysis system  110 , which is used as decoding device  111  in the context of the present invention, for example by means of corresponding design in terms of program technology.  FIG. 2  shows, in a simplified illustration, a schematic construction diagram of this analysis system  110 . Reference is made to both figures. 
     In the exemplary embodiment illustrated, the analysis system  110  comprises a tape cassette  112 , which can be accommodated in an exchangeable manner, for example, in a housing (not illustrated) of the analysis system  110 . A test tape  114  is guided in said tape cassette  112 , said test tape being exposed only at the tip of the tape cassette  112  in a measurement position  136  and having a plurality of test fields or--this term generally being used synonymously—analysis zones  116 , spaced apart in the direction of the tape, for the optical detection of glucose in blood. The tape cassette  112  and the test tape  114  both constitute exemplary embodiments of medical disposable items  117 , which are generally designed for a single use or for a use comprising a limited number of usages. Such medical disposable items  117  can be used as mass-produced products for example in medical diagnostics described here or in other fields of medical technology. The present invention essentially relates to the coding of such medical disposable items, which is described below using the example of the test tape  114 . 
     A coding  118  is applied on the outside of the tape cassette  112 , said coding having the form of a bar code in the example illustrated. However, at this location, too, a coding according to the invention can be used, in principle. This coding  118  can comprise, for example, item-specific information components concerning the test tape  114  or the analysis zones  116  and the test chemicals in these analysis zones  116 . 
     Furthermore, the test tape  114  can comprise positioning markers  120 , which can be printed onto the test tape  114  in the form of bars running transversely with respect to the test tape  114 , in a manner alternating with the analysis zones  116 , for example. These positioning markers  120  can be detected for example through a positioning window  122  in the tape cassette  112 , such that it is possible to correspondingly control a spooling of the test tape  114  through the analysis system  110 . Alternatively or additionally, however, as described in greater detail below, it is also possible for codings  118  on the test tape  114  itself also to be used as positioning markers  120 . 
     Furthermore, in the exemplary embodiment illustrated, the analysis system  110  comprises a detector  124  in the form of an optical module  126 , which engages into a cutout  128  of the tape cassette  112  when the tape cassette  112  is inserted into the analysis system  110 . In the exemplary embodiment illustrated, said detector  124  comprises an image sensor  130  for the spatially resolved recording of image information components, for example a CCD or CMOS image sensor chip. Furthermore, the detector  124  comprises a spatially resolving optical unit  132 , for example in the form of one or more lenses. Furthermore, in the exemplary embodiment illustrated, the detector  124  comprises a light source  134 , which, if appropriate, can also be provided with a corresponding illumination optical unit and which is designed to illuminate the analysis zone  116  situated precisely in the measurement position  136  in the field of view of the detector  124 . 
     In the known analysis system  110  illustrated in  FIG. 1 , a separate detector or a separate measurement system can be used in each case for identifying the position of the test tape  114 , for identifying the coding  118  and for determining the glucose concentration. The division of these metrological tasks leads to increased equipment costs and increases the structural space of the analysis system  110 . Correspondingly, in the case of the simplified illustration of the analysis system  110  in accordance with  FIG. 2 , an option is implemented in which the three metrological tasks mentioned are performed by one and the same detector  124 . It is also possible for just two of the metrological tasks mentioned to be combined, for example. Consequently, additional detectors for identifying coding  118  and an additional positioning sensor (not illustrated in  FIG. 1 ) interacting with the positioning window  122  can be dispensed with by virtue of the detector  124  concomitantly undertaking the positioning task. 
     The illustration of the analysis system  110  in accordance with  FIG. 2  is greatly simplified by comparison with  FIG. 1 . Thus, by way of example, the test tape  114  is merely indicated in this figure. In the region of the measurement position  136 , the tape cassette  112  provides a guide  138  for the test tape  114 , within which guide the test tape  114 , driven by a drive device  140  (merely indicated in  FIG. 2 ) can be guided and hence positioned relative to the measurement position  136  of the detector  124  (merely indicated in  FIG. 2 ). The guide  138  and the drive device  140  can therefore constitute constituent parts of a transfer device  142  for positioning the test tape  114 . 
     Furthermore, the analysis system  110  can comprise an evaluation unit  144 , which can evaluate the measurement of the blood glucose concentration by means of the test tape  114  and the detector  124 , in order thus to enable a quantitative and/or qualitative analysis of the blood sample. In the exemplary embodiment illustrated in  FIG. 2 , the evaluation unit  144  optionally comprises a controller  146  which can control for example the tape positioning by means of the transfer device  142 . In other embodiments, a separate configuration or only a partly common spatial configuration in respect of these components  144 ,  146  is also possible, in principle. In the use of the analysis system  110  as decoding device  111 , the evaluation unit  144  may also comprise an evaluation device  145  for evaluating an optical information component and also a decryption device  147  for converting the code, as will be described in greater detail below. However, the evaluation device  145  and the decryption device  147 , also can be configured wholly or partly as separate components rather than commonly located as illustrated in  FIG. 2 . In this case, the units  144 ,  145 ,  146  and  147  can comprise one or more electronic components, for example one or more microprocessors and/or other types of electronic components. Moreover, one or more input and output units can also be provided, for example interfaces, input keys, displays, optical and/or acoustic indicators or similar devices. Furthermore, one or more of the units  144 ,  145 ,  146 , and  147  can also be combined wholly or partly with other components of the analysis system  110 . Thus, by way of example, the evaluation device  145  and/or the decryption device  147  can also wholly or partly be already integrated for example in the image sensor  130 , for example in a CMOS and/or CCD chip of said image sensor  130 . 
     In the exemplary embodiment illustrated in  FIG. 2 , the detector  124 , as explained above, may be utilized in a multifunctional manner. For this purpose, a coding  118  is applied on the test tape  114 . Alternatively or additionally, however, one or more codings  118  can also be arranged on the medical disposable item  117  in the form of the tape cassette  112 , or at other locations, for example on a packaging of the tape cassette  112 . Various configurations are conceivable. 
     An exemplary embodiment of a test tape  114  which can be used in the context of the analysis system  110  or the decoding device  111  according to the invention is illustrated in  FIG. 3 . In this case, only an excerpt from this test tape  114  is shown, said test tape comprising a linear series of analysis zones  116  with test chemicals for detecting the analyte and codings  118  in the form of corresponding optical information components  119  in an alternating fashion on a carrier  148 , for example a transparent plastic tape. In this case, one coding  118  is respectively assigned to one analysis zone  116 , such that the respective one analysis zone  116  and the assigned coding  118  with the optical information component  119  form a coding/analysis zone pair  150 . However, other assignments are also possible, in principle, such that, by way of example, one coding  118  can be assigned to a plurality of analysis zones  116  or one analysis zone  116  can be assigned to a plurality of codings  118 . In a spooling direction of the tape, said direction being designated symbolically by the reference numeral  152  in  FIG. 3 , the coding  118  can be disposed upstream of the analysis zone  116 , for example, by a known distance X, for example, such that the coding  118  of a coding/analysis zone pair  150 , in the spooling direction  152 , first passes the measurement position  136 , followed by the associated analysis zone  116 . However, other configurations are also possible, in principle. 
     In the embodiment shown in  FIG. 3 , the coding  118  is generally in the form of a coding with optical information components  119  in the form of a plurality of individual two-dimensional fields, the arrangement of which is explained in greater detail by way of example below in  FIG. 6 . In principle, however, another arrangement of the coding, for example a one-dimensional coding, for example a coding in which the fields are arranged one behind another in the spooling direction  152 , is also possible, in principle. 
     In the case of the analysis system  110  proposed, the detector  124  is used in a multifunctional manner. Thus, said detector is firstly used to measure the discoloration of the analysis zone  116 . Furthermore, said detector  124  can optionally also identify the tape position, for example by the coding  118  itself, the positioning markers  120  or the analysis zones  116  being identified by means of the detector  124  and being utilized for positioning. Furthermore, in the context of the present invention and in the context of a decoding device  111  proposed, the detector  124  can also be used as a detection device  125  for detecting the optical information component  119  of the coding  118 , particularly if all information components required for this purpose can be identified simultaneously or successively in a measurement window of said detector  124 . In particular, it is conceivable in this way to apply all required item-specific information components in the form of the optical information component  119  of the optically perceptible coding  118  to the test tape  114 , for example by printing, labeling or similar application methods. Consequently, item-specific information components can therefore be accommodated in the associated coding  118  individually for each analysis zone  116  or for each group of analysis zones  116  which can be detected simultaneously or successively in the measurement position  136  by the detector  124 . In a first position of the test tape  114 , the analysis zone  116  or the group of analysis zones  116  is or are in the measurement position  136 , whereas in a second position of the test tape  114 , the associated coding  118  is in said measurement position. 
     In the exemplary embodiment illustrated in  FIG. 3 , the coding  118  or the optical information component  119  of said coding  118  comprises a coding field  162  for the item-specific information components. This coding field  162  can, as described above, simultaneously also be used as a positioning marker. However, alternatively or additionally, as likewise illustrated in a dashed manner in  FIG. 3 , with a coding field  162  used as positioning marker  120  it is also possible to provide a separate positioning marker in the coding  118 . This positioning marker  120  can, for example, likewise be arranged at a predefined distance from the analysis zone  116 , such that the distance X between the coding  118  and the associated analysis zone  116  can, for example, also be defined from this separate positioning marker  120 . 
     In both cases, that is to say in the case in which the coding  118  comprises a separate positioning marker  120  (such as in dashed-line from  FIG. 3 ) or in the case in which the coding field  162  of the coding  118  containing the item-specific information component is also used for positioning, it is possible that one and the same detector  124  is also able to identify all elements  116 ,  118 ,  120  and is therefore available for determining glucose, identifying the position and evaluating the item-specific information component. In principle, however, other configurations are also possible in the context of the decoding device  111  proposed, for example a separate detection device  125 . 
     In  FIGS. 1 to 3 , the analysis system  110  or the decoding device  111  according to the invention was explained using the example of a medical disposable item  117  in the form of a test tape  114 .  FIGS. 4 and 5  illustrate an exemplary embodiment which is based on the use of test strips  154  as medical disposable item  117 . These test strips  154 , which are illustrated individually as an exemplary embodiment in  FIG. 5 , again comprise a carrier  156 , for example a paper, polymeric, and/or ceramic carrier. At a front end, said carrier  156  has an application zone  158 , in which a liquid sample, for example a drop of blood, can be applied to the test strip  154 . This liquid sample is transported to an analysis zone  116  of the test strip  154  by means of capillary forces in order to bring about an analyte-specific reaction there, colorimetrically or electrochemically corresponding to the proportion of glucose in the liquid sample. 
     At an end lying opposite the application zone  158  in this exemplary embodiment, the test strip  154  furthermore again has a coding  118  with an optical information component  119  containing the item-specific information component in an encrypted form. In this exemplary embodiment, too, the coding  118  is again merely indicated, such that, alongside the two-dimensional optical information component illustrated, it can for example in turn also comprise a one-dimensional coding, for example in the form of individual fields arranged one behind another. For a possible exemplary embodiment of the coding  118 , reference may in turn be made to the subsequent  FIG. 6 . This coding  118  is again optically readable. Furthermore, alongside the item-specific information component, the coding  118  can again also comprise one or more positioning markers  120 , which is not illustrated in  FIG. 5  but is optionally possible and can facilitate the positioning. However, alternatively or additionally, that part of the coding  118  which comprises the item-specific information component can simultaneously also be used as a positioning marker  120 . 
     In an exemplary embodiment of the analysis system  110  as illustrated in  FIG. 4 , which simultaneously functions as a decoding device  111  or comprises such a decoding device  111 , a guide  138  can again be provided as a constituent part of a transfer device  142  for the test strip  154 . This guide  138  has the effect that the test strip  154  can be guided laterally past a detector  124 , which is indicated schematically in  FIG. 4 . Said detector  124  can in turn simultaneously be used as a detection device  125  in the context of the decoding device  111  proposed. However, a separate detection device  125 , which is separate from the detector  124  for detecting the analysis zone  116 , can also be used, in principle. In a second position illustrated in  FIG. 4 , in this case, in the exemplary embodiment illustrated, the coding  118  is arranged wholly or partly in the field of view of the detector  124 . If the test strip  154  is pushed further into the analysis system  110 , for which purpose the guide  138  can be embodied in correspondingly elongated fashion, for example, then the analysis zone  116  of the test strip  154  enters the field of view of the detector  124 , and the test strip  154  is in a first position. The described reaction of the analysis zone  116  can be evaluated in this first position. Otherwise, the functionality of the analysis system  110  in accordance with  FIG. 4  can substantially correspond to the functionality of the analysis system  110  in accordance with  FIGS. 1 and 2 . 
       FIGS. 6 to 9  illustrate different exemplary embodiments of the coding  118  (or of the optical information component  119  containing the item-specific information component) and also examples of a method for evaluation by means of a histogram analysis. In this case,  FIG. 6  shows an exemplary embodiment of the coding  118  in which the coding  118  comprises a two-dimensional coding field  162  comprising a plurality of individual fields  164 . As described above, the coding  118  can additionally also comprise one or more positioning markers  120 , or the coding field  162 , which comprises the item-specific information component in an encoded form, can simultaneously also be used for positioning the test tape  114  and/or the test strip  154 . The coding  118  illustrated in  FIG. 6  can be used, in principle, on test tapes  114 , on test strips  154  or on other types of medical disposable items  117 . 
     The two-dimensional coding with the optical information component  118  in the coding field  162  advantageously utilizes the fact that the detector  124  used for evaluating the analysis zone  116  is in many cases equipped as a spatially resolving detector  124  with a spatially resolving image sensor  130 , for example in the form of a compact sensor array. As described in EP 1 843 148 A1, for example, the evaluation of the analysis zone  116  can also be carried out by means of a gray-scale value analysis, in particular by means of a gray-scale value histogram. This histogram generation can, for example, be implemented directly in the detector  124 , for example in a CMOS chip of the detector  124 . In a similar manner, the gray levels of the optical information component  119  of the coding  118  can also be evaluated, for example likewise once again wholly or partly in the CMOS chip of the detector  124  and/or in some other type of evaluation device  145 . The advantages of the complete or partial implementation of the evaluation device  145  in the image sensor  130 , for example the CMOS chip of the detector  124 , consist in a reduced complexity for peripheral hardware, i.e. in reduced clock times, the possible avoidance of image memories and a reduced energy requirement. 
     On the basis of the example of the coding in  FIG. 6 , an example of an encryption of item-specific information components in the coding  118  or the optical information component  119 , and also an example of the decryption of said information components will be described below. The coding  118  comprises the optical information component  119  in the form of the above-described coding field  162 , which can have an at least approximately square form in the illustrated embodiments. The coding field  162  comprises a plurality of fields  164  (nine fields  164  shown in  FIG. 6 ), which per se can likewise again have a square or at least approximately square shape and which are arranged in a 3×3 matrix. The fields  164  can have a border or else be configured without an edge. Another arrangement of the fields  164  is also possible, in principle, for example a linear arrangement with nine fields  164  arranged one behind another. 
     As illustrated in  FIG. 6 , the fields  164  are filled with gray levels to different degrees of filling. This exemplary embodiment of a coding  118  with two-dimensional optical information components  119  with a gray-level coding thus affords the possibility of carrying out a histogram evaluation. This histogram evaluation, as explained above, can comprise a simple frequency distribution and need not necessarily comprise a graphical evaluation, as illustrated in  FIG. 7 . 
     For the purpose of the histogram evaluation, an image of the coding  118  or of the coding field  162  can be recorded if the test element in the form of the test tape  114  and/or test strip  154  is situated in the above-described second position, in which the coding  118  is arranged at least partly in the field of view of the detector  124  and hence in the measurement position  136 . From the degree of filling of each individual field  164 , each gray level can then be assigned a specific number of pixels with this gray-scale value. In the example, nine gray-scale values are illustrated, each of which can assume four degrees of filling, i.e. from wholly filled (as in the black field  164  in the top left corner of  FIG. 6 ) through ¾ filled, ½ filled to ¼ filled. In order to clarify the degree of filling, the edges of the square fields  164  are also concomitantly marked in  FIG. 6 , but this need not necessarily be the case. Overall, the coding shown in  FIG. 6  results in 36 combination possibilities (9 gray-scale values×4 degrees of filling). This merely represents one exemplary embodiment of a possible coding. Other numbers of possible gray levels and/or degrees of filling are also conceivable and may be selected on the basis of the sensitivity and/or quality of the components employed for performing the optical detection. 
     By way of example, a gray-scale value histogram illustrated in  FIG. 7  would result from the coding illustrated in  FIG. 6 . In this case, the degree of filling a in % is plotted against each gray level g, the gray levels here being numbered consecutively from 1 to 9. If the sequence of the gray levels g in the histogram in accordance with  FIG. 7  is understood to be an order, i.e. for example a sequence of digits, then it is possible to generate 49, equal to 262144, numbers using this 9-field code with 4 degrees of filling, for which purpose, with a standardized bar code, for example, a depth of 18 bits would be necessary since 218 is equal to 49. 
     As an example,  FIGS. 8 and 9  compare the number “262144” using the gray-scale value coding according to the invention ( FIG. 8 ) with a representation using a commercially available bar code (code  25 ,  FIG. 9 ). The reduction of the space requirement for a coding at a given line resolution (here 300 dpi) as made possible as a result of the extension from 2 (black/white) to 9 gray levels is clear in this case, wherein the gray-scale value coding could even be significantly reduced in size. Conversely, with no change in the space requirement for the coding  118  or the optical information component  119  on the medical disposable item  117 , the storage depth or the number of information components that can be encrypted in the coding  118 , for example item-specific information components, could be significantly increased. 
     Especially in the case of a gray-scale value coding, it should be emphasized that the read-out by means of a histogram can be made at least substantially insensitive with respect to translation and/or rotation. This can be effected, as is described for example in EP 1 843 148 A1, by means of a direct, immediate gray-scale value/degree of filling evaluation, without the “detour” via a spatially resolved detection of image information components. This means that even a tilting of the test strip  154  or test tape  114  can enable the coding  118  to be read out in an entirely satisfactory manner. Likewise, the form of the coding is substantially flexible, such that horizontally and/or vertically oriented rectangles, circles, diagonal lines having different gray-scale values and thicknesses, or the like could also be used instead of square fields  164  and/or square coding fields  162 . 
     The selection of the nine gray levels and four filling factors illustrated in  FIG. 6  is likewise a simplified, exemplary illustration. Conceptually, the embodiment of the invention is based on the fact that, in the case of analysis systems  110  optimized for glucose determination, the number of gray-scale values that can be identified is designed precisely with the aim of determining gray-scale values as exactly as possible. This advantage especially, particularly if the same detector  124  is also utilized as a detection device  125  for reading out the optical information component  119 , can also be utilized for reading out the coding  118 . While for glucose determination the requirements made of the accuracy of the measurement are conceptually approximately 0.1% reflectance over a range of approximately 50% reflectance and, therefore, 500 gray levels should be identifiable, it thus appears to be realistic to be able to separately identify at least 50 gray levels for a gray-scale value coding. By way of example, if a detector  124  with an image sensor  130  having 106 pixels is used, then 20,000 pixels would be available for each gray level. Assuming a Poisson distribution, the number of pixels of a specific gray-scale value could then theoretically be determined to 0.7% accuracy. Consequently, the filling factors could be subdivided into 141 levels. Taking account of the technical implementability, in particular the edge effects and the width of the gray-scale value distributions, it appears to be possible to realize at least 30 levels. It can be shown overall that the edge effects for given area of a right-angled quadrilateral are minimal when the rectangle is a square, as a result of which square fields  164  and/or square coding fields  162  are useful. Consequently, it would be possible to encode 5,030 numbers in an image, which corresponds to a binary information depth of approximately 170 bits. Given an information requirement of  406  bits, for example, the information component could thus be represented in at most three images of the detector. 
     If the number pairs of gray-scale value and degree of filling are determined, as shown on the basis of the histogram analysis in  FIG. 7 , for example, then the roles of gray-scale value and degree of filling can also be interchanged during the encoding of numbers. Thus, by way of example, it is possible to effect ordering according to degrees of filling, instead of an order according to gray-scale values. The gray-scale value can then reproduce the value of this location in the code instead of the degree of filling. In this way, in the above example, it is even possible to represent 3,050 instead of 5,030 numbers, which corresponds to a bit depth of 245 bits in a binary system. It can easily be shown that this exchange of roles is advantageous whenever the base (originally 50 here) of the power is greater than the exponent (originally 30 here). 
     For generating the gray-scale values, it is not absolutely necessary to generate a homogenous area with constant gray-scale value, rather it is also possible to use differently structured coding fields  162 , differently structured fields  164 , or otherwise structured areas as long as the image of the structuring at the location of the detector is significantly smaller than 1 pixel. Hatching and dotting are examples of such structuring. 
     If appropriate, it may furthermore be helpful to use the extreme values black and white, as illustrated in  FIG. 6  by way of example in the first field of the first row and, respectively, in the second field of the second row, not only for reading out the coding but at the same time for the scaling of the analysis system  110 . In a histogram of the type illustrated in  FIG. 7 , after the coding has been read out, it is then possible, on the basis of this black-white information regarding the reference values “black” and “white”, to effect a calibration as reference for determining the glucose concentration by means of the analysis zone  116 . As a result of this calibration, the analysis system  110  can be made more robust with respect to fluctuations in the sensor sensitivity, with respect to a degradation of the illumination light intensity of the light source  134  (for example of the LEDs) or with respect to similar fluctuations. 
     The gray-level coding described with reference to  FIGS. 6 and 7  can also be used just for a portion of the item-specific information components required. Thus, by way of example, the batch coding by means of the coding  118  can be used just for a portion of the required code, wherein the remaining portion of the coding can remain on a different coding medium (“split code”). Examples of such split codes are described in the application PCT/EP2008/004293. Thus, by way of example, an additional coding medium, for example in the form of a bar code on the tape cassette  112 , in the form of a ROM key or similar additional coding media can be used. 
     Finally,  FIGS. 10 and 11  illustrate, in a schematic illustration, a flowchart of a possible exemplary embodiment of an encoding method according to the invention ( FIG. 10 ) and, respectively of a decoding method according to the invention ( FIG. 11 ). In this case, the individual method steps are merely indicated schematically, wherein, for possible configurations of these method steps, reference may largely be made to the above description. Furthermore, additional method steps not presented in  FIGS. 10 and 11  can also be encompassed. Moreover, the sequence illustrated is not absolutely mandatory, such that, by way of example, one or more method steps can be carried out in a different sequence than the sequence illustrated, can be carried out temporally in parallel or temporally in overlapping fashion or else can be carried out individually or in groups in repeated fashion. 
     In the case of the encoding method illustrated in  FIG. 10 , firstly at least one information component is provided in method step  166 . Said information component can comprise an item-specific information component, for example, and can be provided, for example, manually, by means of a data carrier, a network, a production device for test elements, or the like. The item-specific information component is merely indicated symbolically in  FIG. 10 . 
     In method step  168 , the information component is converted into a code comprising a plurality of pairs composed of a gray-scale value and a degree of filling. This conversion in step  168  can be effected, for example, on the basis of a predefined conversion specification such as is known to the person skilled in the art for example from the field of the conversion of customary information components into binary codes. In this case, by way of example, a gray-scale value can be inserted at the first location of the pairs, and a degree of filling at the second location, or vice versa, as explained above. The assignment specifications for generating the code in step  168  can be stored, for example, in a computer, in an electronic table or in some other type of code generating device  170 , as indicated symbolically in  FIG. 10 . 
     In a next method step, step  172 , the code in the form of the gray-scale value/degree of filling pairs which was generated in step  168  is then converted into a two-dimensional optical information component  119 . This conversion can be effected by means of a corresponding conversion device  174 , as likewise again indicated symbolically in  FIG. 10 . 
     The optical information component  119  generated in this way is subsequently applied to the medical disposable item  117 , which is symbolized here by way of example in the form of a test tape  114 , by means of an application device  166  in a method step  178 . Said application device  176  can comprise, for example, a printing device, a labeling device or some other type of application device, and also, if appropriate, once again, as likewise indicated in  FIG. 10 , a data processing system. 
     In this case, the code generating device  170 , the conversion device  174  and the application device  176  are illustrated symbolically as different devices in  FIG. 10  and together form an encoding device  180 . It should be pointed out that this encoding device  180  can also be configured differently than the embodiment shown in  FIG. 10 . Thus, by way of example, the devices  170 ,  174  and  176  can also be wholly or partly combined. By way of example, the conversion device  174 , in which the optical information component  119  is generated, can also be arranged wholly or partly in the application device  176 , such that, from the gray-scale value/degree of filling pairs generated in method step  168 , the optical information component  119  can also first be generated directly during application in step  178 , for example by means of a corresponding printer, which can directly process and convert the gray-scale value/degree of filling pairs as input information. 
       FIG. 11  illustrates a schematic flowchart of a decoding method according to the invention. The observations with regard to possible further method steps, other sequences, temporally parallel implementations and similar indications with regard to the schematic illustration which were mentioned above with regard to  FIG. 10  analogously apply to  FIG. 11  as well. The decoding method illustrated in  FIG. 11  can be used, in particular, for decoding a coding produced by means of the method in accordance with  FIG. 10 . 
     In a first method step, step  182 , the optical information component  119  of the code  118  is detected by means of a detection device  125 . The detection device  125  is in turn merely illustrated symbolically in  FIG. 11  and comprises, for example, a data processing device. As described above with reference to  FIG. 2 , said data processing device can be integrated, for example, wholly or partly in the image sensor  130  and/or in a separate evaluation unit  144 . 
     Afterward, in steps  184  and  186 , which can also be combined to form a common step, by means of a histogram analysis (step  184 ), the optical information component  119  is converted into a code composed of gray-scale value/degree of filling number pairs. This can again be effected, for example, wholly or partly in an evaluation device  145 . The separation of steps  184  and  186  in  FIG. 11  indicates an option which has been described above and according to which the actual histogram analysis in step  184  can be effected, for example, in the image sensor  130  as evaluation device  145 , wherein the actual conversion into a code can be effected, for example, in the evaluation unit  144  of an analysis system  110  as evaluation device  145 . The conversion into the code composed of gray-scale value/degree of filling number pairs in steps  184  and  186  constitutes, in principle a reversal of the encoding in steps  168  and  172  as described in  FIG. 10 , such that reference may at least largely be made to the above description. 
     Afterward, in method step  188 , the original information is recovered from the code generated in step  186 . In principle, this constitutes a reversal of step  166  or  168  in  FIG. 10 , such that in this regard reference may again largely be made to the above description. By way of example, for this purpose, a decryption device  147  can in turn be used, which, by way of example, can be wholly or partly identical to the evaluation unit  144  of an analysis system  110  in respect of components. Consequently, the components  125 ,  145  and  147  together form a decoding device  111 , which, by way of example, can be used in an analysis system  110  or which itself can be configured as an analysis system  110 . In this way, by way of example, item-specific information components of medical disposable items  117  in the form of test tapes  114  and/or test strips  154  can be read out and used in the analysis of liquid samples. It should again be pointed out that a different configuration of the decoding device  111  is also possible, for example a different type of combination of the components  125 ,  145  and  147 . 
     The features disclosed in the above description, the claims and the drawings may be important both individually and in any combination with one another for implementing the invention in its various embodiments. 
     It is noted that terms like “preferably”, “commonly”, and “typically” are not utilized herein to limit the scope of the claimed invention or to imply that certain features are critical, essential, or even important to the structure or function of the claimed invention. Rather, these terms are merely intended to highlight alternative or additional features that may or may not be utilized in a particular embodiment of the present invention. 
     For the purposes of describing and defining the present invention it is noted that the term “substantially” is utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. The term “substantially” is also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue. 
     Having described the present invention in detail and by reference to specific embodiments thereof, it will be apparent that modification and variations are possible without departing from the scope of the present invention defined in the appended claims. More specifically, although some aspects of the present invention are identified herein as preferred or particularly advantageous, it is contemplated that the present invention is not necessarily limited to these preferred aspects of the present invention.