Abstract:
A machine vision vehicle wheel alignment system optical target assembly which incorporates an adaptor for attachment of an optical target to a vehicle wheel assembly. The adaptor includes a circular sinusoidal edge for seating in a non-determined position against surfaces of a vehicle wheel assembly, and a pair of pivoting arm assemblies capable of independent movement which are configured to position tire hooks for gripping the tread surfaces of a tire mounted to the wheel rim. Forces exerted between the pivoting arms are transferred to the tire hooks to hold the optical target assembly in contact with the wheel assembly surface. The optical target is integrated into the adaptor, and maintained in a stationary relationship to the wheel assembly thereby during a vehicle wheel alignment procedure.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is related to, and claims priority from U.S. Provisional Patent Application Ser. No. 60/938,947 filed on May 18, 2007, which is herein incorporated by reference. The present application is further a continuation-in-part of co-pending U.S. patent application Ser. No. 11/535,881 filed on Sep. 27, 2006 which is related to, and claims priority from, U.S. Provisional Patent Application Ser. No. 60/721,206 filed on Sep. 28, 2005, both of which are herein incorporated by reference. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
       [0002]    Not Applicable. 
       BACKGROUND OF THE INVENTION 
       [0003]    The present invention relates to machine vision vehicle service systems, and in particular to an optical target assembly configured for mounting to a surface of a vehicle, such as a vehicle wheel, during a machine-vision vehicle wheel alignment procedure. 
         [0004]    A machine-vision vehicle service system, such as a vehicle wheel alignment system like the Series 811 Wheel Alignment System utilizing the DSP 600 Series sensors, manufactured and sold by Hunter Engineering Company of Bridgeton, Mo., consists generally of a console having a computer or processing unit, one or more display devices such as a monitor, and one or more input devices such as a keyboard. In a machine-vision vehicle wheel alignment system, one or more imaging sensor arrays are mounted away from a vehicle undergoing an alignment inspection, and are configured to obtain images of alignment targets or other identifiable features associated with the vehicle for communication to the processing unit. Correspondingly, the processing unit is configured with one or more software applications, at least one of which is adapted to facilitate the alignment of vehicle wheels which generally consist of a rim and an associated tire, using input received from the imaging sensors. 
         [0005]    The machine-vision imaging sensors are traditionally part of a camera system or imaging system configured to view optical targets within associated fields of view to obtain images thereof for processing by the software applications in the console. Commonly, the observed optical targets incorporate highly accurate patterns that have known control features. The positions and relationships of the features in the images are determined, and the orientation of the wheels or other vehicle components to which the optical targets are attached are calculated by well known algorithms. Exemplary configurations for the high-accuracy optical targets are described in U.S. Pat. No. 6,064,750 to January, and in U.S. Pat. No. 6,134,792 to January. Each optical target consists of a target face, on which are disposed identifiable optical elements, a precision flat base, and a mounting shaft adapted for attachment to a separate clamping assembly secured to the vehicle or vehicle wheel assembly. 
         [0006]    The conventional configuration for an optical target is precisely engineered with high-contrast optical elements such as circles, squares, or triangles. The accuracy of such conventionally configured optical targets is dependant upon how well the high contrast edges of the optical target elements can be located in an image produced by the imaging components of the wheel alignment system. For the best accuracy, the individual optical elements must be large enough to have relatively long straight or curved boundaries, and they must be separated far enough to prevent the individual optical target elements from appearing to fuse into a single object when reduced edge sharpness causes two or more optical target elements to bleed into the same pixel in the imaging system. These factors combine to limit the number of individual image pixels generated by the imaging system whose values are utilized to calculate a position and orientation of a conventionally configured optical target. 
         [0007]    Each image of conventional high-contrast optical target acquired by the optical imaging vehicle wheel alignment system is processed to identify a number of reference points in the image. Either the computer or the imaging system is configured to mathematically manipulate the positional relationships of the observed reference points, as identified in an image, to match them with a set of predetermined positional relationships based on the known parameters of the conventional high-contrast optical target. Once the relationship between the observed positional relationships and the predetermined positional relationships is identified for the reference points, the position and orientation in three-dimensional space of the target (and an associated vehicle wheel) relative to the position and orientation of the imaging system is identified, from which one or more vehicle wheel alignment angles can be identified. Accordingly, for an optical imaging vehicle wheel alignment system to function, it is necessary for the system to be capable of extracting a set of control or reference points from acquired images. 
         [0008]    To further facilitate the operation of a machine vision vehicle wheel alignment system, the separate optical targets are secured to the vehicle wheels with precision wheel adaptors configured to clamp onto the vehicle wheel edges and to position a mounting point for the optical target substantially coaxial with the wheel rim&#39;s axis of rotation. The traditional precision wheel adaptors typically include a set of claws or feet adapted to secure the wheel adaptor to the vehicle wheel assembly by engaging the lip or rim of the wheel rim at the tire junction. A centering mechanism on the wheel adaptor ensures that the claws or feet of the wheel adaptor are adjusted in a symmetrical manner to maintain the mounting point for the optical target in a determined centered configuration in relation to the axial center of the wheel rim. 
         [0009]    Some variations of traditional wheel adaptors, such as the Tire Clamp Adaptor Model No. 20-1789-1 from Hunter Engineering Co., and those shown in U.S. Pat. No. 5,987,761 to Ohnesorge and U.S. Pat. No. 6,131,293 to Maioli et al. further utilize a set of gripping arms adapted to engage tire surfaces in conjunction with a set of contact supports and centering mechanisms for symmetrically engaging the circumferential lip of the wheel rim and securing the wheel adaptors in an axially centered position on the vehicle wheel assembly. 
         [0010]    Other vehicle-specific wheel adaptors, such as those for use with Mercedes Benz and BMW automobiles, are configured with a set of pins which are designed to pass through the wheel assembly, and to contact predetermined surfaces on the vehicle wheel hubs, positioning the vehicle-specific wheel adaptor in a predetermined axially centered location about the wheel assembly. These vehicle specific wheel adaptors are then held in place by means of tire clamps or spring mechanisms which grip to the tire tread surfaces. 
         [0011]    Traditional wheel adaptors that will universally adapt to the wide range of wheel sizes on the market today are difficult to design and costly to build. Many times additional parts are required, such as extenders, in order to allow the adaptor to work with wheels that are very small or very large which also adds additional cost and complication to the adaptor system. Additionally, traditional adaptors have to provide a substantial amount of clamping force in order to hold the weight of the target or sensor on the wheel assembly. This clamping force can scratch or dent the wheel assembly where it is attached. This is very undesirable especially when the wheel assembly is a very costly aftermarket wheel. 
         [0012]    Accordingly, it would be advantageous to provide a machine vision vehicle service system, such as a wheel alignment system, with an optical target assembly which incorporates both the optical target and a simplified adaptor for attachment to a vehicle wheel, and which does not require a determined precision mounting on the vehicle wheel assembly in relation to the wheel axis of rotation. 
         [0013]    It would be further advantageous to provide a machine vision vehicle wheel alignment system with a mechanically simplified optical target assembly which is light weight, dimensionally stable, less abrasive to the wheel rim surfaces, and which does not require precision construction. 
       BRIEF SUMMARY OF THE INVENTION 
       [0014]    Briefly stated, the present invention provides a machine vision vehicle wheel alignment system optical target assembly which incorporates an adaptor for attachment of an optical target to a vehicle wheel assembly. The adaptor includes a circular and generally sinusoidal edge for seating in a non-determined position against surfaces of a vehicle wheel assembly, and a pair of pivoting arm assemblies capable of independent movement which are configured to position tire hooks for gripping the tread surfaces of a tire mounted to the wheel rim. Forces exerted between the pivoting arms are transferred to the tire hooks to hold the optical target assembly in contact with the wheel assembly surface. The optical target is integrated into the adaptor, and maintained in a stationary relationship to the wheel assembly thereby during a vehicle wheel alignment procedure. 
         [0015]    The foregoing and other objects, features, and advantages of the invention as well as presently preferred embodiments thereof will become more apparent from the reading of the following description in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0016]    In the accompanying drawings which form part of the specification: 
           [0017]      FIG. 1  is a perspective view of a vehicle wheel optical target mounting assembly of the present disclosure; 
           [0018]      FIG. 2  is an exploded view of the optical target mounting assembly of  FIG. 1 ; 
           [0019]      FIG. 3  is a top plan view of the optical target mounting assembly of  FIG. 1 ; 
           [0020]      FIG. 4  is a front plan view of the optical target mounting assembly of  FIG. 1 ; 
           [0021]      FIG. 5  is a rear perspective view of the optical target mounting assembly of  FIG. 1 ; 
           [0022]      FIG. 6  is an exploded view of a wheel grip handle assembly of the optical target mounting assembly of  FIG. 1 ; 
           [0023]      FIG. 7  is a perspective view of the a sectional view of the bar clamp assembly of the optical target mounting assembly of  FIG. 1 ; 
           [0024]      FIG. 8  is a sectional view of the bar clamp assembly of  FIG. 7 ; 
           [0025]      FIG. 9  is an exploded view of the bar clamp assembly of  FIG. 7 ; and 
           [0026]      FIG. 10  is a perspective view of the optical target mounting assembly of  FIG. 1  secured to a vehicle wheel assembly. 
       
    
    
       [0027]    Corresponding reference numerals indicate corresponding parts throughout the several figures of the drawings. 
       DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0028]    The following detailed description illustrates the invention by way of example and not by way of limitation. The description clearly enables one skilled in the art to make and use the invention, describes several embodiments, adaptations, variations, alternatives, and uses of the invention, including what is presently believed to be the best mode of carrying out the invention. 
         [0029]    Turning to  FIG. 1 , an embodiment of the optical target assembly  100  of the present invention is shown in a perspective view. The optical target assembly  100  consists of a base assembly  102 , a pair of pivot arm assemblies  104 A and  104 B pivotally coupled to the base assembly  102 , a target support assembly  106  rigidly coupled to the base assembly  102 , and an optical target  108  integrated into the target support assembly  106 . Those of ordinary skill will recognize that the base  102  may be of unitary construction or of any other suitable configuration. 
         [0030]    The optical target  108  provides visible features which are identifiable in images acquired by an imaging system associated with a vehicle service device, and which provide a sufficient number of data points to enable a determination as to the position and orientation of the optical target  108  in three-dimensional space from acquired images. For example, the optical target  108  may include a set of geometric figures arranged in a predetermined configuration as shown in U.S. Pat. No. 6,134,792 to January, herein incorporated by reference, or simply a set of identifiable fixed features, such as shown in U.S. Pat. No. 6,894,771 to Dorrance et al., herein incorporated by reference. The visible features (data points) of the optical target  108  need not be disposed on a planar surface, but rather, may be disposed on any dimensionally stable surface or shape, including non-planar surfaces, smoothly curved surfaces, or angled surfaces. 
         [0031]    It is less costly to manufacture a target where the identifiable fixed features are not precisely known. U.S. Pat. No. 6,894,771 to Dorrance et al. describes an optimization method that may be employed to precisely determine the location of the features by acquiring multiple images of the target while it is rotated. This method could be used on every alignment that is performed when the vehicle is rolled on the runway surface to determine the axis of rotation, or the method may be performed once as a target calibration procedure where the location of the features are stored and later used via methods outlined by U.S. Pat. No. 6,134,792 to January. 
         [0032]    The unitary base assembly  102  is generally defined by a short tubular segment or annular member  102 A, having a distal end surface  102 B. The distal end surface  102 B preferably undulates smoothly and continuously in a generally sinusoidal form to define at least three spaced shallow “peaks” and at least shallow three “valleys”, with an average between the peaks and valleys defining an average base plane. Preferably, a whole number multiple of the wavelength of the generally sinusoidal form is equal to the circumferential distance about the distal end surface  102 B. The distal end surface  102 B is adapted for abutting contact with the generally vertical outer surfaces of a vehicle wheel assembly, such as the tire sidewall, or the vehicle wheel rim between the outer circumferential lip of the wheel rim and the wheel assembly axis of rotation. In one embodiment, the distal end surface is configured as a low-amplitude sinusoid, having a wavelength which equals the circumference of the unitary base assembly  102 . Alternatively, those of ordinary skill in the art will recognize that the distal end surface  102 B may be configured in any of a variety of non-planar configurations which provide at least three contact points for abutting contact with the surfaces of a vehicle wheel rim. The distal end surface  102 B may be either continuous or non-continuous. The configuration of the distal end surface  102 B enables the unitary base  102  to contact a vehicle wheel rim at multiple points which are not required to be co-planar, providing for a stable placement of the optical target assembly  100  against the vehicle wheel rim, as seen in  FIG. 10 . The tubular segment  102  further defines a central opening  109  which facilitates placement about an axial hub-end portion of the vehicle wheel rim  10 . Since the assembly  102  of the present invention is intended for a non-determined placement against a wheel assembly surface, the unitary base assembly  102  does not include any adjustment mechanisms for centered positioning relative to either the wheel rim circumferential lip or axis of rotation, such as those commonly found in self-centering or adjustable wheel adaptors. 
         [0033]    The target support assembly  106  consists of a pair of support arms  106 A and  106 B, which are rigidly secured to the base assembly  102  at diametrically opposite fixed positions, and which jointly support a target housing  106 C. The optical target  108  is disposed in within the target housing  106 C, and is held rigidly in a position which is generally perpendicular to an average base plane defined by the unitary base assembly  102 . 
         [0034]    To hold the distal end surface  102 B in engagement with a generally vertical surface of a vehicle wheel rim  10 , such as shown in  FIG. 10 , the pivot arm assemblies  104 A and  104 B are pivotally coupled to the unitary base assembly  102  and, through additional components, to the vehicle wheel tire tread. Each pivot arm assembly  104  includes an upper pivot arm  104 U and a lower pivot arm  104 L, which are each coupled to the unitary base assembly  102  at shared diametrically opposed pivot points  110 A and  110 B, adjacent the distal end surface  102 B. The pivot points  110 A and  110 B define a generally vertical axis of rotation about which each pivot arm assembly  104 A,  104 B may rotate. The upper and lower pivot arms  104 U and  104 L each meet at an apex  104 X which further supports a pivoting tire hook handle assembly  112 , having an adjustable-position tire hook  114  for engagement with a tire tread surface. 
         [0035]    Each tire hook  114  is configured to grip a tire tread surface of a vehicle wheel assembly  10 , such as shown in  FIG. 10 . The tire hooks  114  are preferably constructed from a rigid material, such as steel, and may be coated with plastic, rubber, or any other suitable protective layering to prevent accidental damage to vehicle body surfaces which may be contacted during use. To facilitate engagement of the tire hooks  114  with vehicle wheel assemblies of different sizes, the position of each of the opposed pivot arm assemblies  104 A and  104 B is adjustable, in concert with the tire hook handle assemblies  112 , to accommodate wheel assemblies of different dimensions. A resilient tension and engagement clamping force is applied between the opposed pivot arm assemblies  104 A and  104 B by a tension spring  116  and a clamping force mechanism  118 , each of which are coupled between the apices of the opposed pivot arm assemblies  104 A and  104 B. The tension spring  116  maintains the pivot arm assemblies  104 A and  104 B in a stored position during non-use, during which they are aligned at approximately a 45 degree angle relative to the base assembly  102 . During use, each pivot arm assembly  104 A and  104 B may be pivoted independently about the axis connecting pivot points  110 A and  110 B, between the rest position and the base assembly  102 , such that the apices of each pivot arm assembly  104 A and  104 B move through arcs in a plane which is generally parallel to the surface upon which the vehicle wheel assembly rests. 
         [0036]    To engage each tire hook  114  with a tire tread surface, such as shown in  FIG. 10 , the distal end surface  102 B of the unitary base  102  is seated against the generally vertical vehicle wheel rim surface, and the pivot arm assemblies  104 A and  104 B are pivoted inward towards the vehicle wheel rim assembly. Simultaneously, as best seen in  FIG. 3 , the tire hook handle assemblies  112  are rotated about their respective pivot points at each apex  104 X, and extended longitudinally as required, to bring the tire hooks  114  into substantially parallel engagement with the tire tread surfaces. Once the tire hooks are each engaged with the tire tread surfaces on substantially opposite sides of the vehicle wheel assembly, the tension force exerted between each of the pivot arm assemblies  104 A and  104 B by the tension spring  116  will temporarily maintain the optical target assembly  100  in place against the vehicle wheel surface until a clamping force is applied by the clamping force mechanism  118  as is described below. Removal of the optical target assembly  100  from a vehicle wheel assembly is merely the reverse of the installation. 
         [0037]    Turning to  FIG. 6 , a tire hook handle assembly  112  and tire hook  114  are shown in an exploded view which illustrates the various components which enable longitudinal adjustment and rotational adjustment of the tire hook position. The tire hook handle assembly  112  consists generally of a support shaft  200  which is offset from a cylindrical coupling  202  defining the apex  110  of a pivot arm assembly  104 . The cylindrical coupling  202 , and correspondingly, the support shaft  200 , is freely pivotable about an axial stub shaft  204  which is coupled between the upper and lower arms of a pivot arm assembly  104  at the apex  110 . The rotational axis about which the support shaft  200  pivots is parallel to the rotational axis for the associated pivot arm assembly  104  between pivot points  110 A and  110 B. The end of the support shaft  200  opposite from the cylindrical coupling  202  is retained for longitudinal movement within a body of the tire hook handle assembly  112 , defined by upper and lower portions  112 A and  112 B. A conventional pawl mechanism engages detents in the surface of the support shaft  200 , enabling a selectable longitudinal adjustment between the support shaft  200  and the body of the tire hook handle assembly  112 , lengthening or shortening the tire hook handle assembly  112  as required to engage a vehicle wheel with the tire hook  114 . 
         [0038]    To further facilitate engagement of a vehicle wheel with the tire hook  114 , each tire hook  114  consists of an angled segment  114 A terminating in a distal hook  114 B. The angled segment  114 A is coupled to the body of the tire hook handle assembly by a pivoting coupling  206 , opposite from the cylindrical coupling  202 . The pivoting coupling  206  enable the tire hook  114  to pivot through an arc about an axis which is parallel to the rotational axis of the cylindrical coupling  202 , i.e., in the same plane within which the support shaft  200  moves. Preferably, the pivoting coupling  206  provides a set of predetermined positions to which the tire hook  114  may be pivoted, and provides a suitable locking and release mechanism. 
         [0039]    Those of ordinary skill in the art will recognize that any of a variety of mechanical components may be utilized to achieve the desired range of pivoting and longitudinal movement for the tire hooks  114 , handle assemblies  112 , and pivot arm assemblies  104 , including, but not limited to, sliding assemblies, threaded assemblies, pivoting assemblies, and expanding assemblies. It is not required that the hooks, handles or pivot arm assemblies be adjusted synchronously, or that they be disposed in mirror-image configurations, provided the tire hooks  114  are sufficiently positioned to engage the tire tread surfaces of a vehicle wheel to secure the distal end surface  102 B of the base assembly  102  against the surfaces of the wheel rim  10  between the circumferential lip and the axial center point, in a stationary and stable manner during wheel alignment angle measurements and procedures. 
         [0040]    During use, the optical target assembly  100  is held against the vehicle wheel assembly by forces exerted between the pivot arm assemblies  104 A and  104 B by the clamping force mechanism  118 , which in turn pulls the optical target assembly  100  against the vehicle wheel assembly using the tire hooks  114 . The geometry of the entire adapter mechanism transfers the load from the clamping force mechanism to the tire hooks and in turn creates a force pulling the adapter firmly against the face of the wheel. 
         [0041]    Turning to  FIGS. 7-9 , the clamping force mechanism  118  consists generally of a left end  300  and a right end  302  linked by a spring-biased floating bar and clamp assembly  304 . The left end  300  is pivotally coupled to the pivot arm assembly  104 B adjacent to associated apex  104 X, and the right end  302  is pivotally coupled to the pivot arm assembly  104 A adjacent to associated apex  104 X, thereby defining a force coupling between each of the pivot arm assemblies  104 A and  104 B. 
         [0042]    The clamping force mechanism  118  is actuated by lever knob  306  of the bar and clamp assembly  304  coupled to the right end  302 . The knob  306  rotates a shaft assembly  308  which pulls a pawl  310 . The pawl  310  binds onto a bar  312  coupling the left and right ends, and pulls the bar  312  through a set stroke towards the right end  302 . The opposite end of the bar is coupled to the left end  300  through a compression spring  314 , which is compressed during the stroke movement of the bar  312 . With a set spring rate on the compression spring  314 , and a set stroke length for binding of the pawl  310 , a consistent load is applied between left and right ends each time the knob  306  is rotated from an unlocked to locked position. When the knob  306  is in the unlocked position, as shown in  FIGS. 7-9 , the pawl  310  slides along the bar  312 , and is generally biased towards the unlocked position by a compression spring  316 . This allows the pivot arm assemblies  104 A and  104 B to pivot freely when attaching the optical target assembly  100  to the vehicle wheel assembly  10 . The lever knob  306  and associated parts are arranged in a manner that they toggle over center during rotation from the locked to unlocked position. This automatically locks the mechanism when the full load of the high force compression spring  314  is reached. To release the optical target assembly  100  from the vehicle wheel assembly after use, the knob  306  is rotated from the locked position to the unlocked position, releasing the pawl  310  from the bar  312 , and relaxing the compression spring  314 . With compression spring  314  relaxed, only the tension spring  116  is acting on the pivot arm assemblies  104 A and  104 B, allowing the operator to uncouple the tire hooks  114  from the vehicle wheel assembly with relative ease. 
         [0043]    Those of ordinary skill in the art will recognize that the clamping force mechanism may have a variety of different configurations suitable for exerting forces on the pivot arms and other components of the optical target assembly to achieve the effect of providing a clamping force to hold the optical target assembly to a vehicle wheel rim. For example, threaded screw components, or resilient elastic components may be utilized in place of spring-biased mechanisms, and/or the geometric configuration of the various components may be varied to produce different forces and moments which achieve the desired effect of clamping the optical target assembly securely against the vehicle wheel rim surface. 
         [0044]    During use, an optical target assembly  100  of the present invention is positioned against a generally vertical outer surface of a vehicle wheel rim  10 , such that the visible features of the optical target  108  associated with the target support assembly  106  are orientated for viewing by one or more imaging sensors. The specific placement of the optical target assembly  100  against the outer surface of the wheel rim  10  need not be coaxial with the wheel assembly, i.e., may be eccentric with the vehicle wheel assembly, but must be sufficiently stable to prevent the optical target from tilting, wobbling, or slipping from the initial position during a vehicle service procedure. To maintain the optical target support assembly in a stable position against the wheel rim surface, the pivot arm assemblies  104 A and  104 B, together with the tire hook handles  112  and tire hooks  114 , are adjusted to grip tread surfaces of the vehicle wheel assembly, preferably at or above a horizontal plane through which the wheel axis of rotation AR passes. The interaction of gravity, the geometry of the pivot arm assemblies  104 A,  104 B, the clamping force mechanism  118 , and the distal end surface  102 B of the optical target assembly  100  interact to maintain the distal end surface  102 B against the wheel rim surface, and to hold the optical target  108  in a stable position during a vehicle service procedure and through a limited range of wheel assembly movement. 
         [0045]    Since the optical target  108  disposed on the optical target assembly  100  is not secured to the vehicle wheel assembly in any predetermined position, e.g., concentric with the wheel axis of rotation AR, it is necessary to determine the wheel axis of rotation AR for purposes of calculating vehicle wheel alignment angle measurements from images of the optical targets  108 . It is also desirable to compute the wheel assembly center point to further increase accuracy of the alignment measurements. Methods to determine the axis of rotation and center point are described in the co-pending U.S. patent application Ser. No. 11/013,057, herein incorporated by reference. 
         [0046]    The present invention can be embodied in part in the form of computer-implemented processes and apparatuses for practicing those processes. The present invention can also be embodied in part in the form of computer program code containing instructions embodied in tangible media, such as floppy diskettes, CD-ROMs, hard drives, or an other computer readable storage medium, wherein, when the computer program code is loaded into, and executed by, an electronic device such as a computer, micro-processor or logic circuit, the device becomes an apparatus for practicing the invention. 
         [0047]    The present invention can also be embodied in part in the form of computer program code, for example, whether stored in a storage medium, loaded into and/or executed by a computer, or transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via electromagnetic radiation, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes an apparatus for practicing the invention. When implemented in a general-purpose microprocessor, the computer program code segments configure the microprocessor to create specific logic circuits. 
         [0048]    In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results are obtained. As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.