Abstract:
An apparatus and method for displaying the weight or cost of an uncut selected segment of an item involves passing a position indicating member over the item lying on a support surface. The position indicating member carries one or more sensors which generate signals corresponding to succeeding cross sectional contours of the item as the member is traversed along the item from a reference position to a selected other position over this item, defining the selected segment of the item. At the same time, a motion detector arrangement preferably comprised of one or more microelectromechanical (MEMS) accelerometer devices generates signals corresponding to motion of the position indicator support member as it is moved along the item. These signals are processed in a signal processor to determine the volume of the uncut selected segment of the item lying between selected successive positions of the indication member. Each of these cumulative volume determinations are converted into numeric weight or price values based on the density factor for the particular type of item, whereby numeric weight and price values (based on weight) are displayed as the member is traversed along the item, thus enabling the operator to contemporaneously provide an on-looking consumer weight or price information before a particular segment is cut from the item. A visible light band is projected from the sensor bar onto a section of the item to clearly show the selected segment bounds corresponding to the numeric display to the onlooker.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is a divisional of U.S. Ser. No. 11/142,626, filed Jun. 1, 2005, now U.S. Pat. No. 7,010,457, which is a continuation-in-part of U.S. utility application U.S. Ser. No. 10/744,059, filed Dec. 23, 2003, which claims benefit of U.S. provisional application Ser. No. 60/576,229, filed Jun. 2, 2004 and of U.S. provisional application Ser. No. 60/577,652, filed Jun. 7, 2004, and is a continuation-in-part of PCT Application No. PCT/US03/41365, filed on Dec. 23, 2003 which claims benefit of U.S. provisional application Ser. No. 60/440,801, filed Jan. 16, 2003, and claims benefit of U.S. provisional application Ser. No. 60/453,816, filed Mar. 11, 2003, and claims benefit of U.S. provisional application Ser. No. 60/498,639, filed Aug. 29, 2003, and claims benefit of U.S. provisional application Ser. No. 60/520,812, filed Nov. 17, 2003. 

   BACKGROUND OF THE INVENTION 
   The present application and the prior applications referenced above are concerned with apparatus and methodology for aiding in portioning an item. This needs to be done for example in accurately portioning an irregularly shaped fish fillet or meat cut to a weight or price desired by a customer at the point of sale in a retail market. 
   In the apparatus and method described in the co-pending U.S. application Ser. No. 10/744,059, a sensor arrangement support is positioned above an item over a first reference section and then moved to a position over a second selected section, the portion between the two sections comprising a selected segment of the item. Various contour sensing arrangements and displacement detector devices are described to generate signals corresponding to the extent and direction of travel of the support in moving to the second section as well as to the cross sectional contours of sections of the item along the selected segment. From the signals of the displacement detector and contour sensor devices, the volume of any segment of the item is computed and a corresponding numeric value (weight or price) is displayed for viewing by the customer and the server. This provides a convenient way of displaying the weight or price of any segment of the item defined between any two sections of the item. The item can therefore be cut so as to provide any desired portioning of the item and this portion will be of an accurately known weight or price prior to being cut. 
   The aforementioned co-pending patent application describes a wide variety of contour sensor arrangements including an array of mechanical plungers or an inline series of non-contacting sensors, such as sonic or optical sensors. 
   Some of the various sensors described therein are relatively costly and/or not ideally suited to environments in which the apparatus is contemplated as being used, i.e., where contact of the apparatus with foods will inevitably occur, and where the equipment must be regularly cleaned thoroughly. Also, abuse of the equipment must be expected when unskilled personnel operate the same, particularly in a rushed atmosphere and delicate sensors might not be able to function well over a reasonable service life or need frequent repair or adjustment. 
   It is the object of the present invention to provide an apparatus and method of the above described type in which improved devices are used to determine displacements which are low in cost, rugged and reliable, and yet provides very accurate determination of the extent and direction of displacement of various components of the apparatus. 
   SUMMARY OF THE INVENTION 
   The above object and other objects which will be understood upon a reading of the following specification and claims are achieved by incorporating motion detectors into the apparatus of the type described in the cross referenced co-pending patent application to generate signals corresponding to the direction and extent of displacement of various components used to determine the volume of segments of an item of interest and to simplify and improve the serviceability of this apparatus. 
   In addition, where an arrangement of extendable plungers is utilized to generate signals corresponding to the cross sectional contours of the item or to mark or score an item, the extent of such plunger motion may be detected by such motion detectors. 
   The motion detectors are preferably accelerometers and of the microelectromechanical or “MEMS” type which are now very well known and in wide spread use in various applications. Various terms and acronyms are used to describe the technology of such miniature (or ultra-miniature) devices. Terms often used include MST (Micro Structure Technology), microstructures, microsystems, and mechatronics. Although definitions vary, the term MEMS may be defined as micro-electromechanical systems comprised of moving parts smaller than a human hair that contain both electrical and mechanical components on a silicon chip. The term “MEMS accelerometers” or the equivalently meaning “MEMS based accelerometers” will be used predominately throughout this specification. These terms will be employed in this specification as a general term applying to various types of technologies whereupon small scale accelerometers are based, without implying that all of such devices are based on micro electromechanical principles. These devices are often comprised of miniature accelerometers which are designed in accordance with a variety of principles to detect slight motions of a “proof mass”, such as by detecting capacitance changes, piezoelectric signals, or tunneling currents. 
   Another type of miniature accelerometer utilizes relative movement of a moveable microcomb suspended over a fixed microcomb, relative movement therebetween induced by motion of the structure to be monitored. An optical motion signal is created by interference effects between the microcombs. 
   Although one accelerometer enables the determination of the extent and direction of motion along one axis, a plurality of such accelerometers can detect acceleration along more than one orthogonal axes, and can be combined together in a single device capable of detecting motion along two or more axes to determine the extent and direction of displacement, tilt, or lifting of a sensor arrangement support member. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a pictorial view of an apparatus according to the present invention. 
       FIG. 1A  is a pictorial view of a sensor bar shown in  FIG. 1  with motion detectors at first alternate locations thereon. 
       FIG. 1B  is a pictorial view of a sensor bar shown in  FIG. 1  with motion detectors at second alternate locations thereon. 
       FIG. 2  is an enlarged pictorial view of an instrumentation casing including a display and signal processing electronics included in the apparatus shown in  FIG. 1 . 
       FIG. 3  is a pictorial view of a second embodiment of an apparatus according to the present invention. 
       FIG. 4  is a partially sectional view of a third embodiment of an apparatus according to the present invention. 
       FIG. 5  is an enlarged partially sectional view of one of a plurality of plunger assemblies included in the third embodiment, with an included plunger member shown in an extended position. 
       FIG. 6  is a partially sectional view of the plunger assembly shown in  FIG. 5  with the plunger member shown in a retracted position. 
       FIG. 7  is a pictorial view of an item in place on a support surface with a reference indicator element in position across one section of the item and a thin light band projected onto another section of the item. 
       FIG. 8  is a partially sectional view of a sensor bar positioned over an item on a support surface, the sensor bar having a series of visible light emitters mounted on the underside thereof to enable a thin light band to be projected across an item placed below the sensor bar. 
       FIG. 9  is a partially sectional view of a sensor bar having interposed visible light emitters located between optical triangulation contour sensors along the underside of a sensor bar. 
   

   DETAILED DESCRIPTION 
   In the following detailed description, certain specific terminology will be employed for the sake of clarity and a particular embodiment described in accordance with the requirements of 35 USC 112, but it is to be understood that the same is not intended to be limiting and should not be so construed inasmuch as the invention is capable of taking many forms and variations within the scope of the appended claims. 
   Referring to  FIG. 1 , the apparatus  10  according to a first embodiment of the invention includes a contour sensor arrangement supported by a support member, here shown as comprised of an elongated sensor bar  16  which mounts a series of height or thickness sensors  38  extending along the length of the sensor bar  16 . Sensor bar support posts  20 ,  22  are provided at each end of the manually movable sensor bar  16 , a handle  18  provided at one end to enable convenient manual movement by a user. The posts  20 ,  22  locate the sensor bar  16  at a predetermined height above a support surface defined by a table  12 . 
   A motion detector arrangement is provided to generate signals corresponding to the extent and direction of motion of the sensor bar  16 , during manual stroking of the sensor bar  16  over the surface of the table  12  and along an item  14  to be portioned resting on the table  12 . In this embodiment, the motion detector arrangement includes motion detectors  40 ,  42  located at the bottom end of each support post  20 ,  22 , respectively. 
   As described in the cross referenced co-pending application, a contour sensing arrangement comprised of a linear series of height sensors  38  installed extending along the length of the sensor bar  16  which produce signals corresponding to the height of the upper surface of the item  14  above the support surface defined by the table  12  at points along the cross section of the item  14  aligned with the sensor bar  16 . Alternatively, sensors  38  may sense the thickness of the item  14  at points along the section of the item lying below the sensor bar  16 , as described in the co-pending cross-referenced application. This contour sensor arrangement generates signals corresponding to the cross sectional contour of the item  14  at each section lying below and aligned with the sensor bar  16  at successive positions thereof along the item  14 . 
   The height or thickness sensors  38  can be of various types, as described in detail in the cross-referenced co-pending application, such as optical or sonic sensors emitting and receiving light or sound waves respectively and receiving reflections thereof from the item  14 , or penetrating the item  14  and reflecting from the surface of the table  12 . 
   The motion detector and sensor arrangement signals are transmitted to a signal processor  24  which may be a programmable microprocessor contained in a casing  26  as shown in  FIG. 2 , which computes the total volume of the selected segment of the item  14  from the motion detector and contour sensor arrangement signals. This calculated volume is converted into a corresponding numeric value, usually the weight or a price based on the weight of a selected segment of the item  14 . This numeric value is displayed substantially contemporaneously in an upright display  30  which may be mounted to the casing  26  as shown in  FIGS. 1 and 2 . 
   The motion detectors  40 ,  42  each generate electronic signals corresponding to the direction and extent of horizontal motion of the bottom end of each support post  20 ,  22  respectively as the sensor bar  16  is moved in either direction along the item  14  from a starting or reference position over any selected section of an item  14  to be portioned to reach a position over another selected section of said item  14 . As the sensor bar  16  is moved along the item  14  on the table surface  12 , the bottom end of each support post  20 ,  22  is intended to be kept in constant contact with the surface of the table  12 . 
   According to the present invention, the signals generated by each of the motion detectors  40 ,  42  are processed to determine the displacement and direction of displacement of the bottom of each post  20 ,  22  respectively. The motion detectors  40 ,  42  are each preferably comprised of accelerometers included therein, and preferably of accelerometers of a type known as “MEMS” (Micro Electro-Mechanical Systems) accelerometers. 
   MEMS accelerometers may be based on various designs and sensing methods some of which are described in an article titled “Design of Padless Mouse System with MEMS Accelerometers and Analog Read-Out Circuitry” (by Seungbae Lee, Gi-Joon Nam, Junseok Chae, and Hanseup Kim, Department of EECS, University of Michigan, USA). This article discusses some MEMS accelerometer sensing technologies including piezoelectric, tunneling, and capacitive. Other technologies include (but are not limited to) strain gauge sensing. This article is hereby incorporated by reference into this application in its entirety. 
   MEMS accelerometer devices are well known and are also described in U.S. published application 2004/0211258, and U.S. Pat. Nos. 5,392,650; 5,006,487; 4,945,765; 4,699,006; and 4,512,192, also incorporated herein by reference. 
   As described in the referenced article, the use of two such MEMS accelerometers mounted orthogonally to each other enables the determination of the positions in a plane of a member that is moved over a 2-dimensional flat surface. Also, as described, the use of three orthogonally arranged MEMS accelerometers enables the determination of the positions in space of a member that is moved about in that space. Thus, in a three dimensional implementation, if a member that is moved over a flat surface is lifted off the flat surface or tilted, the three axis arrangement of MEMS accelerometers will enable detection of that occurrence. 
   Each of the motion detectors  40 ,  42  associated with the respective sensor bar support posts  20 ,  22  may consist of an orthogonal arrangement of two MEMS accelerometers that enables the sensing of the accelerations of the respective sensor bar support posts  20 ,  22  about two orthogonal axes as the sensor bar  16  traverses the table  12  with the support posts  20 ,  22  staying in constant contact with the surface of the table  12 . The corresponding generated signals are communicated to and processed by a signal processor  24  to derive signals corresponding to displacements of the end of each sensor bar support post  20 ,  22  as the sensor bar  16  is moved along the item  14 . 
   An orthogonally arranged cluster of three MEMS accelerometers may also be employed as motion detectors  40 ,  42  that are associated with the respective sensor bar support posts  20 ,  22 . The use of three clustered MEMS accelerometers enables the detection of three axes of acceleration of the lower free end of each of the respective sensor bar support posts  20 ,  22  as the sensor bar  16  is moved along and above the item  14 . The detector signals are communicated to and processed by the signal processor  24  to determine the displacements of the end of each sensor bar support post  20 ,  22  as the sensor bar  16  is moved along the item  14  on the table surface  12 . The resultant ability to detect vertical axis accelerations allows detection of lift off of one or both of the sensor bar support posts  20 ,  22  from the surface of the table  12  such as when an operator inadvertently lifts one or both of the support posts off the table  12  when passing the sensor bar  16  over the item  14 . An audible alarm  28  ( FIG. 2 ) in the display case  26  may be sounded when this occurs, thus alerting the operator of the need to start over in scanning the item  14  in order to ensure accurate results. The use of a single axis MEMS accelerometer aligned to sense vertical movement of the sensor bar  16  may also accomplish this same purpose. 
   The sensor bar  16  and support posts  20 ,  22  should be consistently held in a substantially vertical orientation. The determination of the support post motion in three axes may be utilized to detect tilting of the sensor bar  16 . For this determination, alternative higher locations of the motion detectors  40 A,  42 A (as exemplified in  FIG. 1A ) or  40 B,  42 B (as exemplified in  FIG. 1B ), are preferred, as an out-of-plumb sensor bar  16  position would usually cause a greater sensor bar vertical axis positional change at the top of the support posts  20 ,  22  or the sensor bar  16  itself than at the bottom thereof. Thus slight tilting will be more easily detectable. 
   An out-of-plumb alarm or indicator  34  ( FIG. 2 ) in the case  26  may be triggered responsive to an excessive tilted orientation of the sensor bar  16  as detected by the motion detectors,  40 A,  42 A,  40 B,  42 B. This arrangement also supplements or could eliminate the need for a separate spirit level  36  ( FIG. 2 ) or other tilt indicator. 
   The orientation of the sensor bar  16  may also be used to mathematically compensate when calculating the weight or price of a selected segment of the item  14  when the sensor bar  16  is tilted, instead of merely activating a tilt alarm  34 . 
   Thus, the preferred MEMS based accelerometers used in the motion detectors  40 A,  42 A or  40 B,  42 B are those that are comprised of a three axis cluster of MEMS accelerometers that enables the determination of the orientation of the sensor bar  16  as the sensor bar  16  is traversed over the table surface  12 , enables a determination if one or both of the sensor bar support posts  20 ,  22  has lifted off of the table surface  12 , and enables the determination of the extent and direction of motion of each of the support posts  20 , 22 . 
   The unlimited variety of locations for the MEMS accelerometer based motion detectors enables these detectors to be placed in the most secure/stable locations that are less subject to vibrational, physical, or other stresses, thus avoiding possible false readings or displacement detector damage. Such stresses would often occur at the lower ends of sensor bar support posts  20 ,  22  as this area is in constant contact with the surface of the table  12  as the sensor bar  16  traverses the surface of the table  12 . This versatility in motion detector placement enables a more flexible sensor bar design in order to meet the demands of various applications, manufacturing requirements, or aesthetic requirements. 
   The use of multiple axis clustered accelerometer versions of MEMS motion detectors  40 ,  42  enables detection of lift up of one or both of the support posts  20 ,  22  off the table surface  12  by detecting vertical motion thereof. This offers clear advantages over the displacement detectors described in the above cross referenced parent utility application. 
   Although optical based displacement detectors described therein can detect a loss of reflected light from the surface of the table  12  due to the lifting of displacement support posts  20 ,  22  off the surface of the table  12 , such loss of reflected light can also result from other conditions such as a dirty or dull finished surface of the table  12 . 
   Although electromagnetic based displacement detectors also described in the parent application may also detect when sensor bar support posts are lifted off of the surface of the table  12  by sensing the absence of magnetic fields, the use of those displacement detectors requires a specialized digitizer tablet type table surface instead of an off-the-shelf conventional cutting board as can be used with the MEMS accelerometer motion detectors  40 ,  42 . 
   Similarly, although previously described firm-pointed stylus pressure sensitive based displacement detectors may detect when support posts  20 ,  22  are lifted off the surface of the table  12  by sensing the lack of pressure from the pointed stylus, the use of such displacement detectors requires a specialized pressure sensitive tablet based table surface whereas an off-the-shelf conventional cutting board can be used with the MEMS accelerometer based motion detectors  40 ,  42 . 
   Alternatively, separate MEMS accelerometer based motion detectors that each contain only a single axis MEMS accelerometer may be placed elsewhere on or in the sensor bar  16 , or carried on or in other components on the sensor bar  16  to determine if the sensor bar  16  has moved upwards (indicating one or both of the sensor bar support posts  20 ,  22  has moved upwards off of the table surface  12 ). 
   MEMS accelerometer based motion detectors may be utilized in all sensor bar configurations such as those described in this application as well as the cross referenced parent application in place of displacement detectors based on other technologies such as optical, optical-mechanical, electromagnetic, pressure-sensitive tactile, etc. For example, the Moiré fringe optical displacement detector described in the parent application may be replaced with one or both of the MEMS accelerometer based motion detectors  44 A or  44 B as illustrated in  FIG. 3 . That is, either one or both of motion detectors  44 A or  44 B may be mounted to respective sides of either upright  46  or  48  as shown in  FIG. 3 . Alternatively, a single MEMS accelerometer based motion detector  44 A,  44 B may be mounted to only one of the uprights  46 ,  48  or to the connected portion of the sensor bar  16 A to sense single axis motion only along the direction of constrained movement across the table  12 A since the sensor bar  16 A is itself constrained to move along a single axis over the table  12 A. Both detectors  44 A,  44 B may be used for the sake of redundancy or to detect skewing caused by bearing wear, etc. The MEMS based accelerometers  44 A,  44 B are each comprised of a single axis MEMS accelerometer as only the determination of the extent and direction of linear motion is required. 
   The MEMS accelerometer based motion detectors used to replace other displacement detectors in the cross referenced co-pending application may incorporate either a combination of two orthogonally oriented MEMS based accelerometers to sense movements along two orthogonal axes in the plane of the item support surface or a cluster of three orthogonally oriented MEMS based accelerometers to detect motion along three orthogonal axes in the plane of the item support surface and the space above the support surface. 
   Each of the MEMS accelerometer based motion detectors  40 ,  42 ,  40 A,  42 A,  40 B,  42 B,  44 A,  44 B are preferably encased in a sealed housing isolated from the environment whereby they are not subject to damage by debris, water, dirt, oils, cleaning products, or other contaminants. Furthermore, this sealed environment isolates the MEMS accelerometer based displacement detector from physical damage (e.g., chipping, cracking, scratching, or frictional induced damage) caused by contact with either the table surface  12  or other materials, surfaces, equipment, or utensils and thus can better withstand operator abuse or neglect such as a standard knife or other kitchen utensil may encounter. 
   MEMS accelerometer based motion detectors  40 ,  42 ,  40 A,  42 A,  40 B,  42 B,  44 A,  44 B also do not have any macro moveable components that are subject to macro frictional wear. Furthermore, due to the sealed housings and maintenance free aspect of the MEMS accelerometer based motion detector, the disassembly, removal, or special handling of the motion detectors is not required prior to or during cleaning of the sensor bar  16 . 
   As MEMS accelerometer based motion detectors  40 ,  42 ,  44 A,  44 B do not interact with the surface of the table  12 , their operation is independent of the type of table employed as well as the condition of the table surface  12 . Hence, acceptable tables may be constructed out of virtually any type of material such as wood, plastic, marble, etc. Acceptable surfaces for the table  12  may also be smooth, rough, reflective, non-reflective, greasy, oily, wet, slippery, dusty, etc. The lower ends of the sensor bar support posts  20 ,  22  easily maintain constant contact with virtually any table surfaces  12  as they are able to glide on smooth, rough, reflective, non-reflective, greasy, oily, wet, slippery, or dusty surfaces as the sensor bar  16  (or other sensor arrangement support) traverses the table surface  12 . These just described surface conditions are common in many situations where for example portioning of fish filets is carried out. 
   As is fully described in the apparatus described in the cross referenced co-pending application, as the sensor bar  16  (or other sensor arrangement support implementations) traverses the table surface  12 , the displacement of the sensor bar  16  is continually determined from the signals generated by the motion detectors  40 ,  42  employed. Such determinations of displacements are required in order to carry out calculations to determine the volume of a segment and thus the weight or price of any selected segment of the item  14  defined between any two selected sections of the item lying below the sensor bar  16  in two positions thereof as described in the cross referenced co-pending U.S. patent application. 
   As described in the cross referenced co-pending patent application, a linear displacement sensor based on a photoelectric reflection array may be used to measure the vertical displacement of plungers  50  shown in  FIG. 4  which are used as a sensor arrangement for determining the cross sectional contour of successive sections of the item  14 , or for marking, scoring, or cutting of the item  14 . A linear displacement sensor may also be used to determine when a plunger  50  rests on the top surface of the item  14 , or to determine when a plunger  50  has been fully withdrawn into its retracted position inside of the sensor bar  16 B. Each such linear displacement sensor based on photoelectric reflection array technology may be replaced with a MEMS accelerometer based linear motion detector that utilizes a single axis MEMS accelerometer, to determine vertical displacements. 
   Each MEMS accelerometer based linear motion sensor detector  52  is shown mounted within the lower end of plunger  50  in  FIGS. 4 and 6 . Another acceptable location of a MEMS accelerometer based linear motion sensor  52 A ( FIG. 5 ) is between the plunger stem  47  and main plunger body  54 . Only one of the single axis motion sensors  52 ,  52 A would normally be mounted to each plunger  50 . 
   The use of the MEMS type accelerometers in detectors  52 ,  52 A enables the sensing of the vertical Z axis acceleration of the plunger  50  as the plunger  50  moves up and down (and possibly stops) through the cavity  58  formed by the solenoid coil windings  56 . As illustrated in  FIGS. 5 and 6 , by utilizing MEMS accelerometer based linear motion detectors,  52 , 52 A, the optical components associated therewith described in the cross referenced co-pending application is eliminated, and the plungers  50  may completely occupy the cavity  58  formed by the solenoid coil windings  56 . MEMS accelerometer based linear motion detectors  52 ,  52 A also do not require that the springs  60  have a matte finish. 
   The signals corresponding to the acceleration of the plungers  50  generated by the associated MEMS accelerometer  52 ,  52 A are transmitted to the signal processor  24  ( FIG. 2 ) to compute the relative vertical or Z axis displacement of each plunger  50  as the plunger  50  moves up and down (or stops) within the above described cavity  58 . The signal processor  24  contained in case  26  ( FIG. 2 ) processes those signals to calculate the cross sectional contour of the section of the item  14  under the sensor bar  16 B, or to determine when a plunger  50  has settled (without movement) onto the top surface of the item  14 , or to determine when a plunger  50  has settled (without movement) into its fully retracted position inside of the sensor bar  16 B. 
   As the MEMS accelerometer based linear motion detectors  52 ,  52 A are each contained within or otherwise associated with the plunger  50 , the plunger  50  is a one-piece unit which is contained within the cavity  58  formed by solenoid windings  56 . This one-piece construction simplifies the construction of the overall plunger assembly. Since the MEMS accelerometer detector  52 ,  52 A of this one-piece unit acts independently of surrounding assemblies or mechanisms, the possibility of misalignment during installation and use is minimal. Furthermore, as exemplified by the location of the detectors  52  or  52 A in  FIGS. 5 and 6 , the MEMS accelerometer motion detectors  52 ,  52 A may be placed in various locations. This provides for flexibility of design and manufacturing and also enables the MEMS accelerometer motion detectors  52  to be placed in areas less subject to physical and vibrational stresses as undergone at locations near the bottom end of plungers  50 . Each of the MEMS accelerator based linear motion detectors  52 ,  52 A are preferably encased in a sealed housing isolated from the environment whereby they are not subject to damage by debris, water, dirt, oils, cleaning products, or the other contaminants. 
   When the position of a sensor bar  16  is used to visually indicate to an observer the sections of the item  14  which define an item segment of interest, it may be desirable to make it easier to see the bounds of the segment of the item as it corresponds to the numeric display. Since the sensor bar  16  may have appreciable thickness and is spaced above the item  14 , the exact item section lying directly beneath the sensor arrangement associated with the sensor bar  16  may not be easily ascertained by an onlooker. Similarly, the viewing angle of an observer such as a customer or operator may affect his or her ability to determine the exact location of that section. When plungers  50  are used, this is not a problem, but with non-contact sensors it may be desirable to provide a clearer indication to the observer of the exact item segment corresponding to the display. A more accurate discernment of the segment bounds may be enabled by projecting an elongated pattern, i.e., a narrow band of visible light onto the item  14  extending across the section which contour is being determined from the signals generated by the sensors  38 . 
   This is shown in  FIG. 7  where a selected start reference section of the item  14  is temporarily indicated by a curved wire marker element  63  positioned on the surface of the table  12  by the weight of attached blocks  61 , or by magnetic attraction of magnetized blocks  61  to a magnetic support surface  12 . The marker element  63 , is placed in alignment with a narrow light band projected from the sensor bar  16  onto item  14  at a start or reference position of the sensor bar  16 . The sensor bar  16  is then shifted to a second position where a narrow visible light band  62  is projected to impinge onto the item  14  extending across a section spaced from the start position. The light band is projected from the underside of a sensor bar  16 C,  16 D ( FIGS. 8 ,  9 ). The weight or cost of a segment of the item  14  defined between the start section below wire marker element  63  and the offset section at the light band  62  in the second position of the sensor bar  16 C,  16 D will be numerically shown by display  30 . This provides a more readily seen visual indication of the bounds of the particular segment of the item  14  corresponding to the displayed weight or cost.” 
     FIG. 8  shows one arrangement for producing the projected narrow visible light band  62 . A series of lamps, visible light emitting diodes or other visible light emitters  64  is mounted along the underside of a sensor bar  16 C, suitably masked and focused to project downwardly from the sensor bar  16 C the narrow light band  62  aligned with the sensors  38  on the sensor bar  16 C so that the light band  62  lies on the same item  14  section which is housing its cross sectional contour determined from the sensor  38  signals. Thus, the numeric value displayed at any time will correspond to the segment bounded on one side by the light band  62 . The light band  62  is readily visible on the surface of the item  14  to an observer even if he or she is standing some short distance away. This indication removes any problems with parallax effects and is precise enough to satisfy the interests of the on-looking person being served or the server. 
   The sensor bar  16 C will also mount for example, acoustic, optical or other sensors (not shown) as described in the cross referenced patent application for determining the cross sectional contours of sections of the item  14  in order to enable calculation of volumes of selected segments of the item described therein. The narrow visible light band should be located to be aligned with the item section which is being scanned at that time by the contour sensors  38  in order to provide an accurate correspondence therebetween. 
   An example of such an arrangement is shown in  FIG. 9  where visible light emitters  66  on the underside of a sensor bar  16 D are aligned with and placed between optical triangulation emitter-receiver  68  of a type described in the cross referenced co-pending application or other types of height or thickness sensors. It would also be possible to use visible light in the optical contour measuring sensors  68  themselves therein to project the readily seen narrow band of visible light onto the item  14 .