Abstract:
A system, suitable for high-speed operation, by which raw product ( 45 ), such as a slab of meat, can be accurately processed, such as by slicing into segments of desired weight, comprises a product profiling apparatus ( 15 ). The product profiling apparats ( 15 ) meassures the profile of the physical process. The product profiling apparatus ( 15 ) includes line lasers ( 75, 85 ) for directing a line of light across the upper and lower surfaces of the product ( 45 ) and visual image cameras ( 80, 90 ) directed toward the profile surface to capture, at fixed increments, the product profile. The product may also be weighed and the product density determined from the overall profile measurements. A controller ( 150 ) receives this data, and instructs the physical process accordingly.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a national stage application of PCT/US00/10691, filed Apr. 20, 2000 and claiming priority from U.S. Provisional Application No. 60/130,208, filed Apr. 20, 1999. 

   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not Applicable 
   BACKGROUND OF THE INVENTION 
   The present invention relates to an apparatus for determining the profile of a product that is to undergo a subsequent physical process. The subsequent physical process is one in which the product profile is needed to insure proper processing of the product. 
   In the particular embodiment disclosed herein, the specific subsequent physical process includes slicing the product into individual slices on a slicing machine. Such slicing machines are principally, but not exclusively, used for slicing food products such as cheese, meat and pressed or molded meat products. 
   Typically such slicing machines include a rotating blade and a product feeder that drives the product forward towards the blade so that successive slices are cut from one face of the product. The distance through which the product is advanced between successive cuts of the blade determines the thickness of the slices. Where the product is of uniform shape and density, it may be sufficient to use a single predetermined slice thickness to give a slice or group of slices of the required weight. Further, it may be sufficient to provide an output scale proximate the output side of the blade to measure the current weight of the slice to product and adjust the thickness of the subsequent slice(s) to make the desired unit weight. 
   In general, however, variations in the shape and density of the product mean that the weight of a slice of a given thickness varies. A previous approach to dealing with this variation is described and claimed in U.S. Pat. No. 4,428,263, which is hereby incorporated by reference. That patent describe a process in which an automatic slicing machine is programed to vary the thickness of the slices in accordance with a typical weight distribution for the product. 
   It has also been proposed to make some determination of the cross-sectional area of the product as it is cut. One such system is purportedly disclosed in U.S. Pat. No. 5,136,906, titled “Slicing Machine”, and assigned to Thurne Engineering Co., Ltd. According to that patent, a slicing machine for cutting slices from a product includes a camera arranged to view a cut face of the product, boundary recognition apparatus arranged to process image signals from the camera to determine a boundary of the cut face, calculating apparatus arranged to calculate a parameter characteristic of the cut face from image data corresponding to regions of the cut face within the boundary, and control signal generating apparatus arranged to generate a control signal to control the operation of the slicer in accordance with the determined parameter. 
   Although the foregoing system may be suitable for low-throughput slicing machines, it is significantly less suitable for high-speed slicing machines, such as those available from Formax, Inc., of Mokena, Ill., under the brand name S-180™. First, by calculating the product profile at the cut face, a very limited amount of processing time is available to perform the calculations that are necessary to ensure the proper thickness of each slice before the cut face must again be imaged for processing the thickness of the next slice. Second, substantial measurement inaccuracies may result from shadowing effects resulting from the relative positions of the illumination source, cut face, and slicing machine components—a problem not addressed in the &#39;906 patent. Third, further measurement inaccuracies are introduced by the apparent assumption that the profiles at the bottom and a side of the product are linear. Finally, by attempting to measure the product profile at the cut face, substantial inaccuracies may be introduced due to the presence of scrap product. One of the goals of the apparatus described in the &#39;906 patent is to remove the inaccuracies introduced by the scrap product. However, by addressing this problem at the cut face, the apparatus of the &#39;906 must necessarily introduce a further level and higher degree of image processing. 
   The present inventors have addressed many of the foregoing problems inherent in the product profiling operations of prior art apparatus. To this end, they have developed an accurate and cost-effective product profiling apparatus that is suitable for use, for example, in connection with high-speed product slicing machines. 
   BRIEF SUMMARY OF THE INVENTION 
   An apparatus for acquiring a profile of a product for use in subsequent processing of the product is set forth the apparatus includes a scanning chamber for accepting the product and one or more product drives that are operable to drive the product through the scanning chamber prior to delivery of the product to subsequent product processor. The apparatus also includes a vision system disposed to acquire visual information relating to the profile of the product prior to delivery of the product to a subsequent product processor and a control system connected for control of the vision system and operating to convert the information received from the vision system into a format suitable for use by a subsequent product processor. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  is a perspective view of a product processing system constructed in accordance with one embodiment of the present invention. 
       FIG. 2  is a schematic block diagram of one embodiment of a control system that may be used in the profiling apparatus of the system illustrated in FIG.  1 . 
       FIG. 3  is an exemplary image obtained by the upper vision system of the embodiment of the profiling apparatus illustrated in FIG.  1 . 
       FIGS. 4 and 5  are cross-sectional views of one embodiment of a profiling apparatus that may be used in the system FIG.  1 . 
       FIG. 6  is a schematic cross-sectional view showing an input stacker. 
       FIG. 7  is a schematic cross-sectional view showing a product stopper at the inlet to the vision system housing. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  illustrates a product processing system, shown generally at  10 , that performs a physical process on a product in which the physical process is dependent on accurate measurement of the profile of the raw product. As shown, product processing system  10  is comprised of a product profiling apparatus  15  and a product processor  20 . The product profiting apparatus  15  functions to measure the profile of the raw product and provide the profile information to the product processor  20  that, in turn, uses the information to accurately execute the physical process that is to be performed on the raw product. 
   In the illustrated embodiment, the acquisition of the product profile information is completed before the particular raw product undergoes physical processing in the product processor  20 . Using the configuration shown in  FIG. 1  in which the profiling apparatus  15  is disposed prior to the product processor  20 , it is possible to acquire complete product profiles for several individual raw products before each of the raw products is provided to the input of the product processor  20 . Additionally, if the profiling apparatus  15  is designed as a stand-alone apparatus, then the profiling apparatus  15  may be used to provide product profile information to a plurality of different product processors that are operating in either a time sequential or concurrent manner. 
   Generally stated, the profiling apparatus  15  is comprised of an input section  25 , a scanning section  30 , and an output section  35 . The input section  25  includes a plurality of support bars  40  that are disposed to support the product  45  that is to be profiled. A plurality of upstanding fingers  50  extend through interstitial regions between the support bars  40 . The fingers  50  engage a rear portion of product  45  and drive it into the scanning section  30 . The fingers are arranged to be vertically above the support bars when moved in the driving direction and vertically beneath the bars when conducted in the return direction. 
   Scanning section  30  includes a housing  55  having an input end that is open to receive product  45  and an outlet end that is open to allow product  45  to exit therefrom. In the illustrated embodiment, housing  55  comprises a principal housing portion  60 , an upper vision system housing  65 , and a lower vision housing  70 . The upper vision system housing  65  includes an upper vision system disposed therein. The upper vision system of the disclosed embodiment includes a vertically directed line laser  75  for illuminating one side of the product in a fixed plane traversed by the driven product and an associated camera  80  vertically angled for imaging the laser-illuminated contour of the product  45 . Similarly, the lower vision system housing  70  includes a lower vision system disposed therein that is comprised of a line laser  85  and corresponding camera  90  for addressing the other side of the product. Each of the upper and lower vision system housings  65  and  70  includes an opening that is positioned to allow the respective vision system to view a product  45  passing through the principal housing  60 . These openings may merely comprise cut out sections. Preferably, however, the openings are covered with a transparent material to form a window that mechanically isolates the vision system components from the components disposed in the principal housing  60  yet does not interfere with the vision system operation. 
   Although, for purposes of this overview description of the product profiling apparatus  15 , with reference to the early Figures, a single line laser is shown for use in each of the upper and lower vision system housings  65  and  70 , it is considered more preferable, as further discussed below with respect to a more detailed discussion of structure and operation of the system machinery, that each of the vision system housings contain two opposing line lasers for illuminating downwardly and across the product from opposed sides of the product. In instances of a considerably uneven profile and/or in the event of highly reflective surface characteristics, opposed sides illumination on the product provides for higher resolution camera imaging. 
   Within principal housing  60 , product  45  is supported by a plurality of rounded support bars  95 . These support bars  95  may be formed as extensions of support bars  40 , or may be formed as a support component that is distinct from support bars  40 . The number and diameter of the support bars  95  should be minimized to facilitate accuracy of the scanning measurements provided by the lower vision system. Most preferably, although not shown, the diameters of the support bars  95  are substantially reduced to a minimum where they cross the laser light line emanating from the lower vision system laser. 
   Product  45  is driven through the principal housing  60  by a product drive, shown generally at  100 . In the illustrated embodiment, the product drive  100  is comprised of a product engagement member  105  that is disposed to engage a rear portion of product  45  and drive it along support rods  95  through the principal housing  60 . Product engagement member  105  includes a plurality of slots that are disposed to allow concurrent operation of the fingers  50  and product engagement member  105  at the input end of the principal housing  60 . A pair of upstanding members  110  are connected to opposite ends of the product engagement member  105 . The upstanding members  110 , in tun, are fastened to respective drive belts  115  and  120  to move the product engagement member  105  and corresponding product  45  through the principal housing  60 . The drive belts  115  and  120  are preferably driven at a constant, precise velocity by, for example, a servo motor, a motor with a resolver, etc. 
   At the outlet end of the principal housing  60 , the product  45  is engaged by another set of fingers  130  that extends through interstitial regions of support bars  95 . Support bars  95  may be extended to the output section  35  or, alternatively, a further distinct set of support bars may be used to support the product  45  at the output section  35 . Fingers  130  engage the rear portion of product  45  and drive it to the output section  35  and therefrom to the processing apparatus  20 , which, in the disclosed embodiment, is a slicing machine. 
     FIG. 2  is a schematic block diagram of one embodiment of a control system suitable for controlled operation of product profiling apparatus  15 . In the illustrated embodiment, the control system comprises a central controller  150  that is responsible for 1) controlling the drive mechanisms associated with various portions of the profiling apparatus  15 ; 2) coordinating the operation of the vision systems, including acquisition of the profile data; and 3) communicating the profile data to control systems for one or more product processors  20 . To this end, the central controller  150  is connected to receive sensed signals from and provide motion control signals to each of the input and output section drives  155  and  160  and the scanning section drive  165 . Similarly, the central controller  150  is connected to receive sensed signals from and provide scanning control signals to the upper and lower vision systems  170  and  175 . Ultimately, the profile information acquired from the upper and lower vision systems  170  and  175  is communicated to the control system  180  of at least one product processor  20 . The profile information may be communicated to the control system  180  in any one of a variety of processing states. For example, the central controller  150  may communicate raw profile data to the control system  180 . Alternatively, or in addition, the central controller  150  may communicate the profile information after the raw data it acquires has been processed at the central controller  150  thereby relieving the control system  180  from much of the additional processing overhead associated with profile calculations. 
   If more than one product processor  20  is to be served by a single product profiling apparatus  15 , then a method for tracking each product  45  through the system to insure that each of the product processors  20  receives the correct profile data must be provided. For example, each of the products  45  may be provided with a bar-code or other visual image marker that may be acquired or otherwise input to the central controller  150  as well as the particular control system  180 ,  180 ′,  180 ″ associated with the particular product processor  20  that is to slice the particular product. When the identity of the product  45  that is to be sliced by the product processor is determined by the respective control system  180 ,  180 ′,  180 ″, the particular control system may request the profile data associated with the identified product from the central controller  150 . 
   Operation of the product profiling apparatus  15  can be described with respect to  FIGS. 1 and 2 . First, the product  45 , shown here as a slab of bacon or the like, is provided at input section  25  where it is supported by support rods  40 . Central controller  150  then activates input section drive  155  so that fingers  50  engage the rear portion of product  45  and drive it into the scanning section  30 . Product engagement member  105  is preferably hinged to swing out of the way or otherwise glide over the upper surface of product  45  as it is moved through the opening at the input of the scanning section  30 . The central controller  150  directs the scanning section drive  165  to operate so that the product engagement member  105  contacts the rear portion of product  45  and begins to drive product  45  through the interior chamber of the principal housing  55 . Preferably, the product  45  is driven a small distance over support rods  95  before reaching the position in the principal housing  55  in which product scanning begins. This allows the product to settle upon the support rods  95  and against product engagement member  105  before scanning thereby increasing the accuracy of the resulting profile data. 
   In accordance with one embodiment of the profiling apparatus  15 , a resolver or the like associated with the scanning section drive  165  generates control pulses corresponding to incremental movement of the product  45  over a fixed distance through the principal housing  55 . These control pulses are used as synchronization signals that the central controller  150  uses to trigger the acquisition of a profile reading. Here, the profile readings are in the form of a visual image captured by the cameras  80  and  90  at fixed increments along the length of the product  45 . The product profile is accentuated by directing a line of laser light across the upper and lower surfaces of the product  45 . Accordingly, the interior of the principal housing  55  should be as dark as possible so that cameras  80  and  90  may detect the line projected by line lasers  75  and  85 . 
     FIG. 3  is an exemplary image acquired by camera  80  of profiling apparatus  15 . Although camera  80  is capable all of providing an image of 640×480 pixels, only a sub-portion of that entire available image is extracted by central controller  150  for further processing. As shown, the resulting image is comprised of linear end regions  200 . The linear end regions are formed by reflection of the light from line laser  75  by a pair of reference reflectors that, preferably, are disposed to be even with the upper surfaces of support rods  95 . There are a plurality of elevated, non-linear regions between linear regions  200 . These nonlinear regions correspond to the upper profile of product  45  that has been illuminated by line laser  75 . By taking measurements of the vertical distance (e.g., the number of vertical pixels) between linear end regions  200  and the elevated, non-linear regions, it is possible to calculate the contour of the profile of the product at the position along the interior of principal housing  55  at which the image was acquired. By acquiring a number of such images along the length of product  45 , an accurate representation of the upper profile of product  45  can be obtained. Similar images are concurrently acquired by camera  90  based on illumination of the lower portion of product  45  by line laser  85 . As in the case of the upper profile measurements, linear reference regions are formed by reflection of the light from line laser  85  by a pair of reference reflectors. From the images of the upper and lower product surfaces that are acquired by the upper and lower vision systems  170  and  175 , the central controller  150  can provide a substantially accurate data representation of the complete product profile to control system  180  of product processor  20 . 
   Depending on the content of the product  45 , the laser light impinging on the upper surface of product  45  may be dispersed in different manners. For example, if the product  45  is bacon or another fat-containing comestible, fatted regions, such as at  205  disperse the laser light to a greater degree than lean regions  210 . As a result, a broader light band is formed at the fatted regions  205 . Controller  150  may compensate for this dispersion by, for example, selecting the area of highest dark pixel concentration for the vertical measurement. Alternatively, a vertical distance measurement may be obtained by taking the average vertical distance of the uppermost vertical distance measurement and the lowermost vertical distance measurement 
   As shown in  FIG. 3 , the light reflected from the surface of product  45  may be blocked from the view of the camera. These regions appear as void regions  215 . In such regions, central c controller  150  may be programmed to assume a linear transition of the surface contour. Since u void regions  215  are generally of a very limited dimension, this assumption still provides for an accurate representation of the overall product profile. Similarly, an assumption that there is a linear transition of the surface contour at the regions of the lower surface of product  45  that are blocked by support rods  90  does not significantly diminish the accuracy of the profile measurements. To minimize any inaccuracies introduced by the presence of support rods  95 , the number and diameter of support rods  90  should be minimized. Further, support rods  95  should have a generally round cross-section so that they generate obstructed or otherwise unusable regions of the profile image that are substantially equal in the length. 
   Once product  45  as been driven to the outlet portion of scanning section  30 , the central controller  150  controls the output section drive  160  so that fingers  130  engage the rear portion of product  45  and drive it from the interior of scanning section  15  to output section  35 . Product  45  may be removed by an operator from section  35  and provided to the input of a subsequent product processor  20 . Alternatively, the output section  35  and corresponding output section drive  160  may be designed to drive product  45  into a loading position on the subsequent product processor. 
   Profiling apparatus  15  may include a digital scale  230  (shown schematically in  FIG. 1 ) for weighing the product  45 . The output of the digital scale may be provided to central controller  150 . Central controller  150  may be programmed to calculate the overall volume of product  45  based on the profile measurements. Central controller  150  may then, use the overall product value and the weight provided by the digital scale to calculate the average density of the product  45 . The average density measurement may be used by a slicing machine, such as product processor  20 , in combination with the profile measurements to calculate the product slice thicknesses that are required to make a particular weight, such as the weight of product slices that are to be provided in a single consumer package. Alternatively, one or more of the average density, overall volume, or product profile measurements/calculations may be executed by the control system  180  of the slicing machine. 
     FIGS. 4 and 5  illustrate a specific embodiment of the profiling apparatus  15  in which like parts are similarly numbered. Of note in connection with the embodiment shown in these. Figures are the drive mechanisms associated with input section  25 , scanning section  30 , and output section  35 . 
   It has been found and is considered preferable that, rather than using a single line laser to illuminate a surface of the product as shown in  FIG. 4 , a pair of generally opposed lasers applying overlapping beams to cover that surface of the product can yield more profile data and better resolution in the camera image. This would be the case especially in instances where the product surface is quite irregular and/or contains large fatted regions since these situations tend to result in shadowing an/or blurring in the camera image. The more the profile data and the better the resolution in the camera image, the more definite and precise is the surface profile data, there being less need for averaging or extrapolation. 
   In the case of using more than one line laser in each of the vision system housings above and below the product, the lasers are preferably disposed on opposite sides of the product and projecting their beams down onto and across the product. The camera position generally does not change. In this way, a triangulated approach to capture of the surface profile on both respective sides of the product is utilized. 
   As illustrated, the drive mechanisms associated with the input section  25  and output section  35  are interrelated. More particularly, the drive mechanisms are comprised of a single, dual-ended pneumatic actuator, shown generally at  300  that is mounted below support rods  40  (the support rods throughout are continuous and formed as a single set of rods). Actuator  300  includes a piston rod  305  having a first end connected to a first finger engagement assembly  315  and a second end connected to a second finger engagement assembly  310 . Finger engagement assembly  310  includes the fingers  50  thereon while finger engagement assembly  315  includes the fingers  130  thereon. Fingers  50  are disposed on a pivot rod  320  along with one or more counterbalance mechanisms  325 . The counterbalance mechanisms  325  urge fingers  50  to rotate about a horizontal axis defined by pivot rod  320  until fingers  50  engage one or more stop members  330 . The one or more stop members  330  are disposed to the stock fell rotation of fingers  50  when they are in an upright position. This arrangement allows fingers  50  to slide under a successive product  45  disposed on the input section  25  as the fingers are driven back to the home position after delivering a previous product  45  to the scanning section  30 . 
   A similar arrangement is provided for finger assembly  315  disposed at the first end of piston rod  305 . Here, however, the one or more counterbalance mechanisms  335  of the finger assembly  315  are positioned to engage a further stop member  340  at the output position of the output section  35 . As the fingers  130  drive product  45  along output section  35 , counterbalance mechanisms  335  are driven into engagement with the further stop mechanisms  340 . This causes the fingers  130  to rotate about a horizontal axis defined by pivot rod  345  which assists in driving the product  45  from output section  35  to, for example, the input of a slicing machine. 
   In the embodiment shown in  FIGS. 4 and 5 , the scanning section drive includes motor  350  that is connected to rotate drive roller  355 . Drive roller  355 , in turn, drives belts  115  and  120 , each of which extends between drive roller  355  and idle roller  360 . Securement mechanisms  365  are connected to upstanding members  110  (shown in  FIG. 5 ) to secure upstanding members  110  and product engagement member  105  with drives belts  115  and  120 . The securement mechanisms  365  are connected to one another by a strut  372  to enhance the rigidity of the overall drive mechanism. Additionally, securement mechanisms  365  each engage respective guide rods  377  that extend along the length of the transport path along which the product engagement member  105  moves product  45  through scanning section  30 . Preferably, securement members  365  each include a pivoted connection  378  that allows the product engagement member  105  to glide over the upper surface of a product  45  disposed in the scanning section  30  as member  105  is returned to its home position after driving a product from the scanning section  30 . Alternatively, the product engagement member  105  may be actively moved by, for example, an actuator, so that its movement to the home position is not obstructed by the product  45 . 
   To further facilitate and enhance continuous, automated running of the invention product processing system, the product is preferably supplied to the input section  25  from a stacked input.  FIG. 6  illustrates a specific embodiment of a vertically extending stacker  400 , in the form of a chute the walls of which are defined by columns of rollers  410 . The lower end of the chute is immediately above, and opens onto, the input section  25 . The upper end of the chute extends above and angles away from the input section. The chute defines a gravity-drop passage in which a plurality of the products can be stacked one on top of the other for successive and automatic loading onto the input section  25 . After each previous, underlying product has landed on the input section support bars and been passed from beneath the chute into the scanning section  30  by the fingers  50 , the next product in the stack drops onto the input section support bars such that the system is automatically loaded for a continuous running operation. 
   As a back-up precaution in the event the scanning section drive  350  gets ahead of the return movement of the fingers  130 , there is preferably provided a product stop  380 , shown in  FIG. 7 , which could hold the movement of the product under the influence of the engagement member  105  until the fingers  130  have fully returned to engage the next product The product stopper  380  is freely pivotable about a transverse, horizontal axis, and formed at a forward side with an L-shaped stop wall  381  and on the other side of the pivot axis with a counterweight abutment  382 . Until the piston carrying the fingers  130  is fully returned, the L-shaped stop wall  381  is in a raised blocking position in the path of conveyance of the next product being delivered to the vision system housing, as shown by the dotted line image in FIG.  7 . With the piston in its fully-returned position, the counterweight abutment  382  is engaged and raised, causing the stop wall  381  to be lowered and not obstructing the conveyance movement of the next product In this case, the engagement member  105  is able to conduct the product over the tilted-own fingers  130 , as well as the lowered stop wall, and fully into the vision system housing for further conveyance, from behind, by the then raised fingers  130 . 
   Other features of the specific embodiment that are shown in  FIGS. 4 and 5  include reference reflectors  375 . The reference reflectors  375  are those referenced above in connection with the operation of the profiling apparatus  15 . 
   Numerous modifications may be made to the foregoing system without departing from the basic teachings though the present invention has been described in substantial detail with reference to one or more specific embodiments, those of skill in the art will recognize that changes may be made thereto without departing from the scope and spirit of the invention as set forth herein.