Abstract:
An inspection system for verifying package contents comprises a spectrometer having an input for receiving light energy and a light energy aggregator. The light energy aggregator comprises a light energy input terminal, a light energy output terminal, where the light energy output terminal is coupled to the spectrometer input, and at least two sample probes coupled to the light energy input terminal. Each of the sample probes is configured to direct light energy from a source to the light energy input terminal.

Description:
PRIORITY 
     The present application claims priority to U.S. provisional application No. 60/268,483 and titled NIR Screening of Materials to Be Packaged, filed on Feb. 12, 2001, which is hereby incorporated by reference. 
     RELATED APPLICATIONS 
     The present application is based on disclosure document No. 481228 deposited with the U.S. Patent and Trademark Office on Oct. 17, 2000. The present application is also related to U.S. patent application Ser. No. [Cooley Godward docket No. ASDI-004/00US], filed on even date herewith and titled System and Method for Grouping Reflectance Data, and U.S. patent application Ser. No. [Cooley Godward docket No. ASDI-005/00US], filed on even date herewith and titled System and Method for the Collection of Spectral Image Data. Each of the above documents are hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention pertains to spectrometer and reflectance data analysis and more particularly to the screening and identification of materials such as pharmaceutical or food products being packaged in an automated machine. 
     BACKGROUND OF THE INVENTION 
     Optical spectrometers allow the study of a large variety of samples over a wide range of wavelengths. Materials can be studied in the solid, liquid, or gas phase either in a pure form or in mixtures. Various designs allow the study of spectra as a function of temperature, pressure, and external magnetic fields. 
     Near-Infrared (NIR) spectroscopy is one of the most rapidly growing methodologies in product analysis and quality control. In particular, NIR is being increasingly used as an inspection method during the packaging process of pharmaceuticals or food products. More and more often, this technique is augmenting or even replacing previously used vision inspection systems. For example, an NIR inspection system can be used to inspect a pharmaceutical blister package (such as an oral contraceptive or allergy medication) for, among other things, physical aberrations, chemical composition, moisture content, and proper package arrangement. 
     Most notably, NIR spectrometry inspection systems can be used to evaluate the chemical composition of products during the packaging process. Particularly with solid dosage pharmaceutical products, a group or package of products may look identical in the visible portion of the spectrum but may have unique chemical signatures in the near-infrared range (e.g. the 800-2500 nm range). Variations in the chemical composition of a tablet or capsule are usually grounds for rejecting a package containing a tablet with such a discrepancy. In operation on a pharmaceutical blister packaging machine, a still uncovered blister pack containing tablets or capsules passes an inspection station where it is examined. Once the inspection device inspects the blister pack to ensure that the correct material is located in each of the tablet or capsule wells, the packaging machine seals the blister pack. Those packages that fail the inspection process are rejected at a subsequent station. Subject to regulatory requirements, the rejected tablets may also be recycled for further processing. 
     The use of vision systems as an inspection mechanism continues to become less desirable as the need for more in depth inspection procedures and near 100% inspection processes are desired. Of particular concern is that known vision systems are inherently incapable of performing a chemical analysis of the product being packaged. Rather, vision systems rely solely on a comparison of a visual snapshot of the package to a previously stored reference image. Known vision packaging inspection systems “look” at each individual package to see whether it has the correct number of doses in the pack. For example, vision systems look for missing or overfilled tablet wells. In some cases, physical discrepancies, cracks, or gouges on a tablet will also cause a vision system to reject the package. What may not be detected by a vision system is the situation where each of the products in a package appears to be similar and in conformance with a reference image but the formulation of one or more products within the package are incorrect, or the wrong product composition is inserted into the packaging. The limitations of these types of known visions systems become readily apparent when higher levels of inspection are required and when they are compared with the expanded capabilities of a spectrometer-based inspection system. 
     Even though spectrometer-based monitoring and inspection systems are becoming more prevalent, many of them still have limited capabilities. These limitations are primarily due to the requirement that each tablet or capsule in a package be independently inspected by the spectrometer system. Therefore, a conventional spectrometer can only look at and analyze one sample at a time. Thus, the larger the number of products that are being inspected, the longer it will take to perform the inspection. Adding additional spectrometers is not a preferred solution because of the costs and maintenance issues associated with the increased hardware. Since spectrometer-based systems are meant in large part to replace vision systems, both accuracy and speed remain important factors when utilizing such systems. Thus, it would be desirable to have a spectrometer-based inspection system that can maintain the throughput of traditional vision systems without sacrificing the ability to perform accurate chemical composition analysis and without requiring the addition of expensive and problem prone equipment. 
     In many cases, multiple formulations are packaged into a single blister pack. Therefore, it is also desirable to have a spectrometer-based inspection system that can detect when an item is in the wrong location within the larger package that is being inspected while at the same time realizing the benefits of a spectrometer based inspection system. 
     Finally, it is desirable to have a spectrometer-based inspection system that can execute a self-referencing calibration in order to obtain conforming data to compare with during an inspection process as well as to determine item locations from a previously unknown package layout. 
     SUMMARY OF THE INVENTION 
     In one aspect, an inspection system for verifying package contents comprises a spectrometer, the spectrometer having an input for receiving light energy and a light energy aggregator. The light energy aggregator comprises a light energy input terminal, a light energy output terminal, wherein the light energy output terminal is coupled to the spectrometer input, and at least two sample probes coupled to the light energy input terminal, wherein each of the sample probes is configured to direct light energy from a source to the light energy input terminal. 
     In another aspect, an inspection system for monitoring a chemical composition of packaged products comprises a light energy aggregator. The light energy aggregator comprises a light energy input terminal adapted to couple with a plurality of fiber optic sample probes and a light energy output terminal coupled to a spectrometer. The light energy aggregator is adapted to direct an average reflected light signal through the light energy output terminal and the average reflected light signal is based on light energy received through the plurality of fiber optic sample probes. 
     In yet another aspect, a method for verifying the contents of a product package containing a plurality of items comprises obtaining a reflected light signal from each of the plurality of items, combining the reflected light signals to form a combined reflected light signal, directing the combined reflected light signal into a spectrometer, comparing the combined reflected light signal with a predetermined reflectance signal range, and determining whether the combined reflectance signal falls within the predetermined reflectance signal range. 
     In a further aspect, an inspection head for a packaging system comprises a probe housing, the housing including a mounting surface, a plurality of sample probes mounted substantially normal to the mounting surface, wherein each of the plurality of sample probes is attached to a first end of a fiber optic cable, and a light energy aggregator having an input terminal and an output terminal, wherein a second end of each of the plurality of fiber optic cables is attached to the light energy input terminal. 
     As will become apparent to those skilled in the art, numerous other embodiments and aspects will become evident hereinafter from the following descriptions and claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawings illustrate both the design and utility of the preferred embodiments of the present invention, wherein: 
     FIG. 1 is a general overview of an inspection system; 
     FIG. 2 is a diagram of a first embodiment of an inspection head constructed in accordance with the present invention; 
     FIG. 3 is a schematic representation of the inspection head of FIG. 2; 
     FIG. 4 is a diagram of a second embodiment of an inspection head constructed in accordance with the present invention; 
     FIG. 5 is a schematic representation of the inspection head of FIG. 4; 
     FIG. 6 is a diagram of a further embodiment of an inspection head constructed in accordance with the present invention; 
     FIG. 7 is a schematic representation of the inspection head of FIG. 6; 
     FIG. 8 is a diagram of a light energy aggregator constructed in accordance with an embodiment of the present invention; 
     FIGS. 9-12 are details of a splitter block constructed in accordance with an embodiment of the present invention; 
     FIGS. 13-15 are perspective diagrams of an inspection head constructed in accordance with various aspects of the present invention; 
     FIGS. 16 and 17 are flow charts depicting inspection methods in accordance with various embodiments of the present invention; 
     FIG. 18 is a cross-section of a scanning spectrometer system constructed in accordance with an embodiment of the present invention; 
     FIGS. 19A-19C are plan views of a package at various stages of an inspection system constructed in accordance with an embodiment of the present invention; and 
     FIG. 20 is a flow chart depicting a method in accordance with an embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 depicts an inspection system  100 . The inspection system  100  is generally arranged to allow the inspection of a product, for example tablets or capsules  130 , that have been loaded into a package  125 . As shown in FIG. 1, the packages  125  move along a conveyer  120  mounted within a filling unit  105 . The filling unit  105  is preferably one component of a larger manufacturing and packaging system. As an example, such manufacturing and packaging systems are typically utilized in pharmaceutical and chemical manufacturing facilities, although similar systems are often utilized in other applications such as food processing and consumer product facilities. Aspects of the present invention can be applied to virtually any of these applications. For purposes of illustration only, the present invention will be described in conjunction with a pharmaceutical packaging system used to seal tablets or capsules in a blister-type package. Also shown in FIG. 1, and included as a component of the inspection system  100 , is an inspection head  110  constructed in accordance with various aspects of the present invention. 
     The inspection head  110  bridges the conveyer  120  that carries the packages  125 . The inspection head  110  includes an array of sample probes  115  extending downward from the inspection head  110  and substantially aligning with the items  130  contained in the passing packages  125 . Generally, a light source (not shown) illuminates the packages  125  including the tablets  130  as they pass under the inspection head  110  and the sample probes  115 . Light is reflected by the tablets  130  and the reflected light energy is gathered by one or more of the probes  115 . In the general arrangement of FIG. 1, a single sample probe  115  corresponds to a single tablet. Either the web of packages  125  moves in steps, where the step increment matches the size of the packages in the direction of motion, or the web moves continuously. In the stepped progression, item inspection occurs when the package web is stationary. In the continuous progression, item inspection occurs during the time interval when the items are in the field of view of the probes  115 . As discussed below, various other arrangements of the sample probes are contemplated by an inspection system constructed in accordance with the present invention. 
     The reflected light energy gathered by each of the probes  115  is analyzed to determine specific properties of each of the tablets  130  that pass beneath the inspection head  110 . Light energy gathered by the sample probes  115  is then directed through fiber optic cables, to a spectrometer that may be housed within the inspection head  110  (not shown). The collected light energy is analyzed by the spectrometer according to predetermined criteria. The information generated by the spectrometer is then forwarded via a data cable  140  to a computer  135  for display, storage, or further analysis. The computer  135  may be preloaded with processing information pertaining to the specific packaging or inspection operation being conducted. The information gathered about the tablets  130  contained in each package  125  may then be used to determine whether the specific tablets being inspected conform with a predetermined quality criteria. 
     By gathering spectrographic data about each of the tablets  130 , a determination can be made as to whether the packages have been properly filled or contain the proper product. Spectrographic analysis also allows other determinations to be made that are not available with known vision-based systems, such as proper pharmacological composition, water content, and other chemical and physical properties. 
     FIG. 2 shows in further detail a diagrammatic representation of a lower portion of the inspection head  110 , and more particularly, the array of sample probes and how they interact with the tablets passing along the conveyer  120 . The probe array is generally referred to in FIG. 2 as reference number  200 . In the example of FIG. 2, a product package  215 , such as a filled but yet un-sealed blister package, contains fifteen (15) individual tablets in a three-by-five arrangement. Various other arrangements of the tablets are contemplated and the three-by-five arrangement of FIG. 2 is shown merely as an example. The tablets in the package  215  are arranged into five columns. From left to right in FIG. 2, column one includes tablets  225   a ,  225   b , and  225   c , column two contains tablets  230   a ,  230   b , and  230   c , column three contains tablets  235   a ,  235   b , and  235   c , column four contains tablets  240   a ,  240   b , and  240   c , and column five contains tablets  245   a ,  245   b , and  245   c . Corresponding to each of the fifteen tablets in FIG. 2 is a sample probe. From left to right, the sample probes also are divided into five columns with three sample probes in each column. Column one contains sample probes  325   a ,  325   b , and  325   c , column two contains sample probes  330   a ,  330   b , and  330   c , column three contains sample probes  335   a ,  335   b , and  335   c , column four contains sample probes  340   a ,  340   b , and  340   c , and column five contains sample probes  345   a ,  345   b , and  345   c . As the conveyer system moves the package  215  into position under the inspection head  110 , the fifteen sample probes are positioned to correspond respectively to a similarly positioned tablet in the package  215 . Namely, the sample probes are positioned substantially above the correspondingly positioned tablet. 
     Each of the sample probes are connected to a fiber optic cable which in turn is connected to a light energy aggregator  350 . In FIG. 2, the fifteen fiber optic cables are represented as reference numbers  250 ,  255 ,  260 ,  265 ,  270 ,  275 ,  280 ,  285 ,  290 ,  295 ,  300 ,  305 ,  310 ,  315 , and  320 . Each one of the fiber optic cables corresponds to a single sample probe and thus also corresponds to a light reading from the corresponding tablet passing beneath the inspection head. 
     The light energy aggregator  350  operates to combine the light energy gathered by each of the fifteen sample probes (via the fiber optic cables) and output the combined light energy through a single output terminal. Further details of a preferred embodiment of a light energy aggregator constructed in accordance with the present invention are described in conjunction with FIGS. 8-12. Briefly, the combined light energy from the light energy aggregator  350  is directed to an entrance slit on a spectrometer  355  where it is subsequently analyzed. Light sources  220   a and  220   b illuminate the tablets as they pass beneath the sample probes. 
     In operation, the inspection head allows a system to evaluate whether any of the fifteen tablets in the package  215  are misplaced, defective, missing, chemically non-conforming, or have another problem, while utilizing a single spectrometer  355 . As the packaging system begins a run, reflectance data is acquired from a known representative sample package of tablets as it passes beneath the tips of the sample probes, and statistics are compiled based on the combined spectra of the items being inspected. The representative package is of a known quality, and this initial run is thus classified as a calibration run. Appropriate preprocessing of the spectra such as smoothing or first or second differencing is applied. During the normal inspection process associated with a packaging run, the spectrum of each group or package of tablets is compared back to the representative spectra collected during the calibration run. This comparison may be through principal component analysis in which the first two or more eigenvectors are calculated and applied to the spectrum of each group of inspected items. Another comparison method relies on the dot product between the vector containing values from each of the spectral wavelength channels in the calibration run and the spectral vector of the package to be inspected. Any spectrum that deviates in its totality by more than a specified number of standard deviations is deemed to contain foreign material and a signal is sent to the packaging machine causing the group of items/package in question to be rejected and removed from the line before final packaging. Further details of spectra comparisons, as well as other methods of comparison, can be found in the  Handbook of Near-Infrared Analysis , Donald Bums and Emil W. Ciurezak, Marcel Dekker, Inc. 1992, the details of which are hereby incorporated by reference into the present application. Alternately, if reflectance values are known for a particular item or package, this information can be input directly into the inspection system and a calibration run becomes unnecessary. 
     Turning to FIG. 3, a schematic diagram of an inspection system  400  constructed in accordance with the present invention is shown. The schematic diagram of FIG. 3 generally corresponds to FIG.  2 . The diagram of FIG. 3 represents how a number of different sample probes P 1 −P N  can be utilized to obtain a spectrographic measurement from any number of individual samples and feed the collected information to a single spectrometer as a combined input. Based on the combined reading from all of the sample probes, an evaluation can be made as to whether a defect (either chemical or physical) exists somewhere in the package. Since a combined value is obtained, the package as a whole is analyzed for a defect rather than each particular tablet. If the package as a whole is determined to have a defect, that entire package can be rejected. Utilizing such a system allows faster analysis while utilizing a single spectrometer thereby making the system as a whole less expensive and easier to maintain. 
     With continuing reference to FIG. 3, Each of the sample probes P 1  through P n , represented by reference numbers  405 ,  410 ,  415 ,  420 ,  425 ,  430 ,  435 ,  440 , and  445  are connected to a fiber optic cable, shown as reference numbers  407 ,  412 ,  417 ,  422 ,  427 ,  432 ,  437 ,  442 , and  447  respectively. The fiber optic cables are, in turn, connected to a light energy aggregator  450 . The light energy aggregator  450  operates to combine the light energy gathered by each of the fiber optic cables and output the combined light energy through a single output terminal. Further details of a preferred embodiment of a light energy aggregator constructed in accordance with the present invention are described in conjunction with FIGS. 8-12. Briefly, and as shown in FIG. 3, the combined output light energy from the light energy aggregator  450  is directed through a single fiber optic cable  455  and through an entrance slit  457  of a spectrometer  460 . The combined light energy is subsequently analyzed by the spectrometer  460 . A processor  465  is coupled to the spectrometer  460  and further analyzes the combined light energy received by the spectrometer  460 . The processor  465  then compares these results to a pre-determined or pre-assigned value that represents an acceptable measurement of the package (i.e. a package without an unacceptable level of defects). The comparison value can either be obtained by a calibration run as described above or can be input into the processor based on known values. If the defect level does not conform to the comparison value, a rejection unit  470  coupled to the processor sends a signal to the packaging line to discard or remove the package with the defect. 
     The embodiment of the inspection system of FIGS. 2 and 3 utilizes a single spectrometer to analyze the collective samples of fifteen different sample probes and thus can reject or accept a package based on whether the package spectra as a whole meets a pre-determined criteria. As mentioned above, the use of a single spectrometer to evaluate the conformance of an entire package of tablets increases the speed of the inspection process while simultaneously reducing the cost of such an inspection system. However, the system of FIGS. 2 and 3 is unable to distinguish the precise location within the package of the foreign substance or damaged tablet. Often, it is desired to more accurately and precisely locate the non-conforming tablet(s) from within each package. 
     Turning to FIG. 4, a diagrammatic representation of an inspection system constructed in accordance with a further aspect of the present invention is shown. FIG. 4 shows in further detail a diagrammatic representation of the lower portion of an inspection head  110  used in conjunction with an inspection system, and more particularly, an array of sample probes and how they interact with the tablets passing along a conveyer. The probe array is generally referred to in FIG. 4 as reference number  500 . In the example of FIG. 4, a product package  515 , such as a filled but yet un-sealed blister package, contains fifteen (15) individual tablets in a three-by-five arrangement. Various other arrangements of the tablets are contemplated and the three-by-five arrangement of FIG. 4 is shown merely as an example. The tablets in the package  515  are arranged into five rows. From left to right in FIG. 4, column one includes tablets  525   a ,  525   b , and  525   c , column two contains tablets  530   a,    530   b,  and  530   c,  column three contains tablets  535   a ,  535   b , and  535   c,  column four contains tablets  540   a,    540   b,  and  540   c,  and column five contains tablets  545   a,    545   b,  and  545   c.  Corresponding to each of the fifteen tablets in FIG. 2 is a sample probe. From left to right, the sample probes also are divided into five columns with three sample probes in each column. Column one contains sample probes  625   a,    625   b,  and  625   c,  column two contains sample probes  630   a,    630   b,  and  630   c,  column three contains sample probes  635   a,    635   b,  and  635   c,  column four contains sample probes  640   a,    640   b,    640   c,  and column five contains sample probes  645   a,    645   b,    645   c.  As the conveyer system moves the package  515  into position under the inspection head  110 , the fifteen sample probes are positioned to correspond respectively to a similarly positioned tablet in the package  515 . Namely, the samples probes are positioned substantially above the correspondingly positioned tablet. 
     Each of the sample probes are connected to a fiber optic cable which in turn is connected to one of five different light energy aggregators  650 ,  660 ,  670 ,  680 , or  690 . In FIG. 4, the fifteen fiber optic cables are represented as reference numbers  550 ,  555 ,  560 ,  565 ,  570 ,  575 ,  580 ,  585 ,  590 ,  595 ,  600 ,  605 ,  610 ,  615 , and  620 . Each one of the fiber optic cables corresponds to a single sample probe and thus also corresponds to a light reading from the corresponding tablet passing beneath the inspection head. 
     Each of the light energy aggregators  650 ,  660 ,  670 ,  680 , and  690  operates to combine the light energy gathered by the three sample probes (via the fiber optic cables) that feed light energy into it. Each light energy aggregator then outputs the combined light energy through a single output terminal. In the embodiment of FIG. 4, each of the light energy aggregators  650 ,  660 ,  670 ,  680 , and  690  is associated with the fiber optic cables and sample probes from a single column. More specifically, light energy aggregator  650  receives light energy input from fiber optic cables  550 ,  555 , and  560 , light energy aggregator  660  receives light energy input from fiber optic cables  565 ,  570 , and  575 , light energy aggregator  670  receives light energy input from fiber optic cables  580 ,  585 , and  590 , light energy aggregator  680  receives light energy input from fiber optic cables  595 ,  600 , and  605 , and light energy aggregator  690  receives light energy input from fiber optic cables  610 ,  615 , and  620 . Further details of a preferred embodiment of a light energy aggregator constructed in accordance with the present invention are described in conjunction with FIGS. 8-12. Briefly, the combined light energy from each of the light energy aggregator&#39;s  650 ,  660 ,  670 ,  680 , and  690  is directed to an entrance slit on a corresponding spectrometer  655 ,  665 ,  675 ,  685 , or  695  where it is subsequently analyzed. Light sources  520   a  and  520   b  illuminate the tablets as they pass beneath the sample probes. 
     In operation, the inspection head allows a system to evaluate whether one or more of the fifteen tablets in the package  515  are misplaced, defective, missing, chemically non-conforming, or otherwise non-conforming. As the packaging system begins a run, reflectance data is acquired from a known representative sample package of tablets as they pass beneath the tips of the sample probes and statistics are compiled based on the combined spectra of the items being inspected. The representative package is of a known quality and this initial run is thus classified as a calibration run. Preprocessing of the spectra is applied in a similar manner as described above in conjunction with FIG. 2, however, information is gathered on a column-by-column basis rather than on a whole-package-basis as in the embodiment of FIG.  2 . In this manner, if a defect or other abnormality is discovered within the package  515 , the location of the defect can be narrowed down to a particular column within the package allowing segregation of the defective component and allowing more of the conforming tablets to be reused in the packaging run. Less waste and higher throughput is therefore realized. 
     Similarly, where blister packs contain more than one formulation, e.g. the package in FIG. 4 could have up to  5  formulations (one in each row), the system would be able to detect a misplaced tablet in any of the columns. Single spectrometer systems would not be able to detect when a tablet in one row got inadvertently switched with a tablet in a second row having a different formulation. Probes from the multiple spectrometer system of FIG. 4 can be arranged in any configuration and not just in rows as shown. 
     Turning to FIG. 5, a schematic diagram of an inspection system  700  constructed in accordance with the present invention is shown. The schematic diagram of FIG. 5 generally corresponds to FIG.  4 . The diagram of FIG. 5 represents how a number of different sample probes P A1 −P E3  can be utilized to obtain a spectrographic measurement from any number of individual samples on a column-by-column basis and feed the collected column-by-column information through a column specific light energy aggregator to a column-specific spectrometer as a combined input. Based on the combined reading from the sample probes in each row, an evaluation can be made as to whether a defect (either chemically or physically) exists somewhere in the package. In the case of a blister package containing tablets with several different formulations, groups of probes feeding light to each of the light energy aggregators are positioned above the groups of tablets having a single formulation. A further determination can be made as to which column the defect or other abnormality resides. Since a combined value is obtained for each column of tablets, a particular column as a whole is analyzed for a defect rather than each particular tablet. Thus, the system can detect when tablets with a given formulation are placed in the wrong row. In many cases, any such formulation misplacement will cause the entire package to be rejected, however, it is contemplated that the otherwise conforming tablets can be salvaged and stored for later reuse or can be automatically placed back into the packaging line for inclusion in a subsequent package. Utilizing such a system allows faster analysis while requiring a fewer number of spectrometers thereby making the system as a whole less expensive and easier to maintain. 
     With continuing reference to FIG. 5, each of the sample probes P A1  through P E3 , represented by reference numbers  702 ,  704 ,  706 ,  708 ,  710 ,  712 ,  714 ,  716 ,  718 ,  720 ,  722 ,  724 ,  726 ,  728 , and  730  are connected to a corresponding fiber optic cable, shown as reference numbers  732 ,  734 ,  736 ,  738 ,  740 ,  742 ,  744 ,  746 ,  748 ,  750 ,  752 ,  754 ,  756 ,  758 , and  760  respectively. The subscript designation in each of the probe labels refers to the column and row of each sample probe respectively. Namely, the letter designations, A, B, C, etc. refer to the first, second, third, etc. columns while the number designations  1 ,  2 , and  3 , refer to the row designation in each column. Each one of the array of fifteen sample probes can therefore be uniquely represented. 
     The column-by-column groupings of fiber optic cables are in turn connected to a corresponding light energy aggregator  762 ,  764 ,  766 ,  768 , or  770 . Each of the light energy aggregators operate to combine the light energy gathered by the fiber optic cables from a particular column and output the combined light energy through a single output terminal. Further details of a preferred embodiment of a light energy aggregator constructed in accordance with the present invention are described in conjunction with FIGS. 8-12. Briefly, and as shown in FIG. 5, the combined output light energy from the light energy aggregator  762  is directed through a single fiber optic cable  771  and through an entrance slit  763  of a spectrometer  772 . The combined light energy is subsequently analyzed by the spectrometer  772 . The combined output light energy from the light energy aggregator  764  is directed through a single fiber optic cable  773  and through an entrance slit  765  of a spectrometer  774 . The combined light energy is subsequently analyzed by the spectrometer  774 . The combined output light energy from the light energy aggregator  766  is directed through a single fiber optic cable  775  and through an entrance slit  767  of a spectrometer  776 . The combined light energy is subsequently analyzed by the spectrometer  776 . The combined output light energy from the light energy aggregator  768  is directed through a single fiber optic cable  777  and through an entrance slit  769  of a spectrometer  778 . The combined light energy is subsequently analyzed by the spectrometer  778 . The combined output light energy from the light energy aggregator  770  is directed through a single fiber optic cable  779  and through an entrance slit  771  of a spectrometer  780 . The combined light energy is subsequently analyzed by the spectrometer  780 . 
     A processor  790  is coupled to each of the five spectrometers  772 ,  774 ,  776 ,  778 , and  780  by data cables  782 ,  784 ,  786 ,  788 , and  789  and further analyzes the combined light energy received by the spectrometers. The processor  790  then compares these results to a pre-determined or pre-assigned value that represents an acceptable measurement of the package (i.e. a package with an acceptable level of defects). The comparison value can either be obtained by a calibration run as described above or can be input into the processor based on known values. If the defect level does not conform to the comparison value, a rejection unit  794  coupled to the processor  790  via link  792  sends a signal to the packaging line to discard or remove the package with the defect. 
     Turning to FIG. 6, a diagrammatic representation of a further aspect to an inspection system constructed in accordance with the present invention is shown. FIG. 6 shows in further detail a diagrammatic representation of the lower portion of an inspection head  110  used in conjunction with an inspection system, and more particularly, an array of sample probes and how they interact with the tablets passing along a conveyer. The probe array is generally referred to in FIG. 6 as reference number  800 . In the example of FIG. 6, a product package  815 , such as a filled but yet un-sealed blister package, contains fifteen (15) individual tablets in a three-by-five arrangement. Various other arrangements of the tablets are contemplated and the three-by-five arrangement of FIG. 6 is shown merely as an example. The tablets in the package  815  are arranged into five columns, each having three rows. From left to right in FIG. 6, column one includes tablets  825   a ,  825   b ,  825   c , column two contains tablets  830   a ,  830   b , and  830   c , column three contains tablets  835   a ,  835   b , and  835   c , column four contains tablets  840   a ,  840   b , and  840   c , and column five contains tablets  845   a ,  845   b , and  845   c . Corresponding to each of the fifteen tablets in the example of FIG. 6 is a example probe. From left to right, the sample probes are also divided into five columns with three sample probes in each column. Column one contains sample probes  925   a ,  925   b , and  925   c , column two contains sample probes  930   a ,  930   b , and  930   c , column three contains sample probes  935   a ,  935   b , and  935   c , column four contains sample probes  940   a ,  940   b , and  940   c , and column five contains sample probes  945   a ,  945   b , and  945   c . As the conveyer system moves the package  815  into position under the inspection head  110 , the fifteen sample probes are positioned to correspond respectively to a similarly positioned tablet in the package  815 . Namely, the samples probes are positioned substantially above the correspondingly positioned tablet. 
     Each of the sample probes are connected to a pair of fiber optic cables which in turn are connected to one of five different column light energy aggregators  950 ,  960 ,  970 ,  980 , or  990  and to one of three different row light energy aggregators  1080 ,  1090 , or  1100 . Thus, each sample probe is connected to one column light energy aggregator and to one row light energy aggregator. In FIG. 6, the thirty fiber optic cables connecting the sample probes to the eight light energy aggregator are represented as reference numbers  850 ,  855 ,  860 ,  865 ,  870 ,  875 ,  880 ,  885 ,  890 ,  895 ,  900 ,  905 ,  910 ,  915 ,  920  (corresponding to the column light energy aggregators),  1000 ,  1005 ,  1010 ,  1015 ,  1020 ,  1025 ,  1030 ,  1035 ,  1040 ,  1045 ,  1050 ,  1055 ,  1060 ,  1065 , and  1070  (corresponding to the row light energy aggregators). Each one of these thirty fiber optic cables corresponds to a single sample probe and thus also corresponds to a light reading from a single tablet passing beneath the inspection head. Since there are two fiber optic cables for each sample probe, a reading from a particular sample probe is passed to both a column light energy aggregator and to a row light energy aggregator. 
     Each of the light energy aggregators  950 ,  960 ,  970 ,  980 ,  990 ,  1080 ,  1090 , and  1100  operate to combine the light energy gathered by the sample probes (via the fiber optic cables) that feed light energy into it. Each light energy aggregator then outputs the combined light energy through a single output terminal. In the embodiment of FIG. 6, each of the light energy aggregators  950 ,  960 ,  970 ,  980 , and  990  is associated with the fiber optic cables and sample probes from a single column, while each of the light energy aggregators  1080 ,  1090 , and  1100  is associated with the fiber optic cables and sample probes from a single row. More specifically, light energy aggregator  950  receives light energy input from fiber optic cables  850 ,  855 , and  860 , light energy aggregator  960  receives light energy input from fiber optic cables  865 ,  870 , and  875 , light energy aggregator  970  receives light energy input from fiber optic cables  880 ,  885 , and  890 , light energy aggregator  980  receives light energy input from fiber optic cables  895 ,  900 , and  905 , and light energy aggregator  990  receives light energy input from fiber optic cables  910 ,  915 , and  920 . Light energy aggregator  1080  receives light energy input from fiber optic cables  1000 ,  1005 ,  1010 ,  1015 , and  1020 , light energy aggregator  1090  receives light energy input from fiber optic cables  1025 ,  1030 ,  1035 ,  1040 , and  1045 , and light energy aggregator  1100  receives light energy input from fiber optic cables  1050 ,  1055 ,  1060 ,  1065 , and  1070 . 
     Further details of a preferred embodiment of a light energy aggregator constructed in accordance with the present invention are described in conjunction with FIGS. 8-12. Briefly, the combined light energy from each of the light energy aggregators  950 ,  960 ,  970 ,  980 ,  990 ,  1080 ,  1090 , and  1100  is directed to an entrance slit on a corresponding spectrometer  955 ,  965 ,  975 ,  985 ,  995 ,  1085 ,  1095 , or  1105  where it is subsequently analyzed. Light sources  820   a  and  820   b  illuminate the tablets as they pass beneath the sample probes. 
     In operation, the inspection head allows a system to evaluate whether one of the fifteen tablets in the package  815  are misplaced, defective, missing, chemically nonconforming, or has another problem. As the packaging system begins a run, reflectance data is acquired from a known representative sample package of tablets as they pass beneath the tips of the sample probes and statistics are compiled based on the combined spectra of the items being inspected. The representative package is of a known quality and this initial run is thus classified as a calibration run. Preprocessing of the spectra is applied in a similar manner as described above in conjunction with FIG. 2, however, information is gathered on a column-by-column and row-by-row basis rather than on a whole-package-basis as in the embodiment of FIG.  2 . In this manner, if a defect or other abnormality is discovered within the package  815 , the location of the defect can be narrowed down to a particular row and a particular column within the package allowing precise segregation of the defective component and allowing all of the conforming tablets to be utilized in a subsequent packaging run. Less waste and higher throughput is therefore realized. 
     Turning to FIG. 7, a schematic diagram of an inspection system  1200  constructed in accordance with the present invention is shown. The schematic diagram of FIG. 7 generally corresponds to FIG.  6 . The diagram of FIG. 7 represents how a number of different sample probes P A1 −P E3  can be utilized to obtain a spectrographic measurement from any number of individual samples on a row-by-row and column-by-column basis. The collected row information is fed through a row specific light energy aggregator to a row-specific spectrometer as a combined input and the collected column information is fed through a column specific light energy aggregator to a column-specific spectrometer as a combined input. Based on the combined reading from the sample probes corresponding to each row and the sample probes corresponding to each column, an evaluation can be made as to whether a defect (either chemical or physical) exists somewhere in the package. A further determination can be made as to which row and column the defect or other abnormality resides, and therefore, the precise location of the non-conforming item can be ascertained. Since a combined value is obtained for each row and column of tablets, a particular row as a whole or a particular column as a whole is analyzed for a defect rather than each particular tablet. If a particular row or particular column as a whole is determined to have a defect, the entire package can be rejected but the conforming tablets can be salvaged and stored for later reuse or be automatically placed back into the packaging line for insertion into a subsequent package. Utilizing such a system allows faster analysis while utilizing a fewer number of spectrometers thereby making the system as a whole less expensive and easier to maintain. 
     With continuing reference to FIG. 7, each of the fifteen sample probes P A1  through P E3 , represented by reference numbers  1202 ,  1204 ,  1206 ,  1208 ,  1210 ,  1212 ,  1214 ,  1216 ,  1218 ,  1220 ,  1222 ,  1224 ,  1226 ,  1228 , and  1230  are connected to a pair of corresponding fiber optic cables. The fiber optic cables corresponding to the five columns of sample probes are shown as reference numbers  1232 ,  1234 ,  1236 ,  1238 ,  1240 ,  1242 ,  1244 ,  1246 ,  1248 ,  1250 ,  1252 ,  1254 ,  1256 ,  1258 , and  1260  respectively. The fiber optic cables corresponding to the three rows of sample probes are shown as reference numbers  1302 ,  1304 ,  1306 ,  1308 ,  1310 ,  1312 ,  1314 ,  1316 ,  1318 ,  1320 ,  1322 ,  1324 ,  1326 ,  1328 , and  1330  respectively. The subscript designation in each of the probe labels refer to the column and row of each probe. Namely, the letter designations, A, B, C, etc. refer to the first, second, third, etc. columns and the number designations  1 ,  2 , and  3  refer to the row designation in each column. Each of the array of fifteen sample probes can thus be uniquely represented. 
     The column-by-column grouping of fiber optic cables are connected to a corresponding column light energy aggregator  1262 ,  1264 ,  1266 ,  1268 , and  1270 , and the row-by-row groupings of fiber optic cables are in turn connected to a corresponding row light energy aggregator  1332 ,  1334 , and  1336 . Each of the light energy aggregators operate to combine the light energy gathered by the fiber optic cables from a particular column or row and output the combined light energy through a single output terminal. Further details of a preferred embodiment of a light energy aggregator constructed in accordance with the present invention are described in conjunction with FIGS. 8-12. Briefly, and as shown in FIG. 7, the combined output light energy from the column light energy aggregator  1262  is directed through a single fiber optic cable  1272  and through an entrance slit  1273  to a spectrometer  1282 . The combined light energy is subsequently analyzed by the spectrometer  1282 . The combined output light energy from the column light energy aggregator  1264  is directed through a single fiber optic cable  1274  and through an entrance slit  1275  to a spectrometer  1284 . The combined light energy is subsequently analyzed by the spectrometer  1284 . The combined output light energy from the column light energy aggregator  1266  is directed through a single fiber optic cable  1276  and through an entrance slit  1277  to a spectrometer  1286 . The combined light energy is subsequently analyzed by the spectrometer  1286 . The combined output light energy from the column light energy aggregator  1268  is directed through a single fiber optic cable  1278  and through an entrance slit  1279  to a spectrometer  1288 . The combined light energy is subsequently analyzed by the spectrometer  1288 . The combined output light energy from the column light energy aggregator  1270  is directed through a single fiber optic cable  1280  and through an entrance slit  1281  to a spectrometer  1290 . The combined light energy is subsequently analyzed by the spectrometer  1290 . 
     Similarly, the combined output light energy from the row light energy aggregator  1332  is directed through a single fiber optic cable  1338  and through an entrance slit  1339  to a spectrometer  1344 . The combined light energy is subsequently analyzed by the spectrometer  1344 . The combined output light energy from the row light energy aggregator  1334  is directed through a single fiber optic cable  1340  and through an entrance slit  1341  to a spectrometer  1346 . The combined light energy is subsequently analyzed by the spectrometer  1346 . The combined output light energy from the row light energy aggregator  1336  is directed through a single fiber optic cable  1342  and through an entrance slit  1343  to a spectrometer  1348 . The combined light energy is subsequently analyzed by the spectrometer  1348 . 
     A processor  1360  is coupled to each of the eight spectrometers  1282 ,  1284 ,  1286 ,  1288 ,  1290 ,  1344 ,  1346 , and  1348  by data cables  1292 ,  1294 ,  1296 ,  1298 ,  1300 ,  1350 ,  1352 , and  1354  respectively. The processor  1360  further analyzes the combined light energy received by the spectrometers. The processor  1360  then compares these results to a pre-determined or pre-assigned value that represents an acceptable measurement of the package (i.e. a package with an acceptable level of defects). The comparison value can either be obtained by a calibration run as described above or can be input into the processor based on known values. If the defect level does not conform to the comparison value, a rejection unit  1365  coupled to the processor  1360  sends a signal to the packaging line to discard or remove the package containing the defect. 
     FIG. 8 shows a general schematic representation of a light energy aggregator  1500  utilized in an inspection system constructed in accordance with the present invention. The light energy aggregator  1500  collects the light signals transmitted by a number of fiber optic input cables, aggregates the light signals, and transmits the aggregated light signals as a single light energy output. Preferably, the light energy output represents an average reflectance value obtained through the several fiber optic input cables. The light energy aggregator  1500  includes a housing  1535  having an input end  1536  and an output end  1538 . The input end  1536  includes input terminals  1520 ,  1522 ,  1524 ,  1526 , and  1528  which connect fiber optic input cables  1502 ,  1504 ,  1506 ,  1508 , and  1510  respectively to the light energy aggregator housing  1535 . A fewer or greater number of input terminals also are contemplated. The input terminals are preferably an SMA or other type of known fiber optic connection device. The output end  1538  includes a single output terminal  1532  connected to an output fiber optic cable  1530 . Alternatively, the individual light input optical fibers  1502 - 1510  may be combined into the single output bundle  1530  without the use of any intervening fiber optic connectors. An optional reflective chamber  1501  is applicable to an alternative embodiment (described below) of light energy aggregator  1500 . 
     FIGS. 9-12 show a preferred embodiment of a light energy aggregator utilized in accordance with the present invention. The light energy aggregator embodied in FIGS. 9-12 utilizes a splitter block  1540 . In conjunction with an inspection system constructed in accordance with the present invention, sample probes  1550  and  1555  take light energy readings from an item to be sampled and bring the collected light energy to the splitter block  1540 . Each of the two sample probes  1550  and  1555  in FIG. 9 contain two fiber optic strands  1553  and  1554  (See cross section in FIG.  10 ). The fiber optic strands  1553  and  1554  are encased in an insulating and non-light transmitting material  1552 . The entire probe  1550  is contained in a PVC sheathing  1551 . Connection devices  1560  and  1565  connect each of the sample probes to a flexible tube  1570  or  1575  which can be directed to an input end  1542  of the splitter block  1540 . While the light energy aggregator shown in FIGS. 9-12 utilizes two sample probes, it is contemplated that any number of sample probes and corresponding fiber optic strands can be utilized in an inspection system constructed in accordance with the present invention. 
     Again referring to FIG. 9, the splitter block  1540  includes a single bundled cable  1580  coupled to an output end  1544  of the splitter block  1540 . The cable  1580  leads to a spectrometer connector  1590  having a spectrometer input tip  1595 . In conjunction with the splitter block  1540 , the input tip  1595  functions to bring all of the collected light energy from each of the sample probes (in this case  1550  and  1555 ) to a spectrometer. The input tip  1595  is therefore adapted to engage with a light entrance slit of a spectrometer. 
     FIG. 11 shows a cross-section of the splitter block  1540 . While the cross-section of FIG. 11 is representative of the splitter block shown in FIG. 9, nine probe connections are shown rather than the two embodied in FIG.  9 . The nine probe connections  1600 ,  1602 ,  1604 ,  1606 ,  1608 ,  1610 ,  1612 ,  1614 , and  1616  are substantially identical in structure, each including two separate fiber optic strands. The splitter block  1540  combines the eighteen (18) total fiber optic strands engaging the input end  1542  of the splitter block into a single bundled cable  1580  engaging the output end  1544 . The bundled cable  1580  is preferably covered with a PVC sheathing  1585 . FIG. 12 shows a cross section of the input tip  1595  of the bundled cable  1580  as it is adapted to align and couple with the entrance slit of a spectrometer. 
     The splitter block embodiment of a light energy aggregator  1500  depicted in FIGS. 9-12 is one example of such a light energy aggregator. Other embodiments of a device that combines the light energy from two or more sample probes are contemplated by the present invention. For example, with reference to FIG. 8, another embodiment of a light energy aggregator  1500  uses a reflective chamber  1501  to receive collected light energy from each of the sample probes. As all of the light energy is combined within the reflective chamber  1501 , a single output distributes the aggregated light energy and directs it through a single fiber optic strand in output fiber optic cable  1530 . This single fiber optic strand is then directed to the entrance slit of a spectrometer. Such an embodiment of a light energy aggregator  1500  is beneficial since it reduces the complexity of the entrance slit connection. The reflective chamber  1501  is preferably highly polished, such as a gold plated finish or electro-polished stainless steel, so that light energy losses are kept to a minimum. 
     FIGS. 13-15 show a preferred embodiment of an inspection head  1700  as it mounts over a conveyer-based packaging line and inspection system. The inspection head  1700  includes a probe housing  1715  mounted over a conveyer unit  1710 . The conveyer unit  1710  includes a pair of channels  1712  and  1714  that are adapted to carry, for example, filled blister packages past the inspection head  1700  and its associated sample probes. The inspection head  1700  also includes near-infrared light source housings  1725   a  and  1725   b  mounted on either side of the conveyer unit  1710 . The two housings  1725   a  and  1725   b  contain a near-infrared light source that is directed at the channels  1712  and  1714  where the items to be inspected travel. It is contemplated that in other embodiments, the number of channels in the conveyer unit  1710  may be more or less than two. 
     In FIG. 14, a front faceplate of the probe housing is removed to illustrate the arrangement of an array of sample probes  1730 . Generally, the sample probes  1730  are positioned so that they each align with a single item in a package  1716  passing beneath. FIG. 14 is shown with four individual sample probes corresponding to each of the packages  1716 , since each of the packages contain four items in FIG.  14 . Of course, in a system adapted to inspect packages with a different number of items, a corresponding number of sample probes would be included. Preferably, the probe housing  1715  can be easily retooled to accommodate a varying number of sample probes, for example, probe housing modules having a set number of sample probes can be utilized to easily change the format of the inspection head. Also, a probe mounting plate that has a pattern of holes for holding the probes positioned above each of the items may be utilized. The probe mounting plate may be adapted to be easily changed to accommodate a different layout of items. Pre-assembled sample probe manifolds can also be utilized to accomplish the goal of an easy exchange for use with different packaging and inspection systems that utilize varying sized packages. An array of fiber optic cables  1740  connects each of the sample probes to a spectrometer housing  1720  mounted above the sample probe housing  1715 . 
     FIG. 15 shows a cross section of the inspection head  1700  and more particularly the connections between the sample probes  1730 , the fiber optic cables  1740 , a light energy aggregator  1750  and a spectrometer  1760 . Preferably, the light energy aggregator  1750  and the spectrometer  1760  are both mounted within the spectrometer housing  1720  although it is contemplated that the light energy aggregator may be positioned elsewhere in the inspection head  1700 . It is also contemplated that the light aggregator  1750  and/or the spectrometer  1760  may be located outside of the inspection head  1700 . FIG. 15 illustrates how the sample probes  1730  align with each of the items contained in the package  1716  and combine the signal gathered by the probes in the light energy aggregator  1750 . The combined signal is then transferred to the spectrometer  1760  for processing. 
     FIGS. 16 and 17 present several flow charts describing methods of inspection and analyzing reflectance data in accordance with the present invention. In FIG. 16, a method  1800  includes illuminating a target or package at  1810  and then obtaining a reference reflectance value for that package at a  1820 . The reference reflectance value can be obtained either by a calibration run  1825  or by inputting the known values at  1830 . 
     After the reference reflectance value is obtained, reflected light is collected at  1835  from all items in the target package. This reflected light is combined at  1840  and input into a spectrometer at  1845  where the light energy is measured and the reflectance calculated at  1850 . A comparison is made between the reference reflectance value and the acquired reflectance value at  1855  and a determination is made at  1860  whether the acquired reflectance data falls within the reference data acceptance criteria. If the acquired reflectance data is acceptable the process continues at  1865 , a next target or other sample is prepared at  1875  and the process repeats at  1890 . If the acquired reflectance data is not within acceptable criteria, the target package is rejected at  1870 , a next target or other sample is prepared at  1875 , and the process repeats at  1890 . 
     Turning to FIG. 17, a method  1900  includes illuminating a target or package at a  1905  and then obtaining a reference reflectance value for that package at  1910 . The reference reflectance value can be obtained either by a calibration run  1915  or by inputting the known values at  1920 . At  1925 , item-by-item reflected light is collected, and then a determination is made at  1930  whether more detailed information about the package reflectance data is required, i.e. whether column-by-column or row-by-row reflectance data is desired. If the more detailed reflectance data is required, then the column data is sorted at  1935 , the row data is sorted at  1940  and the row and column data are combined at  1945 . The combined reflected light is then input into a spectrometer at  1955 . If row and column specific information is not required then reflected light is combined for all of the items in the package at  1950 , and the combined reflected light is input into a spectrometer at  1955 . 
     The light energy is measured and reflectance calculated at  1960 , a comparison is made between the reference reflectance value and the acquired reflectance value at  1965 , and a determination is made at  1970  whether the acquired reflectance data falls within the reference data acceptance criteria. If the acquired reflectance data is acceptable the process continues at  1975 , a next target is prepared for inspection, and the process repeats. 
     If the acquired reflectance data is not acceptable a further determination is initiated at  1980  to isolate the location of the non-conforming item or items within the package. Once the non-conforming item or items are located, the target package is rejected at  1985  and the location data is sent to a user for further processing or analysis at  1990 . Alternately, the rejected package is automatically sorted and the conforming items are reinserted into the packaging system. The inspection process continues by preparing a next target for inspection and repeating the inspection process. 
     As mentioned above, an inspection device constructed in accordance with the present invention is preferably used in conjunction with a pharmaceutical packaging system, although it is contemplated that such an inspection system can be used with a variety of other applications such as food manufacturing/packaging, consumer goods, as well as industrial applications. 
     The methods and systems outlined above for inspecting and analyzing packaged items utilize an individual sample probe to collect the reflected light from each item in the package. The sample probes in the above examples and embodiments are aligned with the individual items in the package. This technique is most applicable when the location within the package of the item being analyzed is well known, such as when a standardized packaging unit is used, i.e. a blister pack for a regularly processed pharmaceutical. Other examples include oral contraceptive packaging, antihistamine packaging, and vitamin packages where multiple dosage formats are included in a single package, e.g. day and night antihistamine dosages or contraceptive dosages. 
     For situations where the location within the package of each item is not predetermined, the concepts of imaging spectrometry may be utilized in accordance with an embodiment of the present invention to identify the individual item locations. In addition to identifying the item location within a package, an imaging spectrometer can be simultaneously used in accordance with an embodiment of the present invention to capture the spectrum of the individual items for analysis. 
     Imaging spectrometers simultaneously capture data in as many as hundreds of contiguous registered spectral bands, such that a spectral vector containing as much information as an individual spectrometer spectrum is measured for each picture element (pixel). The field of view of an imaging spectrometer may be considered as a collection of picture elements (pixels) or resolution elements (reselms). This field can be imaged onto an array of detector elements in a focal plane array (FPA), or it may be imaged by a single detector or small array that is scanned over the field. Further information and details regarding imaging spectrometers can be found in  Introduction to Imaging Spectrometers , William L. Wolfe, 1997, which is hereby incorporated by reference. 
     Generally, in a push-broom scanning-type imaging spectrometer, the spectral data is acquired one image line at a time. By moving the items to be scanned underneath the imaging element a second spatial dimension is provided, a two dimensional spatial image can be developed with a third spectral dimension. With a complete image field of a package obtained, identification and isolation of individual items within the package of items can be made by comparing the spectra obtained at each pixel with the corresponding pixel from a known background, i.e. an unfilled package. After the pixels corresponding to the filled package and the product items within the package have been isolated, any one of the analyses described above in conjunction with FIGS. 1-17 can be applied to determine whether the package items conform to a pre-determined standard. 
     A push broom imaging spectrometer (IS) is one that uses a 2-D detector array. One dimension of the detector is used to collect the spatial information (i.e. it images a row of spatial pixels corresponding to the various positions across the conveyor transporting the items by the head) and the other is used to collect the spectral information (i.e. each column of the array simultaneously measures the spectrum corresponding to a single spatial pixel). The image is acquired one line at a time. Optics are used to project an image of the surface under observation onto the entrance slit of the IS. The height of the entrance slit defines the height of the spatial pixels in the final image. Inside the IS, the dispersed image of the light transmitted through the entrance slit is focused onto the 2-D detector array. The wide dimension of the entrance slit is focused across the width of the detector array. Thus, the width of the detector in pixels is equal to the width of the spatial image in pixels. 
     The grating disperses the light perpendicular to the wide dimension of the entrance slit. Thus, the other dimension of the detector is used to collect the spectral information. The number of wavelengths measured corresponds to the dimension of the detector in this direction. 
     The second spatial dimension is acquired by moving the sensor relative to the surface under observation. The end result is a 3-D data set: 2 spatial and one spectral dimension. 
     Standard image analysis routines are used to define the centers of the items under inspection. Spectra corresponding to these center pixels (one or more pixels averaged for each item depending on the size of the item and the size of the spatial pixels) are then analyzed in the same manner as the non-IS example. Also note that because a complete image is acquired, the IS-based approach also provides the shape of the items under inspection. 
     With reference to FIG. 18, a push-broom scanning imaging spectrometer system  2000  constructed in accordance with an embodiment of the present invention is shown. The imaging spectrometer system  2000  is preferably used to obtain item-location data corresponding to a package  2030  that contains, for example, an array of items  2040 . As an example, the package  2030  may comprise a blister pack that includes an array of tablet wells shaped and sized to each hold an individual tablet. The spectrometer system  2000 , includes an imaging spectrometer  2010  and a fore-optics unit  2015 . The push broom scanning spectrometer  2000  is mounted above a conveyer system  2020  that carries the package  2030  through a field of view  2017  of the fore-optics unit  2015 . The conveyer system  2020  is similar to those described in conjunction with FIGS. 1-15. 
     Also shown on the conveyer  2030  is an unfilled, or “blank” package  2025 . The blank package  2025  in FIG. 18 also shows empty tablet wells  2035 . The direction of the conveyer movement is indicated by an arrow  2027  and illustrates how the blank package  2025  passes the imaging element  2015  first, thereby providing a reference image. When the filled package  2030  passes the imaging element  2015 , the spectral data gathered can be compared to the reference image previously obtained and a determination can be made as to the specific locations of the individual items  2040  within the package  2030 . 
     Preferably, there are two reference images. The first without items in place, the second with items in place. These reference images can then be used to indicate the general location of each item with the specific location determined by standard image processing methods applied to the new image of each group of items. Alternatively, the system can use the reference image (this time only with the tablets in place) to train the system to recognize the items wherever they are located within the system&#39;s field-of-view. 
     FIGS. 19A-19C show a plan view representing the product packages that correspond to the embodiment of FIG.  18 . FIG. 19A shows a blank package  2100  having a four-by-four array of item locations  2110 . Each item location includes a tablet well  2115 . FIG. 19B shows a filled package  2125 . The arrangement of the package  2125  is identical to that of the package  2100  except that tablets  2130  are loaded into each of the tablet wells  2115 . Finally, FIG. 19C illustrates how the imaging spectrometer scans the package  2125  one image line at a time. A single row of image pixels  2160  is scanned in a given time frame by the spectrometer. As the package  2125  passes beneath the scanning element, sequential rows of image pixels are scanned until an array of pixels  2155  is formed. The array  2155  represents an image of the package  2125 . The package image is then compared to the reference image previously obtained and the item locations can be precisely ascertained. 
     FIG. 20 depicts a scanning method  2200  in accordance with an embodiment of the present invention. The spectral reference images of both a blank, unloaded package, and a filled package are first obtained at  2210 . The spectral image of a package under inspection is obtained at  2215 . Obtaining the spectral image of a package under inspection  2215  is shown in more detail in FIG. 20 as collecting the first line of the image at  2220 , incrementing the position of the package at  2222 , and looping back to  2220  until the complete image is acquired at  2224 . The reference spectral image(s) are compared with the spectral image of the package under inspection at  2230 , the item locations are then determined, and the image pixels corresponding to the item locations are isolated at  2240 . Spectral analysis of the item compositions can then be accomplished by any of the methods and systems previously described and illustrated as well as by other known inspection systems and methods. 
     Although the present invention has been described and illustrated in the above description and drawings, it is understood that this description is by example only and that numerous changes and modifications can be made by those skilled in the art without departing from the true spirit and scope of the invention. The invention, therefore, is not to be restricted, except by the following claims and their equivalents.