Abstract:
A scent collection method comprising putting an item bearing a sample of a scent to be identified in an enclosure and heating the item is disclosed. A quantity of air is introduced into the enclosure. The air from the enclosure is withdrawn after the item has been heated. The withdrawn air is passed through a scent collection member to collect scent on the scent collection member. The scent collection member may be cooled during the scent collection process and the scent collection member is then sealed in an envelope. The scent collection member is removed from the envelope in which the scent collection member has been sealed. The scent collection member is then heated and air passed through the scent collection member. The air passed through the scent collection member is used as a stimulus or other input in a scent identification procedure.

Description:
TECHNICAL FIELD  
       [0001]     The invention relates to systems, devices and methods for the efficient collection, storage, utilization and evaluation of scent samples particularly useful in forensic applications.  
       CROSS REFERENCE TO RELATED APPLICATIONS  
       [0002]     Not applicable.  
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT  
       [0003]     Not applicable.  
       BACKGROUND OF THE INVENTION  
       [0004]     Since antiquity, the olfactory precision and sensitivity of animals has been known. For almost as long, man has harnessed these capacities for a wide range of applications. Even today, there are no commercial instrumentation systems that can match the sensitivity of pigs trained to detect the subtle aromas of truffles hidden under earth, leaves and brush in the forest. Similarly, dogs trained to track or identify people, or to detect substances such as explosives and marijuana, remain the backbone of law enforcement in an age where instrumentation and computers dominate virtually all other areas of forensics.  
         [0005]     Techniques have been substantially advanced from the classic situation where specially trained dogs smell a garment belonging to a runaway criminal, and the chase begins. Dogs have also been used in less frenetic applications, such as the detection of a lost child, and in various forensic comparative applications.  
         [0006]     For example, trained dogs may be used to identify suspects in a scent lineup. A garment removed from a crime scene may be permeated with scent sufficient to identify individuals who were present at the crime scene. In such circumstances, detectives may collect garments, home furnishings, or the like and place them in plastic bags to preserve the scents which they carry for a later detection process.  
         [0007]     Generally, techniques may be classified as 1) scent detection techniques which involve the provision of a stimulus comprising a scent sample to an animal which is trained to seek and identify another source of the scent, and 2) scent identification techniques involving the presentation of an objective known scent as a primary stimulus to an animal, followed by presentation of a plurality of unknown scents as secondary stimuli to the same animal to determine which of the unknown scents provokes an identification response. This latter procedure it is sometimes referred to as a “scent lineup”.  
         [0008]     As alluded to above, recent years have seen the application of electronic instrumentation to scent identification problems. Electronic instrumentation offers the advantage of sensitivity to a wide range of materials including biologicals as well as other substances which may be dispersed by an individual, and/or the things about him, into his environment. Instrumentation outputs, as compared to the binary identity information provided by trained dogs, contain a wealth of information, both quantitative and qualitative. For example, a sample may be screened for a wide variety of materials, the detection of the materials indicated and the quantitative concentrations of such materials included in an output.  
         [0009]     Over the years, scent concentration techniques have also been developed. For example, a small area of a gauze pad may be wiped over the entire surface of a hard object, such as a tabletop in an effort to collect scent deposited on the tabletop. The gauze pad is then put in envelope, for example one made of mylar, and the envelope with the gauze pad in it is sealed for later use. Thus, scent may be collected at a crime scene at a point in time when the scents are relatively freshly deposited and most plentiful, and used at a later point in time when scent has been collected from a suspect. In such circumstances, the scent collected from the suspect can be compared to the scent collected at the crime scene to determine whether the scents are the same. Such determination may be made using specially trained dogs.  
         [0010]     Techniques are also available for the collection of scent from the air. Thus, if a crime has been detected relatively quickly after the time of its commission, an air pump may be used in a vacuum cleaner-like configuration to drive, for example, all of the air in a room through a collection pad made of gauze. Here again, after the collection process has been completed, the gauze pad, imbued with the scent in the room, is put in a sealed mylar bag for later use. It is noted that in accordance with the invention other means may be used to preserve a collector imbued with odiferous materials, including, in particular, a glass or plastic vial.  
         [0011]     While these techniques work well, they do suffer from significant limitations. For example, preservation of a scent in a sealed envelope necessarily involves losses over time. Hence, the desirability of scent collection and concentration, as in the above example of a gauze pad being rubbed over a tabletop, or the alternative example of a vacuum cleaner-like device being used to collect a quantity of scent from the air in a room.  
         [0012]     Another advantage of concentration techniques is that the process makes more viable the use of electronic instrumentation, such as a mass spectrograph. In the age of electronic instrumentation, results from such devices often have a greater degree of reliability. Certainly, their operation may be more easily understood and output results more intuitively grasped by a finder of fact in a judicial proceeding. Hence, there is a higher likelihood that a positive indication of identification will be accepted by a jury or a judge in a proceeding.  
         [0013]     However, electronic detection systems are substantially less sensitive to odiferous agents as compared to animals. Accordingly, any system or method which results in concentrating a greater amount of scent improves the possibility of using electronic instrumentation. Likewise, such techniques improve the shelf life of scent samples in a scent bank. Finally, concentration of scents in a sample by more efficient collection also improves the possibility of a positive indication in a wider variety of circumstances, when using animals such as dogs to perform a scent detection or identification operation.  
       SUMMARY OF THE INVENTION  
       [0014]     In accordance with the invention a scent collection method comprises putting an item bearing a sample of a scent to be identified in an enclosure and heating the item. A quantity of air is introduced into the enclosure. The air from the enclosure is withdrawn after the item has been optionally heated. The withdrawn air is passed through a scent collection member to collect scent on the scent collection member. The scent collection member is cooled during the scent collection process and the scent collection member is then sealed in an envelope. The scent collection member is removed from the envelope in which the scent collection member has been sealed. The scent collection member is then heated and air passed through the scent collection member. The air passed through the scent collection member is used as a stimulus or other input in a scent identification procedure.  
         [0015]     The procedure may comprise using electronic instrumentation or trained animals to obtain information respecting the collected scent. Heating of the item may be performed after the enclosure has been sealed, after an item of information has been uncovered relating to the sample.  
         [0016]     An alternative method of collecting scent from a smooth surface for forensic evaluation, comprises wiping a scent collecting member over a portion of the smooth surface and enclosing the smooth surface in a scent-containing container containing air. The smooth surface is optionally heated with a sufficient degree of heat to release relatively volatile scent material into the air, while retaining less volatile material on the smooth surface. The air is driven through a collection member to collect in the collection member volatile scent material released into the air. The collection member may be cooled while driving the air through the collection member to collect in the collection member volatile scent material released into the air.  
         [0017]     In accordance with the invention a scent collection apparatus comprises an enclosure for receiving an item bearing a sample of a scent to be identified, a first heater for increasing the temperature of the item, and an air blower having an output and having an input, the input being coupled to withdrawn air from the enclosure containing the item. A scent collection member is coupled to receive the output of the air blower, whereby odiferous materials entrained within the air output by the blower are caused to accumulate on the scent collection member. A cooling member may be thermally coupled to the scent collection member. A second heater may be coupled to the scent collection member. A second air blower may be coupled to drive air to the scent collection member. A conduit passes air passed through the scent collection member to an output port for use as a stimulus in a scent identification procedure. The scent collection member may comprise a zeolite, or activated charcoal.  
         [0018]     The cooling member may comprise a Peltier cell. The first heater may comprise an electrochemical heat releasing cartridge. Alternatively, the cooling member comprises an electrochemical cooling cartridge. The second heater may comprise an electrical heater. The cooling member may also comprise a refrigerant based cooler.  
         [0019]     In accordance the invention, it is also possible to collect scent from a sample using a vacuum, with or without the heating of the sample or cooling of the collector. The invention also provides for the output of scent from a collector using a vacuum with or without the heating of the collector. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]     The operation of the invention will become apparent from the following description taken in conjunction with the drawings, in which:  
         [0021]      FIG. 1  is a perspective view of a scent collection member constructed in accordance with the present invention;  
         [0022]      FIG. 2  is a cross-sectional view of the scent collection member of  FIG. 2 a  long lines  1 - 1  of  FIG. 1 ;  
         [0023]      FIG. 3  illustrates an alternative embodiment of a scent collection member constructed in accordance with the present invention and including a narrowed portion to facilitate cooling or heating of the same;  
         [0024]      FIG. 4  is a cross-sectional view of the scent collection member of  FIG. 3  along lines  4 - 4  of  FIG. 3 ;  
         [0025]     FIGS.  5  is a cross-sectional view similar to that of  FIG. 4  showing the use of a Peltier cell to cool the same;  
         [0026]     FIGS.  6  is a perspective view of a slotted bottle for cooling or heating the scent collection member constructed in accordance with the present invention;  
         [0027]      FIG. 7  cross-sectional view similar to that of  FIG. 5  but showing the use of a slotted bottle to achieve cooling or heating of a scent collection member;  
         [0028]      FIG. 8  is a perspective view of an alternative slotted bottle;  
         [0029]      FIG. 9  is a schematic view of a system for concentrating scent in a scent collector;  
         [0030]      FIG. 10  is a schematic view of an alternative system for concentrating scent in a scent collector;  
         [0031]      FIG. 11  is a schematic view of another alternative system for concentrating scent in a scent collector;  
         [0032]      FIG. 12  is a schematic view of a system for outputting concentrated scent from a scent collector;  
         [0033]      FIG. 13  is a flowchart illustrating a method of performing a forensic odiferous material identification in accordance with the present invention;  
         [0034]      FIG. 14  is a flowchart illustrating an alternative method of performing a forensic odiferous material identification in accordance with the present invention;  
         [0035]      FIG. 15  is a flowchart illustrating another method of performing a forensic odiferous material identification in accordance with the present invention; and  
         [0036]      FIG. 16  is a schematic view of an alternative system for concentrating scent in a scent collector. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0037]     In accordance with the present invention, a collection cartridge  10  constructed of a tubular plastic member  12  is provided with an internal collection member  14  which may be made from a wide range of materials, such as packed fibrous material, for example cotton or polyester. In accordance with a preferred embodiment of the present invention, the material may be selected with desired surface characteristics. For example one may use a hydrophobic material or a hydrophilic material, depending upon the characteristics of the materials which one anticipates collecting.  
         [0038]     In accordance with a preferred embodiment, collection member  14  is made of charcoal. Charcoal or acticated charcoal is particularly advantageous, as it is porous and the pores can absorb and retain large amounts of molecules. Collection member is baked and out gassed to ensure that the charcoal is free of any contaminating scents from handling, manufacturing, and so forth. The uncontaminated collection member is then packaged in a sealed bag, made, for example, of metalized plastic film, such as Mylar (R) plastic. The bag is opened just before it is to be used. This is especially critical in the event that crime scene air is to be used as a scent source.  
         [0039]     Collection member  14  may also be of a non-fibrous nature, such as open cell foam plastic, particles, or any other material whose structure allows air to pass through it, such as a collection screen, wire mesh, or the like. All of the same may also be given desired hydrophilic or hydrophobic characteristics.  
         [0040]     In accordance with one particularly preferred embodiment of the invention in which a collection cartridge  10  is cooled in order to maximize the amount of scent material collected, collection members  14 , having a high specific heat or thermal capacity and thus the ability to absorb or release a large amount of heat, if cooled prior to a collection operation are particularly effective to collect material for analysis.  
         [0041]     Sand, metal grindings, powdered glass and the like will also function, if pre-cooled, to effectively condense odiferous materials.  
         [0042]     Charcoal and zeolites and other porous structures are particularly preferred collection materials in collection member  14 .  
         [0043]     If desired, the collection member  14  may be kept in place by a pair of support walls  16  and  18 . Support walls  16  and  18  define holes  20 , which provide for the passage of air containing odiferous materials. During use, air carrying various scents is caused to enter into an inlet port  22 , pass through holes  20 , and enter collection member  14 . The odiferous materials are then caused to collect on the constituent fibers, particles, or the like of collection member  14 . Air which has been stripped of odiferous materials then passes through holes  20  in support wall  16  and pass to output port  24 .  
         [0044]     When the collection operation has been completed, airtight plugs  26  and  28  may be inserted into ports  22  and  24  to lock in collected odiferous material. In accordance with a preferred embodiment of the invention, this sealing operation would be made further effective by putting the plugged collector  10  in a plastic bag (for example a metalized plastic bag), and then sealing the bag and removing all excess air from the bag.  
         [0045]     An alternative collection cartridge  110  is illustrated in  FIG. 3 . Generally the construction of cartridge  110  is similar to that of the cartridge of  FIG. 1 , except that the central area  130  is of a relatively flattened configuration in order to promote the cooling of collection members  114 , as is illustrated in  FIG. 4 .  
         [0046]     Such cooling may be achieved using something as simple as a bag of ice water, dry ice, or the like. Alternatively, referring to  FIG. 5 , an electrothermal cooling device  132  may be used to provide the desired degree of cooling. Still another alternative cooling device is a bottle filled with a coolant, such as cold water, powdered dry ice, or the like. Such a bottle  134  is illustrated in  FIG. 6 . As illustrated in  FIG. 7 , bottle  134  has a cap  136  allowing the inside  138  to be filled with a cooling material. Bottle  134 , after it is filled with a coolant, such as powdered dry ice, is sealed with cap  136 . Bottle  134  defines a central space  140  which may be slid over central portion  130  of cartridge  110 . Such an arrangement is shown in  FIG. 7 .  
         [0047]      FIG. 8  illustrates an alternative bottle  234  having an elongated neck which may be easier to fill with material and which also has a higher capacity for cooling a scent collection cartridge because of its increased volume.  
         [0048]     An apparatus  350  for collecting odiferous material in accordance with the invention is illustrated in schematic form in  FIG. 9 . In accordance with the invention, a blower  352  exhausts air into a chamber  350  which contains a scent bearing item, such as a garment  356 . Air which passes over garment  356  draws away odiferous materials which are driven into a cartridge, such as cartridge  10  which is cooled by a coolant device, such as bottle  234 . They air, stripped of these odiferous materials, is then exhausted through an output duct  358 . After the operation has been completed, cartridge  10  is put in an air tight envelope, as described above.  
         [0049]     An alternative arrangement is illustrated in  FIG. 10 . In this arrangement, the output of blower  452  is heated by heater  460 . Thus, the air circulating around and passing through garment  456  is heated and this results in a greater removal of odiferous materials from the garment located in chamber  454 . The air exiting chamber  454  is then driven into cartridge  434 , where odiferous material is collected.  
         [0050]     Referring to  FIG. 11 , an arrangement incorporating the advantages of the arrangements of  FIG. 9  and  FIG. 10  is illustrated. In this arrangement, the output of blower  552  is heated by heater  560 . Thus, the air circulating around garment  556  is heated and this results in a greater removal of odiferous materials from the garment located in chamber  554 . The air exiting chamber  554  is then driven into cartridge  510 , where odiferous material is collected. Cartridge  510  is cooled by a coolant device  534 . After the operation has been completed, cartridge  510  is put in an air tight envelope, as described above.  
         [0051]     Referring to  FIG. 12 , when it is decided to analyze the odiferous material saved in a cartridge fabricated in accordance with the present invention and loaded with odiferous material in accordance with the present invention, a cartridge, such as cartridge  10 , is placed in a system  660  such as that illustrated in  FIG. 12 . System  660  comprises a blower  662 . Blower  662  blows air into a heater  660 , resulting in the introduction of warm air into cartridge  10 . The use of warm air in cartridge  10  results in a greater release of odiferous material in a relatively short period of time resulting in a relatively sensitive detection of odiferous material by an analytic device  664 , such as a GC head space mass spectrometer.  
         [0052]     The methodology of the present invention is illustrated in  FIG. 13 . In accordance with this embodiment of the invention, a method  700  begins with the step  710  of encasing an item of evidence such as a garment in an airtight plastic bag. The air in the plastic bag is heated at step  712 . A cartridge, such as cartridge  10 , is then cooled at step  714 . Air is then driven through the garment at step  716  and the exhaust is collected on collector  10  at step  718 . The loaded collector  10  is then put in a sealed plastic bag at step  720  and deposited in a bank at step  722 . At an appropriate time, the loaded collector  10  is selected at step  724  and heated at step  726  in an apparatus such as that illustrated in  FIG. 12 . At the same time, hot air is passed through collector cartridge  10  and the exhaust collected at step  728 . At step  730  the exhaust is passed to an analyzer which produces a fingerprint of the odiferous materials, volatiles and the like previously collected in collector cartridge  10  and released during step  728 . At step  730  the analysis is sent to a database of odiferous data which is consulted to determine whether there is any match during a comparison step  734 . If there is a match, at step  736 , an indication is made, or a rating of the match is given. If a match or close match is not found, the system returns to the database to make a comparison with other fingerprints stored in the database. Alternatively, all fingerprints in the database may be compared and the top matches indicated at step  740 .  
         [0053]     An alternative process is illustrated in  FIG. 14 . However, in this method  800 , close comparison is assessed at step  842 , and if there is not a finding within preset ranges, the system returns to consult the database at step  832 . If the degree of closeness is within the preset ranges, the information with respect to the database entry is stored at step  844 . If the degree of closeness is strong enough to result in the finding of a match, this is determined at step  846  and the output provided at step  840 . If the sample does not qualify as a scent match to a scent in the database, the system returns at step  846  to step  832 , where the database is again consulted. When all entries in the database have been consulted, the system evaluates results and outputs the best matches at step  840 . Such output takes the form of a list of candidates with decreasing scores, where the score is proportional to the exactness of the matching.  
         [0054]     In many cases, and odors is taken from a crime scene and have information which one would like to preserve until more evidence is found. The options are to create an electronic record on the scent and put it into a database for later identification as in the methods of the  FIGS. 13 and 14 . Alternatively, one may choose to simply preserve a collector cartridge with a particular scent until a later piece of evidence is found to which it can be compared. In the second case, two collectors would be heated simultaneously and compared.  
         [0055]     In accordance with this method  900 , an item of evidence is encased at step  910 , treated as in the method of  FIG. 13  and stored at step  922 . When an item of evidence is discovered at a later time, it is encased at step  1010 , processed as in the method of  FIG. 13 , and transported at step  1022 .  
         [0056]     The collector cartridge containing the later discovered evidence is then heated, and heated air is blown through it for analysis at step  1030 . Likewise, the stored sample is selected at step  924 , heated and subjected to a flow of heated air and the exhaust collected and analyzed at step  930 , in much the same manner as the method of  FIG. 13 . The two analyses are then compared to each other at step  934  and the degree of match then noted for presentation as evidence, for example by an expert in a court hearing at step  936 .  
         [0057]     If desired, multiple samples may be taken at a crime scene, or even from a single garment by cutting the garment into two or more pieces, and when an identification is made with a forensic instrument, dogs may be used to make a collaborating identification.  
         [0058]     Referring to  FIG. 16 , still yet another alternative embodiment of the inventive apparatus for collecting scent is illustrated. In accordance with this embodiment, a sample of clothing is placed in a bag  1054 . A cartridge  1010  is connected to receive air from bag  1054 . The system is completed by a vacuum source  1052  which is activated after clothing has been put in bag  1054  and cartridge  1010  inserted in line. The result is to draw air containing scent through cartridge  1010 . In accordance with the preferred embodiment, the system of  FIG. 17  may be modified through the use of a coolant device as illustrated in  FIG. 9 , for the purpose of cooling collector cartridge  1010 . Alternatively or in addition, means may be provided for heating the contents of bag  1054  to induce the outflow of more odiferous material. In accordance with a preferred embodiment of the invention, it is anticipated that the inventive system will include a charcoal scent collecting filter. Before being used, the filter is treated in a baking or out gassing operation to ensure that the charcoal is free of any contaminating scent from handling, manufacturing or any other processes through which it has been. The treated charcoal filter is sealed in a plastic bag and only opened when it is being used at the crime scene or when it is being used in the lab.  
         [0059]     In accordance with the invention, it is not necessary that such a charcoal filter, or any filter be cooled. Likewise, it is not necessary that samples of material bearing scents, such as clothing, be heated.  
         [0060]     It is also noted that accordance with the present invention a collection cartridge, for example any charcoal or zeolite collection filter may be simply left in a room where a crime has been committed and scents allowed to be absorbed into it. Another option in accordance with the present invention is to blow air from the crime scene through a collector. For example, the room where the crime has been committed may be sealed and a scent collection cartridge placed in the room with a blower to blow air through it.  
         [0061]     It is particularly advantageous in accordance with the present invention to use scent collection materials, such as charcoal or zeolites which have pores in them and which have the capacity of collecting large amounts of scent.  
         [0062]     It is also noted that in accordance with the present invention, specific scent-collection materials, such as charcoal or zeolites may be selected for their characteristic of being selective or effective with respect to the collection of various target scent material(s).  
         [0063]     In addition, it is noted that any appropriate a device may be used for the purpose of measuring the characteristics of odiferous materials, as may be used in the art. However, it is believed that a GC head space mass spectroscopy instrument is most effective in quantitatively measuring a “scent fingerprint” given the relatively modest amounts of odiferous material typically found or collectible at a crime scene.  
         [0064]     While an illustrative embodiment of the invention has been described, it is, of course, understood that various modifications may be made by those of ordinary skill in the art. Such modifications are within the spirit and scope of the invention, which is limited and defined only by the appended claims.