Abstract:
Disclosed is a portable non-destructive testing (NDT) instrument system that transmits spectrum data measured from a test material sample to a remotely located computer for computation of the sample&#39;s atomic element composition. The atomic element composition is subsequently transmitted back to the portable instrument for display to the operator in real time. The precision and accuracy of the compositional computation is improved by the greater processing power of the high performance remote computer. The operator of the NDT instrument may choose to use the remote computer to perform part or all of the compositional computation.

Description:
FIELD OF THE INVENTION 
       [0001]    The present disclosure relates to portable x-ray fluorescence (XRF) analytical inspection instruments, and more particularly to an instrument system which measures the elemental composition (henceforth referred to as ‘chemistry’) of a test sample, and which is operable by selectively transmitting measured spectrum data to a remotely located computer for remote computation of the chemistry. The chemistry result is subsequently transmitted back to the portable instrument for display to the user in real time. 
       BACKGROUND OF THE INVENTION 
       [0002]    Conventional portable XRF analytical instruments consist of an emitter which emits an excitation, a sensor which senses response signals emanating from a test material sample, and a spectrum constructor which constructs a spectrum of the intensity vs energy or wavelength of the response signals. The spectrum is converted to the sample&#39;s chemistry by a series of computationally intensive algorithms, and then rendered on the display of the portable instrument. 
         [0003]    In the case of an energy dispersive XRF device, the spectrum is a histogram of the energy levels sensed by the X-ray detector during the measurement process. In the case of optical sensor-based instruments, such as Laser Induced Breakdown Spectroscopy (LIBS) and Near Infrared Spectroscopy (NIRS), among others, the spectrum is a histogram of the wavelengths of the electromagnetic energy emanating from the test material sample. 
         [0004]    The primary purpose for using such analytical instrument technologies is to quickly and accurately determine the chemistry of a material test sample in order to classify it qualitatively or quantitatively. A qualitative classification indicates that one or more atomic elements of interest are present in a material test sample. A quantitative classification indicates the concentration of one or more atomic elements of interest that are present in a material test sample. For optimal inspection productivity, and to reduce measurement variability, it is important to minimize the time interval between the start of a measurement cycle and its end when the chemistry result is displayed. This has been a long standing challenge for designers of analytical portable instruments. 
         [0005]    Presently, all of the signal processing required to derive chemistry information from a raw spectrum is performed entirely within the portable instrument. This is hereafter referred to as “on-board” processing. In on-board processing, the signal processing performance is not optimal due to the practical constraints associated with a portable instrument, such as power consumption and electronics packaging space. Accordingly, the limits placed on the speed and amount of signal processing required for producing a highly accurate chemistry result cause conventional instruments to be far from optimal as compared to what could be achieved if such constraints did not exist. 
       SUMMARY OF THE INVENTION 
       [0006]    It is the general object of the present disclosure to overcome the problems associated with background art by introducing an instrument system with a substantially improved measurement chemistry result that can be displayed to the user of a portable analytical instrument in real time. 
         [0007]    More specifically, the general object of the present disclosure is to improve the speed, precision and accuracy of the chemistry calculation performed on the spectrum data acquired by the portable instrument from a test sample material. This is achieved by transmitting the spectrum data to a high performance remote computer in order to perform the intensive signal processing required to determine the sample&#39;s chemistry with a high degree of fidelity, and then returning the result to the portable instrument to be displayed in real time without any noticeable delay. (i.e. The complete measurement cycle should be less than about one second). This method of transmitting data to a high performance remote computer is hereafter referred to as “remote” or “off-board” processing, the two terms being used interchangeably. 
         [0008]    The foregoing and other objects of the present disclosure may be realized with a portable instrument, a remote computing capability, a communication interface that can be wireless or have a physical cable connection, and a means to apply spectrum processing and/or chemistry conversion outside of the portable instrument. The remote computing capability may include connection to a specific computer or connection via internet to distributed computation capability hereafter referred to as “the Cloud”. 
         [0009]    In accordance with various embodiments of the invention, disclosed is an arrangement of an analog to digital converter (ADC), a spectrum constructor, an on-board data processing unit having two or more operation modes, and having physical or wireless data connections with one or more remote computers, including computers located in the Cloud. The on-board data processing unit is thereby able to take advantage of the increased processing power of remote computers during measurement of the chemistry of a material sample. The primary object of the present disclosure is to outsource the hardware limitations of a portable instrument to a computer system of greater processing power. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a schematic view of the preferred embodiment according to the present disclosure. 
           [0011]      FIG. 2A  is a schematic view of the embodiment with regular on-board data processing selected according to the present disclosure. 
           [0012]      FIG. 2B  is a schematic view of the embodiment wherein the remote computer performs all of the spectrum processing and conversion to chemistry according to the present disclosure. 
           [0013]      FIG. 2C  is a schematic view of the embodiment where the portable instrument performs the spectrum processing and the remote computer performs the conversion to chemistry according to the present disclosure. 
           [0014]      FIG. 2D  is a schematic view of the embodiment where the portable instrument performs part of the spectrum processing and the remote computer completes the spectrum processing and then performs the conversion to chemistry according to the present disclosure. 
           [0015]      FIG. 3A  is a flow chart showing initialization of the communication between the portable instrument and a remote computer. 
           [0016]      FIG. 3B  is a flow chart of the embodiment where the remote computer performs all of the spectrum processing and conversion to chemistry. 
           [0017]      FIG. 3C  is a flow chart of the embodiment where the portable instrument performs the spectrum processing and the remote computer performs the conversion to chemistry. 
           [0018]      FIG. 3D  is a flow chart of the embodiment where the portable instrument performs part of the spectrum processing and the remote computer completes the spectrum processing and then performs the conversion to chemistry. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]      FIG. 1  illustrates an X-ray analytical system according to the present disclosure, the system typically being used for chemical composition analysis. The system comprises a portable X-ray analytical instrument (not shown), an X-ray source  8  emitting X-rays, a test material sample  4 , a detector  2 , an analog to digital converter (ADC)  12 , a spectrum constructor  34 , an on-board data processing unit  10 , an off-board data processing unit  11 , and a display  19 . The X-ray analytical system of  FIG. 1  has various operation modes, optionally including an on-board operation mode  28 , a remote operation mode  46 , a first shared operation mode  54  and further optionally a second shared operation mode  64 . On-board data processing unit  10  includes an operator mode selector  17  acting on a logical mode switch  25 . Data from spectrum constructor  34  is passed to mode switch  25  via data path S- 6 . Mode switch  25  directs the data to the one selected operation mode  28 ,  46 ,  54  or  64  via the corresponding data path S- 1 , S- 2 , S- 3  or S- 4 . 
         [0020]    The portable instrument performs a measurement cycle by exposing test material sample  4  to the output of excitation source  8  and detecting the resulting response with detector  2 . The output signal of detector  2  is provided to ADC  12 , the output of which is sent to spectrum constructor  34 , which is a fast processor such as a Field Programmable Gate Array (FPGA) programmed to produce a spectrum from the data acquired during the measurement. Depending on operator mode selection  17 , processing of the output from spectrum constructor  34  is accomplished either by on-board operation mode  28 , or by remote operation mode  46 , or by first shared operation mode  54 , or by second shared operation mode  64 . Complex and computationally intensive algorithms, well known to those skilled in the art, are required to derive the chemistry of test material sample  4  from the spectrum created by spectrum constructor  34 . Steps in deriving the chemistry of test material sample  4  may include application of calibration data for the particular portable instrument being used, application of algorithms to correct for the effect of the sample matrix on the elemental data in the spectrum, or comparison of processed elemental data with known material compositions to identify the material of the test material sample  4 . As disclosed in the various embodiments of the present invention, depending on operator selection, all these steps may be performed on-board the portable instrument, or they may all be performed remotely, or the steps may be shared in various ways between the portable instrument and the remote computing capability. 
         [0021]    Also shown in  FIG. 1  is a two-way data transmission system  20  transmitting data between on-board data processing unit  10  and off-board data processing unit  11 . The data transmission system comprises a pair of transceivers  20   a  and  20   b , which may receive and transmit data wirelessly or via a physical data connection. Two-way data transmission system  20  enables exchange of information between on-board data processing unit  10  and off-board data processing unit  11  by means of a standard wireless interface, such as WLAN or Bluetooth, or by means of a physical data connection, which may consist of a cable with a standard data transfer interface, such as USB, Ethernet or RS232. When a description of an embodiment refers to either the wireless or the cable connection, it is intended to denote that the other may be used if necessary or desired. 
         [0022]    It should be noted that the signals exchanged between on-board data processing unit  10  and off-board data processing unit  11  can pass through a network router, a smart phone, or other intermediary device present in the communication path, and such intermediary devices are within the scope of the present disclosure. 
         [0023]    It should be herein noted that one of the most important novel aspects of the present disclosure is to utilize a means of logical mode selection, such as switch  25 , to allow the selection among at least two operational modes, each having different ways of splitting the task of spectrum processing and conversion to chemistry between a handheld X-ray analytical instrument and a remote computer. 
         [0024]    Another novel aspect of the present disclosure is to allow operators to determine the selection mode based on the factors of inspection setup, i.e., the available data speed of data transmission system  20 , the required resolution and accuracy of the analysis and the required speed of the measurement cycle. 
         [0025]    Although the teachings in the present disclosure apply to any portable X-ray or optical analytical instrument used for non-destructive testing (NDT), the exemplary embodiment described herein is an X-ray fluorescence (XRF) instrument. 
         [0026]    A measurement cycle of the portable instrument ends when the instrument receives and displays the calculated chemical composition of test material sample  4 . The measurement cycle is preferably completed in less than one second; however, users may set a longer time if they wish to obtain a more accurate chemistry result. 
         [0027]    Referring again to  FIG. 1 , when on-board operation mode  28  is selected, spectrum processing and conversion to chemistry are all performed by on-board data processing unit  10 , as further shown in  FIG. 2A , in which on-board data processing unit  10  has no wireless or other remote data connections. When remote operation mode  46  is selected, spectrum processing and conversion to chemistry are all performed by off-board data processing unit  11 , as further shown in  FIG. 2B . When shared processing modules  54  or  64  are selected, spectrum processing and conversion to chemistry can be shared in various ways between on-board data processing unit  10  and off-board data processing unit  11 . Examples of such sharing are further shown in  FIGS. 2C and 2D . 
         [0028]    It should be noted that off-board data processing unit  11  represents all possible remotely accessed computing facilities, commercially available or proprietary to a specific party. It should also be appreciated that off-board data processing unit  11  may be a stand-alone computer or may be part of the Cloud computing network, and such alternation is also within the scope of the present disclosure. 
         [0029]      FIG. 2A  shows the on-board operation mode  28  in more detail. Directed by mode switch  25 , spectrum data from selected data path S- 1  enters on-board operation mode  28 . The data is processed by spectrum processor  36   a  and converted to chemistry by spectrum-to-chemistry converter  38   a . The chemistry result is stored as stored chemistry result  40   a  and/or sent as test result  21   a  to be shown on the on-board display  19 . It should be noted that when mode switch  25  is set to select on-board operation mode  28 , the instrument is effectively a conventional XRF handheld instrument with all data processing completed on-board. 
         [0030]    Reference is now made to  FIG. 2B , which illustrates an alternative operation mode  46 , which is included in both an on-board data processing unit  10  and an off-board data processing unit  11 . Directed by mode switch  25 , spectrum data from selected data path S- 2  enters remote operation mode  46 , and is transmitted to off-board data processing unit  11  by means of data transmission system  20 . A received spectrum  50   b  is processed by a remote spectrum processor  36   b  and converted to chemistry by a remote spectrum-to-chemistry converter  38   b . The chemistry result may be stored remotely at stored chemistry result  40   b  and/or sent as test result  21   b  to the on-board display  19  via sent test result  42   b  and data transmission system  20 . 
         [0031]      FIG. 2C  illustrates a first method of sharing data processing, showing a shared operation mode  54  which is included in both an on-board data processing unit  10  and an off-board data processing unit  11 . Directed by mode switch  25 , spectrum data from selected data path S- 3  enters shared operation mode  54 . The data is processed by on-board spectrum processor  36   c , and then transmitted to off-board data processing unit  11  by means of data transmission system  20 . A received processed spectrum  50   c  is converted to chemistry by a remote spectrum-to-chemistry converter  38   c . The chemistry result may be stored remotely at stored chemistry result  40   c  and/or sent as test result  21   c  to the on-board display  19  via sent test result  42   c  and data transmission system  20 . 
         [0032]      FIG. 2D  illustrates a second method of sharing data processing, showing a shared operation mode  64 , which is included in both an on-board data processing unit  10  and an off-board data processing unit  11 . Directed by mode switch  25 , spectrum data from selected data path S- 4  enters shared operation mode  64 . Data is partially processed by on-board partial spectrum processor 1   36   d , and then transmitted to off-board data processing unit  11  by means of data transmission system  20 . Data from a received partially processed spectrum  50   d  is passed to partial spectrum processor 2   36   e  where spectrum processing is completed. The processed spectrum is then converted to chemistry by a remote spectrum-to-chemistry converter  38   d . The chemistry result may be stored remotely at stored chemistry result  40   d  and/or sent as test result  21   d  to the on-board display  19  via sent test result  42   d  and data transmission system  20 . 
         [0033]    It should be noted that spectrum processors  36   a ,  36   b ,  36   c ,  36   d , and  36   e  preferably use different algorithms for processing, with some requiring less and some requiring more computing power, yielding results of less or more accuracy, respectively. Typically, on-board spectrum processors such as  36   a ,  36   c  and  36   d  have algorithms yielding less accuracy while requiring less computing power. Remote spectrum processors such as  36   b  and  36   e  have algorithms yielding more accuracy while requiring more computing power. Similarly, corresponding spectrum-to-chemistry converters  38   a ,  38   b ,  38   c , and  38   d  are also preferably configured to use different algorithms with some requiring less and some requiring more computing power, yielding results of less or more accuracy, respectively. As such, on-board spectrum converters such as  38   a  have algorithms yielding less accuracy while requiring less computing power. Remote spectrum converters such as  38   b ,  38   c  and  38   d  have algorithms yielding more accuracy while requiring more computing power. This is yet another novel aspect of the present disclosure which allows operators the freedom to choose algorithms and computing power suited to the requirements for speed and accuracy of the specific NDT test procedure. 
         [0034]    In addition, spectrum processors  36   a ,  36   b ,  36   c ,  36   d , and  36   e , and corresponding spectrum-to-chemistry converters  38   a ,  38   b ,  38   c , and  38   d , are depicted as separate functional blocks in  FIGS. 2A-2D . However, each spectrum processor and its corresponding converter can be within the same or separate integrated circuit. Both of these embodiments are within the scope of the present disclosure. 
         [0035]      FIG. 3A  is a flow chart which describes an initialization process  14 , comprising steps of setting up the portable instrument to operate with remote communication capability. In step  600 , both the portable instrument and the remote computer are initialized. In step  602 , the portable instrument verifies its communication link with off-board data processing unit  11 . In step  604 , the portable instrument&#39;s parameters and settings are sent to off-board data processing unit  11 , and in step  606  the portable instrument is ready to perform measurements with both on-board and remote data analysis capability. 
         [0036]      FIG. 3B , which should be viewed in conjunction with  FIG. 2B , is a flow chart describing the steps of performing remote spectrum processing and chemistry conversion with remote operation mode  46 . In step  700 , the portable instrument performs a measurement on test material sample  4 , and in step  702  it sends the resulting spectrum to off-board data processing unit  11 . In step  704 , the remote computer performs processing on the spectrum, and in step  706 , the remote computer applies chemistry conversion algorithms to the spectrum. In step  708 , the remote computer sends the results back to the portable instrument, and in step  710 , the portable instrument displays the chemistry information of test material sample  4 . 
         [0037]      FIG. 3C , which should be viewed in conjunction with  FIG. 2C , is a flow chart describing the steps of a first embodiment of performing shared spectrum processing and chemistry conversion with shared operation mode  54 . In step  800 , the portable instrument performs a measurement on test material sample  4 , and in step  802  it performs on-board processing of the resulting spectrum. In step  804  the portable instrument sends the processed spectrum to off-board data processing unit  11 . In step  806 , the remote computer applies chemistry conversion algorithms to the spectrum. In step  808 , the remote computer sends the results back to the portable instrument, and in step  810 , the portable instrument displays the chemistry information of test material sample  4 . 
         [0038]      FIG. 3D , which should be viewed in conjunction with  FIG. 2D , is a flow chart describing the steps of a second embodiment of performing shared spectrum processing and chemistry conversion with shared operation mode  64 . In step  900 , the portable instrument performs a measurement on test material sample  4 , and in step  902  it performs partial on-board processing of the resulting spectrum. In step  904  the portable instrument sends the partially processed spectrum to off-board data processing unit  11 . In step  905  the remote computer completes processing of the spectrum, and in step  906  the remote computer applies chemistry conversion algorithms to the processed spectrum. In step  908 , the remote computer sends the results back to the portable instrument, and in step  910 , the portable instrument displays the chemistry information of test material sample  4 . 
         [0039]    Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention not be limited by the specific disclosure herein.