Abstract:
Sampling device geometry reduces specular reflectance, using lenses to focus electromagnetic energy to predominately return scattered rather than reflected electromagnetic energy to detector(s), reducing effect of non-matte surfaces and/or window. Sampling device includes inherent automatic optical calibration, and optionally thermal calibration. Calibration detectors are optically isolated with respective emitters.

Description:
BACKGROUND 
     1. Field 
     This disclosure generally relates to evaluation systems, and more particularly to systems that evaluate characteristics of substances using electromagnetic energy. 
     2. Description of the Related Art 
     Various systems employ spectral analysis returned from a sample of a substance to analyze the sample and/or recognize the substance. 
     For example, U.S. Pat. No. 8,076,630 describes systems and methods of evaluating objects using electromagnetic energy. In particular, U.S. Pat. No. 8,076,630 teaches a system for evaluating subject objects, the system which includes at least one physical source operable to emit electromagnetic energy and driver electronics drivingly coupled to at least one physical source. The driver electronics drive at least one physical source as a number of logical sources, using an electromagnetic forcing function where the number of logical sources is greater than the number of physical sources. In addition, the system includes a sensor to receive an electromagnetic response from at least a portion of an evaluation object illuminated by one or more physical sources operated as logical sources, and convert the electromagnetic response to a test response signal indicative of the electromagnetic response of the evaluation object. 
     Also for example, U.S. Pat. No. 7,996,173 describes methods, apparatus and articles to facilitate distributed evaluation of objects using electromagnetic energy. In particular, U.S. Pat. No. 7,996,173 teaches that objects such as manufactured goods or articles, works of art, media such as identification documents, legal documents, financial instruments, transaction cards, other documents, and/or biological tissue are sampled via sequential illumination in various bands of the electromagnetic spectrum, and a test response to the illumination is analyzed with respect to reference responses of reference objects. U.S. Pat. No. 7,996,173 teaches that the sequence may be varied. For instance, the sequence may define an activation order, a drive level and/or temperature for operating one or more sources. Illumination may be in visible, infrared, ultraviolet, or other portions of the electromagnetic spectrum. U.S. Pat. No. 7,996,173 further teaches that elements of the evaluation system may be remote from one another, for example communicatively coupled via a network. 
     As a further example, U.S. Pat. No. 8,081,304 describes the use of spectral information in process control and/or quality control of goods and articles. In particular, U.S. Pat. No. 8,081,304 describes the use of spectral information in process control and/or quality control of media, for example, financial instruments, identity documents, legal documents, medical documents, financial transaction cards, and/or other media, fluids, for example lubricants, fuels, coolants, or other materials that flow, and in machinery, for example, vehicles, motors, generators, compressors, presses, drills and/or supply systems. U.S. Pat. No. 8,081,304 further describes the use of spectral information in identifying biological tissue and/or facilitate diagnosis based on biological tissue. 
     The above described patents are only representative. 
     BRIEF SUMMARY 
     It may be useful to analyze substances to determine various physical characteristics of the substances and/or to recognize the substance as being or not being a specific type of substance. In order to reliably analyze and/or recognize a substance, it may be useful to sample the substance at a relatively large number of distinct wavelengths or bands of wavelengths of electromagnetic energy. The wavelengths may, for example, include some or all wavelengths in an optical portion of the electromagnetic spectrum, from near-infrared (N-IR) to near-ultraviolet (N-UV), inclusive, including a visible portion that is visually perceptible to humans. Accurately performing such analysis or recognition typically requires a relatively large number of distinct sources or emitters, e.g., solid-state sources of electromagnetic energy such as light emitting diodes (LEDs), each operable to emit electromagnetic energy in a respective range or band of wavelengths which may or may not partially overlap with one another. 
     To achieve a high degree of reliability it may be advantageous to perform calibration. Calibration can address issues raised by variations in source performance, for example, variations in wavelength output due to age, changes in temperature, or even in manufacturing tolerances (e.g., from batch to batch from a given emitter manufacturer). However, to be effective, calibration will typically need to be performed automatically, preferably with little to no user or operator interaction. Also, to be effective, calibration with respect to sources or emitters should employ calibration targets or samples with known characteristics (e.g., spectral characteristics) which are stable and do not vary over time. 
     Providing for automatic calibration may enhance the accuracy of sampling devices. Providing for automatic calibration in a compact form factor may further allow for small, portable sampling devices, which are highly accurate. 
     Scattering is a physical process in which some forms of electromagnetic radiation deviate from a straight path or trajectory due to localized non-uniformities in a medium through which the electromagnetic radiation passes. As commonly used, this also includes deviation of reflected electromagnetic radiation from an angle predicted by the law of reflection. Reflections that undergo scattering are often called diffuse reflections, while unscattered reflections are called specular (e.g., mirror-like) reflections. 
     There are two principal scattering mechanisms, Rayleigh scattering and Raman scattering. In Rayleigh scattering most photons are elastically scattered such that scattered photons have the same kinetic energy (frequency and wavelength) as the incident photons. In Raman scattering scattered photons are scattered by excitation, having a frequency that is different from, and usually lower than, that of the incident photons. For any given sample both mechanisms will typically apply, with Raman scattering making up a smaller fraction of the total scattering. Raman is particularly useful in analyzing composition of liquids, gases and solids. 
     Lambertian reflectance characterizes an ideal diffusely reflecting surface. An apparent brightness of such an ideal diffusely reflecting surface is the same regardless of angle of view. Technically, the luminance of a surface is isotropic, and luminous intensity obeys Lambert&#39;s cosine law. Lambertian reflection from polished (i.e., glossy or non-matte) surfaces is typically accompanied by specular reflection. The luminance of a polished or glossy surface is largest when viewed at a perfect reflection direction (i.e., where a direction of the reflected light is a reflection of the direction of the incident light in the surface). The luminance falls off sharply as direction (i.e., angle) changes. 
     To achieve a high degree of accuracy, in some implementations it may be advantageous to eliminate specular reflection or at least allow discrimination between scattered and specular reflection. Such reflection may be from a sample or specimen itself, a surface on which the sample or specimen resides, or even a component of a sampling device, for instance, a protective window or lens cover. 
     To achieve a high degree of accuracy, in some implementations it may be advantageous to separate specular reflection from diffuse reflection, detecting each separately. 
     Sampling devices employing automatic calibration and/or separation of specular reflection may be effective employed in the object analysis, evaluation or identification to various applications, for example: manufacturing process control, quality assurance, media authentication, biological tissue recognition, identification, verification, authentication, classification, and/or diagnostics. 
     A sampling system may be summarized as including a sampling device, the sampling device including: a housing; a plurality of emitters received in the housing, each of the emitters selectively operable to emit electromagnetic energy in a respective range of wavelengths in an optical portion of the electromagnetic spectrum, the ranges of wavelengths of at least some of the emitters different from the ranges of wavelengths of others of the emitters; at least one primary sampling sensor received in the housing and positioned to receive electromagnetic energy returned to the sampling device by a sample, if any, illuminated by the electromagnetic energy emitted by at least one of the emitters, the at least one primary sampling sensor responsive to a number of wavelengths of electromagnetic energy returned to the sampling device; and at least one calibration sensor received in the housing and positioned to receive electromagnetic energy emitted by at least one of the emitters substantially free of electromagnetic energy returned to the sampling device, the at least one calibration sensor responsive to a number of wavelengths of electromagnetic energy emitted by the emitters. 
     The at least one calibration sensor may include at least one calibration sensor per emitter. The calibration sensors may be matched to the output of the respective emitters. 
     The sampling system may further include an endless array of compartments which isolate each of a number of the emitters from one another. 
     The endless array of compartments may be formed as a unitary single-piece annular array arranged about a central passage. Each of the calibration sensors may be positioned in a respective one of the compartments of the endless array of compartments. Each compartment may include a slot that limits entrance into the respective compartment of spectral illumination returned to the sampling device from the specimen, if any. The respective calibration sensors may be positioned in the respective compartments shielded from the respective slots. The compartments may each have walls, the entirety of the wall(s) colored black. 
     The sampling system may further include at least one optical tap that provides a respective distinct optical path between a position at least proximate respective ones of the emitters and respective ones of the calibration sensors. 
     The at least one optical tap may be an integral portion of the endless array of compartments. The at least one optical tap may consist of a high grade optical resin (e.g., cyclic polyolefin). 
     The compartments may each have walls, a portion of the wall(s) colored black and a portion of the wall(s) colored a reference color. The calibration sensors may be matched to the output of the respective emitter with which the calibration sensor is compartmentalized. The calibration sensors may each consist of a single optical sensor chip that detects from near-infrared (N-IR) through near-ultraviolet (N-UV) wavelengths of electromagnetic energy. 
     The sampling system may further include a first circuit board on which the emitters are arrayed in a circular array; and an annular array of distinct lenses physically coupled to one another as an integral one-piece construction which includes a circular band that physically couples the distinct lenses to one another, each of the distinct lenses closely received in a respective one of the compartments of the endless array of compartments. 
     The at least one primary sampling sensor may be carried by the first circuit board disposed centrally with respect to the circular array of the emitters. 
     The sampling system may further include at least one temperature sensor positioned to sense a temperature at least proximate the at least one of the emitters or the at least one primary sampling sensor, and responsive thereto to produce signals indicative of a sensed temperature. 
     The sampling system may further include at least one control subsystem housed separately from the sampling device, and communicatively coupled to receive sensor information at least from the at least one primary sampling sensor and the at least one calibration sensor. 
     The at least one control subsystem may be communicatively coupled to control the emitters. The sampling device may further include at least one temperature sensor positioned to sense a temperature at least proximate the at least one of the emitters or the at least one primary sampling sensor, and responsive thereto to provide signals indicative of a sensed temperature to the at least one control subsystem that is housed separately from the sampling device. The at least one control subsystem may calibrate an output value based at least in part on information from both the calibration sensors and the at least one temperature sensor. The at least one control subsystem may calibrate a drive signal supplied to at least one of the emitters based at least in part on information from both the calibration sensors and the at least one temperature sensor. The at least one control subsystem may be a smartphone. 
     The sampling device may further include at least one control subsystem received in the housing, the at least one control subsystem communicatively coupled to control the emitters, and communicatively coupled to receive sensor information at least from the at least one primary sampling sensor and the at least one calibration sensor. 
     The sampling device may further include at least one temperature sensor communicatively coupled to the at least one control subsystem, the at least one control subsystem controlling operation based at least in part on information from both the calibration sensors and the at least one temperature sensor. 
     The at least one temperature sensor may include a plurality of temperature sensors, at least one of the temperature sensors positioned to sense a temperature at least proximate the at least one of the emitters or the at least one primary sampling sensor. The at least one control subsystem may calibrate an output value based at least in part on information from both the calibration sensors and the at least one temperature sensor. The at least one control subsystem may calibrate a drive signal supplied to at least one of the emitters based at least in part on information from both the calibration sensors and the at least one temperature sensor. 
     The sampling system may further include at least one window that is transmissive to at least some of the wavelengths of electromagnetic energy emitted by the emitters and that provides passage of the wavelengths of electromagnetic energy emitted by the emitters out of an interior of the housing to an exterior of the housing and passage of the wavelengths of electromagnetic energy returned to the sampling device from the exterior of the interior of the housing. 
     The sampling system may further include a single user manipulable switch, operation of which causes the sampling device to sample a specimen. 
     The sampling device may automatically provide a signal indicative of information sensed by the primary sampling sensors and the calibration sensors to a remotely housed control subsystem in response to user activation of the user manipulable switch. The respective range of wavelengths of at least two of the emitters may at least partially overlap. 
     A sampling device operable to sample specimens may be summarized as including a housing having a first end, a second end, and a sampling aperture at least proximate the first end; a plurality of emitters at least partially housed by the housing and arrayed about a first location, the emitters selectively operable to emit electromagnetic energy in respective ranges of wavelengths, the ranges of wavelengths of at least some of the emitters different from the ranges of wavelengths of others of the emitters; at least one annular lens structure at least partially housed by the housing, the at least one annular lens structure positioned with respect to the emitters and the sampling aperture to focus electromagnetic energy emitted by the emitters outwardly from the sampling aperture toward a focal locus; at least one primary sampling sensor at least partially housed by the housing at least proximate the first location and positioned to receive electromagnetic energy returned to the sampling device from a specimen, if any, positioned at the focal locus via the sampling aperture, the at least one primary sampling sensor responsive to at least some of the electromagnetic energy returned to the sampling device via the sampling aperture. 
     The emitters may be arrayed in a circular array and the at least one annular lens structure may include an annular array of distinct lenses physically coupled to one another. The annular array of distinct lenses may take the form of an integral one-piece construction which includes a circular band that physically couples the distinct lenses to one another. The distinct lenses may each extend radially outwardly from the circular band at an angle with respect to a plane defined by the circular band. The annular array of lenses may include a material that does not distort electromagnetic energy in a near-ultraviolet (N-UV) portion of the electromagnetic spectrum. The at least one annular lens structure may include a high grade optical resin (e.g., cyclic polyolefin). The at least one annular lens structure may include a silica material. 
     The sampling device may further include a first circuit board on which the emitters are arrayed in a circular array; and an endless array of compartments which isolate each of the emitters from one another. 
     The endless array of compartments may be formed as a unitary single-piece construction and may be arranged about a central passage. The at least one annular lens structure may include an annular array of distinct lenses physically coupled to one another as an integral one-piece construction which includes a circular band that physically couples the distinct lenses to one another, each of the distinct lenses closely received in a respective one of the compartments of the endless array of compartments. The housing may include a body portion and a lens tube portion that extends from the body portion, the body portion having an interior with an opening, the first circuit board mounted across the opening of the body portion. 
     The sampling device may further include a second circuit board received in a cavity of the housing, the second circuit board carrying control circuitry communicable coupled to the emitters and at least one primary sampling sensor. 
     The sampling device may further include a window across the sampling aperture, the window transmissive to at least some wavelengths of electromagnetic energy. 
     The housing may include a shroud that extends from the lens tube outwardly of the sampling aperture and the window, and which shrouds the sampling aperture and the window. 
     The sampling device may further include a plurality of calibration sensors, each of the calibration sensors positioned in a respective one of the compartments of the endless array of compartments. 
     Each compartment may have a slot to limit entrance into the respective compartment of spectral illumination returned to the sampling device from the specimen, if any, and each of the respective calibration sensors may be positioned to be shielded from the respective slot. 
     The sampling device may further include at least one optical calibration tap that provides a respective distinct optical path between a position at least proximate respective ones of the emitters and respective ones of the calibration sensors. 
     The at least one optical calibration tap may be an integral portion of the endless array of compartments. The at least one optical calibration tap may be a light-toned polymer insert. The calibration sensors may be matched to the output of the respective emitter with which calibration sensor is compartmentalized. The calibration sensors may each consist of a single optical sensor chip that detects from near-infrared (N-IR) through near-ultraviolet (N-UV) wavelengths of electromagnetic energy. The at least one annular lens structure may focus the electromagnetic energy emitted by the emitters such that the at least one primary sampling sensor receives electromagnetic energy returned to the sampling device from the specimen via Rayleigh scattering, substantially free of electromagnetic energy returned to the sampling device from the specimen via Ramen scattering. The at least one primary sampling sensor may consist of a single optical sensor chip that detects from near-infrared (N-IR) through near-ultraviolet (N-UV) wavelengths of electromagnetic energy. The respective range of wavelengths of at least two of the emitters may at least partially overlap. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       In the drawings, identical reference numbers identify similar elements or acts. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not drawn to scale, and some of these elements are arbitrarily enlarged and positioned to improve drawing legibility. Further, the particular shapes of the elements as drawn, are not intended to convey any information regarding the actual shape of the particular elements, and have been solely selected for ease of recognition in the drawings. 
         FIG. 1A  is an exploded, top, rear, right isometric view of a sampling device according to one illustrated embodiment. 
         FIG. 1B  is an exploded, top, front, right isometric of a sampling device according to one illustrated embodiment. 
         FIG. 1C  is an exploded, bottom, front, right isometric view of a sampling device according to one illustrated embodiment. 
         FIG. 1D  is an exploded, bottom, rear, right isometric view of a sampling device according to one illustrated embodiment. 
         FIG. 1E  is a top plan view of a controller printed circuit board for use in the sampling device of  FIGS. 1A-1D , according to one illustrated embodiment. 
         FIG. 1F  is a bottom plan view of the controller printed circuit board for use in the sampling device of  FIGS. 1A-1D , according to one illustrated embodiment. 
         FIG. 2A  is a top isometric view of a transducer printed circuit board (PCB) of the sampling device of  FIGS. 1A-1D , which carries a number of transducers, according to another illustrated embodiment. 
         FIG. 2B  is a bottom isometric view of the transducer PCB of the sampling device of  FIGS. 1A-1D , according to another illustrated embodiment. 
         FIG. 2C  is a top plan view of the transducer PCB of the sampling device of  FIGS. 1A-1D , according to another illustrated embodiment. 
         FIG. 2D  is a bottom plan view of the transducer PCB of the sampling device of  FIGS. 1A-1D , according to another illustrated embodiment. 
         FIG. 2E  is a side elevational view of the transducer PCB of the sampling device of  FIGS. 1A-1D , according to another illustrated embodiment. 
         FIG. 2F  is a side elevational view of the transducer PCB of the sampling device of  FIGS. 1A-1D , according to another illustrated embodiment. 
         FIG. 3A  is a partial exploded rear, left side isometric view of the sampling device of  FIGS. 1A-1D , according to another illustrated embodiment, showing the transducer PCB, light pipe, array of compartments, annular lens structure, tube, window and operational shroud. 
         FIG. 3B  is a partial exploded front, left side isometric view of the sampling device of  FIGS. 1A-1D , according to another illustrated embodiment, showing the transducer PCB, light pipe, array of compartments, annular lens structure, tube, window and operational shroud. 
         FIG. 4  is a cross sectional a portion of the sampling device of  FIGS. 1A-1D , illustrating a relative positioning of the various components, according to one illustrated embodiment. 
         FIG. 5A  is a top plan view of a portion of the sampling device of  FIGS. 1A-1D  illustrating a relative positioning of the various components, according to one illustrated embodiment. 
         FIG. 5B  is a schematic view of a portion of the sampling device of  FIGS. 1A-1D  illustrating exemplary emitted electromagnetic energy and returned of electromagnetic energy from a sample or specimen, according to one illustrated embodiment. 
         FIG. 5C  is a schematic view of a portion of the sampling device of  FIGS. 1A-1D  illustrating exemplary emitted electromagnetic energy and returned of electromagnetic energy from a glossy red painted surface, according to one illustrated embodiment. 
         FIG. 6  is an isometric view of a sampling system that includes one or more sampling devices and one or more processor-based devices to which the sampling devices are communicatively coupled, according to one illustrated embodiment. 
         FIG. 7A  is an isometric view of a sampling device with an optional calibration cap coupled to a front thereof, according to one illustrated embodiment. 
         FIG. 7B  is a rear isometric view of the optional calibration cap of  FIG. 7A , according to one illustrated embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, certain specific details are set forth in order to provide a thorough understanding of various disclosed embodiments. However, one skilled in the relevant art will recognize that embodiments may be practiced without one or more of these specific details, or with other methods, components, materials, etc. In other instances, well-known structures associated with computing systems, networks, servers, microprocessors, memories, buses, sources of electromagnetic energy, and/or detectors or sensors have not been shown or described in detail to avoid unnecessarily obscuring descriptions of the embodiments. 
     Unless the context requires otherwise, throughout the specification and claims which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense, that is as “including, but not limited to.” 
     Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. 
     As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise. It should also be noted that the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise. 
     The headings and Abstract of the Disclosure provided herein are for convenience only and do not interpret the scope or meaning of the embodiments. 
     The ability to recognize, identify, verify, authenticate and/or classify objects has numerous commercial applications. 
     It may be useful to determine analyze characteristics of a sample or specimen being evaluated. For example, it may be useful to determine whether a sample or specimen being evaluated is identical or similar to a previously evaluated sample or specimen, for instance, a reference sample or specimen. Also for example, it may be useful to determine if a sample or specimen is identical to a previously evaluated sample or specimen. 
       FIGS. 1A-1D  show a sample or specimen analysis or evaluation device  100 , according to one illustrated embodiment, referred to herein simply as sampling device  100 . 
     As discussed in detail below, the sampling device  100  is operable to sequentially illuminate an object with a number of bands of electromagnetic energy. The sampling device  100  is also operable to detect, measure or otherwise capture electromagnetic energy reflected, emitted, fluoresced, refracted, diffracted or otherwise transmitted, or otherwise returned from the object in response to the illumination. As used herein and in the claims, the terms illuminate, illuminates, illumination, and variations of such terms mean to expose to or reveal by the use of electromagnetic energy or electromagnetic radiation, whether in the visible portion of the electromagnetic spectrum, the optical portion (e.g., visible, near-infrared, near-ultraviolet), or other portions (e.g., far-infrared, far-ultraviolet, microwave, X-ray, etc.). 
     The sampling device  100  includes a housing  102 , which in the illustrated embodiment includes a tubular main housing portion  102   a , a lens tube  102   b  and optionally a shroud  102   c.    
     The main housing portion  102   a  has a front end  106   a  and a back end  106   b  opposite the front end  106   a . The main housing portion  102   a  has a side wall  108  that defines a cavity  110  which is separated from an exterior  112  of the main housing portion  102   a . The front end  106   a  is open to provide selective access to the cavity  110 . The main housing portion  102   a  may be comprised of any of a large variety of materials, for example, ABS plastic, other plastics, metals (e.g., aluminum) and/or composite materials (e.g., carbon fiber impregnated resin). The main body housing portion  102   a  may be sized and dimensioned to be easily held and operated using a single hand. While illustrated as a cylindrical tube, the main body housing portion  102   a  may take any variety of shapes. 
     The lens tube  102   b  a front end  114   a  and a back end  114   b  opposite the front end  114   a . The lens tube  102   b  has a side wall  116  that defines a passage  118  that extends through the front and back ends,  114   a ,  114   b , respectively. The lens tube  102   b  is physically directly or indirectly coupled via the back end  114   b  to the front end  106   a  of the main housing portion  102   a , and extends therefrom. The lens tube  102   b  may, for example, be physically detachably coupled via a press fit or a detent structure (e.g., annular flange and annular slot). The lens tube  102   b  may be comprised of any of a large variety of materials, for example, ABS plastic, other plastics, metals (e.g., aluminum) and/or composite materials (e.g., carbon fiber impregnated resin), and the side wall  116  is preferably opaque. While illustrated as a fustroconical tube, the lens tube  102   b  may take any variety of shapes. 
     As illustrated, the sampling device  100  may include a window or lens cover  120  received in, and across, the open front end  114   a  of the lens tube  102   b . The window or lens cover  120  may provide environmental protection of components within or rearward of the window or lens cover  120 . The window or lens cover  120  is transmissive (i.e., transparent or at least translucent) to at least those wavelengths of electromagnetic energy (e.g., UV) which are used in the analysis or evaluation of a sample or specimen. The window or lens cover  120  may be comprised of any of a large variety of materials, for example silica (i.e., fused quartz) or a cyclic polyolefin commercially available from Zeon Chemicals of Louisville, Ky. under the trademark Zeonex®, for example having minimal absorption characteristics for wavelengths between approximately 330 nm and extending to or beyond approximately 1,200 nm. 
     The shroud  102   c  has a front end  122   a , and a back end  122   b  opposite the front end  122   a . The shroud  102   c  has a side wall  124  that defines a passage  126  that extends through the front and back ends  122   a ,  122   b , respectively. The shroud  102   c  is physically coupled via the back end  122   b  to the front end  114   a  of the lens tube  102   b , and extends therefrom. The shroud  102   c  may, for example, be physically detachably coupled to the lens tube  102   b  via a press fit or a detent structure (e.g., annular flange and annular slot). Alternatively or additionally, the shroud  102   c  may, for example, be physically detachably coupled to the main housing portion  102   a  via one or more lugs  154   a  (only one called out in  FIGS. 1A, 1B and 1D ). The lugs  154   a  may, for instance, be sized, dimensioned, positioned and/or oriented to be received by slots  154   b  the on the main housing portion  102   a . The shroud  102   c  may be comprised of any of a large variety of materials, for example, ABS plastic, other plastics, metals (e.g., aluminum) and/or composite materials (e.g., carbon fiber impregnated resin), and the side wall  124  is preferably opaque. While illustrated as a generally conical or body of revolution shape, the shroud  102   c  may take any variety of shapes. 
     In the illustrated embodiment, the sampling device  100  includes a transducer printed circuit board (PCB)  130  and a controller PCB  132 . As explained in more detail below, the transducer PCB  130  includes a plurality of transducers, typically in the form of a plurality of emitters (collectively  134 ), one or more primary detectors or sensors (collectively  136 ), and one or more calibration detectors or sensors (collectively  138 ). Also as explained in more detail below, the controller PCB  132  includes various components electrical and electronic components (collectively  140 ) to control operation of the sampling device  100  and/or communications therefrom. The transducer PCB  130  and the controller PCB  132  each include a respective coupler or connector  144   a ,  144   b , respectively, to communicatively couple components or circuits of the transducer PCB  130  with the components or circuits of the controller PCB  132 . 
     The controller PCB  132  may, for example, include one or more communications ports  140   a  (e.g., Universal Serial Bus compliant socket or female connector). The communications port(s)  140   a  may be accessible from the exterior of the housing  102 , for example, via an aperture (not shown) in the back end  106   b  of the main housing portion  102   a . While illustrated as a hardwired communication port  140   a  (e.g., a USB port), the sampling device  100  may include other types of communications ports or devices, for instance, an infrared transceiver, or an RF transceiver (e.g., BLUETOOTH® transceiver). Such may allow the transmission of data, instructions and/or results, to or from the sampling device  100 . Such communications may be via one or more converters, for example a USB to serial converter  140   m.    
     The controller PCB  132  may, for example, include one or more visual indicators (e.g., light emitting diodes or LEDs, two shown collectively referenced as  140   b ). The visual indicators  140   b  may indicate a status or mode of the sampling device, for instance via different colors (e.g., green, red, amber) and or patterns (e.g., flashes). One or more light communicative paths  140   c  (e.g., optical fiber or light pipes) may communicatively coupled light from the visual indicators  140   b  to an exterior of the main housing portion  106   a . Alternatively, one or more visual indicators  140   b  may be carried by or on the main housing portion  106   a , or underlying a window (not shown) in the main housing portion  106   a.    
     The controller PCB  132  may, for example, optionally include a control subsystem, some portions of which are best illustrated in  FIGS. 1E and 1F . Alternatively, the sampling device may be coupled to an external control system, for example, one or more programmed general purpose or special purpose computers or computer systems. 
     The control subsystem may include one or more controllers  140   d . The controller  140   d  may, for example, take the form of an integrated circuit package that includes one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), programmable gate arrays (PGA), programmable logic controllers (PLCs), or other logic executing device, denominated herein as a central processing unit  140   g . The control subsystem may include one or more non-transitory computer- or processor-readable media, for example, one or more memories such as read only memory (ROM) or Flash memory  140   e  and random access memory (RAM)  140   f . While the ROM or Flash memory  140   e  and RAM  140   f  are shown integrated into the same integrated circuit (ICs) package  140   d  as the CPU  140   g , such can be supplied as discrete ICs. One or more buses (not shown) may couple the ROM  140   e  and RAM  140   f  to the controller  140   d . The buses may take a variety of forms including an instruction bus, data bus, other communications bus and/or power bus. The nonvolatile ROM and/or Flash memory  140   e  may store instructions and/or data for controlling the sampling device  100 . The volatile RAM  140   f  may store instructions and/or data for use during operation of the sampling device  100 . 
     The controller PCB  132  may, for example, include an analog-to-digital converter  140   h , communicatively coupled to convert analog signals, for instance from the sensor, to digital signals for use by the CPU  140   g . The controller PCB  132  may, for example, include a level translator  140   i  coupled to translate signal levels. The controller PCB  132  may, for example, include a current source  140   j , to supply a constant current to the other components  140  for instance the LEDs  140   b . The controller PCB  132  may, for example, include an oscillator or clock, for instance a crystal oscillator  140   k , communicatively coupled to the controller  140   d  to provide a clock signal thereto. The controller PCB  132  may, for example, include one or more capacitors, for instance a tantalum capacitor  1401 . 
     The optional controller  140   d  employs instructions and or data from the ROM/Flash  140   e  and RAM  140   f  in controlling operation of the sampling device  100 . For example, the controller  140   d  operates the emitters  134  in one or more sequences. The sequences determine an order in which the emitters  134  are turned ON and OFF. The sequences may also indicate an ordered pattern of drive levels (e.g., current levels, voltage levels, duty cycles) for the emitters  134 . Thus, for example, a controller  140   d  may cause the application of different drive levels to respective ones of the emitters  134  to cause the emitters  134  to emit in distinct bands of the electromagnetic spectrum. The controller  140   d  may process information generated by the primary detector(s) or sensor(s)  136 , which is indicative of the response by at least a portion of a sample or specimen to illumination by the emitters  134 . The information at any given time may be indicative of the response by the sample or specimen to illumination by one or more of the emitters  134 . Thus, the information over a period of time may be indicative of the responses by the sample or specimen to sequential illumination by each of a plurality of the emitters  134 , where each of the emission spectra of each of the emitters  134  has a different center, bandwidth and/or other more complex differences in spectral content, such as those described above (e.g., the width of the band, the skew of the distribution, the kurtosis, etc.). 
     The control subsystem may optionally include a buffer (not shown) to buffer information received from the primary detector or sensors  136 . The control subsystem may further optionally include an analog to digital converter (ADC) (not shown) and/or digital to analog converter (DAC) (not shown). An ADC may, for example, be used for converting analog photodiode responses into digital data for further analysis and/or transmission. A DAC may, for example, be used for converting digital computer or controller commands into analog LED current levels. The control subsystem may additionally or alternatively optionally include an analog signal processor, which may be particularly useful where the sensor takes the form of one or more photodiodes. 
     The control subsystem may include a user interface including one or more user interface devices. For example, the control subsystem  54  may include one or more speakers or microphones (not shown). Also for example, the control subsystem may include and/or one or more visual indicators, such as one or more LEDs  140   b , liquid crystal displays (LCD), or other visual indicator. The LCD may, for example, take the form of a touch sensitive LCD, which displays a graphical user interface, operable by the user of the sampling device  100 . Additionally, or alternatively, the control subsystem may include one or more user operable input elements, such as switches, keys or buttons  142 . The input elements may include a switch  142  for turning the sampling device  100  ON and OFF. Additionally, or alternatively, the input elements may include one or more switches or keys for controlling the operation of the test device  100 , for example, downloading or uploading data or instructions to or from the sampling device  100 . Such may be via one or more connectors, for instance a debug connector  140   n  and a programming connector  140   o , both positioned to be accessible from an exterior of the sampling device  100 . 
     The sampling device  100  may include one or more switches  142  which are operable from an exterior of the sampling device  100 . The switch  142  may take any of a large variety of forms. For example a contact or slideable switch  142  may be actuatable via a window, slot or other aperture in the main housing portion  102   a . Alternatively, a touch sensitive switch may be employed, for instance, an inductive or a capacitive switch. The switch  142  may be responsive to actuation to send a signal, for instance via a tactile switch  140   p  and/or analog switch  140   q , or otherwise cause the sampling device  100  to execute a sampling operation. As discussed in detail below, the sampling operation may be preceded by a calibration operation. 
     The sampling device  100  may optionally include a power source (not shown). The power source may take the form of a portable power source, for example, one or more batteries, fuel cells, and/or super- or ultra-capacitors. Additionally, or alternatively, the power source may take the form of a fixed power source, such as a cable plugged into a port of a computer (e.g., USB cable) or a conventional electrical receptacle (e.g., wall outlet). 
     As illustrated, the controller PCB  132  may be received in the cavity  110  of the main housing portion  102   a . In particular, the controller PCB  132  may be sized and dimensioned to be securely received in the cavity  110 , for example, engaging an inner periphery of the side wall  108  or other attachment structures in the cavity  110 . Engagement may be via a press fit or via some coupling structure such as a detent structure. 
     As illustrated, the transducer PCB  130  may be physically coupled across the otherwise open front end  106   a  of the main housing portion  102   a . As visible in  FIGS. 1A, 1B, 1D , the transducer PCB  130  may include the coupler or connector  144   a , for instance, a slot connector having a slot sized and dimensioned to receive the coupler of connector  144   b  of the controller PCB  132 , for instance, an edge or tab. Each of the couplers or connectors  144   a ,  144   b  typically carry a variety of electrical contacts, although other signal transfer structures (e.g., optical fiber) can be employed. 
     The sampling device  100  includes a compartment structure  146 , having a front end  148   a  and a back end  148   b  opposite the front end  148   a , and which includes an endless array of compartments  150   a ,  150   n  (collectively  150 , twelve shown, only two called out in  FIGS. 1A-1D ). The compartments  150  are each open at the front end  148   a  and the back end  148   b . The compartment structure  146  may be annular and may include a central passage  152  extending between the front and back ends  148   a ,  148   b , respectively. The compartment structure  146  may comprise any of a large variety of materials, for example, plastics or even metals or composite materials. The compartment structure  146  is typically opaque or a substantial portion thereof is opaque, at least to electromagnetic energy that is employed in the analysis or evaluation of the samples or specimens. The compartment structure  146  may, for example, be painted black, coated black, or may include black pigments. 
     The compartment structure  146  is physically coupled to the main housing portion  102   a . In particular, the compartment structure  146  may be physically detachably coupled to the main housing portion  102   a . For example, the compartment structure  146  may include a portion of a bayonet or other physical coupler structure which physically couples to the physical coupler structure of the main housing portion  102   a . For instance, the compartment structure  146  may include a set of slots  154   b  (e.g., L-shaped slots) defined in a perimeter proximate the front end  106   a  of the main housing portion  102   a . The  154   b  (e.g., L-shaped slots) may be sized, dimensioned, positioned, and/or oriented to securely releasably receive a set of lugs  154   a . While illustrated as carried by the shroud  102   c , the lugs  154   a  could be carried by some other component, for instance the lens tube  102   b . Such secures the various components in place, including the compartment structure  146 , yet still allows easy and fast access to various internal components (e.g., transducer PCB  130 , controller PCB  132 ). The compartment structure  146  may include an annular rim portion  156 , sized and dimensioned to be securely received by the passage  118  of the lens tube  102   b , via the back end thereof, for instance, via a press fit. 
     When mounted in front of the transducer PCB  130 , each compartment  150  serves as a mask, separating sets of one or more emitters  134  from other sets of one or more emitters  134  on the transducer PCB  130 . The compartments  150  also separate sets of one or more calibration detectors or sensors  138  from other sets of one or more calibration detectors or sensors  138  on the transducer PCB  130 . In particular, each compartment  150  may house a respective set of emitters  134  with a respective set of calibration detectors or sensors  138 . The compartments  150  may also limit an amount of electromagnetic energy which may leak into the compartment  150  from outside of the compartment  150 , for example, light being returned from a sample or specimen. The central passage  152  allows electromagnetic energy to reach the primary detectors or sensors  136 . The central passage  152  allows electromagnetic energy returned from a sample or specimen to reach the primary detectors or sensors  136 . 
     The sampling device  100  includes an annular lens element  160 . The annular lens element  160  may include a number of distinct lenses  162   a ,  162   n  (collectively  162 , twelve shown, only two called out in  FIGS. 1A-1D ). The distinct lenses  162  may be physically coupled by a band  164  (shown more clearly in  FIGS. 3A and 3B ), on an inner diameter  166  of the annular lens element  160 . Each lens  162  is sized and dimensioned to be received by, or across, a respective one of the compartments  150  of the mask structure  146 . The lenses  162  are distributed about the band  164  to match the arrangement of compartments  150 . Coupling or connecting all the distinct lenses with the band  164  allows all lenses  162  to be easily handled, facilitating manufacturing operation and/or maintenance. At least the distinct lenses  162  should be transmissive of wavelengths of electromagnetic energy (e.g., UV) which will be emitted by the emitters for use in the analysis or evaluation of a sample or specimen. Thus, the lenses  162 , and optionally the band  164 , may be comprised of any of a large variety of materials, for example, silica (i.e., fused quartz) or a cyclic polyolefin commercially available from Zeon Chemicals of Louisville, Ky. under the trademark Zeonex®, for example, having minimal absorption characteristics for wavelengths between approximately 330 nm and extending to or beyond approximately 1,200 nm. 
     The sampling device  100  may optionally include a calibration tap. The calibration tap provides a respective path to respective sets of calibration sensors  138  for electromagnetic energy emitted by emitters  134 , and may take any of a variety of forms. 
     In the illustrated embodiment, calibration tap takes the form of a light-toned polymer insert generally indicated at  170 . The insert  170  may be generally annular having a central passage  172 . The insert  170  may have a plurality of segments  174  (collectively  174 , twelve shown, only one called out in  FIGS. 1A-1D ). The segments  174  correspond in number of position to the compartments  150  of the compartment structure  148 , and are sized and dimensioned to be received by respective ones of the compartments  150 . This allows the compartment structure  150  to, for example, be matte black, while still ensuring that electromagnetic energy emitted by an emitter is received by a respective calibration sensor  138 . As illustrated, the insert  170  may take the form of a unitary one-piece element. 
     The calibration tap may take the form of a band of a known color, for example, a band of a light-tone or white color having a defined or known affect on light reflected or scattered by the band of color. The band may, for example, be carried on an inner annular surface of the compartment structure, for example, being an integral portion of the compartment structure  146 . 
     Alternatively, the calibration tap may take the form of a pipe which is transmissive of wavelengths of electromagnetic energy (e.g., UV) which will be emitted by the emitters for use in the analysis or evaluation of a sample or specimen. Thus, the calibration tap may be comprised of any of a large variety of materials, for example, silica (i.e., fused quartz) or a cyclic polyolefin commercially available from Zeon Chemicals of Louisville, Ky. under the trademark Zeonex®. 
     Table A, below, provides a list of suitable parts for the controller PCB  132 . Such is purely illustrative and is not intended to require any specific parts. 
     
       
         
               
               
               
               
             
           
               
                 TABLE A 
               
               
                   
               
               
                 ITEM 
                   
                   
                   
               
               
                 No. 
                 PART No. 
                 DESCRIPTION 
                 QTY. 
               
               
                   
               
             
             
               
                 140b 
                 APT1608QBC-D 
                 LED 
                 2 
               
               
                   
                 BLUE 
               
               
                 140h 
                 AD1256 
                 ANALOG - DIGITAL 
                 1 
               
               
                   
                   
                 CONVERTER 
               
               
                 140n 
                 FH12A-10S-0.5SH 
                 DEBUG &amp; PROG CONNECTOR 
                 2 
               
               
                 140o 
                 (55) 
               
               
                 140p 
                 SKQGAB 
                 TACTILE SWITCH 
                 1 
               
               
                 140i 
                 ST2378ETTR 
                 LEVEL TRANSLATOR 
                 1 
               
               
                 140d 
                 R5F52108AGFM 
                 CPU 
                 1 
               
               
                 132 
                 PCB 
                 CONTROLLER PCB 
                 1 
               
               
                 140a 
                 MU-10F4-08 
                 10 WAY USB SOCKET 
                 1 
               
               
                   
                   
                 MU-10F4-08 
               
               
                 140j 
                 LT3092XDD 
                 CURRENT SOURCE 
                 1 
               
               
                 140q 
                 ADG728BRUZ 
                 ANALOGUE SWITCH 
                 1 
               
               
                 140k 
                 7B-8.000MAAJ-T 
                 8 MHz CRYSTAL 
                 1 
               
               
                 140l 
                 47Uf 16V 
                 TANTALUM CAPACITOR 
                 1 
               
               
                 140m 
                 FT232RQ 
                 USB TO SERIAL CONVERTER 
                 1 
               
               
                   
               
             
          
         
       
     
       FIGS. 2A-2E  show the transducer PCB  130  of  FIGS. 1A-1D  in more detail. 
     As is best illustrated in  FIGS. 2A and 2C , the transducer PCB  130  carries a number of sets of emitters or sources  134   a - 1341  (twelve shown, individually called out in  FIG. 2C , collectively  134 ) arrayed along an outer perimeter  200  of the transducer PCB  130  about a central portion  202  of the transducer PCB  130 . The sets of emitters or sources  134  may, for example, be arrayed in a generally annular array, as illustrated. Each respective set may include one or more emitters, although typically each set will have a single emitter  134 . Alternatively, each set may include multiple emitters, the emitters of any given set emitting at the same band of wavelengths. Optionally, some sets may include multiple emitters, the emitters of the set emitting at different bands of wavelengths. 
     The emitters  134  may take a variety of forms which are operable to emit electromagnetic energy. The emitters  134  may, for example, take the form of one or more light emitting diodes (LEDs), including, for instance, organic LEDs (OLEDs). Alternatively, or additionally, the emitters  134  may take the form of one or more lasers, for example, one or more laser diodes. The lasers may, or may not, be tunable lasers. Alternatively, or additionally, the emitters  134  may take the form of one or more incandescent sources such as conventional or halogen light bulbs. 
     One, more or all of the emitters  134  may be operable to emit in part or all of an “optical” portion of the electromagnetic spectrum, including the (human) visible portion, near infrared (N-IR) portion and/or or near ultraviolet (N-UV) portion of the electromagnetic spectrum. Additionally, or alternatively, the emitters  134  may be operable to emit electromagnetic energy of other portions of the electromagnetic spectrum, for example, the infrared, ultraviolet and/or microwave portions. 
     In some embodiments, at least some of the emitters  134  are operable to emit in or at a different band than other of the emitters  134 . For example, one or more emitters  134  may emit in a band centered around 450 nm, while one or more of the emitters  134  may emit in a band centered around 500 nm, while a further emitter or emitters  134  may emit in a band centered around 550 nm. In some embodiments, each emitter  134  emits in a band centered around a respective frequency or wavelength, different than each of the other emitters  134 . Using emitters  134  with different band centers advantageously maximizes the number of distinct samples that may be captured from a fixed number of emitters  134 . This may be particularly advantageous where the sampling device  100  is relatively small, and has limited space or footprint for the emitters  134 . 
     The distribution of spectral content for each emitter  134  may vary as a function of drive level (e.g., current, voltage, duty cycle), temperature, and other environmental factors, depending on the specific emitter  134 . Such variation may be advantageously actively employed to operate one or more of the physical emitters or sources  134  as a plurality of “logical emitters or sources,” each of the logical emitters or sources operable to provide a respective emission spectra from a respective physical emitter or source  134 . Thus, for example, the center of the band of emission for each emitter or source  134  may vary according to a drive level and/or temperature. For example, the center of the band of emission for LEDs will vary with drive current or temperature. One way the spectral content can vary is that the peak wavelength can shift. However, the width of the band, the skew of the distribution, the kurtosis, etc., can also vary. Such variations may also be advantageously employed to operate the physical emitters or sources  134  as a plurality of logical emitters or sources. Thus, even if the peak wavelength were to remain constant, the changes in bandwidth, skew, kurtosis, and any other change in the spectrum can provide useful variations in the operation of the sampling device  100 . Likewise, the center of the band of emission may be varied for tunable lasers. Varying the center of emission bands for one or more emitters  134  advantageously maximizes the number of samples that may be captured from a fixed number of emitters  134 . Again, this may be particularly advantageous where the sampling device  100  is relatively small, and has limited space or footprint for the emitters  134 . 
     As is best illustrated in  FIGS. 2A and 2C , the transducer PCB  130  carries a number of primary detectors or sensors  136   a - 136   d  (four shown, collectively  136 ) positioned in the central portion  202  with respect to the array of emitters or sources  134 . The primary detectors or sensors  136  may, for example, include two more sensors or detectors, each responsive to a respective band of wavelengths. Such bands may be mutually exclusive or may be overlapping. The illustrated embodiment employs four primary detectors or sensors  136   a - 136   d , each responsive to a respective band of wavelengths (i.e., 400 nm-1100 nm, 400 nm-1050 nm, 400 nm-1050 nm, 600 nm-1700 nm, respectively). Three primary detectors or sensors  136   a - 136   c  that are responsive to N-UV wavelengths are employed to increase sensitivity. Another embodiment employs one or more wideband primary detectors or sensors  136 . For example, a pyroelectric detector from Pyreos Ltd. Optionally, one or more filters (not shown) may be employed with the primary detectors or sensors  136 , for example, one or more low pass filters, high pass filters, and/or band pass filters. The filters may be optical filters and may be formed or carried directly on the primary detectors or sensors  136 . Alternatively, the filters may be formed on or carried on another surface, in the field of view of but spaced from the primary detectors or sensors  136 . 
     The primary detector(s) or sensor(s)  136  can take a variety of forms suitable for sensing or responding to electromagnetic energy. For example, the primary detector(s) or sensor(s)  136  may take the form of one or more photodiodes (e.g., germanium photodiodes, silicon photodiodes). Alternatively, or additionally, the primary detector(s) or sensor(s)  136  may take the form of one or more photomultiplier tubes. Alternatively, or additionally, the primary detector(s) or sensor(s)  136  may take the form of one or more CMOS image sensors. Alternatively, or additionally, the primary detector(s) or sensor(s)  136  may take the form of one or more charge coupled devices (CCDs). Alternatively, or additionally, the primary detector(s) or sensor(s)  136  may take the form of one or more micro-channel plates. Other forms of electromagnetic sensors may be employed, which are suitable to detect the wavelengths expected to be returned in response to the particular illumination and properties of the object being illuminated. 
     The primary detector(s) or sensor(s)  136  may be formed as individual elements, one-dimensional array of elements and/or two-dimensional array of elements. For example, the primary detector(s) or sensor(s)  136  may be formed by one germanium photodiode and one silicon photodiode, each having differing spectral sensitivities. The test device  14  may employ a number of photodiodes with identical spectral sensitivities, with different colored filters (e.g., gel filters, dichroic filters, thin-film filters, etc.) over the photodiodes to change their spectral sensitivity. This may provide a simple, low-cost approach for creating a set of sensors with different spectral sensitivities, particularly since germanium photodiodes are currently significantly more expensive that silicon photodiodes. Also, for example, the primary detector(s) or sensor(s)  136  may be formed from one CCD array (one-dimensional or two-dimensional) and one or more photodiodes (e.g., germanium photodiodes and/or silicon photodiodes). For example, the primary detector(s) or sensor(s)  136  may be formed as a one- or two-dimensional array of photodiodes. A two-dimensional array of photodiodes enables very fast capture rate (i.e., camera speed) and may be particularly suited for use in assembly lines or high speed sorting operations. For example, the primary detector(s) or sensor(s)  136  may be formed as a one- or two-dimensional array of photomultipliers. Combinations of the above elements may also be employed. 
     In some embodiments, the primary detector(s) or sensor(s)  136  may be a broadband sensor sensitive or responsive over a broad band of wavelengths of electromagnetic energy. In some embodiments, the primary detector(s) or sensor(s)  136  may be a narrowband sensor sensitive or responsive over a narrow band of wavelengths of electromagnetic energy. In some embodiments, the primary detector(s) or sensor(s)  136  may take the form of several sensor elements, as least some of the sensor elements sensitive or responsive to one narrow band of wavelengths, while other sensor elements are sensitive or responsive to a different narrow band of wavelengths. This approach may advantageously increase the number of samples that may be acquired using a fixed number of sources. In such embodiments the narrow bands may, or may not, overlap. 
     As is best illustrated in  FIGS. 2A and 2C , the transducer PCB  130  carries a number of calibration detectors or sensors  138   a - 1381  (twelve shown, collective  138 ), arrayed along the outer perimeter of the transducer PCB  130 , for example, radially inwardly from emitters  134 . Typically, the number of calibration detectors or sensors  138  will correspond to the number of sets of emitters  134 . The calibration detectors or sensors  138  are generally radially aligned with respective emitters  134 , the calibration detectors or sensors  138  and emitters  134 , for example, being arranged in radial segments on a surface of the transducer PCB  130 . The calibration detectors or sensors  138  may match a nominal output of the respective emitter  134  to which the calibration detectors or sensors  138  is paired or segmented. Thus, some of the calibration detectors or sensors  138  may be responsive to different respective bands of wavelengths than the others. Such bands may be mutually exclusive or may be overlapping. In some embodiments, one or more wideband calibration detectors or sensors  138  are, for example, a pyroelectric detector from Pyreos Ltd. Such may advantageously reduce parts counts, while still allowing calibration across the range of wavelengths of the emitters  136 . Optionally, one or more filters (not shown) may be employed with the calibration detectors or sensors  138 , for example, one or more low pass filters, high pass filters, and/or band pass filters. The filters may be optical filters and may be formed on or carried directly on the calibration detectors or sensors  138 . Alternatively, the filters may be formed on or carried on another surface, in the field of view of, but spaced from, the calibration detectors or sensors  138 . 
     The calibration detector(s) or sensor(s)  138  can take a variety of forms suitable for sensing or responding to electromagnetic energy. For example, the calibration detector(s) or sensor(s)  138  may take the form of one or more photodiodes (e.g., germanium photodiodes, silicon photodiodes). Alternatively, or additionally, the calibration detector(s) or sensor(s)  138  may take the form of one or more photomultiplier tubes. Alternatively, or additionally, the calibration detector(s) or sensor(s)  138  may take the form of one or more CMOS image sensors. Alternatively, or additionally, the calibration detector(s) or sensor(s)  138  may take the form of one or more charge coupled devices (CCDs). Alternatively, or additionally, the calibration detector(s) or sensor(s)  138  may take the form of one or more micro-channel plates. Other forms of electromagnetic sensors may be employed, which are suitable to detect the wavelengths expected to be returned in response to the particular illumination and properties of the object being illuminated. 
     The calibration detector(s) or sensor(s)  138  may be formed as individual elements, one-dimensional array of elements and/or two-dimensional array of elements. For example, the calibration detector(s) or sensor(s)  138  may be formed by one germanium photodiode and one silicon photodiode, each having differing spectral sensitivities. The test device  14  may employ a number of photodiodes with identical spectral sensitivities, with different colored filters (e.g., gel filters, dichroic filters, thin-film filters, etc.) over the photodiodes to change their spectral sensitivity. This may provide a simple, low-cost approach for creating a set of sensors with different spectral sensitivities, particularly since germanium photodiodes are currently significantly more expensive that silicon photodiodes. Also, for example, the calibration detector(s) or sensor(s)  138  may be formed from one CCD array (one-dimensional or two-dimensional) and one or more photodiodes (e.g., germanium photodiodes and/or silicon photodiodes). For example, the calibration detector(s) or sensor(s)  138  may be formed as a one- or two-dimensional array of photodiodes. A two-dimensional array of photodiodes enables very fast capture rate (i.e., camera speed) and may be particularly suited for use in assembly lines or high speed sorting operations. For example, the calibration detector(s) or sensor(s)  138  may be formed as a one- or two-dimensional array of photomultipliers. Combinations of the above elements may also be employed. 
     In some embodiments, the calibration detector(s) or sensor(s)  138  may be a broadband sensor sensitive or responsive over a broad band of wavelengths of electromagnetic energy. In some embodiments, the calibration detector(s) or sensor(s)  138  may be a narrowband sensor sensitive or responsive over a narrow band of wavelengths of electromagnetic energy. In some embodiments, the calibration detector(s) or sensor(s)  138  may take the form of several sensor elements, as least some of the sensor elements sensitive or responsive to one narrow band of wavelengths, while other sensor elements are sensitive or responsive to a different narrow band of wavelengths. This approach may advantageously increase the number of samples that may be acquired using a fixed number of sources. In such embodiments the narrow bands may, or may not, overlap. 
     As best illustrated in  FIGS. 2B, 2D, and 2E  the transducer PCB  130  carries a coupler or connector  144   a  to make communicative connection to the controller PCB  132  ( FIGS. 1A, 1B ). 
     Also as best illustrated in  FIGS. 2B, 2D, and 2E  the transducer PCB carries a number of thermal sensors  204   a - 204   d  (four shown, collectively  204 ). The thermal sensors  204  are distributed to detect temperatures at a variety of points or locations. Such temperatures may be indicative of temperatures to which the emitters  134 , primary detectors or sensors  136  and/or calibration detectors or sensors  138 , are subjected. Temperature indicative signals from the thermal sensors may be employed in calibration, for example, calibrating results or responses and/or calibrating drive signals to account for variation from nominal temperatures or other conditions. 
     Table B, below, provides a list of suitable parts for the transducer PCB  130 . Such is purely illustrative and is not intended to require any specific parts, specific wavelengths, or sensitivities. 
     
       
         
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE B 
               
               
                   
               
               
                 Ref. No. 
                 Part No. 
                 Description 
                 Default/Qty. 
               
               
                   
               
             
             
               
                 130 
                 Max2 Sensor PCB 
                 PCB 
                 1 
               
               
                 204a-204d 
                 MCP98242 
                 Thermal Sensor 
                 4 
               
               
                 144a 
                 HSEC8-120-01-X-DV 
                 Connector 
                 1 
               
             
          
           
               
                 134a 
                 350-PLCC2-120 
                 352 
                 nm 
                 1 
               
               
                 134b 
                 SM1206UV-395-IL 
                 400 
                 nm 
                 1 
               
               
                 134c 
                 EL-19-21/BHC-AN1P2/3T 
                 468 
                 nm 
                 1 
               
               
                 134d 
                 PG1112C-TR 
                 567 
                 nm 
                 1 
               
               
                 134e 
                 LTST-C190KYKT 
                 595 
                 nm 
                 1 
               
               
                 134f 
                 SMC810 
                 810 
                 nm 
                 1 
               
               
                 134g 
                 SMC1200 
                 1200 
                 nm 
                 1 
               
               
                 134h 
                 LNJ812R83RA 
                 630 
                 nm 
                 1 
               
               
                 134i 
                 SMC1450 
                 1450 
                 nm 
                 1 
               
               
                 134j 
                 SMC910 
                 910 
                 nm 
                 1 
               
               
                 134k 
                 LN1251CTR 
                 700 
                 nm 
                 1 
               
               
                 134l 
                 SMC970 
                 970 
                 nm 
                 1 
               
               
                 138a 
                 SFH2701 
                 400-1050 
                 nm 
                 1 
               
               
                 138b 
                 SFH2701 
                 400-1050 
                 nm 
                 1 
               
               
                 138c 
                 PDB-C152SM 
                 400-1100 
                 nm 
                 1 
               
               
                 138d 
                 PDB-C152SM 
                 400-1100 
                 nm 
                 1 
               
               
                 138e 
                 PDB-C152SM 
                 400-1100 
                 nm 
                 1 
               
               
                 138f 
                 PDB-C152SM 
                 400-1100 
                 nm 
                 1 
               
               
                 138g 
                 LAPD-1-06-17-LCC 
                 600-1700 
                 nm 
                 1 
               
               
                 138h 
                 PDB-C152SM 
                 400-1100 
                 nm 
                 1 
               
               
                 138i 
                 LAPD-1-06-17-LCC 
                 600-1700 
                 nm 
                 1 
               
               
                 138j 
                 PDB-C152SM 
                 400-1100 
                 nm 
                 1 
               
               
                 138k 
                 PDB-C152SM 
                 400-1100 
                 nm 
                 1 
               
               
                 138l 
                 PDB-C152SM 
                 400-1100 
                 nm 
                 1 
               
               
                 136a 
                 PDB-C152SM 
                 400-1100 
                 nm 
                 1 
               
               
                 136b 
                 SFH2701 
                 400-1050 
                 nm 
                 1 
               
               
                 136c 
                 PDB-C152SM 
                 400-1100 
                 nm 
                 1 
               
               
                 136d 
                 LAPD-1-06-17-LCC 
                 600-1700 
                 nm 
                 1 
               
               
                   
               
             
          
         
       
     
       FIGS. 3A and 3B  show a portion of the sampling device  100  of  FIGS. 1A-1D , illustrating various components in more detail. 
     In particular,  FIGS. 3A and 3B  show an interior of the passage  126  of the shroud  102   c . The passage  126  is tapered to securely receive an outer perimeter of the lens tube  102   b , for example, via a press fit, with the window or lens cover  120  secured therein. 
       FIGS. 3A and 3B  also more clearly show details of the annular lens element  160 , including the distinct lenses  162   a ,  162   n  (collectively  162 ), band  164  and inner diameter  166 . The distinct lenses  162   a  are circumferentially arranged around the band  164  and extend radially outward from the band  164 . Each of the distinct lenses  162   a  forms a tapered segment, the distal portion being generally wider than a portion proximate the band  164 . The distinct lenses  162   a  also extend relatively forward of the band  164 , a distance from the band  164  increasing as an imaginary path on the distinct lens  162  is traversed from a portion proximate the band  164  to a portion distal from the band  164 . The distinct lenses  162   a  may further have a generally arcuate profile or cross-section taken along a major axis of the distinct lens  162 , best illustrated in  FIG. 3B . The annular lens element  160  in some ways resembles a flower, with the distinct lenses  162 ,  162   n  resembling petals. As previously noted, the segmentation of the distinct lenses  162  may be sized, dimensioned and oriented such that each distinct lens  162  is receivable by a respective one of the compartments  150  of the compartment structure  146 . 
       FIGS. 3A and 3B  also show the optional light-toned polymer insert  170 , having segments sized, dimensioned and oriented to be received by respective compartments  150  of the compartment structure  146 . 
       FIGS. 3A and 3B  also show the transducer PCB  130 , with coupler or connector  144   a  ( FIG. 3A ), temperature sensors  204  ( FIG. 3A ), emitters  134  ( FIG. 3B ), primary detectors or sensors  136  ( FIG. 3B ), and calibration detectors or sensors  138  ( FIG. 3B ). 
       FIG. 4  shows a portion of the sampling device  100  of  FIGS. 1A-1D , illustrating various components in more detail, and in particular the relative positioning of the various components. 
     As best illustrated in  FIG. 4 , a portion of an outer perimeter of the side wall  116  of the tubular lens  102   b  securingly engages (e.g., press fit) a portion of an inner perimeter of a side wall  124  of the shroud  102   c , proximate an internal flange  400 . The securing engagement may be selectively releasable under a moderate application of pulling force or tension. The window or lens cover  120  is secured therebetween. The window or lens cover  120  may be flat, providing no magnification or focusing, but simply providing environmental protection to components rearward of the window or lens cover  120 . In this embodiment, the shroud  102   c  may include one or more attachment structures  402  (e.g., slot or tab, only one shown). The attachment structures  402  may allow selectively releasable attachment to another portion (e.g., platform visible in  FIG. 1B ) of the housing  102  ( FIGS. 1A-1D ). For example, attachment structures  402  may allow selectively releasable attachment to complementary attachment structures  154   b  ( FIGS. 1A-1D , e.g., platform, slot or tab) on the main housing portion  102   a.    
     As best illustrated in  FIG. 4 , an outer perimeter of an annular rim portion  156  of the compartment structure  146  securingly engages (e.g., press fit) a portion of an inner perimeter of a side wall  116  of the lens tube  102   b , proximate an internal flange  404 . The securing engagement may be selectively releasable under a moderate application of pulling force or tension. 
     As best illustrated in  FIG. 4 , the light-toned polymer insert  170  is positioned in the compartment structure  146 , with a respective segment of the light-toned polymer insert  170  in a respective one of each of the compartments  150 . In particular, the segments are positioned to cause some of the electromagnetic energy emitted by the respective emitters  136  to be directed (e.g., scattered, reflected) to the respective calibration detectors or sensors  138  in the respective compartment  150 . As previously noted, other structures may be employed to direct electromagnetic energy toward the respective calibration detectors or sensors  138  in each compartment  150 . 
     As best illustrated in  FIG. 4 , for each compartment  150  the compartment structure  146  includes a masking flange  406 . The masking flange  406  masks the respective calibration detector or sensor  138  in the respective compartment. As illustrated in  FIG. 4 , the calibration detector or sensor  138  may be positioned underlying the respective masking flange  406 . The masking flange  406  forms a slot  408 , through which electromagnetic energy emitted by the respective emitter  134  can exit the respective compartment  150 . In particular, the masking flange  406  includes a number of knife edges that form the slot(s)  408 , severely limiting the ingress of electromagnetic energy into the compartment  150  from an exterior thereof, for instance from the ambient environment or returned from the sample or specimen. 
     By commonly housing emitters  134  with respective calibration detectors or sensors  138  in respective compartments  150 , the sampling device may automatically take or capture an electromagnetic energy calibration sample or measurement each time an emitter emits electromagnetic energy. Such is performed in real-time, without any separate calibration mode. Such may be performed individually for each emitter, one at a time, as the emitter is activated. The thermal sensors  204  ( FIG. 2D ) may be sampled each time an emitter is activated. Alternatively, the thermal sensors  204  may be sampled periodically or aperiodically. The electromagnetic energy calibration sample or measurements and thermal calibration sample or measurements may be used to calibrate a detected or measured response. The electromagnetic energy calibration sample or measurements and thermal calibration sample or measurements may additionally or alternatively be used to control operation, for instance, to control a drive signal supplied to the emitters, or control an amplification applied to a signal produced or provided by the primary detectors or sensors  136 . As discussed below, the electromagnetic energy calibration sample or measurements and thermal calibration sample or measurements may be processed on the sampling device  100 , or sent to a separate component (e.g., digital computer) for processing. 
     As best illustrated in  FIG. 4 , the compartment structure  146  may include at least one flange  410  which at least partially supports the annular lens element  160 . The distinct lenses  162  are positioned in respective compartments  150 , oriented to focus electromagnetic energy emitted by the respective emitters  134  outwardly from the compartment  150  and front of the sampling device  100  ( FIGS. 1A-1D ). In particular, the distinct lenses  162  are positioned and oriented to focus electromagnetic energy toward a common or shared focal locus  412 . As best illustrated in  FIG. 5B , the shared focal locus may be positioned slightly forward of the window or lens cover  120 . 
     As also illustrated in  FIG. 4 , a field-of-view of the primary detector(s) or sensor(s)  136  is aligned with a central passage  152  of the compartment structure  146 , a passage  118  of the lens tube  102   b , and a passage  126  of the shroud  102   c . Such provides a transmissive path for electromagnetic energy returned from a sample or specimen to reach the primary detector(s) or sensor(s)  136 . 
       FIG. 5A  shows a portion of the sampling device of  FIGS. 1A-1D , illustrating an annular segmented array or arrangement of emitters  134  and calibration detector(s) or sensor(s)  138 . 
     In particular,  FIG. 5A  shows twelve emitters  134   a - 1341  (collectively  134 ) radially arrayed along or about a perimeter  200  of the transducer PCB  130 .  FIG. 5A  also shows twelve calibration detectors or sensors  138   a - 1381  (collectively  138 ) radially arrayed along or about a perimeter  200  of the transducer PCB  130 , spaced radially inwardly of the emitters. Each of the calibration detectors or sensors  138  is generally aligned with a respective one of the emitters along an imaginary line (broken line  500 , only one called out in  FIG. 5A ) extending between the respective emitter  134  and a center of the array. As illustrated in  FIG. 5A , walls  502  (only one called out in  FIG. 5A ) of the compartments  150  of the compartment structure  146  ( FIGS. 1A-1D ) delineate twelve radial segments. 
     As also illustrated in  FIG. 5A , one or more primary detector(s) or sensor(s)  136  are positioned in a central region of the annular array. The central region can correspond to, or be aligned with, the central passage  152  of the compartment structure  146  ( FIGS. 1A-1D ), delineated by an inner perimeter wall  504  thereof. 
     While  FIG. 5A  shows twelve emitters  134 , twelve calibration detectors or sensors  138 , and twelve compartments  150  or annular radial segments, other embodiments may include fewer or greater number of emitters  134 , calibration detectors or sensors  138  and/or compartments  150  or annular radial segments. As discussed above, some implementations may employ more than one emitter  134  in each set, compartment  150  or annular radial segment. Also as discussed above, some implementations may employ more than one calibration detectors or sensors  138  in each set, compartment  150  or annular radial segment. Thus, the total number of emitters  134 , calibration detectors or sensors  138 , and/or compartments  150  or annular segments should not be considered limiting. While  FIG. 5A  shows four primary detector(s) or sensor(s)  136 , other embodiments may include fewer or greater number of primary detector(s) or sensor(s)  136 . 
       FIG. 5B  shows a schematic illustration of a portion of the sampling device of  FIGS. 1A-1D  in use, sampling a sample or specimen  506 , according to one illustrated embodiment. 
     As illustrated in  FIG. 5B , an emitter  134  emits electromagnetic energy in a compartment  150 . The electromagnetic energy passes through a slot formed by a masking flange  170 . As the ray drawing indicates, a distinct lens element  162  focuses the electromagnetic energy toward a focal locus  412 . The focal locus is a point or set of points at which the various distinct lens elements  162  focus the emitted electromagnetic energy. Typically, the focal locus will be outward from the window or lens cover  120 . In some implementations, the focal locus  412  will be forward or outward of the shroud  102   c  ( FIGS. 1A-1D ). In other implementations, the focal locus  412  will be rearward or within the passage  126  of the shroud  102   c  ( FIGS. 1A-1D ). 
     Representative exemplary dimensions of the embodiment shown in  FIG. 5B , are as follows. A perpendicular distance from a position of a die of the emitter  134  to the lens element  162  is approximately 19 mm. A perpendicular distance from a top surface of the transducer PCB to the sample or specimen  506  is approximately 20 mm. A distance from a position of a die of the emitter  134  to the lens element  162  along an optical axis is approximately 7 mm. A distance from the lens element  162  to the sample or specimen  506  along the optical axis is approximately 15 mm. An included angle between the optical axis and a perpendicular line of symmetry (broke line) is approximately 32 degrees. A width of the lens element  162  is approximately 5 mm. A lateral distance between the die of the emitter  134  and the line of symmetry is approximately 12 mm. A total lateral distance from edge to edge (e.g., diameter of transducer PCB  130  is approximately 28 mm. A diameter of the bottom (e.g., portion closest to transducer PCB  130 ) of the passage  152  of the compartment structure  146  is approximately 10 mm. 
     As the ray drawing indicates, electromagnetic energy strikes the sample or specimen  506 , and is scattered and/or reflected therefrom. A portion of the electromagnetic energy returns from the sample or specimen  506  to the sampling device  100  ( FIGS. 1A-1D ) and falls incident on, and thus is detected by, the primary detector(s) or sensor(s)  136 . A portion of the electromagnetic energy returned from the sample or specimen  506  does not fall incident on, and thus is not detected by, the primary detector(s) or sensor(s)  136 . In particular, the geometry of the sampling device  100  ( FIGS. 1A-1D ) causes at least some of the electromagnetic energy that is scattered from the sample or specimen  506  to be directed to the primary detector(s) or sensor(s)  136  via the passages  126 ,  118 ,  152 . The geometry of the sampling device  100  ( FIGS. 1A-1D ) also causes a substantial portion of electromagnetic energy that is reflected or specular from the sample or specimen  506  to, for the most part, be directed away from the primary detector(s) or sensor(s)  136 . 
       FIG. 5C  shows a schematic illustration of a portion of the sampling device of  FIGS. 1A-1D  in use with a glossy red painted surface, according to one illustrated embodiment. 
     The glossy red painted surface may, as an example, have 15% Lambertian reflectance and 4% gloss or specular reflection. 
     As is readily apparent from the ray drawing, the geometry of the sampling device which arrays the emitters  134  in a generally annular array, locates the primary detectors or sensors  136  in a center of the annular array, and employs an annular lens structure  160  to focus the emitted electromagnetic energy to a common focal locus, substantially reduces or eliminates specular reflection from reaching the primary detectors or sensors  136 . While much of the scattered electromagnetic energy is likewise lost, the scattered electromagnetic energy which does reach the primary detectors or sensors  136  is not longer mixed with the specular reflection. The specular reflection constitutes noise to the sampling device, the reduction of which can improve accuracy. 
     Thus, by suitably angling the projection of electromagnetic energy, specularly reflected light, both from a glossy target surface and from the protective window of the instrument, can be diverted away from the central zone where the primary detectors or sensors  136  are located. 
     While not required, the central passage  152  of the compartment structure  146  may taper from relatively wide to relatively narrow as the compartment structure  146  is traversed along its primary axis (e.g., longitudinal axis) from back to front, the most narrow portion the central passage  152  being at the first end  148   a  of the compartment structure  146 , as illustrated in  FIG. 5B . 
     While  FIG. 5B  includes certain dimension which may be suitable for some embodiments, the sampling device  100  may employ other dimensions. Thus, the specified dimensions should not be considered limiting. 
       FIG. 6  shows a sampling system  600 , according to one illustrated embodiment. 
     The sampling system  600  includes one or more sampling devices  100  (one shown). The sampling system  600  includes one or more processor-based device  602  (one shown). While illustrated as a mobile or handheld processor-based device  602 , for instance, a Smartphone type device, the processor-based device  602  may take a large variety of other forms. For example, the mobile or handheld processor-based device  602  may take the form of the various computers or computing systems, such as a desktop or laptop personal computer, tablet computer, netbook computer, mini-computer, mainframe computer, or server computer. 
     The sampling device  100  is communicatively coupled to the processor-based device  602 . 
     The sampling device  100  may be communicatively coupled to the processor-based device  602  via a physical communicative path such as a cable  604 . 
     The cable  604  will typically include a connector proximate at least one end thereof, and often at both ends. For example, the cable  604  may have a first connector  604   a  (e.g., plug) at a first end  606   a , the first connector  604   a  selectively detachably coupleable to a complimentary connector or port  608  on the processor-based device  602 . Also, for example, the cable  604  may have a second connector  604   b  (e.g., plug) at a second end  606   b , the second connector  604   b  selectively detachably coupleable to a complimentary connector or port  610  on the sampling device  100 . Alternatively, the second end of the cable  604  may be permanently fixed to the sampling device  100 . The physical ports and/or connectors  604   a ,  604   b ,  608 ,  610  and/or cables  604  may comply with any variety of physical and/or logical standards, and may incorporate one or more integrated circuits. For instance, the ports and/or connectors  604   a ,  604   b ,  608 ,  610  and/or cables  604  may comply with standards required of USB® standards or Apple Computer&#39;s Lighting® standards. 
     The cable  604  may, for instance, include a number of distinct electrical conductors (e.g., wires) (not shown) to provide signals between the sampling device  100  from the processor-based device  602 . The electrical conductors may provide for bi-directional communications between the sampling device  100  and the processor-based device  602 . The cable  604  may additionally provide electrical power (e.g., 5V, 10V) to the sampling device  100  from the processor-based device  602 . In such an implementation, the sampling device  100  may omit any on-board consumable power source (e.g., primary or secondary chemical battery, ultra-capacitor, fuel cell) (not shown). Alternatively, the sampling device  100  may include a recharging circuit (not shown) that uses electrical power supplied via the cable  604  to recharge an onboard power source (e.g., secondary chemical battery, ultra-capacitor, fuel cell) (not shown). 
     The cable  604  may include one or more optical paths (e.g., optical fibers) (not shown). The optical paths may provide for bi-directional communications between the sampling device  100  and the processor-based device  602 . 
     The sampling device  100  may be communicatively coupled to the processor-based device  602  via a wireless (e.g., radio frequency, microwave, visible or IR light) communicative path. As discussed below, many processor-based devices  602  include various radios or receivers, including ones that are compliant with cellular (e.g., CDMA, GSM, LTE), BLUETOOTH or WI-FI protocols. In such implementations, the sampling device  100  may include one or more radios or transceivers (not shown) that can be implemented as one or more integrated circuits and/or antennas (not shown). The integrated circuits and/or antennas (not shown) may be carried by the controller PCB  132  ( FIGS. 1A-1D ) or some other PCB, for instance, a dedicated communications PCB (not shown). In such implementations, the sampling device  100  will typically require an on-board consumable power source (e.g., primary or secondary chemical battery, ultra-capacitor, fuel cell) (not shown). 
     The sampling device  100  may be communicatively coupled via one or more networks (not shown) to various processor-based devices  600  and/or other sampling devices  100 . The network may take a variety of forms including LANs, WANs, WLANs, WWANs, PSTN, to name a few. Such may, for example, allow access to one or more storage or databases of information. Such may, for example, allow updating or reconfiguration, for instance, by downloading of processor-executable instructions. Such may, for example, allow troubleshooting of the sampling device  100  should an error condition occur. 
     The processor-based device  602  may include a user interface which may, for example, include a touch-sensitive display  612 , speakers  614  (one shown), microphone  616   a ,  616   b  (collectively  616 ), and/or audio output port  618 . The user interface may also include user selectable icons, collectively  620 , and/or one or more physical switches, keys or buttons  622 . 
       FIG. 6  illustrates a PCB  624  of the processor-based device  602 , removed therefrom to better illustrate various components housed within a housing of the processor-based device  602 . The processor-based device  602  includes one or more processors, for instance, a microprocessor  626 . The processor-based device  602  includes one or more nontransitory computer- or processor-readable media, for instance, ROM or Flash  628  and/or RAM  630 . 
     The processor  626  employs instructions and or data from the ROM/Flash  628  and/or RAM  630  in controlling operation of the sampling device  100 . For example, the processor  626  operates the emitters  134  ( FIGS. 1A-1D ) in one or more sequences. The sequences determine an order in which the emitters  134  ( FIGS. 1A-1D ) are turned ON and OFF. The sequences may also indicate an ordered pattern of drive levels (e.g., current levels, voltage levels, duty cycles) for the emitters  134  ( FIGS. 1A-1D ). Thus, for example, the processor  626  may cause the application of different drive levels to respective ones of the emitters  134  ( FIGS. 1A-1D ) to cause the emitters  134  ( FIGS. 1A-1D ) to emit in distinct bands of the electromagnetic spectrum. The processor  626  may process information generated by the primary detector(s) or sensor(s)  136  ( FIGS. 1A-1D ), which is indicative of the response by at least a portion of a sample or specimen to illumination by the emitters  134  ( FIGS. 1A-1D ). The information at any given time may be indicative of the response by the sample or specimen to illumination by one or more of the emitters  134  ( FIGS. 1A-1D ). Thus, the information over a period of time may be indicative of the responses by the sample or specimen to sequential illumination by each of a plurality of the emitters  134  ( FIGS. 1A-1D ), where each of the emission spectra of each of the emitters  134  ( FIGS. 1A-1D ) has a different center, bandwidth and/or other more complex differences in spectral content, such as those described above (e.g., width of the band, the skew of the distribution, the kurtosis, etc.). 
     The processor  626  employs instructions and or data from the ROM/Flash  628  and RAM  630  to perform analysis or evaluation of the responses. For example, the processor  626  may compare a response to one or more reference responses. The processor  626  may determine whether a response from a sample or specimen sufficiently matches the signature responses from a reference sample or specimen. Such may, for example, be employed to detect a presence or absence of a substance, for instance, an illegal substance (e.g., cocaine), an explosive substance (e.g., nitrate based), or a toxic substance (e.g., carcinogens). The processor  626  may cause display of a result of an analysis or evaluation. For instance, the processor  626  may cause display of a simple indicator (e.g., check, YES/NO, other text, GREEN/RED/AMBER or other color) indicative of the result. Also, for instance, the processor  626  may cause display of a more complex indicator (e.g., graph, table chart) indicative of the result. Additionally or alternatively, the processor  626  may cause an aural indication indicative of a result via speaker  614 , for example a sound such as a beep, buzz, or even spoken or synthesized words. 
     The processor-based device  602  may additionally include a display driver  632 , communicatively coupled to drive the touch-sensitive display  612  and/or detect touches, swipes or other user inputs via the touch-sensitive display  612 . The display driver  632  may be a dedicated integrated circuit, for example, a graphical processing unit. 
     The processor-based device  602  may additionally include one or more radios or transceivers  634  (only one shown) and one or more associated antennas  636  (only one shown). The radios or transceivers  634  and antennas  636  may take any of a large variety of forms, for example, ones suitable for wireless communications such as cellular communications (e.g., CDMA, GSM, LTE), BLUETOOTH communications and/or WI-FI communications. 
     The processor-based device  602  may additionally include one or more accelerometers or gyroscopes. Such components may be capable of producing data indicative of an orientation of the processor-based device  602 . Such components may be capable of producing data indicative of a speed, movement or acceleration of the processor-based device  602 . 
     The various components may be communicatively coupled via one or more buses  638  (only one shown) or other connections, for example, data buses, instruction buses, address buses, power buses, etc. 
       FIGS. 7A and 7B  show a calibration cap  700 , for optional use with a sampling device  100 , according to one illustrated embodiment. 
     The calibration cap  700  is selectively removably coupleable to a front of the sampling device  100 . For example, the calibration cap  700  may be selectively removably coupleable to the shroud  102   c  ( FIGS. 1A-1D ). Alternatively, the calibration cap  700  may be selectively removably coupleable to the lens tube  102   b  ( FIGS. 1A-1D ), in place of the shroud  102   c  ( FIGS. 1A-1D ), the shroud  102   c  removed to allow physical coupling of the calibration cap  700 . The calibration cap  700  may be coupled via a press fit, or alternatively a detent or some other coupler structure (e.g., bayonet mount, screw or threaded mount). 
     The calibration cap  700  includes a side wall  702  which delimits a central passage  704 , the central passage  704  open at a distal proximal end  706  of the calibration cap  700  to the passage  118  of the lens tube  102   b . The side wall  702  may comprise a plastic, which may enhance the ability to use a press fit. 
     The calibration cap  700  includes a calibration or reference target, sample or specimen  708  positioned at a distal end  710  of the calibration cap  700 . The calibration or reference target  708  has known and stable optical characteristics. Thus, the sampling device  100  may take calibration samples using the known calibration or reference target  708 . Such may allow detection of drift in operation of various components. For example, such may allow detection of drift in operation of the emitters  134 . Such may also allow detection of drift in operation of the primary detectors or sensors  136 . Even more importantly, such may allow detection of drift in operation of the calibration detectors or sensors  138 , which would not otherwise be possible. 
     As previously explained, the calibration detectors or sensors  138  may be used to automatically calibrate for drift in operation of the emitters  134  and primary detectors or sensors  136 , for instance each time an emitter emits electromagnetic energy. In contrast, the calibration cap  700  may be used from time-to-time (e.g., periodically, aperiodically) to calibrate for drift in operation of the emitters  134 , primary detectors or sensors  136 , and/or calibration detectors or sensors  138 . For example, the calibration cap  700  may at the start of each day, at the start of each hour, weekly, monthly, or before sampling of each sample or specimen. 
     The sampling device  100  may provide an alert if a condition is detected, for which condition the sampling device  100  is not capable of automatically adjusting to compensate or accommodate, for instance a condition outside a range of adjustable conditions. The sampling device  100  may provide an alert even if a detected condition is one for which the sampling device  100  automatically adjusts to accommodate or compensate. The sampling device  100  may calibration data or information remotely, for example, to one or more processor-based devices  602  ( FIG. 6 ) such as a Smartphone device (e.g., iPhone®, Andriod® based Smartphone). 
     CONCLUDING REMARKS 
     As used herein and in the claims, longitudinal refers to the major dimension or length of a structure, and is not limited to being an axis of revolution of a profile or cross-section of such structure. 
     As used herein and in the claims, the term “non-transitory computer-readable medium” and “non-transitory processor-readable medium” are used interchangeably to refer to any tangible medium that participates in providing instructions for execution or storage of data, parameters or other information. Such a medium may take many forms, including but not limited to, non-volatile media and volatile media. Non-volatile media includes, for example, hard, optical or magnetic disks  161 ,  166 ,  168 , respectively. Volatile media includes dynamic memory, such as system memory  150 . Common forms of computer- or processor-readable media include, for example, floppy disk, flexible disk, hard disk, magnetic tape, or any other magnetic medium, CD-ROM, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, RAM, PROM, EPROM, EEPROM, FLASH memory, any other memory chip or cartridge, or any other tangible medium from which a computer or processor can read. 
     While not illustrated, the sampling device  100  ( FIGS. 1A-1D ) may include one or more elements operable to deflect or otherwise position the emitted or received electromagnetic energy. The elements may, for example, include one or more optical elements, for example, lens assemblies, mirrors, prisms, diffraction gratings, etc. For example, the optical elements may include an oscillating mirror, rotating polygonal mirror or prism, or MEMS micro-mirror that oscillates about one or more axes. The elements may, for example, include one or more other elements, for example permanent magnets or electromagnets such as those associated with cathode ray tubes and/or mass spectrometers. 
     While generally illustrated and described in a standalone form factor, which may, or may not, be communicatively coupled to a processor-based device (e.g., smartphone, tablet computer, netbook computer, laptop computer, desktop computer), the sampling device  100  ( FIGS. 1A-1D ) may have other form factors. For example, the sampling device  100  ( FIGS. 1A-1D ) may be integrated into a smartphone, the various PCBs and other components located in a smartphone housing or shell to form an integral device. Likewise, the sampling device  100  ( FIGS. 1A-1D ) may be integrated into other processor-based devices. Such may allow omission of one or more components from the PCBs, which may rely on components of the processor-based device to avoid duplication, and thereby reducing costs, size and/or complexity. 
     While generally illustrated and described as having a single emitter  134  per compartment  150 , in some implementations there may be more than one emitter in any given compartment  150 . For instance, there may be two emitters  134  with adjacent or even overlapping ranges of wavelengths, for instance to cover the N-IR portion of the electromagnetic spectrum. Thus, any given calibration detector or sensor  138  may receive electromagnetic energy from two or even more emitters  134 , where the calibration detector or sensor  138  has a sensitivity or responsive range that covers the range of wavelengths of the emitters  134 . Such may advantageously reduce parts count, complexity, size, and importantly cost. Suitable calibration detector or sensor  138  may in some instances cost over $60, so the ability to omit one or more calibration detector or sensor  138  is highly advantageous. 
     While generally illustrated and described as employing separate transducer PCB  130  and controller PCB  132 , the sampling device  100  ( FIGS. 1A-1D ) may employ a single PCB, or may employ more than two PCBs. Further, various components illustrated on one PCB, may be carried by the other PCB, or in some instances omitted. Alternatively or additionally, the various components on one PCB  130 ,  132  or both PCBs  130 ,  132  can be implemented in a system on chip (SoC) integrated circuit structure, reducing the parts count as well as the number of PCBs. 
     The various embodiments described above can be combined to provide further embodiments. All of the U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and/or listed in the Application Data Sheet, including but not limited to: U.S. Pat. Nos. 7,996,173; 8,081,304; and 8,076,630; U.S. Provisional Patent Application Ser. Nos. 60/623,881, filed Nov. 1, 2004; 60/732,163, filed Oct. 31, 2005; 60/820,938, filed Jul. 31, 2006; 60/834,662, filed Jul. 31, 2006; 60/834,589, filed Jul. 31, 2006; 60/871,639, filed Dec. 22, 2006; 60/883,312, filed Jan. 3, 2007; 60/890,446, filed Feb. 16, 2007; 61/538,617, filed Sep. 23, 2011; 61/597,586, filed Feb. 10, 2012; 61/597,593, filed Feb. 10, 2012; 61/760,527, filed Feb. 4, 2013; and 61/767,716, filed Feb. 21, 2013, are incorporated herein by reference, in their entirety. Aspects of the embodiments can be modified, if necessary, to employ systems, circuits and concepts of the various patents, applications and publications to provide yet further embodiments. 
     These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.