Patent Publication Number: US-11642051-B2

Title: Common sample zone noninvasive glucose concentration determination analyzer apparatus and method of use thereof

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is:
         a continuation-in-part of U.S. patent application Ser. No. 16/691,611 filed Nov. 22, 2019;   a continuation-in-part of U.S. patent application Ser. No. 16/691,615 filed Nov. 22, 2019; and   a continuation-in-part of U.S. patent application Ser. No. 15/829,877 filed Dec. 2, 2017, which is a continuation-in-part of U.S. patent application Ser. No. 15/636,073 filed Jun. 28, 2017, which claims benefit of U.S. provisional patent application No. 62/355,507 filed Jun. 28, 2016.       

    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates generally to noninvasively determining glucose concentration in a living body using an optical analyzer, such as a visible/near-infrared noninvasive glucose concentration determination analyzer. 
     Discussion of the Prior Art 
     There exists in the art a need for noninvasively determining glucose concentration in the human body. 
     SUMMARY OF THE INVENTION 
     The invention comprises a noninvasive glucose concentration analyzer apparatus and method of use thereof. 
    
    
     
       DESCRIPTION OF THE FIGURES 
       A more complete understanding of the present invention is derived by referring to the detailed description and claims when considered in connection with the Figures, wherein like reference numbers refer to similar items throughout the Figures. 
         FIG.  1    illustrates use of an applied force-optic analyzer; 
         FIG.  2    illustrates a noninvasive analyzer; 
         FIG.  3 A  illustrates an applied force system,  FIG.  3 B  illustrates a transducer, 
         FIG.  3 C  illustrates transducer movement normal to an optical axis,  FIG.  3 D  illustrates a z-axis transducer, and  FIG.  3 E  illustrates a multi-axes off-center spinning mass transducer; 
         FIG.  4 A  illustrates spectrometer components,  FIG.  4 B  illustrates an affixing layer, and  FIG.  4 C  illustrates a coupling fluid enhanced affixer; 
         FIG.  5 A  illustrates a force system coupled to a spectrometer and  FIG.  5 B  illustrates a force system embedded in a spectrometer; 
         FIG.  6    illustrates photons interacting with applied force wave(s) in tissue; 
         FIG.  7 A  illustrates absorbance of skin constituents,  FIG.  7 B  illustrates fat and protein absorbance,  FIG.  7 C  illustrates intensity as a function of depth/distance, and  FIG.  7 D  illustrates scattering; 
         FIG.  8    illustrates detector selection; 
         FIG.  9    illustrates changing detector selection with tissue change; 
         FIG.  10 A  illustrates a transducer force applicator and  FIG.  10 B  and  FIG.  10 C  illustrate transducer force detectors in lines and arcs respectively; 
         FIG.  11 A  illustrates radial optical detection of force waves,  FIG.  11 B  illustrates an array of optical detectors, and  FIG.  11 C  illustrates arcs of optical detectors; 
         FIG.  12    illustrates optical probes observing tissue modified by force waves in a noninvasive glucose concentration determination system/analyzer; 
         FIG.  13    illustrates a multi-sensor analyzer system; 
         FIG.  14 A  illustrates spirally distributed detectors and  FIG.  14 B  and  FIG.  14 C  illustrate depth and radial distance resolution; 
         FIG.  15 A ,  FIG.  15 B ,  FIG.  15 C , and  FIG.  15 D  illustrate depth selection from various angles in two separate units; 
         FIG.  16 A ,  FIG.  16 B ,  FIG.  16 C , and  FIG.  16 D  illustrate tissue sample position selection; and 
         FIG.  17    illustrates a common depth and common detector analyzer probe tip; 
         FIG.  18    illustrates a common depth and common sample position probe tip; 
         FIG.  19 A  and  FIG.  19 B  illustrate a first and second tissue classification system, respectively; 
         FIG.  20 A  and  FIG.  20 B  illustrate a multiplexed common zone sample system; and 
         FIG.  21    illustrates a common detector/common zone sample system. 
     
    
    
     Elements and steps in the figures are illustrated for simplicity and clarity and have not necessarily been rendered according to any particular sequence. For example, steps that are performed concurrently or in different order are illustrated in the figures to help improve understanding of embodiments of the present invention. 
     Problem 
     There remains in the art a need for a noninvasive glucose concentration analyzer. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention comprises a method and apparatus for sampling a common tissue volume and/or a common skin layer skin of a person as a part of noninvasive analyte property determination system, comprising the steps of: providing an analyzer, comprising at least three detectors at least partially embedded in a probe housing, the probe housing comprising a sample side surface, the detectors including a first and second range detection zones of differing radial distances from a first illumination zone and second illumination zone, respectively coupled to separate sources; repetitively illuminating the illumination zones of the skin with photons in a range of 1200 to 2500 nm; and detecting portions of light from the sources with the at least three detectors, the detectors positioned on a common line with the sources. 
     Herein, generally, when describing an optical portion of the applied force-optic analyzer, a z-axis is aligned with a mean direction of the photons in a given sub-portion of the analyzer, such as along a longitudinal path of the photons into skin of a subject, and x- and y-axes form a plane perpendicular to the z-axis, such as at an interface point of incident photons into the skin of the subject. At the point of contact of the applied force-optic analyzer with the biological sample, the z-axis is normal/perpendicular to the sample and the x/y-plane tangentially contacts the sample. For instance, the light moves dominantly along the z-axis along vectors approaching perpendicular to an upper arm of a subject or a patient and the x/y-plane tangentially touches the upper arm along the z-axis. In particular cases, a second x,y,z-axis system is used to describe the sample itself, such as a z-axis being along the longitudinal length of a body part, such as along a digit or a finger or along the length of an arm section and the x/y-plane in this case is a cross-section plane of the body part. 
     A sample is optionally any material responding to an applied physical force in a manner observed by a probing optical system. However, for clarity of presentation and without loss of generality, the sample is described as a person, subject, patient, and/or a living tissue, such as skin and/or a portion of a human or animal. While the analyzer is described as a noninvasive analyzer probing into and optionally through the outer layers of skin, the noninvasive analyzer is optionally used as and or in conjunction with a minimally invasive glucose concentration analyzer and/or in conjunction with an invasive glucose concentration analyzer. 
     Herein, an illumination zone and/or an imaging zone is a point, region, or area of intersection of the illumination/imaging beam and/or pulse with an incident surface of the sample to yield a spectrum and/or an image of a desired volume of the sample. Herein, a detection zone is a point, region, or area of the sample sampled and/or visualized by one or more detectors. Similarly, herein an applied force zone is an incident point, region, or area of intersection at which an applied force is applied to the sample and a detected force zone is a point, region, or area of the sample interfacing with a force detector. 
     Applied Force-optic Analyzer 
     Referring now to  FIG.  1   , a noninvasive analysis system  100  using an analyzer  110 , such as an applied force-optic analyzer system is illustrated. Generally, an optional force system  200  is used to apply one or more applied forces, physical distortions, and/or force waves to a sample  300 . The applied force travels with a wave front, as a wave, in a pattern of compression and rarefication, and/or as a traveling displacement through the sample  300  or portions thereof. With or without application of the force waves, a spectrometer  140  is used to noninvasively collect spectra of the sample  300  and photometrically determine one or more properties of the sample, such as a glucose concentration. As described infra, the applied force is optionally in the form of an acoustic wave. However, the applied force is optionally and preferably a physical displacement of a portion of skin of a person, where the physical displacement is caused by movement of a mechanical object relative to the body to yield a time varying displacement of skin and/or constituents of the skin by the mechanical object. As described, infra, a variety of force provider technologies are available to variably displace the skin in a controlled manner. For clarity of presentation and without loss of generality, a transducer is used as an example to represent an applied force section of the force system  200 , where a transducer comprises a device that receives a signal/force in the form of one type of energy and converts it to a signal/force in another form. Again for clarity of presentation and without loss of generality, a piezoelectric actuator is used to represent a transducer and an off-center spinning mass is used to represent a transducer. Hence, again for clarity of presentation and without loss of generality, a piezoelectric-optical analyzer or simply a piezo-optic analyzer, a transducer, and/or a transducer force applicator is used to describe any and all applied force electromechanical sources in the force system  200 . Optionally, more than one transducer is used to yield displacement of the surface of the skin/skin, such as at a function of time and/or position. 
     Referring now to  FIG.  2   , use of the analyzer  110  is described. Generally, the analyzer  110  is optionally calibrated using a reference  310  and is used to measure a subject  320 , where the subject  320  is an example of the sample  300 . Optionally and preferably, the analyzer  110  and/or a constituent thereof communicates with a remote system  130  using a wireless communication protocol  112  and/or a wired communication protocol. 
     Force System 
     Referring now to  FIGS.  3   (A-E), the force system  200  is further described. Generally, the force system  200  comprises a force delivery transducer that directly and/or indirectly contacts the sample  300 , such as an outer skin surface  330  of the subject  320  and/or a patient. The subject  320  has many skin layers  340 , which are also referred to herein as tissue layers. For clarity of presentation, the skin layers  340  are represented as having a first skin layer, such as a stratum corneum  342 ; a second skin layer, such as an epidermis  344  or epidermal layer; a third skin layer, such as a dermis  346  or dermis layer; and a fourth layer, such as subcutaneous fat  348  or a subcutaneous fat layer. It is recognized that skin is a complex organ with many additional layers and many sub-layers of the named layers that vary in thickness and shape with time. However, for clarity of presentation and without loss of generality, the stratum corneum, epidermis, dermis, and subcutaneous fat layers are used to illustrate impact of the force delivery transducer on the skin layers  340  of the subject  320  and how the applied force waves alter optical paths of probing photons in the spectrometer  140  of the analyzer  110  in the noninvasive analysis system  100 . 
     Still referring to  FIG.  3 A , at a first time, t 1 , the tissue layers  340  are in a first state. As illustrated, the tissue layers  340  are in a compressed state  340 , such as a result of mass of the force system  200  sitting on the skin surface  330 , as a result of dehydration of the subject  320 , and/or as a result of a physiological and/or environmental force on the tissue layers  340  of the subject. At a second time, t 2 , the force system  200  applies a force wave  250  to the skin surface  330  of the patient  320 , which sequentially propagates into the stratum corneum  342 , epidermis  344 , dermis  346 , and given enough force into the subcutaneous fat  348 . In additional to the force wave propagating into the skin layers  340  along the z-axis, the force wave propagates radially through the skin layers, such as along the x/y-plane of the skin layers. As illustrated at the second time, t 2 , as the force wave  250  propagates into the tissue layers  340 , the tissue layers expand and/or rarefy, such that the thickness of the epidermis  344  and/or the dermis  346  layers expands. The rarefication of the epidermis  344  and particularly the dermis  346  allows an increased and/or enhanced perfusion of blood  350  into the rarefied layers. The increased prefusion increases water concentration in the perfused layers, increase and/or changes distance between cells in the perfused layers, and/or changes shapes of cells in the perfused layers, such as through osmolarity induced changes in concentration in and/or around blood cells, such as red blood cells. Generally, scattering coefficients of the epidermis layer and/or especially the dermis layer changes, which is observed by the spectrometer  140  in the range of 400 to 2500 nm with larger changes at smaller wavelengths in the visible, 400 to 700 nm, and/or near-infrared, 700 to 2500 nm, regions. As illustrated at the third time, t 3 , as the force wave  250  continues propagation in the tissue layers  340 , the perfusion  350  continues to increase, such as to a maximum perfusion. As illustrated at the fourth time, t 4 , after discontinuation of the force wave  250 , the skin layers  340  revert toward the initial state of the non-force wave induced perfusion to a local minimum perfusion, which may match the initial perfusion, is likely higher than the initial perfusion, and is at times less than the initial perfusion due to changes in state of the environment, such as temperature, and/or generalized state of the subject  320 , such as hydration, localized hydration of skin, such as due to food intake, insulin response to food intake, exercise level, blood pressure, and/or the like. Generally, the tissue layers  340  of the subject increase in thickness and/or rarefy during application of the transducer applied force wave  250  and decrease and/or compress after termination of the transducer applied force wave  250  to the skin surface  330  of the subject  320 . The process of applying the force wave  250  is optionally and preferably repeated n times, where n is a positive integer of greater than 1, 2, 5, 10, 100, 1000, or 5000 times in a measurement period of an analyte of the subject  320 , such as a glucose concentration. Generally, the cycle of applying the force wave  250  results in a compression-rarefication cycle of the tissue that alters an observed scattering and/or absorbance of probing photons in the visible and near-infrared regions. The force wave  250  is optionally and preferably applied as a single ping force in a tissue state classification step, as multiple pings in a tissue classification step, and/or as a series of waves during a tissue measurement step. Individual waves of a set of force waves are optionally controlled and varied in terms of one or more of: time of application, amplitude, period, frequency, and/or duty cycle. 
     Still referring to  FIG.  3 A  and referring now to  FIGS.  3   (B-D), a force wave input element  210  of the force system  200  is illustrated. As illustrated, the force wave input element  210 , such as a transducer  220 , is equipped with one or of: a left transducer  221 , a right transducer  222 , a front transducer  223 , a back transducer  224 , a top transducer  225 , and/or a bottom transducer  226 . For instance, the left and/or right transducers  221 ,  222  move the force wave input element  210  left and/or right along the x-axis; the front and/or back transducers  223 ,  224  move the force wave input element  210  forward and/or back along the y-axis; and/or the top and bottom transducers  225 ,  226  move the force wave input element  210  up and/or down along the z-axis along and/or into the skin surface  330  of the subject  320 , which moves the skin, skin layers  340 , and/or skin surface  330  of the subject relative the spectrometer  140  and/or is a source of the force wave  250  moving, in the skin layers  340 , along the z-axis into the skin, and/or radially outward from an interface zone of the force wave input element  210  of the force system  200 . A transducer itself is optionally used as the force wave impulse element  210 . Referring now to  FIG.  3 E , one or more off-center mass elements  230  is optionally spun or rotated, such as with an electric motor, along one or more of the x,y,z-axes to move the force wave input element  210  relative to the skin surface  330  of the subject  320  resulting movement of the skin of the subject  320  relative to the spectrometer  140  and/or cycling and/or periodic displacement of the tissue layers  340  of the subject  320  due to movement of the force wave input element  210  resulting in the force wave(s)  250 . Generally, the force system  200  induces a movement of a sampled zone of skin of the subject  320 , applies a displacement of a sampled zone of the skin of the subject  320 , and/or applies a propagating force wave into and/or through a sample zone of tissue layers  340  of the subject, where the sampled zone is probed using photons from the spectrometer  140  and/or is measured using a set of detection zone transducers, described infra. The force wave(s) are optionally and preferably applied as a single input ping wave, a set of input ping waves, and/or are applied with a frequency of 0.01 Hz to 60 Hz. Optionally and preferably, the force waves  250  are applied with a frequency greater than 0.01, 0.02, 0.05, 0.1, or 1 Hz. Optionally and preferably, the force waves  250  are applied with a frequency of less than 200, 100, 50, 40, 30, or 20 Hz. Optionally and preferably, the force waves  250  are applied with a frequency within 5, 10, 25, 50, or 100 percent of 2, 4, 6, 8, 10, 12, 15, and 20 Hz. 
     Optical System 
     Referring now to  FIG.  4 A , the spectrometer  140  of the analyzer  110  is further described. The spectrometer  140  comprises a source system  400 , which provides photons  452  in the visible and/or infrared regions to the subject  320 , such as via a photon transport system  450 , at an illumination zone. After scattering and/or absorbance by the tissue layers  340  of the subject  320 , a portion of the photons are detected at a detection zone by a detector system  500 . The source system  400  includes one or more light sources, such as any of one or more of a light emitting diode, a laser diode, a black body emitter, and/or a white light source, that emits at any wavelength, range of wavelengths, and/or sets of wavelengths from 400 to 2500 nm. Each source system photon source is optionally controlled in terms of time of illumination, intensity, amplitude, wavelength range, and/or bandwidth. The photon transport system  450  comprises any fiber optic, light pipe, air interface, air transport path, optic, and/or mirror to guide the photons from the light source to one or more illumination zones of the skin surface  330  of the subject  320  and/or to guide the photons from one or more detection zones of the skin surface  330  of the subject  320  to one or more detectors of the detector system  500 . Optionally and preferably, the photon transport system  450  includes one or more optical filters and/or substrates to selectively pass one or more wavelength regions for each source element of the source system  400  and/or to selectively pass one or more wavelength ranges to each detector element of the detector system  500 . Herein, the reference  310  is optionally an intensity and/or wavelength reference material used in place of the sample and/or is used in a optical path simultaneously measured by the analyzer  110 . 
     Still referring to  FIG.  4 A  and referring now to  FIG.  4 B  and  FIG.  4 C , the subject  320  optionally and preferably wears the analyzer  110  in the physical form of a watch head, band, and/or physical element attached to the body with a band and/or an adhesive. For example, the analyzer  110 , the spectrometer  140 , the source system  400 , and/or the photon transport system  450  is optionally attached to the subject  320 , such as at the wrist or upper arm, using thin affixing layer  460 , such as a double sided adhesive  462 . Referring now to  FIG.  4 B , the double sided adhesive  462  optionally contains an aperture  464  therethrough. The photons  452  optionally and preferably pass through the aperture  452  to the skin surface  330  of the subject. The force wave  250  optionally moves the skin surface  330  through the aperture into intermittent contact with the analyzer  110 . Optionally, referring now to  FIG.  4 C , a thin affixing layer  466 , such as less than 1, 0.5, or 0.25 mm thick, is continuous in nature in front of the incident surface and/or incident photon coupling zone and/or is continuous in nature in front of the detection zone, where photons exiting the skin surface  330  are detected by the detector system  500 . The affixing layer  466  is optionally permeated with a fluid, such as a coupling fluid, an air displacement medium, an optical coupling fluid, a fluorocarbon liquid, a fluorocarbon gel, an index of refraction matching medium, and/or any fluid that increases a percentage of photons from the source system  400  entering the skin surface  330  compared to an absence of the fluid and/or is any fluid that increases a percentage of photons from the tissue layers  340  exiting the detection zone and reaching the detector system  500  as compared to a case where the fluid is not embedded into the affixing layer. Hence, the affixing layer serves several purposes: attaching the analyzer or a portion thereof to the skin surface  330  of the subject  320 , coupling forces from the force system  200  to the skin surface  330  of the subject  320 , forming a constant sampling interface location on the skin surface  330  of the subject, and/or altering a coupling efficiency, angular direction, and/or reproducibility of coupling of photons enter the skin of the subject  320  and/or exiting the skin surface  330 . 
     Coupled Force System/Spectrometer 
     Referring now to  FIG.  5 A  and  FIG.  5 B , the force system  200  is illustrated working in conjunction with the spectrometer  140 . Referring now to  FIG.  5 A , the analyzer  110  is illustrated with the force system  200  being attached to and/or within 1, 2, 3, 5, 10, 20, or 50 mm of the spectrometer  140 . Referring now to  FIG.  5 B , the analyzer  110  is illustrated with the force system  200  being integrated into the spectrometer  140 , such as within 20, 10, 5, 2, or 1 mm of the source system  400  of the analyzer  110  and/or in a single housing unit of the analyzer  110 . 
     Several examples are provided that illustrate how the force system  200  alters the tissue layers  340  of the subject  320  and how a selection of detected signals from the spectrometer  140  is performed as a function of time and respective radial separation between the one or more illumination zones and the one or more detection zones, such as using water signal, fat signal, and/or protein signal to determine the correct detection signals to use for noninvasive glucose concentration determination. 
     EXAMPLE I 
     Referring now to  FIG.  6   , a first example of the analyzer  110  using the force system  200  and the source system  400  at the same time and/or within less than 60, 30, 15, 10, 5, or 1 second of each other is provided. In this example, the force system  200  applies a force to the tissue layers  340  at a first time, t 1 , when the dermis has a first mean z-axis thickness, th 1 . Optionally and preferably, the analyzer  110  acquires signals representative of the tissue layers  340  of the subject  320  using the source system  400  and the detector system  500 . Illustrated are three representative photon pathways, p 1-3 , reaching the detector system  500 , such as at a first detector element, a second detector element, and a third detector element, respectively, at the first time, t 1 , and/or within less than 60, 30, 15, 10, 5, or 2 seconds from the first time, t 1 . Notably, at the first time, the first photon pathway, p 1 , has an average path that does not penetrate into the dermis  346 , while the second and third photon pathways, p 2-3 , have mean pathways that penetrate through the dermis into the subcutaneous fat  348 . 
     In at least one preferred use of the analyzer, noninvasive glucose concentration determination is performed using a mean photon pathway that penetrates into the dermis  346  and not into the subcutaneous fat  348  and/or uses signal from a detector element at a first/minimal radial distance from the illumination zone, where the first/minimal radial distance is the smallest radial distance observing an increase in a fat signal/dominantly fat related signal, such as from the subcutaneous fat  348 , compared to a water signal/dominantly water related signal from skin layers  340  closer to the skin surface  332  than that subcutaneous fat  348 . Examples of wavelengths containing dominantly water absorbing signals are wavelengths correlating with the peaks of the water absorbance bands  710 ,  FIG.  7 A , and/or peaks of the protein absorbance bands,  FIG.  7 B , and examples of wavelengths containing an increased fat absorbance to water absorbance ratio when a mean photon path enters the subcutaneous fat  348  are at the fat absorbance bands  720 . For instance, a protein band-to-fat band ratio optionally compares the protein absorbance band  730 , such as at 1690 nm, with the fat absorbance band  720 , such as at 1715 nm, where either range is ±5 or ±10 nm. Still referring to  FIG.  6   , at a second time, t 2 , the force wave  250  from the force system  200  has expanded the dermis layer to a second thickness, th 2 , which is at least 0.1, 0.2, 0.3, 0.5, 1, 2, 5, 10, 20, or 50% thicker than the first thickness, th 1 , and/or has an increased water absorbance, as measure by the first, second, and/or third detector element of the detector system  500 , representative of the first through third photon pathway, p 1-3 , in the condition of the larger dermis thickness at the second time, t 2 , as represented by a fourth, fifth, and sixth photon pathway, p 4-6 . Notably, the fifth and sixth photon pathways, p 5,6 , with the same illumination zone to detection zone radial distance as the first and second photon pathways, p 1-2 , have mean photon pathways that penetrate into the dermis  346  and not into the subcutaneous fat  348 . Thus, the water-to-fat ratio and/or the protein-to-fat absorbance ratio of the observed signal continues to increase with radial distance for the second and third detectors after the force system  200  increased the thickness of the dermis  346  to the second thickness, th 2 . 
     Again, at least one preferred measurement/metric is a measurement with a higher water-to-fat absorbance ratio and/or a higher protein-to-fat absorbance ratio as the metric indicates that the photons are sampling the dermis  346  without undue sampling of the subcutaneous fat  348 , where the metric is used with or without an applied displacement force from the transducer. In this example, at the second time, the water-to-fat absorbance ratio of the fifth optical path, p 5 , is greater than observed with the second optical path, p 2 , despite have the same source zone-to-detector zone radial distance. Further, in this example a preferred optical signal is from the sixth optical path, th 6 , at the second time, t 2 , with a largest ratio of mean pathlength in the dermis  346  to total mean detected pathlength. For illumination zone-to-detector zone distances established to sample the dermis  346 , as discussed infra, determining a current thickness of the protein/water rich dermis  346  yields knowledge of an appropriate glucose illumination zone-to-glucose detection zone, such as for photons in the range of 1500 to 1600 nm, probing the dermis  346  as glucose is soluble in the water rich dermis  346 . 
     Referring now to  FIG.  7 C , for clarity of presentation and without loss of generality, a particular metrics  760 , such as a fat band metric, a protein band metric, and/or a water band metric are illustrated. As illustrated, a first signal  722  related to the fat absorbance band  720  decreases in intensity with radial distance between an illumination zone and a detection zone. The decrease in intensity with radius for a first radial distance, r 1 , a second radial distance, r 2 , and a third radial distance, r 3 , relates dominantly to a decreased photon density as a function of distance from the illumination zone, scattering, and water absorbance. However, a rapid first change in intensity, Δl 1 , is observed between the third radial distance, r 3 , and the fourth radial distance, r 4 , which at wavelengths related to the fat absorbance band  720 , such as about 1710 nm, indicates that a larger concentration of fat is observed to begin between the third and fourth radial distances indicating that the mean maximum depth of penetration of the probing photons has crossed from the dermis  346  into the subcutaneous fat  348 . Hence, the large first change in intensity, Δl 1 , at the fourth radial distance indicates that a radial distance corresponding to a maximum depth of penetration sampling the dermis  346  is the third radial distance, r 3 . Similarly, the second signal  732  related to the water absorbance  710  and/or the protein absorbance  720  has a trend breaking second change in intensity, Δl 2 , between the third radial distance, r 3 , and the fourth radial distance, r 4 , which indicates that the second probing photons at a wavelength dominated by a water absorbance, such as at 1450±10, 20, 30, 40, 50, 60, or 70 nm, or a protein absorbance, such as at 1690±5 or 10 nm, are observing a lower concentration of the water and/or protein, such as by crossing the same dermis—subcutaneous fat interface. Hence, any of the metrics related to water, protein, and/or fat are used independently and/or in any mathematical relationship, such as a ratio or derivative, to find a first sample probe geometric distance, between a first illumination zone and a first detection zone, associated with a first maximum mean depth of penetration in the glucose rich dermis layer  346 , such as at the first radius, r 3 , and/or a second sample probe geometric distance associated with a second maximum mean depth of penetration in the glucose poor subcutaneous fat layer  348 , such as at the fourth radius, r 4 . 
       FIG.  7 D  illustrates increased scattering with decreasing wavelength at a first scattering coefficient, μ s1 ,  740  and a second scattering coefficient, μ s2 ,  750 . Optionally and preferably, an expected decrease in observed intensity with increasing radial distance between a given illumination zone and a given detection zone includes use of a scattering coefficient, which is wavelength dependent. 
     EXAMPLE II 
     Referring now to  FIG.  8   , a second example is provided where the analyzer  110  uses the force system  200  to alter the sample  300  to enhance a noninvasive analyte property determination using the spectrometer  140 . As above, the force system  200  provides one or more force waves  250  into the subject  320 , which alters positions of cells  260  in the dermis  346  relative to the illumination zone of the illumination system  400  and or relative to one or more detection zones associated with a single element detector and/or one or more detectors of an array of detector elements  510 . As illustrated, the cells  360  have a first average intercellular distance at a first time, t 1 , which is altered by application of the force wave  250  to a second average intercellular distance at a second time, t 2 , where the net change in cell position alters detected spectrophotometric absorbance signals at a give detector element of the detector system  500  by greater than 0.01, 0.02, 0.05, 0.1, 0.5, 1, 2, 5, or 10 percent, such as by a change in observed scattering and/or observed absorbance at a fixed radial distance between an illumination zone and a detection zone. Similarly, the average percentage volume of the intercellular fluid  350  in the dermis layer differs by greater than 0.01, 0.02, 0.05, 0.1, 0.5, 1, 2, 5, or 10 percent as a result of the applied force wave(s)  250 . All of a change in thickness, change in observed mean pathlength, change in radial distance of detection, change in mean intercellular spacing, change in scattering, and change in water concentration, related to perfusion, are illustrated between the first time, t 1 , and the second time, t 2 , as a result of the applied force wave  250 . Notably, a selected detector signal from the array of detectors  510  changed from a second detector  512 /second detector element/second detection system at a first radial distance, r 1 , from the illumination zone to a fourth detector  514  at a second radial distance, r 2 , from the illumination zone based on the above described larger observed water signal-to-observed fat signal ratio and/or as the second pathlength, b 2 , is longer than the first pathlength, b 1 , in the dermis layer. Similarly, absorbances of skin constituents, such as protein, albumin, globulin, keratin, and/or elastin increase relative to fat absorbance for the second pathlength, b 2 , as the mean pathlength spends more time in the dermis layer compared to the subcutaneous fat layer  348 , as described supra. 
     EXAMPLE III 
     Referring now to  FIG.  9   , a third example of using the force system  200  to alter properties of the subject  330  to enhance performance of a noninvasive glucose concentration determination using the spectrometer  140  is provided. In this example, the detector array  510  of the detector system  500  contains n detector elements at differing radial distances from a time correlated illumination zone. For clarity of presentation, the detector array  510  is illustrated with four detector elements: a first detector  511 /first detector element/first detector system, a second detector  512 /second detector element second detector system, a third detector  513 /third detector element/third detector system, and a fourth detector  514 /fourth detector element/fourth detector system. At a first time, t 1 , the large water absorbance, protein absorbance, and/or protein and water absorbance-to-fat ratio is observed using the second detector  512  having a first illumination zone-to-detection zone radial distance, r 1 , and a first mean optical pathway, d 1 , penetrating into the dermis  346  with minimal to no mean penetration into the subcutaneous fat  348 . However, at a second time, t 2 , after the provided force wave  250  has altered the skin of the subject  320 , the third detector element is observed, at a selected detection point in time, to have the largest metric for detector selection, such as a smoothly falling observed intensity with radial distance at a fat absorbance wavelength, where a sudden decrease in observed intensity at the fat absorbance wavelength indicates mean penetration of the observed optical pathway into the subcutaneous fat  348 , such as at the second radial distance, r 2 . Notably, the largest radial distance is selected for a given water, protein, and/or fat based metric as at the larger radial distance a difference between a shortest possible pathlength between the illumination zone and the detection zone, the radial distance, is closest to the largest possible observed pathlength, which is based upon a maximum observable absorbance by a detector type for a fixed number of photons. For example, if the maximum observable absorbance is 3.9 and the absorbance per millimeter is 1.3, then a maximum observable pathlength is 3.0 mm. If the observed radial pathlength is 1.5 mm then a first range of observed pathlengths is 1.5 to 3.0 mm with a difference of 1.5 mm. Hence, a first ratio of observed pathlength difference to radial distance is 1:1 (1.5 mm: 1.5 mm), which is a 100% error. However, if the observed radial pathlength is 2.5 mm, then a second range of observed pathlengths is 2.5 to 3.0 mm with a difference of 0.5 mm. Hence, a second ratio of observed pathlength difference-to-radial distance is 1:5 (0.5 mm: 2.5 mm), which is a second pathlength error of 20% or one-fifth of the pathlength error of the first case. In general, the largest radial distance yielding and intensity-to-noise ratio beyond a threshold, such as 0.5, 1, 1.5 or 2, is preferred as error in a range of observed pathlengths decreases, which reduces the error in b, in Beer&#39;s Law: equation 1,
 
A=molar absorptivity * b *C  (eq. 1)
 
     where A is absorbance, b is pathlength, and C is concentration, which is central to visible and near-infrared absorbance and/or scattering models used to determine an analyte property, such as a noninvasive glucose concentration as measured using photons optically probing skin. 
     Skin State Classification 
     Skin state is optionally classified using a single force pulse or single impulse function, also referred to herein as a ping. Generally, an applied force, such as the force wave  250  provided by the force system  200 , takes time to propagate through the subject  320 . The travel time of the force wave varies as a function of state of the body, such as hydration, temperature, glucose concentration, triglyceride concentration, hematocrit and/or any constituent of skin, blood, and/or interstitial fluid. Hence, the amount of time to travel radial distances to force wave detectors is optionally used to classify the state of the subject and/or to map the state of the subject in regions probed by the force wave. For clarity of presentation and without loss of generality, two example of force wave detection are provided here using: (1) a transducer force detector and/or (2) an optical force wave classifier. 
     EXAMPLE I 
     Referring now to  FIGS.  10   (A-C), transducer force detectors are optionally used to detect transit times of the force wave  250  from the force wave input element  210  to one or more detectors of a set of transducer force detectors  260 . Generally, a transducer force detector converts mechanical motion, such as passage of the force wave  250  and/or skin movement into a measured electrical signal. Referring now to  FIG.  10 A , for clarity of presentation and without loss of generality, a first transducer force detector  262 , a second transducer force detector  264 , and a third transducer force detector  266  are illustrated that represent n transducer based force detectors, where n is a positive integer of greater than 1, 2, 3, 5, 10, or 20. As illustrated in  FIGS.  10 B and  10 C , the n transducer based force detectors are optionally positioned in a linear array, in a two-dimensional array, and/or along arcs, such as at differing radial distances from one or more light sources in the source system  400 . Referring still to  FIG.  10 A , as illustrated, at a first time, the force wave  250  has propagated to the first transducer force detector  262  as a first wave front position  254 ; at a second time, t 2 , the force wave  250  has propagated to the second transducer force detector  264  as a second wave front position  256 ; and at a third time, t 3 , the force wave  250  has propagated to the third transducer force detector  266  as a third wave front position  258 . Timing of each wave front to each transducer based force wave detector allows: (1) generation of a sub-surface tissue map of constituents of the skin of the subject  320  using mathematical techniques used for seismic mapping known to those skilled in the art of seismic mapping and/or (2) a classification of state of the subject  320  versus a calibration set of classifying states of force wave propagation radial translation times. For instance, the classification is as simple as slow, medium, or fast translation times to a given transducer detector or a more involved combination of translation times for one or more of: (1) responses at a single detector position and (2) responses at a set of detector positions and/or responses to varying inputs of the force wave, such as time, direction, amplitude, and/or frequency of one or more pings from the force wave input elements and/or time varying induced applied pressure and/or displacement of a portion of the skin of the subject  320  by the force system  200 . 
     EXAMPLE II 
     Referring now to  FIGS.  11   (A-C), propagation of the force wave(s)  250 , such as force wave fronts  254 ,  256 ,  258  is detected using a set of optical detectors and using the results in a manner similar to detecting the force wave  250  using the set of transducer based wave detectors. For instance, as the force wave  250  propagates through the tissue layers  340 , the density, absorbance, and/or scattering of voxels of the skin of the subject  320  change, which alters an observed mean optical path between a given source of photons and a photon/photonic detector. One or more sources of the source system  400  coupled to the array of optical detector elements  510  via the subject  320  is optionally used to detect propagation times of the force wave(s)  250 . For clarity of presentation and without loss of generality, a first optical detector  521 , a second optical detector  522 , and a third optical detector  523  are illustrated that represent n optical detectors, where n is a positive integer greater than 0, 1, 2, 3, 5, 10, 15, 16, 20, 25, 100, 500, 1000, and 5000. As illustrated in  FIGS.  11 B and  11 C , the n optical detectors are optionally positioned in a linear array, in a two-dimensional array, and/or along arcs, such as differing radial distances from one or more light sources in the source system  400  and/or from one or more force wave sources. Notably, one or more detectors of the array of optical detector elements  510  are optionally and preferably used to detect photons from the source system  400  during a measurement phase of an analyte and/or tissue property with or without a tissue classification step. As illustrated, the first optical detector  521  detects a first optical signal, modified by the force wave  250 , with a first pathlength, p 1 , at a given point in time; the second optical detector  522  detects a second optical signal, modified by the force wave  250 , with a second pathlength, p 2 , at the given point in time; and the third optical detector  523  detects a third optical signal, modified by the force wave  250 , with a third pathlength, p 3 , at the given point in time. Each detected optical signal contains absorbances due to any sample constituent, such as water, protein, fat, and/or glucose and/or is representative of state of the tissue, such as a measure of scattering and/or temperature. As the force wave(s) propagate through the tissue, the first, second, and third pathlengths, p 1 , p 2 , p 3 , vary. Hence, the state of the subject  320  is optionally characterized and/or mapped in a manner similar to the transducer wave detection classification and/or mapping; however, optical signals with chemical meaning are used in the process, such as detected intensity, absorbance, and/or scattering related to temperature, one or more tissue layer properties, collagen, elastin, water, albumin, globulin, protein, fat, hematocrit, and/or glucose, such as a concentration, change in tissue state, or a physical structure. 
     Referring again to  FIG.  11 A  and  FIG.  12 A , the applied pressure/force wave/displacement optionally generates a gap and/or varies an applied pressure at a first interface  305  of the source system  400  and the skin surface  330  and/or at a second interface  390  of the detector system  500  and/or any element thereof and the skin surface  330 . A resulting air gap between the analyzer  110  and the subject  320  and/or a time varying change between an air gap and contact between the analyzer  110  and the subject  320  is used to determine times of contact/relative contact, which is in turn optionally and preferably used in a selection of detected signals step, described infra. For example, loss of optical contact yields a sudden increase in observed intensity in a wavelength region of high absorbance, such at as region dominated by water absorbance in the range of 1350 to 1550 nm, 1400 to 1500 nm, and/or within 5, 10, 15, 25, and/or 50 nm of 1450 nm. Removal of non-contacting signals aids in the development of an outlier analysis algorithm and/or in determining state of the tissue and/or in determination of a degree of applied force from the source system  400 , detector system  500 , and/or analyzer  110  to the skin surface  330  of the subject  320  as a function of time and/or position. 
     Force Wave/Optical Probe Analyte State Determination 
     Referring now to  FIG.  12   , a process of determining an analyte property, such as a glucose concentration, using one or more optical signals optionally and preferably modified by an applied force, force wave, and/or displacement is provided. 
     Referring still to  FIG.  12   , in a process, such as a first process or a second process, a force is applied  1210 , such as in the form of a force wave and/or displacement induced force wave. For example, the force wave/displacement is generated with a transducer to generate application of a transducer force  1212 , which is a single ping  1214 /displacement and/or a series of pings and/or is a force/displacement varied in frequency  1216  and/or varied in amplitude  1218 , such as via a controller, such as a main controller of the analyzer  110 . Subsequently, the force wave  250 /tissue displacement induced pressure propagates in the sample  1220 . 
     Referring still to  FIG.  12   , in another process, such as a first or second process, a result of the tissue displacement induced force wave is measured and/or detected  1230 , such as through a transducer force detection  1232  and/or an optical force detection  1234 . 
     Referring still to  FIG.  12   , in still another process, such as a second and/or third process, selection of a sub-set of detected signals  1240  is performed, such as a function of position  1241 , time  1242 , detector  1243 , contact  1244 , pressure  1245 , and/or spectroscopic response  1246  and an analyte state is determined  1250 , such as via generation of a calibration  1252  and/or use of a generated calibration in a prediction step  1254 . 
     Multiple-Sensor System 
     Referring again to  FIG.  4 A  and referring now to  FIG.  13   , the analyzer  110  optionally comprises multiple sub-sensor systems that operate independently to collect data but operate in concert for determination of state of the subject  320 . For instance the spectrometer  140  optionally comprises a first spectrometer version/system  142  connected/affixed to a first part of the subject  320 , such as on the arm of the subject  320 , and a second spectrometer system/version  144  connected/affixed to a second part of the subject  320 , such as on the leg of the subject  320 . Optionally, the spectrometer  140  is affixed to any part of the body, such as an ear lobe, webbing of the hand, forehead, torso, limb, arm, or leg. 
     Still referring to  FIG.  13   , generally, the spectrometer  140  refers to n spectrometers/analyzers, where each of the n spectrometers optionally and preferably collects data independently, where n is a positive integer, such as 1, 2, 3, 4, 5, or more. Optionally, each of the n spectrometers collect and analyze data independently. However, preferably, each of the n spectrometers collect data and after little or no pre-processing, collected data is sent to the analyzer  110 , a central processor, a personal communication device, such as a cell phone  122 , and/or to the web for further processing, which allows a central system to process data from the multiple sub-spectrometer systems. 
     Still referring to  FIG.  13   , optionally, each of the n spectrometers are of the same type and design. However, preferably, each of the n spectrometers are distinct in type and/or design. For instance, the first spectrometer version  142  comprises first sources, optics, and detectors that are directed to measurement of a first constituent/property of the subject  320  and the second spectrometer version  144  comprises second sources, optics, and detectors that are directed to measurement of a second constituent/property of the subject  320 . 
     Still referring to  FIG.  13   , for example, the n spectrometer systems are optionally and preferably configured to interface to separate portions of the body and/or to measure separate and/or overlapping properties/constituents of the subject  320 , such as percent oxygen saturation, heart rate, heart rate variability, glucose concentration, protein concentration, fat, muscle, protein concentration, albumin concentration, globulin concentration, respiration rate, an electrocardiogram, blood pressure, and/or body temperature and/or environmental temperature and/or acceleration of the subject  320 , such as to indicate a fall of the subject  320  and/or an interfering movement of the subject  320  that affects the measurements of the one or more spectrometers  140 . 
     Still referring to  FIG.  13   , herein, for clarity of presentation and without loss of generality, the spectrometer  140  is illustrated as a noninvasive glucose concentration analyzer. However, the spectrometer  140  optionally measures any constituent of the body noninvasively, in a minimally invasive manner, and/or operates in conjunction with a noninvasive, minimally invasive, and/or invasive reference system, such as for calibration and quality control procedures. Examples of a first spectrometer version  142  and a second spectrometer version  144  determining an analyte property is provided, infra. 
     EXAMPLE I 
     Referring still to  FIG.  13   , an example of interfacing  1300  the analyzer  110  to an arm  370  of the subject  320  is illustrated. As illustrated, a first analyzer/spectrometer version  371  of the analyzer  110  is coupled to a section of an upper arm  372  of the subject&#39;s arm and a second analyzer/spectrometer version  373  of the analyzer  110  is coupled to a forearm/wrist  374  of the patient&#39;s arm  320 . Notably, the first analyzer version  371  interfaces to the subject  320  at a first interface zone along a first z-axis perpendicular to a first x/y-axis plane that is tangential to the subject  320  and that is independent and different from a second interface of the second analyzer version  373 , which interfaces to the subject  320  along a second z-axis perpendicular to a second x/y-axis system that is tangential to a second interface zone of the subject. Generally, n analyzers  110 , optionally linked to a single main controller  112 , interface to n interface zones of the subject  320 , where the main controller  112  is optionally and preferably electrically, mechanically, and/or communicatively linked with any and preferably all subsystems of the analyzer  110  and is used to control the analyzer  110 , such as via computer hardware and associated software. 
     EXAMPLE II 
     Still referring to  FIG.  13   , each of the analyzers interfacing to the subject  320  optionally comprise any system of the analyzer  110 . As illustrated, the first analyzer version  371 , which is an example of the analyzer  110  comprises three analyzer versions, illustrated as the first spectrometer version  142 , the second spectrometer version  144 , and the third spectrometer version  146 . As illustrated, the first spectrometer version  142 , optionally in the form of a watch head, interfaces to the subject  320  along a first z-axis perpendicular to a first x/y-plane, which tangentially touches the upper arm  372  at a first interface point; the second spectrometer version  144  has the form of a watch band link and interfaces to the subject  320  along a second z-axis perpendicular to a second x/y-plane, which tangentially touches the upper arm  372  at a second interface point; and the third spectrometer version  146 , optionally in the form of a watch band attachment, interfaces to the subject  320  along a third z-axis perpendicular to a third x/y-plane, which tangentially touches the upper arm  372  at a third interface point. Each of the three spectrometer versions  142 ,  144 ,  146  are optionally attached to the upper arm  146  via double-sided adhesives and are thus attached in the manner of a sticker. As illustrated, the three spectrometer versions  142 ,  144 ,  146  are attached to the upper arm  372  with a flexible band  148 , such as a watch band or an elastic band. The individual spectrometer versions  142 ,  144 ,  146  are optionally connected using one or more hinge components and or rotating connectors. The individual spectrometer versions  142 ,  144 ,  146  are optionally replaceably connected to the subject along separate planes forming angles therebetween of greater than 1, 2, 5, 10, 15, 25, or 25 degrees. The hinge allows tangential interfacing of illumination zones of the respective spectrometer version along a curved surface of the subject  320 . Optionally, the hinge allows for rotation of a first spectrometer unit relative to a second spectrometer unit to maintain tangential contact of the illumination zones with the subject  320  as the skin of the subject moves, such as by allowing a rotation of greater than 0.1, 0.5, 1, 2, or 5 degrees. The multiple planes of attachment of the analyzer  110  to the subject  320  allow attachment of multiple sources and/or detectors to the subject  320  along a curved skin surface of the subject  320 , such as around the upper arm  372  and/or the lower arm  374 , as illustrated with the second analyzer/spectrometer version  373  attached to the wrist of the subject  320 , with minimal applied tissue deformation forces at each of the analyzer/subject interface zones. Reduced forces, such as an applied mass, stress, and/or strain aids precision and/or accuracy of the analyzer  110  by reducing movement of fluids within the tissue layers  340  of the subject  320 , reducing changes in pathlength, and/or reducing changes in pressure induced scattering of light. 
     EXAMPLE III 
     Still referring to  FIG.  13   , in a first case, each of the first spectrometer version  142 , second spectrometer version  144 , and third spectrometer version  146  optionally contain all of the functionality of the analyzer  110 . However, optionally, one or more optical sources are in one interfacing aspect of the first analyzer version  371 , such as in the second spectrometer version  144 , without any functional optical detectors in the second spectrometer version  144 . In this case, the optical detectors are in a second interfacing aspect of the first analyzer version  371 , such as in the first spectrometer version  142 . For clarity of presentation and without loss of generality, a particular example is provided. In this example, the detector system  500  is positioned in the analyzer  110  in the first spectrometer version  142  along with optional illuminators of the source system  400 . However, the source system also includes photon sources in the second spectrometer version  144 , such as in a watch band link position. In this manner, photonic illuminators with short optical distances to the detector system  500  are positioned in the first spectrometer version  142 , such as in close proximity to the detector system  500 . For instance, photonic sources emitting in wavelength ranges: (1) with an optical absorbance of greater than one unit per millimeter of pathlength and/or (2) in the 1350 to 1560 nm range, such as within 25 mm of 1510, 1520, 1530, or 1540 nm are positioned near the detector system  500 , such as in the same housing as the detector system  500 , in the first spectrometer version  142 , and/or with a radial distance between an illumination zone and a detection zone of less than 10, 8, 6, 5, 4, 3, 2, 1.5, or 1 millimeters. However, photonic sources emitting in lower absorbance regions, such as from 400 to 1350 nm and/or 1565 to 1800 and/or in regions of absorbance by skin at a level of less than one absorbance unit per millimeter of pathlength are positioned in the second spectrometer version  144 , thus giving the photons a longer pathlength to the detector system  500  in the first spectrometer version  142 . The longer selected pathlength, as selected by a detector element of the detector system  500 , from a given source reduces a range of observed pathlengths by photons from the given source, as described supra. Further, each spectrometer version  142 ,  144 ,  146  allows an independent mean photon path entering the skin of the subject  320  to be perpendicular to the subject  320  despite the radius of curvature of the skin of the subject  320  as the differing spectrometer versions  142 ,  144 ,  146  are each positioned with an x/y-plane interface tangential to the local curvature of the skin of the subject  320 , such as at different positions on a watch band equivalent. Optionally and preferably, the x/y-planes tangential to the subject  320  at local sample interface sites for the n interface points of the analyzer  110 , such as the first interface location of the first spectrometer version  142 , the second interface location of the second spectrometer version  144 , and the third interface location of the third spectrometer version  146  are separated by greater than 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, or 20 millimeters as measured along the skin surface. Hence, second photon sources for providing second wavelengths for measuring oxygen and/or scattering of light, such as from 400 to 1300 nm, are optionally placed in a second housing along a second position of the watch band while first photon sources for providing first wavelengths, such as at glucose absorbing wavelengths from 1500 to 2400 nm, are optionally placed in a first housing proximate detector elements, where the detector elements in the first housing detect photons from second, third, . . . , n th  housings, such as along a circumferential band around a curved body part, where n is a positive integer greater than 1, 2, or 3. 
     EXAMPLE IV 
     In the first spectrometer version  371  of the analyzer  110 , three sample interface zones are used, a first sample interface zone, such as the back of a watch zone where the source system  400 , force system  200 , and/or a first set of optics, such as in the first spectrometer version  142 , interface to the subject  320 ; a second interface zone, such as where a second set of optics, such as in the second spectrometer version  144 , interface to the subject  320 ; and a third interface zone, such as where a third set of optics, such as in a third spectrometer version  146 , interface to the subject  320 . Generally, any number n of sets of optics interface to the subject  320  to yield n sets of data on a state of the subject  320  where n is a positive integer, such as 1, 2, 3, 4, 5 or more. Optionally, the n sets of optics generate simultaneous data on a single state of the subject  320 . However, each sub-set of optics in the n sets of optics are optionally configured to measure the same analyte and/or different analytes, such as one of more of percent oxygen saturation, heart rate, heart rate variability, glucose concentration, protein concentration, fat, muscle, protein concentration, albumin concentration, globulin concentration, respiration rate, an electrocardiogram, blood pressure, body temperature, environmental temperature, and acceleration of the subject  320 . 
     Depth Resolution 
     Photons scatter in tissue. However, a mean photon path between an illumination zone and a detection zone has a mean/medium/average depth of penetration into the skin layers  340  and glucose is present at differing concentrations as a function of depth into the skin layers  340 . A target zone of probing photons is the epidermis  344  and/or dermis  346  between the stratum corneum  342  and the subcutaneous fat  348 . Targeting these well perfused tissue layers is described herein by way of non-limiting examples. 
     EXAMPLE I 
     Referring now to  FIG.  14 A , an example of a probe tip  1400  of the source system  400  of the analyzer  110  is presented. The probe tip  1400  has a tissue contacting surface  1410  and at least one illumination zone of a set of illumination zones  1420 . For clarity of presentation and without loss of generality, a single illumination zone is illustrated which is optionally and preferably one illumination zone of a plurality of illumination zones, such as where a given illumination zone is a surface area of the skin/probe tip interface illuminated by a given source, such as a given light emitting diode. More particularly, 2, 3, 4, or 5, or more, light emitting diodes/laser diodes couple to the skin, optionally via intervening optics of the photon transport system  450 , to illuminate a corresponding second, third, fourth, and fifth, or more, skin/probe tip interface areas, referred to herein as illumination zones. Similarly, a given detector element optically couples, such as by the photon transport system  450  to a given surface area of the skin/probe tip interface, which is referred to as a detection zone. More particularly, 2, 3, 4, or 5, or more, detector elements, of the detector system  500 , optically interface, such as through optics of the photon transport system  450  with the skin, to detect photons emitting from a corresponding second, third, fourth, and fifth, or more, skin/probe tip interface area, referred to herein as detection zones. A mean optical path for a set of photons is a mean pathway through the tissue layers  340  of the subject  320  between a given illumination zone and a given detection zone. Optionally, the probe tip  1400  is of any geometry. Optionally, illumination zones are of any pattern on the probe tip  1400 . Optionally, detection zones are of any layout on the probe tip  1400 . 
     EXAMPLE II 
     Referring still to  FIG.  14 A  and referring now to  FIG.  14 B , resolution of a mean depth of penetration of probing photons between an illumination zone and rings of detectors  1430  is provided. As illustrated, a first ring of detectors  1432 , coupled to a first set of detection zones, is at a first radius, r 1 , from the illumination zone and a second ring of detectors  1434 , coupled to a second set of detection zones, is at a second radius, r 2 , from the illumination zone. For clarity of presentation and without loss of generality, the detectors and detector zones are illustrated with the same circular graphical representation herein. Further, the circular graphical representations are optionally illustrative of the ends of fiber optics coupled to corresponding detectors or sources. At close distances having an observed absorbance of less than one, the mean depth of penetration of probing photons increases with radial distance. The first and second ring of detectors  1432 ,  1434  are separated by a radial distance difference, Δr 1 . Referring now to  FIG.  14 B , the first ring of detectors  1432  corresponds to a first mean optical path  1472  having a first depth of penetration into the tissue layers  340  and the second ring of detectors  1434  corresponds to a second mean optical path  1474  having a second depth of penetration into the tissue layers  340 . As illustrated, for a first radial detector  1482  at the first radial distance, r 1 , the maximum depth of the first mean optical path  1472  and the second mean optical path, for a second radial detector  1484  at a second radial distance, r 2 , have a depth of penetration difference, Δd 1 . Notably, the second ring of detectors  1434  is spatially positioned at a closest linear distance, the line passing through an illumination zone of the set of illumination zones  1420 , to the first ring of detectors  1432 . Thus, the best resolution of depth is the depth of penetration difference, Δd 1 , corresponding to a first range of tissue thicknesses  1482 . However, in many cases, as the thicknesses of the epidermis  344  and dermis  346  changes with applied pressure, force, hydration, spatial orientation, movement, and/or changes in blood constituent concentration, the targeted dermal layers are not resolved using the best resolution of concentric detector rings with a difference in radial distance, Δr 1 , to the illumination zone corresponding to the resolved depth, Δd 1 . 
     EXAMPLE III 
     Referring still to  FIG.  14 A  and  FIG.  14 B  and referring now to  FIG.  14 C , a comparison of resolution of a mean depth of penetration of probing photons between an illumination zone and rings of detectors  1430  and arcs of detectors  1450  is provided. Herein, an arc of detectors is a set of detectors along a curved path of multiple radial distances from an illumination zone. The arced path is not an arc of a circle. Rather, the arced path is along a spiral and/or curve covering a range of radial distances from an illumination zone. As illustrated an arc of detectors  1450 , along an optional arc layout  1462 , starts at the first radial distance, r 1 , of the first ring of detectors  1432  and ends at the second radial distance, r 2 , of the second ring of detectors. While the first and second ring of detectors have a first linear radial distance difference, r 1 , that is based on the size of the detector element housing, fiber optic, and/or detection zone, the illustrated arc of detectors  1450  has a second linear radial distance difference, r 2 , that is smaller than, Particularly, with the seven illustrated detectors in the arc of detectors, the second linear radial distance, r 2 , is one-seventh that of the first radial distance, Generally, the difference in radial distance is better than ½, ⅓, ¼, ⅕, . . . , 1/n that of the spatially constrained concentric rings of detectors for n detector elements in an arc bounded by the first and second radial distances, r 1  and r 2 , of the concentric rings of detectors, where n is a positive integer of greater than 2, 3, 4, 5, 10, or 20. Comparing now the first and second mean depths of penetrations  1472 ,  1474  for the first and second ring of detectors  1432 ,  1434  and the first and second detector  1482 ,  1484 , with the range of mean depths of penetrations in  FIG.  14 C  corresponding to the individual illumination zones, of the set of illumination zones  1420 , to detection zones of detector elements in the ring of detector elements  1450 , the enhanced resolution is illustratively obvious. Particularly, the above described first resolved depth, Δd 1 , corresponding to the first and second ring of detectors  1432 ,  1434  is seven times larger than a second resolved depth,  66  d 2 , between a third mean path  1437  and a fourth mean path  1474  corresponding to the second radial detector  1484  and a closest intermediate radial detector  1486 , two detector elements in the arc of detectors  1450 . Particularly, a second range of tissue thicknesses  1484  is thinner than the first range of tissue thicknesses  1482 , described supra. Generally, the difference in resolved tissue depth is better than ½, ⅓, ¼, ⅕, . . . , 1/n that of the spatially constrained concentric rings of detectors for n detector elements in an arc bounded by the first and second radial distances, r 1  and r 2 , of the concentric rings of detectors, where n is a positive integer of greater than 2, 3, 4, 5, 10, or 20. Thus, arcs of detection zones corresponding to arcs of detectors and/or coupling optics, such as fiber optics, spanning a range of radial distances from an illumination zone yield an enhanced resolution of tissue depth. Further, as described supra, dynamic selection of signals from detector elements radially inward from an outwardly positioned detector element observing a disproportionate increase in a fat band absorbance, which is an example of a spectroscopic marker, from the subcutaneous fat  348 , at a greater depth than the targeted dermis  346 , yields the largest radial distance observing the desired/targeted dermal layers. Further, as the epidermis  344  and dermis  346  change in thickness, such as due to subject movement, orientation, and/or hydration, and/or changes in body chemistry, the range of resolved depths of penetration corresponding to the range of radial distances between the illumination zone and individual detection zones allows dynamic selection of source-to-detector distances currently probing the desired dermal layers, such as the epidermis  344  and the dermis  346 . 
     Depth/Location Selection 
     Referring now to  FIGS.  15 A,  15 B,  15 C,  15 D,  16 A,  16 B,  16 C,  16 D, and  17   , a method and apparatus are described for selecting, as a function of wavelength, illumination zone-to-detection zone distances yielding a common and/or overlapping depth of sampling and/or position of sampling. In the examples provided, for clarity of presentation and without loss of generality, notation of a first, second, third, . . . , n th  source and/or detector is used where the n th  source/detector in one example is optionally distinct from the n th  source/detector in another example. Further, it is understood that skin layers are not homogenous and that variations occur from tissue voxel to tissue voxel. However, sampling a common depth and location aids in measuring a common sample state within the non-homogenous tissue layers, especially when used in conjunction with one or more of: a larger illumination zone, a larger detection zone, sample movement relative to the analyzer, and/or analyzer movement relative to the sample. 
     EXAMPLE I 
     Referring now to  FIG.  15 A ,  FIG.  15 B ,  FIG.  15 C , and  FIG.  15 D  in this first example, a common depth selection system  1500  and method of use thereof is described. 
     Referring now to  FIG.  15 A . The spectrometer includes a first source  401 /source element, illuminating a first illumination zone of the set of illumination zones  1420 . Light from the first illumination zone is detected by a first set of detectors  1510 , such as a first detector  511  detecting photons at a first detection zone, a second detector  512  detecting photons at a second detection zone, a third detector  513  detecting photons at a third detection zone, and/or a fourth detector  514  detecting photons at a fourth detection zone. Herein, the sources and detectors are illustrated at the skin surface for clarity of presentation and without loss of generality. However, it should be understood that the actual source and/or detector elements, are optionally positioned anywhere, and are optionally and preferably optically coupled to their respective source zone/detection zone via air and/or one or more optics. For instance, a source optionally uses a fiber optic, or any optic, to deliver light from the source to the outer skin surface  330 . Similarly, a detector optionally uses any optic to deliver a portion of the photons emitting from a detection zone, optically visible to the detector, to the detector element. 
     Referring still to  FIG.  15 A  and referring now to  FIG.  15 B , depths of penetration of photons passing from the set of illumination zones  1420  to the second set of detectors  1520  is illustrated. As illustrated, photons have a first mean path, p 1 , from the first illumination zone associated with and/or optically linked to the first source  401  and to a first detection zone associated with and/or optically linked to the first detector  511 . Similarly, as illustrated, photons have a second mean path, p 2 , from the first illumination zone associated with and/or optically linked to the second source  402  and to a second detection zone associated with and/or optically linked to the second detector  512 . Similarly, a third mean path, p 3 , and fourth mean path, p 4 , link the third detector  513  and fourth detector  514  to the first source  401 . It should be understood that the actual mean optical paths are not clear arcs as illustrated and the mean paths rather illustrate the point that differing illumination zone-to-detector zone distances have differing coupling mean pathways and/or the pathways probed differing sample layers at different weights. As illustrated, the second mean path, p 2 , is the longest path in the dermis layer  346  that does not substantially pass through the subcutaneous fat layer  348 , which is a first selection metric, which is an example of a selection metric. In this example, the second mean path, p 2 , is a first selected path based upon the selection metric. Selection metrics are optionally generated using one or more readings related to absorbance of fat, water, and/or protein. It should be understood that the first source  401  is illustrated at a first illumination zone only for clarity of presentation and the first source is optionally and preferably embedded into the analyzer  110  and coupled to the illustrated illumination zone with or without a coupling optic and that this general presentation approach holds for each source and similarly holds for each detector where a given detector is illustrated at a detection zone where optionally and preferably the given detector is configured to view the detection zone with or without an intervening optic. 
     Referring still to  FIG.  15 A  and  FIG.  15 B , depths of penetration of photons passing from the set of illumination zones  1420  to the second set of detectors  1520  is further described for a second wavelength range, where photons from the first source  401  have a first distribution of intensity as a function of wavelength and a first mean wavelength and photons from a second source  402  have a second distribution of intensity as a function of wavelength and a second mean wavelength differing from the first mean wavelength by greater than 1, 2, 5, 10, 20, 50, or 100 nm. Photons from the second source  402  interact with tissue differently from the photons from the first source  401 , in terms of absorbance and scattering, which results in differing total pathlengths and sample pathlength in tissue layers, such as the epidermis  344 , dermis  346 , and/or subcutaneous fat  348 . As illustrated, a second set of wavelengths, from the second source  402 , reaching the surface of the skin  330  have longer observed mean pathlengths than a first set of wavelengths, from the first source  401 , reaching the outer skin surface  330  or surface of the skin. For instance, the second set of wavelengths cover a wavelength range with lower overall absorbance of the sample constituents, such as a lower water absorbance, than the first set of wavelengths. As above, photons from the second source  402  have a fifth mean optical path, p 5 ,/fifth path/fifth mean path; a sixth mean path, p 6 ; a seventh mean path, p 7 ; and an eighth mean path, p 8 , to a fifth, sixth, seventh, and eighth detection zone observed by a fifth detector  515 , a sixth detector  516 , a seventh detector  517 , and an eighth detector  518 , respectively. Generally, any number of sources, m; any number of detectors, n; and/or any number of radial distances, r, are optionally used, where m and n are positive integers and r is a distance of greater than 0.01, 0.1, 0.5, 1, 1.5, 2, 3, 4, 5, or 10 millimeters. Still referring to  FIG.  15 A  and  FIG.  15 B , using the same criteria of the longest observed path in the dermis layer  346  that does not substantially pass through the subcutaneous fat layer  348 , the seventh path, p 7 , is a second selected path based upon the first selection metric. The first selected path, p 2 , and the second selected path, p 7 , are both weighted to a common sample depth, the dermis  346 . Hence, (1) the first source  401  coupled to the second detector  512  and (2) the second source  402  coupled to the seventh detector  517  each have weighted sampling to a common sample, the dermis  346 . In stark contrast, at a common radial distance, such as observed at the first detector  511  and fifth detector  515 , the mean photons sample differing samples; the first source  401  dominantly sampling both the epidermis  344  and dermis  348 , as illustrated by the first path, p 1 , and the second source  402  dominantly sampling the epidermis  344 , as illustrated by the fifth path, p 5 . 
     Referring now to  FIG.  15 C , the chosen radial separations of the sources and detectors, such as chosen in the preceding paragraph of this first example, are illustrated in an optional second probe configuration  1502 . Particularly, (1) a first selected radial distance, r 1 , between the first source  401  and the selected second detector  512  is maintained and (2) a second radial distance, r 2 , between the second source  402  and the selected seventh detector  517  is maintained without the need of the additional detector elements. Thus, for a static sample, the benefits of the common depth selection system  1500  are maintained in the second probe configuration  1502 . 
     EXAMPLE II 
     Referring now to  FIG.  16 A ,  FIG.  16 B ,  FIG.  16 C , and  FIG.  16 D  in this second example, a common sample position selection system  1600  and method of use thereof is described, where the common sample position is optionally and preferably at the common depth, such as the dermis, described supra. 
     Referring still to  FIG.  16 A  and  FIG.  16 B , the common sample position system  1600  is first described through an illustrated addition of two additional wavelength ranges to the common depth selection system  1500 , described supra, where the resulting four wavelength ranges have four distinct mean wavelengths reaching the detector and where each of the four distinct mean wavelengths are separated from each other by at least 10 nm. Particularly, the separation of the first source  401  from the second detector  512  by the first radial distance, r 1 , is maintained from the prior example as is the separation of the second source  402  from the seventh detector  517  by the second radial distance, r 2 . Added to the illustration is a separation of the third source  403  from the sixth detector  516  by a third radial distance, r 3 , and a separation of a fourth source  404  from a ninth detector  519  by a fourth radial distance, r 4 . Notably, all of the illustrated source-to-detector distances are selected, such as by the method of the first example and/or through use of a metric, such as a measure of water, protein, and/or fat absorbance, to sample a common depth, which as illustrated is the dermis  346 . An apparatus setting each of the four wavelength ranges to a same mean lateral x-position and/or y-position is described, infra. 
     Referring now to  FIG.  16 C  and  FIG.  16 D , the four source-to-detector distances, described supra, selected to sample a common depth, such as the dermis, are positioned in a probe face to yield a common lateral position at depth within the tissue or a common central zone  1610  at the surface. Particularly, a mean position between each of the source-to-detector positions is overlaid on at a common x-axis, as illustrated, and/or a common y-axis position to within less than 2, 1, 0.5, 0.4, 0.3, 0.2, or 0.1 mm. 
     Referring now to  FIGS.  15   (A-D) and  FIGS.  16   (A-D), while skin is not homogeneous, overlapping the photonic pathways of a set of differing wavelengths detected by a set of detectors, in terms of a common depth and/or a common position, yields a higher probability of sampling a common tissue state. 
     EXAMPLE III 
     Referring now to  FIG.  17   , in this third example, a common depth selection and common detector system  1700  and method of use thereof is described. 
     Still referring to  FIG.  17   , generally, different wavelengths of light, in the range of 1100 to 2500 nm, have different mean depths of penetration into skin due to skin having a large range of absorbance and/or a large range of scattering as a function of wavelength. For instance, first photons at a first wavelength where the skin absorbs heavily, such as at and/or near a peak of the water absorbance bands  710 , at 1450 nm, and/or at 1900 nm, have a shallow maximum mean depth of penetration into the skin layers, such as only penetrating into the epidermis  344 . Similarly, second photons at wavelengths having a lower absorbance, such as on a shoulder of the water absorbance bands  710 , have a mean detected photonic path that penetrates deeper into the skin, such as into the dermis  346 . Again similarly, third photons having wavelengths at a still lower absorbance, such as at and/or near a valley of the water absorbance bands  710 , have a mean detected photonic path that penetrates still deeper into the skin, such as into the subcutaneous fat  348 . Hence, traditional systems sampling different wavelength ranges sample different mean sample depths. 
     Generally, a magnitude of absorbance of the skin is inversely related to a maximum mean depth of penetration of detected photons into the skin and water absorbance, optionally modified by scattering, dominates an overall magnitude of absorbance of the skin due to waters high absorbance in the range of 1100 to 2500 nm relative to other skin constituents. 
     As a result of sampling differing sample depths, errors are introduced into traditional analyzers, such as a noninvasive glucose concentration analyzer, as the skin layers  340  differ in both chemical and physical makeup and hence the wavelengths actually probe different samples. Here, a system of sampling a common skin layer is described, where optionally and preferably signals with differing illumination zone-to-detector zone distances are measured with a common detection zone optically linked to a detection system, such as a detector and/or a detector optically coupled to the common detection zone with one or more optics. 
     Referring again to  FIG.  17   , for clarity of presentation and without loss of generality, a specific case of a range of wavelengths sampling a common skin layer is described. Particularly, in this case the first source  401  comprises a higher relative sample absorbance, such as within 10, 20, 30, 40, 50, 75, or 100 nm of a peak water absorbance at 1450 or 1900 nm and a first detected signal of photons from the first source  401  is dominated by a water signal at a first radial distance, r 1 , to the first detector  511 , where the first radial distance is set at a distance yielding a maximum mean photonic path in the dermis  346 . Further, in this case the second source  402  comprises a mid-range sample absorbance, such as within 10, 20, 30, 40, or 50 nm of a mid-point absorbance of the peak water absorbance bands, such as at 1410, 1520, 1870, 2020, or 2380 nm, where the second detected signal of photons from the second source  402  is still dominated by a water signal at a second radial distance, r 2 , but, the second wavelength range also samples another sample constituent, such as glucose, while still yielding a maximum mean photonic path in the dermis  346 . Notably, to sample the same depth as the first illumination zone-to-detection distance, while being as a second wavelength of lower overall absorbance, the second radial distance is larger than the first radial distance. Still further, in this case the third source  403  comprises a still lower sample absorbance, such as within 10, 20, 30, or 40 nm of a first quartile point of the peak water absorbance bands, such as at 1380, 1550, 1850, 2090, or 2350 nm, where the third detected signal of photons from the third source  403  is still dominated by a water signal at a third radial distance, r 3 , but, the third wavelength range also samples another sample constituent, such as protein, while still yielding a maximum mean photonic path in the dermis  346  by having the third radial distance be longer than the second radial distance, which is in turn larger than the first radial distance. Yet still further, in this case the fourth source  404  comprises the still lower sample absorbance, such as within 10, 20, 30, or 40 nm of the first quartile point of the peak water absorbance bands, such as at 1380, 1550, 1850, 2090, or 2350 nm, where the fourth detected signal of photons from the fourth source  404  is still dominated by a water signal at a fourth radial distance, r 4 , but, the fourth wavelength range also samples another sample constituent, such as the subcutaneous fat  348 , by having the fourth radial distance be further from detection zone relative to the third radial distance. Stated again, although the third source  413  emits third detected photons at a higher water absorbance wavelength/value relative to a lower water absorbance/value in a range of fourth detected photons, the maximum mean depth of the fourth photons penetrates further into the sample, such as the subcutaneous fat  348  relative to the dermis  346  probed by the third photons, due to the larger radial distance of the fourth radial distance relative to the third radial distance. Optionally, the third radial distance is configured to measure protein, such as at a wavelength with 5, or 10 nanometers of 1690 nm. Optionally, the fourth radial distance is configured to measure subcutaneous fat, such as at a wavelength with 5 or 10 nanometers of 1710 nm. 
     Still referring to  FIG.  7 A , optionally, a common detection zone linked to a common detector system is used to sample light from the first, second, third, and fourth radial distances from the first source  401 , the second source  402 , the third source  403 , and the fourth source  404 , respectively. Generally, targeting skin layers  340  is demonstrated for each of a set of range of wavelength ranges, where each member of the set of wavelength ranges comprising a source-to-detector distance set by prior analysis, skin absorbance, water absorbance, and/or scattering. Notably, enhanced precision of depth targeting is achieved by measuring a range of illumination zone-to-detection zone distances. In this example, the higher relative absorbance is at least 20, 30, 40, 50, 75, or 100 percent higher than the mid-range absorbance. In this example mid-range absorbance is at least 20, 30, 40, 50, 75, or 100 percent higher than the lower quartile absorbance. In this example, the second radial distance is at least 0.2, 0.3, 0.4, 0.5, 0.75, or 1 mm larger than the first radial distance; the third radial distance is at least 0.2, 0.3, 0.4, 0.5, 0.75, or 1 mm larger than the second radial distance; and/or the third radial distance is at least 0.2, 0.3, 0.4, 0.5, 0.75, or 1 mm larger than the fourth radial distance. 
     Optionally and preferably, the sources are light emitting diodes, laser diodes, and/or provide a narrow band of light through use of a long pass filter, a short pass filter, a bandpass filter, and/or an optical filter. Generally, a given optional source system intended to illuminate a given wavelength region may provide additional photons at other regions of higher water absorbance, where the water absorbance blocks the additional photons. Generally, a given source intended to illuminate a given wavelength range, in the 1100 to 2500 nm wavelength region, does not provide more than 20, 10, 5, or 0 percent of the light in a lower absorbing region. For instance, a source intended to provide photons for analysis of fat at 1710 nm may provide photons from 1700 to 1720 nm, where photons at 1900 to 2000 nm are optionally provided as they are absorbed by water in the skin, and where photons at 1500 to 1650 nm are provided only at low intensity or are optically blocked as the water of the skin allows more of the photons in the 1500 to 1650 nm region to reach the detector and are thus avoided for analysis of the fat. Similarly, each intend wavelength, for analytes such as water, protein, and glucose, have similar source requirements for a common detector system. In an optional case where one or more detector systems has blocking optics for different wavelengths, the limitations on the source systems described herein is removed. 
     EXAMPLE IV 
     Referring now to  FIG.  18   , in this third example, a common depth selection and common sample position analyzer  1800  and method of use thereof is described. Generally, for each member of a set of sources a common mid-zone  999  and/or mid-point to a detector for each source is used to provide a common/overlapping sample position. Further, a radial distance for each source/detector combination is set according to absorbance/scattering of the tissue. For instance, the first radial distance, r 1 , in the previous example for the first source  401  and the common detector  511  is maintained and used here for the distance between the first source  401  and a first selected detector,  1   d ,/first selected detection zone to yield a maximum mean photonic path in the dermis  346 , as described supra, for a water dominated wavelength, such as about 1410±25 nm. Similarly, the second source  402 , third source  403 , and fourth source  404  are separated by the second, third, and fourth radial distances of the previous example from a second selected detector,  2   d , a third selected detector,  3   d , and a fourth selected detector,  4   d , respectively, which yields a common mean maximum sample depth, such as in the dermis  346 . Combined, a common sample position and common depth system is illustrated as: (1) each source-to-detector distance comprises a mid-point in the probe tip  1400  about a central sampling location/central sampling zone  999 , which yields a common location and (2) the radial distances between a given illumination zone-to-detection zone being set with radial distances based upon the wavelength yields a common depth. 
     Still referring to  FIG.  18   , the mid-zone  999 /sample zone is illustrated on a sample side face of a probe housing of the analyzer  110 , such as on a surface of the probe tip  1400 . When a linked illumination zone and detection zone reside on opposite sides of the sample zone, a common sampled tissue volume resides in the tissue on the z-axis down from the sample zone, such as if the illumination zone-to-sample zone distance is within ten or twenty percent of the sample zone distance-to-detection zone distance. 
     Still referring to  FIG.  18   , selection of a common sample position and common depth is illustrated for a range of skin types/skin states. Through time, a given skin state changes from a thicker dermis to a thinner dermis as a function of time or vise-versa, due to factors such as age, temperature, hydration, and water shifting to the gastro-intestinal region for digestion of recently ingested food. Similarly, the transducer  220  is optionally used to dynamically change the thickness of the dermis  346  as a function of time, such as described supra. Hence, a given illumination zone-to-detection zone distance for a given source/detector combination for a given wavelength range is optionally and preferably dynamically selected based upon the current state of the skin and/or the current state/thickness of the dermis  346 . Particularly, for the first illumination zone-to-first detection zone distance, a first set of detectors  1510  includes the first selected detector,  1   d , set at the first radial distance, r 1 , from the first illumination zone associated with the first source  401 , but also optionally and preferably includes a second optionally selected detection zone positioned radially inward from the first detector and a third optionally selected detection zone positioned radially outward from the first detector, relative to the first illumination zone. As a result, when the dermis  346  is thinner, the radially inwardly positioned detection zone associated with the first set of detectors  1510  is selected/used to sample the dermis and when the dermis  346  is thicker, the radially outwardly positioned detection zone associated with the first set of detectors  1510  is selected/used to sample the dermis. Similarly, the second detector,  2   d , the third detector,  3   d , and the fourth detector,  4   d , of the second set of detectors  1520 , a third set of detectors  1530 , and a fourth set of detector  1540 , respectively, each have radially inward and radially outward positioned detection zones, relative to the second source  402 , third source  403 , and fourth source  404 , respectively, which are optionally dynamically selected as a detected thickness of the dermis  346  changes and/or as a state of the sample changes. As a result of a crossing geometry of the assorted source-to-detector positions, such as illustrated, when a given selected source-to-detector distance is altered, such as to a radially inwardly positioned detection zone, to maintain a constant mean sampling depth, the sample path still crosses the common sample zone. Thus, a common depth and common sampling system is described, where the common sample zone comprises a cross-section length of less than 0.25, 0.5, 0.75, 1, 1.5, 2, 3, or 4 mm. 
     Tissue Classifier 
     Referring now to  FIG.  19 A  and  FIG.  19 B  a tissue state classification system  1900  is illustrated. Generally, skin changes with time and spectroscopic signals are used to classify the skin state into two or more groups/classes/states. Calibration models are constructed for each group and when a prediction spectrum is classified into a given group, the corresponding group model is used to predict/estimate a noninvasively determined analyte property. For clarity of presentation and without loss of generality, the following example classifies spectra into three groups based upon a metric determined as a function of illumination zone-to-detection zone distance. More generally, any number of sub-classes are identified using one or more metrics, such an m subclasses and n metrics, where m and n are positive integers, and any number of models corresponding to tissue states are generated as calibration models/applied as predictions from the associated calibration model. 
     EXAMPLE I 
     Referring still to  FIG.  19 A , a first example of use of the tissue state classification system  1900  is illustrated. Initially, a set of data is collected  1910 . As illustrated, photons are delivered to a first illumination zone by the first source  401  and photons are collected at a series of detection zones respectively linked to the first detector  511 , the second detector  512 , and the third detector  513 . As illustrated, at a first time, t 1 , a best fit to a given metric, such as described supra, is to data from the first detector  511  optically sampling a first mean illumination zone-to-detection zone distance, which corresponds to a first tissue state  1912 ; at a second time, t 2 , the best fit to the given metric is to data from the second detector  512  optically sampling a second mean illumination zone-to-detection zone distance, which corresponds to a second tissue state  1912 ; and at a third time, t 3 , the best fit to the given metric is to data from the third detector  513  optically sampling a third mean illumination zone-to-detection zone distance, which corresponds to a third tissue state  1913 . Generally, the metric is applied at a range of radial distances between a given source illuminating at a given illumination zone and a given detector observing a given detection zone. Optionally and preferably, the metric is sensitive to at least a given tissue thickness/optical density, such as described above for a varying thickness of the dermis  346 . Optionally and preferably, the metric is alternatively/also sensitive to sample position as even a given layer of the skin, such as the dermis  346 , is not optically homogenous. As illustrated, when the metric best fits the first illumination zone-to-first detection zone distance, the data indicates that the sample falls into a first tissue state where a first calibration model/prediction model  1922  is applied, where in a calibration step, the data is optionally added to the calibration model and in a prediction step, the first calibration model is applied to the data. Similarly, when the metric best fits the second tissue state and third tissue state, the data is added to or acted upon by the second calibration/prediction model  1924  and third calibration/prediction model  1926 , respectively. Notably, a lack of match of the metric, applied to data, to any tissue state having a corresponding calibration is optionally and preferably used to determine the data as being outlier data. Generally, the classification method is applied to any optical layout described herein. 
     EXAMPLE II 
     Referring still to  FIG.  19 A  and referring again to  FIG.  19 B , the above described tissue classification system  1900  is applied to an overdetermined/multiplexed tissue state classification system  1950 . Generally, in the multiplexed tissue state classification system  1950 , a tissue state of the person at a point in time or over a short period of time, such as in a period of less than 120, 60, 30, 15, 10, 5, 4, 3, 2, or 1 minutes, is determined more than once, such as with two different wavelength regions, each wavelength region sampled as a function of radial distance to corresponding detector setups. Without loss of generality, two wavelength ranges are illustrated here. However, more generally greater than 2, 3, 4, 5, 7, 10, or 15 wavelength ranges are optionally used, where any given two wavelength ranges comprise at least one of mean wavelengths differing by at least 5, 10, 15, 20, 25, or 50 nm and/or a full-width at half height differing by at least 5, 10, 15, 20, 25, or 50 nm. As illustrated, the second illumination zone  402  optically linked to the second source  402  is separated from a fourth, fifth, and sixth detection zone optically linked to the fourth detector  514 , fifth detector  515 , and sixth detector  516 , respectively. As above, at the first time, t 1 , a second metric applied to the collected data  1910  again indicates that the skin is in the first tissue state and that the first calibration/prediction model  1922  is to be updated/used. Similarly, as above, at the second and third times, the second metric identifies the skin as being in the second sample state and third sample state, respectively. Notably, as the first metric and second metric are applied to differing data, in terms of detected wavelengths and radially sampled distances in the skin, which sample overlapping and/or differing tissue depths, the first and second metrics are optionally and preferably combined to determine additional tissue states. For instance, if the first metric is used to identify m tissue states and the second metric is used to identify n tissue states, then the total number of identified tissue states is greater than m and/or n, such as by one or two additional states, and/or is used to identify m+n tissue states. Again, any number of metrics are used and are applied to any number of wavelength ranges where responses to each wavelength ranges are determined at one or more radially separated distances from a corresponding illumination zone. 
     Common Sample Zone 
     Referring now to  FIG.  20 A ,  FIG.  20 B , and  FIG.  21   , a common zone sampling system  2000  is described. Generally, in the common zone sampling system  2000 , an area of the probe tip  1400  of the spectrometer  140  contacting the outer skin surface  330  of the subject during use has a common sample zone  2010 . Generally, the common sample zone  2010  is positioned on the z-axis next to the skin, such as above the skin, and sample a common and/or overlapping tissue volume. Particularly, first tissue volumes probed with a first illumination zone-to-detection zone distance overlap second tissue volumes probed with a second illumination zone-to-detection zone distance, which reduces the impact of sample inhomogeneity within a given tissue layer, such as in the epidermis  344  and/or in the dermis  346 . Optionally and preferably, the common zone sampling system  2000  also probes a common tissue depth and/or a common sample location as described, supra. For clarity of presentation and without loss of generality, several examples illustrate the common zone sampling system  2000 , such as in combination with the common depth system described supra, with a fully or partially multiplexed analyzer, and/or with detectors coupled with two or more sources as a function of time. 
     EXAMPLE I 
     Referring still to  FIG.  20 A , a first example of the common zone sampling system  2000  is described. For clarity of presentation and without loss of generality, this exemplary system is laid out using the first illumination zone-to-detection zone radial system described in previous examples. More particularly, the first illumination zone-to-detection zone is illustrated as two fiber diameters, one intervening “fiber diameter” distance (further described infra), and an inner detector element and an outer detector element are positioned one fiber diameter closer to and further from the illumination source. Similarly, the second, third, and fourth illumination zone-to-detection zone distances from the previous examples is maintained with a separation of 2, 3, and 3.5 fiber diameters between respective illumination zones and detection zone. Similarly, an inwardly positioned detection zone and an outwardly positioned detection zone is provided, coupled to a common zone set of detectors, for each selected illumination zone-to-detection zone distance selected (the 1, 2, 3, and 3.5 fiber diameter spacings). Hence, as the tissue layer thicknesses change, such as with use of the transducer and/or through normal physiological variations with time, sampling of the common tissue layer, such as the dermis  346 , is maintained through appropriate selection of the detection element, as described supra. Herein, the fiber diameter optionally and preferably refers to a unit of measure with a corresponding readily manufactured component. Hence a separation referring to a separation of one “fiber diameter” refers to a distance without actually requiring a fiber optic, such as 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000 micrometers. 
     Still referring to  FIG.  20 A , as illustrated, a common zone set of detectors  1550  is used and a common zone  2010  is an area below the common zone set of detectors  1550  where photons of differing wavelengths sample a common depth and/or a common position, such as by setting illumination zone-to-detection zone distances differently for each wavelength range, further described infra. For instance, when the second source  402  and the second detector position,  2   d , is used, and when the third source  403  and the third detector position,  3   d , is used, each illumination zone-to-detection zone pairing samples: (1) a common depth, as described supra, and (2) a common location, such as any position in common between the two illumination zone-to-detection zone pairings. Similarly, as the tissue state changes and the radially inwardly positioned detection element for the second illumination zone-to-detection zone distance is selected while the radially inwardly positioned detection element for the third illumination zone-to-detection zone distance is selected, a common position, b, is still maintained between the selected second source-detector pairing and the third selected source-detector pairing. Similarly, as the tissue state changes again and the radially outwardly positioned detection element for the second illumination zone-to-detection zone distance is selected while the radially outwardly positioned detection element for the third illumination zone-to-detection zone distance is selected, a common position,  3   d , is still maintained between the selected second source-detector pairing and the third selected source-detector pairing. Generally, for two or more linearly arranged illumination-detection zone pairings, such as for detection zones placed between illumination zones, a common depth and/or a common position exists for the two or more linearly arranged illumination zone pairings even as tissue layer thicknesses change. As illustrated, four linearly arranged illumination-detection zone pairings are illustrated,  1   s - 1   d ,  2   s - 2   d ,  3   s - 3   d , and  4   s - 4   d , where a common zone  2010  comprises: (1) a common maximum mean depth beneath all of the detection positions between the linearly aligned sources and (2) a common sample position exists at or about mid-points between multiple pairs of the linearly aligned sources with detection positions between the paired sources. 
     Still referring to  FIG.  20 A , in the common zone sampling system  2000 , three or more illumination zone-detection zone pairings sample a common depth and/or a common sample location. For instance, the  1   s - 1   d ,  2   s - 2   d ,  3   s - 3   d , and  4   s - 4   d  illumination zone pairings all sample a common depth in the tissue, where the  1   s - 2   s - 2   d ,  3   s - 3   d , and  4   s - 4   d  all sample a common position in the tissue, such as common position b, which is positioned in a common position between each illumination zone-detection zone pairing. 
     Still referring to  FIG.  20 A , in the illustrated example of the common zone sampling system  2000 , the analyzer  110  is fully multiplexed. Specifically, the first source  401 , the second source  402 , the third source  403 , and the fourth source  404 , are all simultaneously operable and detected at corresponding detectors,  1   d ,  2   d ,  3   d , and  4   d , at the same time while sampling the same tissue depth and overlapping tissue volumes. As the corresponding detectors,  1   d ,  2   d ,  3   d , and  4   d , each have a radially inwardly positioned detection zone and a radially outwardly positioned detection zone, the common depth and/or the overlapping sampled tissue volumes continue to overlap as the selected illumination zone-to-detection zone varies in correlation with changes in the tissue layer thicknesses. 
     EXAMPLE II 
     Referring now to  FIG.  20 B , a second example of the common zone sampling system  2000  is described where additional “fiber diameter” spacings are used, such as in the optional arc layout  1462  system described supra. For clarity of presentation, the spacings of the illumination and detection zones of the previous example is maintained, while additional detection zones are added. Generally, hardware, such as an optic, drill hole, and/or fiber optic has a diameter and two closely spaced optics, drill holes, and/or fiber optics then have a center-to-center closely packed minimum distance of a diameter of the closely spaced optics, drill holes, and/or fiber optics, such as a distance between a center of the “a” detection zone and the “ 1   d ” detection zone, which limits depth resolution in the tissue. 
     However, following the logic of the optional arc layout  1462 , additional optional detection zones,  1   d   b  and  1   d   c , are illustrated at intermediate distances between a common illumination zone,  1   s , and: (1) the “a” detection zone and (2) the close packed “ 1   d ” detection zone, such as the illustrated 1⅓ and 1⅔ distances of the  1   d   b  and  1   d   c  detection zones, optionally positioned on opposite sides of a common line between illumination zones. 
     Still referring to  FIG.  20 B , the set of illumination zones and detection zones positioned on a line is optionally repeated, such as on a second or n th  line for use with a second or n th  set of wavelength ranges. Further, if the n th  line is positioned close to the first line, such as in parallel to the first line and intersecting the  1   d   b  or  1   d   c  detection zones, then detectors in the n th  line are optionally and preferably used as higher depth resolution detectors for one or more illumination zones in a n+1 th  or n−1 th  line parallel and adjacent to the n th  line. 
     EXAMPLE III 
     Referring now to  FIG.  21   , a third example of the common zone sampling system  2000  is described where a reduced number of detection zones are used to reduce the size of the probe tip  1400  or the analyzer  110 . Particularly, again using the illumination-detection zone spacing of the previous two examples, a single detection zone, c, is used in place of all three of the  1   d ,  2   d ,  3   d  detection zones while maintaining all of the illumination zone-to-detection zone distances of the previous two examples, the tradeoff being a partially multiplexed system as the “c” detector is used as a function of time with use of the first source  401 , the second source  402 , and the third source  403 , respectively. 
     Referring again to  FIG.  20 A ,  FIG.  20 B , and  FIG.  21   , first source-detector combinations having first wavelengths associated with high water absorbance per millimeter of pathlength generally have smaller illumination zone-to-detection zone distances than second source-detector combinations having second wavelength combinations associated with lower water absorbance per millimeter of pathlength. For instance, at a higher water absorbing wavelength, such as at about 1400±50, 1900±50, 2000±50, or 2500±50 nm, a first illumination zone-to-detector distance, associated with detected wavelengths of 1400±50, 1900±50, 2000± 50 , is less than a second illumination zone-to-detection distance for detection of wavelengths having a medium water absorbance, such as within 10, 20, 30, 40, or 50 nm of a mid-point absorbance of the peak water absorbance bands, such as at 1410, 1520, 1870, 2020, or 2380 nm, and the second illumination zone-to-detection distance used with the medium absorbing wavelengths of water is in turn less than a third illumination zone-to-detection zone distance used for source-detector combinations observing wavelength ranges of light associated with a still smaller water absorbance per millimeter of pathlength, such as within 10, 20, 30, or 40 nm of a first quartile point of the peak water absorbance bands, such as at 1380, 1550, 1850, 2090, or 2350 nm. 
     Acousto-Optic Analyzer vs. (1) UPI and (2) an AOTF 
     An applied force-optic analyzer is described herein. Optionally and preferably, the applied force results in a mechanical disturbance of the tissue resulting in a force being applied to the sample. However, in a sub-case of the applied force-optic analyzer, the applied force comprises an acoustic force yielding an acousto-optic analyzer. Notably, in the sub-case of the applied force-optic analyzer being an acousto-optic analyzer, as used herein an acousto-optic analyzer starkly contrasts with both: (1) an ultrasonic photoacoustic imaging (UPI) system and (2) an acousto-optic tunable filter (AOTF) spectrometer, as described infra. 
     Acousto-Optic Analyzer 
     As described, an acousto-optic analyzer (AOA) introduces an acoustic vibration wave to the sample to impact the state of the sample, such as tissue, and the state of the sample is measured using an optical probe. 
     Photoacoustic Imaging 
     In stark contrast, according to Wikipedia, ultrasonic photoacoustic imaging, also referred to as (UPI), photoacoustic imaging (PI), and/or optoacoustic imaging, delivers non-ionizing laser pulses to biological tissue, which results in absorbed energy and resultant heat in the form of transient thermoelastic expansions detected as wideband megaHertz ultrasonic emissions detected by ultrasonic transducers. The detected signals are used to produce images. As optical absorbance relationships exist with physiological properties, such as hemoglobin concentration and oxygen saturation, the detected pressure waves may be used to determine hemoglobin and oxygen concentration. 
     Hence, an acousto-optic analyzer starkly contrasts with photoacoustic imaging. Stated again, while the acousto-optic analyzer described herein may induce a heat wave like in photoacoustic imaging, in photoacoustic imaging the sound wave is detected whereas photons, from an external source, are detected in the acousto-optic analyzer described are detected after interacting with the sample being displaced/heated/disturbed by the sound wave. 
     Acousto-Optic Tunable Filter 
     According to Wikipedia, an acousto-optic tunable filter (AOTF), diffracts light based on an acoustic frequency. By tuning the frequency of the acoustic wave, the desired wavelength of the optical wave can be diffracted acousto-optically. 
     Hence, an acousto-optic analyzer (AOA) starkly contrasts with an acousto-optic tunable filter (AOTF) as, while the input sound wave of the AOA may diffract light, the separation of the input light is not the primary use of the sound wave. Indeed, a narrow-band light emitting diode (LED) is optionally used in conjunction with a broadband detector in the acousto-optic analyzer making any separation of the narrow band light source pointless. Further, in the AOA, the sound wave is used to change the state of the biological sample itself, whereas in the AOTF the sound wave is introduced to a birefringent crystal in a wavelength separation module of the spectrometer and is not introduced into the sample. 
     Still yet another embodiment includes any combination and/or permutation of any of the elements described herein. 
     The main controller, a localized communication apparatus, and/or a system for communication of information optionally comprises one or more subsystems stored on a client. The client is a computing platform configured to act as a client device or other computing device, such as a computer, personal computer, a digital media device, and/or a personal digital assistant. The client comprises a processor that is optionally coupled to one or more internal or external input device, such as a mouse, a keyboard, a display device, a voice recognition system, a motion recognition system, or the like. The processor is also communicatively coupled to an output device, such as a display screen or data link to display or send data and/or processed information, respectively. In one embodiment, the communication apparatus is the processor. In another embodiment, the communication apparatus is a set of instructions stored in memory that is carried out by the processor. 
     The client includes a computer-readable storage medium, such as memory. The memory includes, but is not limited to, an electronic, optical, magnetic, or another storage or transmission data storage medium capable of coupling to a processor, such as a processor in communication with a touch-sensitive input device linked to computer-readable instructions. Other examples of suitable media include, for example, a flash drive, a CD-ROM, read only memory (ROM), random access memory (RAM), an application-specific integrated circuit (ASIC), a DVD, magnetic disk, an optical disk, and/or a memory chip. The processor executes a set of computer-executable program code instructions stored in the memory. The instructions may comprise code from any computer-programming language, including, for example, C originally of Bell Laboratories, C++, C#, Visual Basic® (Microsoft, Redmond, Wash.), Matlab® (MathWorks, Natick, Mass.), Java® (Oracle Corporation, Redwood City, Calif.), and JavaScript® (Oracle Corporation, Redwood City, Calif.). 
     Herein, any number, such as 1, 2, 3, 4, 5, is optionally more than the number, less than the number, or within 1, 2, 5, 10, 20, or 50 percent of the number. 
     Herein, an element and/or object is optionally manually and/or mechanically moved, such as along a guiding element, with a motor, and/or under control of the main controller. 
     The particular implementations shown and described are illustrative of the invention and its best mode and are not intended to otherwise limit the scope of the present invention in any way. Indeed, for the sake of brevity, conventional manufacturing, connection, preparation, and other functional aspects of the system may not be described in detail. Furthermore, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and/or physical couplings between the various elements. Many alternative or additional functional relationships or physical connections may be present in a practical system. 
     In the foregoing description, the invention has been described with reference to specific exemplary embodiments; however, it will be appreciated that various modifications and changes may be made without departing from the scope of the present invention as set forth herein. The description and figures are to be regarded in an illustrative manner, rather than a restrictive one and all such modifications are intended to be included within the scope of the present invention. Accordingly, the scope of the invention should be determined by the generic embodiments described herein and their legal equivalents rather than by merely the specific examples described above. For example, the steps recited in any method or process embodiment may be executed in any order and are not limited to the explicit order presented in the specific examples. Additionally, the components and/or elements recited in any apparatus embodiment may be assembled or otherwise operationally configured in a variety of permutations to produce substantially the same result as the present invention and are accordingly not limited to the specific configuration recited in the specific examples. 
     Benefits, other advantages and solutions to problems have been described above with regard to particular embodiments; however, any benefit, advantage, solution to problems or any element that may cause any particular benefit, advantage or solution to occur or to become more pronounced are not to be construed as critical, required or essential features or components. 
     As used herein, the terms “comprises”, “comprising”, or any variation thereof, are intended to reference a non-exclusive inclusion, such that a process, method, article, composition or apparatus that comprises a list of elements does not include only those elements recited, but may also include other elements not expressly listed or inherent to such process, method, article, composition or apparatus. Other combinations and/or modifications of the above-described structures, arrangements, applications, proportions, elements, materials or components used in the practice of the present invention, in addition to those not specifically recited, may be varied or otherwise particularly adapted to specific environments, manufacturing specifications, design parameters or other operating requirements without departing from the general principles of the same. 
     Although the invention has been described herein with reference to certain preferred embodiments, one skilled in the art will readily appreciate that other applications may be substituted for those set forth herein without departing from the spirit and scope of the present invention. Accordingly, the invention should only be limited by the Claims included below.