APPLICATION NUMBER
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`FILING or 371 (c) GRP ART UNIT
`DATE
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`FIL FEE REC'D
`
`ATTY.DOCKET.NO DRAWINGS
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`TOT CLAIMS
`
`IND CLAIMS
`
`11/537,986
`
`10/02/2006
`
`2863
`
`0.00
`
`854263.419
`
`3
`
`27
`
`3
`
`UNITED STATES DEPART:vIENT OF COMMERCE
`United States Patent and Trademark Office
`Addm" COMMISSIC!I\ER FOIZ PA'l'l':N'l'S
`PO Rox 1410
`Alexandria, Virginia 22313-1450
`wv1w.uspto.gov
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`SEED INTELLECTUAL PROPERTY LAW GROUP PLLC
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`
`CONFIRMATION N0.1286
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`FILING RECEIPT
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`Date Mailed: 11/07/2006
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`Receipt is acknowledged of this regular Patent Application. It will be considered in its order and you will be
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`
`Applicant( s)
`
`Fabio Pasolini, S. Martino Siccomario, ITALY;
`Iva Binda, Voghera, ITALY;
`
`Assignment For Published Patent Application
`
`STMICROELECTRONICS S.R.L., Agrate Brianza, ITALY
`Power of Attorney: None
`
`Domestic Priority data as claimed by applicant
`
`Foreign Applications
`
`EUROPEAN PATENT OFFICE (EPO) 05425684.7 10/03/2005
`
`If Required, Foreign Filing License Granted: 11/06/2006
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`The country code and number of your priority application, to be used for filing abroad under the Paris Convention, is
`US11/537,986
`
`Projected Publication Date: To Be Determined - pending completion of Missing Parts
`
`Non-Publication Request: No
`
`Early Publication Request: No
`
`Title
`
`METHOD FOR CONTROLLING A PEDOMETER BASED ON THE USE OF INERTIAL
`SENSORS AND PEDOMETER IMPLEMENTING THE METHOD
`
`IPR2018-00387
`Ex. 3001
`
`

`

`Preliminary Class
`
`702
`PROTECTING YOUR INVENTION OUTSIDE THE UNITED STATES
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`international application under the Patent Cooperation Treaty (PCT). An international (PCT) application
`generally has the same effect as a regular national patent application in each PCT-member country. The
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`FILING LICENSE GRANTED" DOES NOT appear on this form. Applicant may still petition for a license
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`
`

`

`METHOD FOR CONTROLLING A PEDOMETER BASED ON THE USE OF
`
`INERTIAL SENSORS AND PEDOMETER IMPLEMENTING THE METHOD
`
`BACKGROUND OF THE INVENTION
`
`Field of the Invention
`
`5
`
`The present invention relates to a method for controlling a pedometer
`
`based on the use of inertial sensors and to a pedometer implementing said
`
`method.
`
`Description of the Related Art
`
`As is known, a pedometer is a device that can be carried by a user
`
`10 and has the function of counting the number of steps during various walking or
`
`running activities for estimating accordingly the distance traveled. The indications
`
`supplied are useful for quantifying the motor activity performed by a person in the
`
`course of a given period, for instance, for clinical purposes, for assessing the
`
`athletic performance, or even just for simple personal interest.
`
`15
`
`The reliability of a pedometer obviously depends on the precision in
`
`estimating the step length of the user at the various rates of locomotion, but also
`
`on the selectivity in recognizing and ignoring events not correlated to the gait,
`
`which, however, cause perturbations resembling those produced by a step. For
`
`example, many pedometers are based on the use of inertial sensors, which detect
`
`20 accelerations along a substantially vertical axis, and recognize that a step has
`
`been being made by a user when the time plot of the acceleration signal shows
`
`given morphological characteristics. Basically, a step is recognized when the
`
`pedometer detects a positive acceleration peak (i.e., a peak directed upwards)
`
`having an amplitude greater than a first threshold, followed, at a distance of some
`
`25
`
`tenths of second, by a negative acceleration peak (directed downwards) having an
`
`amplitude greater than a second threshold. However, there are many random
`
`1
`
`

`

`events that can interfere with correct recognition of the step. Impact or other
`
`external vibrations and given movements of the user can, in fact, give rise to so(cid:173)
`
`called "false positives", i.e., to events that are recognized as steps even though in
`
`actual fact they are not, because the morphological characteristics produced are
`
`5
`
`compatible. Events of this type are very frequent also in periods of rest, when the
`
`user, albeit not walking, in any case performs movements that can be detected by
`
`the pedometer. In the majority of cases, also "isolated" steps or very brief
`
`sequences of steps are far from significant and should preferably be ignored
`
`because they are, in effect, irrelevant in regard to assessment of the motor activity
`
`10
`
`for which the pedometer is being used.
`
`Of course, in all these situations, the count of the steps may prove to
`
`be completely erroneous.
`
`BRIEF SUMMARY OF THE INVENTION
`
`One embodiment of the present invention is a method for controlling
`
`15 a pedometer and a pedometer which overcome the described above limitations.
`
`One embodiment is a method for controlling a pedometer. The
`
`method includes: generating a signal correlated to movements of a user of the
`
`pedometer; detecting steps of the user based on the signal; checking whether
`
`sequences of the detected steps satisfy pre-determined conditions of regularity;
`
`20 updating a total number of valid steps if the conditions of regularity are satisfied;
`
`and preventing updating of the total number of valid steps if the conditions of
`
`regularity are not satisfied.
`
`BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
`
`For a better understanding of the invention, an embodiment thereof is
`
`25 now described, purely by way of non-limiting example and with reference to the
`
`attached plate of drawings, wherein:
`
`2
`
`

`

`Figure 1 shows a simplified and partially sectioned perspective view
`
`of a portable electronic device incorporating a pedometer according to the present
`
`invention;
`
`Figure 2 is a simplified block diagram of the pedometer of Figure 1;
`
`5
`
`Figure 3 shows a flowchart corresponding to a control method
`
`according to the present invention executed by the pedometer of Figures 1 and 2;
`
`Figure 4 is a more detailed flowchart corresponding to a first step of
`
`the method of Figure 3;
`
`Figure 5 is a graph that represents first quantities used in the method
`
`10 according to the present invention;
`
`Figure 6 is a graph that represents second quantities used in the
`
`method according to the present invention;
`
`Figure 7 is a more detailed flowchart corresponding to a second step
`
`of the method of Figure 3; and
`
`15
`
`Figure 8 is a more detailed flowchart corresponding to a third step of
`
`the method of Figure 3.
`
`DETAILED DESCRIPTION OF THE INVENTION
`
`With reference to Figures 1 and 2, a pedometer 1 is integrated within
`
`a portable electronic device, such as a cell phone 2. The pedometer 1 comprises
`
`20 an inertial sensor 3, a control unit 5, equipped with a nonvolatile-memory module
`
`(not illustrated herein), a display 6, and a communication interface 8, all housed on
`
`a card 9, which is, in turn, fixed within a casing 10 of the cell phone 2. In the
`
`embodiment described herein, the control unit 5 performs control functions of the
`
`pedometer 1 and, moreover, presides over bi-directional communication and over
`
`25 handling of the functions envisaged for the cell phone 2. Likewise, the display 6,
`
`which is obviously arranged so as to be visible from the outside of the casing 10,
`
`can be used for displaying both information regarding the pedometer 1 and, more
`
`in general, information regarding the operation of the cell phone 2.
`
`3
`
`

`

`The inertial sensor 3 is a linear accelerometer of a MEMS (micro(cid:173)
`
`electromechanical systems) type and is mounted on the card 9 so as to have a
`
`detection axis Z substantially parallel to a longitudinal axis L of the casing 10 of the
`
`cell phone 2. In practice, the detection axis Zand the longitudinal axis Lare
`
`5
`
`substantially horizontal, when the cell phone 2 is resting on a surface, and
`
`substantially vertical or slightly inclined with respect to the vertical when the cell
`
`phone 2 is handled. The inertial sensor 3 supplies at output an acceleration signal
`
`Az, which is correlated to the accelerations undergone by the inertial sensor 3 itself
`
`along the detection axis Z.
`
`10
`
`The control unit 5 receives and processes the acceleration signal Az
`
`as explained in detail hereinafter for identifying and counting a total number of
`
`valid steps Nvr made by a user wearing or carrying the pedometer 1, for example,
`
`on his belt or on his shoulder. In addition, the control unit 5 is preferably
`
`configured for generating an estimate of the distance traveled by the user and
`
`15 other data, such as, for example, estimates of the average speed during
`
`movement and energy consumption. The total number of valid steps Nvr and the
`
`other data possibly produced are sent to the display 6.
`
`The communication interface 8 in this case is based on the
`
`transceiver system (known and not shown) of the cell phone 2 and, preferably,
`
`20 also comprises a port (also known and not shown) for communication with a
`
`computer. The communication interface 8 can thus be used both for downloading
`
`the data produced by the pedometer 1 (amongst which at least the total number of
`
`valid steps Nvr) and for uploading operating parameters for the pedometer 1 into
`
`the control unit 5.
`
`25
`
`The control unit 5 is configured for executing a control procedure, as
`
`illustrated with reference to Figures 3-8.
`
`Upon switching-on of the pedometer 1, an initialization step is
`
`executed (block 100, Figure 3), in which a first counter of the total number of valid
`
`steps Nvr; a second counter, hereinafter referred to as number of valid control
`
`4
`
`

`

`steps Nvc; and a third counter, hereinafter referred to as number of invalid steps
`
`N1Nv, are set to zero.
`
`The control unit 5 then executes a first counting procedure (block
`
`110), based upon the sampling of the acceleration signal Az at a pre-determined
`
`5
`
`frequency, for example 25 Hz. In this step, the user is considered at rest and the
`
`control unit 5 is considered as waiting to recognize, on the basis of the
`
`acceleration signal Az, sequences of events corresponding to a sequence of steps
`
`that are close to one another, which satisfy pre-determined conditions of regularity
`
`described in detail hereinafter. When a sequence of steps corresponding to a
`
`10
`
`regular gait of the user is recognized, the first counting procedure is interrupted.
`
`Alternatively, the first counting procedure terminates when a time interval Tc that
`
`has elapsed from the last step recognized is longer than a first time threshold T81 ,
`
`for example 10 s. On exit from the first calculation procedure, the control unit 5
`
`sets a state flag Fsr to a first value C, if a sequence of steps that satisfies the
`
`15
`
`conditions of regularity has been recognized, and to a second value PD, if the first
`
`time threshold Ts1 has been exceeded.
`
`At the end of the first counting procedure, the control unit 5 checks
`
`whether the state flag Fsr has been set at the first value C (block 120), i.e.,
`
`whether a sequence of steps has been recognized. If so (output YES from block
`
`20 120), a second counting procedure is executed (block 130). The user is
`
`considered to be moving, and a first counter, hereinafter referred to as total
`
`number of valid steps Nvr, is incremented whenever an event corresponding to a
`
`step is recognized. Furthermore, the control unit 5 checks the regularity of the
`
`sequences of steps, as explained hereinafter, and, when an interruption in the
`
`25
`
`locomotion is detected, the second counting procedure is terminated, and
`
`execution of the first counting procedure resumes (block 110).
`
`If, instead, the state flag Fsr has the second value PD, the
`
`pedometer 1 is set in a low-consumption wait state ("power down" state), and the
`
`control unit 5 executes a surveying procedure (block 140). The surveying
`
`5
`
`

`

`procedure terminates when a variation of the d.c. component of the acceleration
`
`signal Az is detected, i.e., when the cell phone 2 that includes the pedometer 1 is
`
`moved. The control unit 5 then returns to execution of the first calculation
`
`procedure (block 110).
`
`5
`
`The first counting procedure is illustrated in greater detail in Figure 4.
`
`Initially, the control unit 5 reads a sample of the acceleration signal
`
`Az (block 200) and then evaluates whether the time interval Tc that has elapsed
`
`from the last step recognized is higher than the first time threshold Ts1, i.e.,
`
`whether the step recognition fails for a period longer than the first time threshold
`
`10 T s1 (block 205). If so (output YES from block 205), the state flag Fsr is set at the
`
`second value PD (block 210) and the first counting procedure is terminated (in this
`
`eventuality, after the test on the state flag Fsr of block 120 of Figure 3, the
`
`surveying procedure is executed, block 140). Otherwise (output NO from block
`
`205), the duration of the time interval Tc is compared with a second time threshold
`
`15 Ts2, shorter than the first time threshold Ts1 and equal, for example, to 3 s (block
`
`215). If the second time threshold Ts2 has been exceeded (output YES from block
`
`215), the number of valid control steps Nvc and the number of invalid steps N1Nv
`
`are set to zero (block 220); then a step-recognition test is carried out (block 225).
`
`Otherwise (output NO from block 215), the control unit 5 directly executes the step-
`
`20
`
`recognition test.
`
`In the step-recognition test of block 225, the control unit 5 verifies
`
`whether the time plot of the acceleration signal Az (i.e., the sequence of the
`
`samples acquired) has pre-determined characteristics. In particular (Figure 5), a
`
`step is recognized if the acceleration signal Az shows a positive peak, higher than
`
`25 a positive acceleration threshold Azp, followed by a negative peak, smaller than a
`
`negative acceleration threshold AzN, and if the negative peak falls within a time
`
`window TW of pre-determined amplitude and, moreover, located at a pre(cid:173)
`
`determined distance after the positive peak.
`
`6
`
`

`

`If the control unit 5 does not recognize an event corresponding to a
`
`step (output NO from block 225), a new sample of the acceleration signal Az is
`
`read (block 200). If, instead, the step-recognition test is passed (output YES from
`
`block 225), the control unit 5 executes a first validation test, corresponding to the
`
`5
`
`regularity of the individual step (block 230). With reference also to Figure 6, the
`
`validation occurs when the duration ~T Kofa current step K is substantially
`
`homogeneous with respect to the duration ~ T K-1 of an immediately preceding step
`K-1 (the duration of a generic step is determined by the time that has elapsed
`
`between an instant of recognition of the step of which the duration is evaluated and
`
`10 an instant of recognition of the step that immediately precedes it). More precisely,
`
`the last step recognized is validated if the instant of recognition of the current step
`
`T R(K) falls within a validation interval TV, defined with respect to the instant of
`
`recognition of the immediately preceding step T R(K-1 ), in the following way:
`
`TV= [T R(K-1 )+~T K-1-TA, T R(K-1 )+ ~T K-1+ TB]
`
`15 where TA and TB are complementary portions of the validation interval TV. In the
`
`embodiment of the invention described herein, the complementary portions TA, TB
`
`are defined as follows, for the generic current step K:
`
`TA=~TK-1/2
`
`TB= ~TK-1
`
`20
`
`Consequently, the validation interval is asymmetrical with respect to
`
`the instant T R(K-1 )+~T K-1 and has an amplitude equal to 3~ T K-112. The validation
`
`interval TV could, however, be symmetrical and have a different amplitude. In
`
`practice, it is verified that the last step recognized is compatible with the frequency
`
`of the last steps made previously.
`
`25
`
`If the verification yields a negative result (output NO from block 230),
`
`the number of invalid steps N1Nv is incremented by one (block 235) before being
`
`compared with a first programmable threshold number Nr1, for example 3 (block
`
`240). If the number of invalid steps N1Nv has reached the first threshold number
`
`7
`
`

`

`Nr1 (output YES from block 240), both the number of invalid steps N1Nv, and the
`
`number of valid control steps Nvc are set to zero (block 245), and the first counting
`
`procedure is resumed, with reading of a new sample of the acceleration signal Az
`
`(block 200). If, instead, the number of invalid steps N1Nv is smaller than the first
`
`5
`
`threshold number Nr1 (output NO from block 240), the number of valid control
`
`steps Nvc is decremented (block 250). In the embodiment described herein, the
`
`decrement is equal to two. If the result of the decrement operation is negative, the
`
`number of valid control steps Nvc is set to zero (in practice, the updated value of
`
`the number of valid control steps Nvc is equal to the smaller between zero and the
`
`10 previous value of the number of valid control steps Nvc, decreased by two). Then,
`
`the control unit 5 reads a new sample of the acceleration signal Az (block 200).
`
`If the first validation test of block 230 is passed, the number of valid
`
`control steps Nvc is incremented by one (block 255), and then the control unit 5
`
`executes a first test on regularity of the sequence of steps recognized (block 260).
`
`15 The first regularity test is based upon a first condition of regularity and envisages
`
`comparing the number of valid control steps Nvc with a second programmable
`
`threshold number Nr2 greater than the first threshold number Nr1 (for example, 8).
`
`In practice, the first condition of regularity is satisfied when there is a significant
`
`prevalence of steps spaced in a substantially uniform way, at the most interrupted
`
`20
`
`sporadically by a number of irregular steps smaller than the first threshold number
`
`Nr1. If the number of valid control steps Nvc is smaller than the second threshold
`
`number Nr2 (output NO from block 260), the first condition of regularity is not
`
`satisfied, and the first regularity test indicates that there has not yet been identified
`
`a sequence of steps corresponding to a sufficiently regular gait, and hence the
`
`25
`
`control unit 5 acquires once again a new sample of the acceleration signal Az
`
`(block 200), without the total number of valid steps Nvr being incremented.
`
`Otherwise (output YES from block 260), a sequence of steps is recognized that
`
`satisfies the first condition of regularity, and the first regularity test is passed. The
`
`number of invalid steps N1Nv and the number of valid control steps Nvc are set to
`
`8
`
`

`

`zero, whereas the total number of valid steps Nvr is updated and incremented by a
`
`value equal to the second threshold number Nr2 (block 265). Furthermore, the
`state flag Fsr is set at the count value, and the first counting procedure is
`
`terminated. In this case, after the test on the state flag of block 120 of Figure 3,
`
`5
`
`the second counting procedure is executed (block 130).
`
`In practice, the first counting procedure enables the pedometer 1 to
`
`remain waiting for a sequence of events corresponding to a sequence of steps that
`
`satisfies the first condition of regularity. The regularity of the gait is considered
`
`sufficient when the number of valid control steps Nvc reaches the second threshold
`
`10 number Nr2. The events considered irregular or a waiting time that is too long
`
`between two successive steps cause the decrement (block 250) or the zeroing
`
`(blocks 220 and 245) of the number of valid control steps Nvc, so that the first
`
`counting procedure resumes from the start. As long as the pedometer 1 is in the
`
`waiting condition, the total number of valid steps Nvr is not incremented because
`
`15
`
`the user is still considered as at rest. However, when the first regularity test (block
`
`260) is passed, the total number of valid steps Nvr is immediately updated so as to
`
`take into account the valid steps (equal to Nr2) that make up the sequence
`
`considered as being regular. Isolated events and sequence of steps that are in
`
`any case too short are thus advantageously ignored, whereas counting of the
`
`20
`
`steps promptly resumes also in the case of isolated irregularities (for example, due
`
`to a non-homogeneous acceleration or to a loss of balance at the start of
`
`locomotion).
`
`The possibility of programming the value of the first threshold number
`
`Nr1 and of the second threshold number Nr2 enables modification of the sensitivity
`25 of the pedometer in recognizing an initial sequence of steps. For example, the
`
`user can program lower values of the first threshold number Nr1 and of the second
`
`threshold number Nr2 (for example 2 and 4, respectively) when he remains for a
`
`long time in a closed environment, for example an office or a room, where it would
`
`not in any case be possible to maintain a regular gait for a long time. In this way,
`
`9
`
`

`

`shorter sequences of steps are validated and counted. Instead, during a more
`
`constant and intense activity, such as running, the gait remains constant for a long
`
`time, and hence the first threshold number Nr1 and the second threshold number
`
`Nr2 can be programmed with higher values (for example, 4 and 12, respectively).
`
`5 Step sequences that are shorter and not very significant in relation to the activity
`
`performed can be ignored.
`
`Figure 7 illustrates in detail the second counting procedure (executed
`
`in block 130 of Figure 3).
`
`The control unit 5 initially reads a sample of the acceleration signal
`
`10 Az (block 300), and then evaluates whether the time interval Tc that has elapsed
`
`from the last step recognized is higher than the first second time threshold Ts2
`
`(block 305). If so (output YES from block 205), the number of invalid steps N1Nv
`
`and the number of valid control steps Nvc are zeroized (block 310), and the
`
`second counting procedure is terminated. Otherwise (output NO from block 305),
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`15 a step-recognition test is carried out (block 315), identical to the step-recognition
`
`test of block 225 of Figure 3. Also in this case, then, step recognition is based
`
`upon the detection of a positive peak of the acceleration signal Az followed by a
`
`negative peak that falls in the time window TW (see Figure 5).
`
`If the control unit 5 does not recognize an event corresponding to a
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`20
`
`step (output NO from block 315), a new sample of the acceleration signal Az is
`
`read (block 300). If, instead, the step-recognition test is passed (output YES from
`
`block 315), a second validation test is made, corresponding to the regularity of the
`
`individual step (block 320). The second validation test is altogether similar to the
`
`first validation test carried out in block 230 of Figure 3. Also in this case, then, the
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`25
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`last step recognized is validated if the instant of recognition of the current step
`
`T c(K) falls within the validation interval TV defined above. In practice, it is verified
`
`that the last step recognized is compatible with the frequency of the last steps
`
`made previously.
`
`10
`
`

`

`If the check yields a positive result (output YES from block 320), the
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`control unit 5 updates the total number of valid steps Nvr and the number of valid
`
`control steps Nvc, incrementing them by one (block 325). The number of valid
`
`control steps Nvc is then compared with a third programmable threshold number
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`5 Nr3 (block 330), which, in the embodiment described herein, is equal to the second
`
`threshold number Nr2. If the number of valid control steps Nvc is smaller than the
`
`second threshold number Nr2 (output NO from block 330), the control unit 5 once
`again directly acquires a new sample of the acceleration signal Az (block 300),
`
`whereas otherwise (output YES from block 330), the number of invalid steps N1Nv
`
`10 and the number of valid control steps Nvc are set to zero (block 335) prior to
`
`acquisition of a new sample Az.
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`If, instead, the second validation test of block 320 is negative, the
`
`number of invalid steps N1Nv is incremented by one (block 340) before being
`
`compared with a fourth programmable threshold number Nr4 (block 345), which, in
`the present embodiment, is equal to the first threshold number Nr1. If the number
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`15
`
`of invalid steps N1Nv is smaller than the fourth threshold number Nr4 (output NO
`
`from block 345), the number of valid control steps Nvc is decremented (block 350),
`
`here by two. Also in this case, if the result of the decrement operation is negative,
`
`the number of valid control steps Nvc is set to zero (the updated value of the
`
`20 number of valid control steps Nvc is equal to the smaller between zero and the
`
`previous value of the number of valid control steps Nvc, decreased by two). Then,
`
`the control unit 5 reads a new sample of the acceleration signal Az (block 300). If
`
`the number of invalid steps N1Nv has reached the fourth threshold number Nr4
`
`(output YES from block 345), the number of invalid steps N1Nv and the number of
`valid control steps Nvc are set to zero (block 355), and the second counting
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`25
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`procedure is terminated.
`
`In practice, the second counting procedure is based on a second
`
`condition of regularity, which is satisfied as long as sporadic irregular steps occur
`
`within sequences of steps spaced in a substantially homogeneous way. More
`
`11
`
`

`

`precisely, the second condition of regularity is satisfied as long as the number of
`
`invalid steps N1Nv is smaller than the fourth threshold number Nr4 • Consequently,
`
`the second counting procedure continues to update and increment the total
`
`number of valid steps Nvr as long as the gait of the user is kept regular. Possible
`
`5
`
`isolated irregularities are ignored and do not interrupt or suspend updating of the
`
`count, which is, instead, interrupted when prolonged pauses occur or in the
`
`presence of significant discontinuities in locomotion. However, if the gait becomes
`
`regular again, even with a different rhythm, also the count promptly resumes,
`
`because the first counting procedure is once again executed. This prevents a
`
`10
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`significant number of steps from being neglected.
`
`The surveying procedure executed in block 140 of Figure 3 will now
`
`be described in greater detail, with reference to Figure 8.
`
`When the surveying procedure is started, a current mean value AzM
`
`of the acceleration signal Az is stored in the nonvolatile-memory module (not
`
`15
`
`illustrated) of the control unit 5 (block 400). The current mean value AzM
`
`represents an estimate of the DC component of the acceleration signal Az, which,
`
`when the cell phone 2 containing the pedometer 1 is stationary, is determined
`
`substantially by the contribution of the acceleration of gravity along the detection
`
`axis Z. In practice, then, the current mean value AzM provides an estimate of the
`
`20 position of the cell phone 2 and of the pedometer 1.
`
`After storage of the current mean value AzM, the pedometer 1 is set
`
`in a low-consumption operating condition (power-down condition), in which at least
`
`the inertial sensor 3 is inactive (b