c12) United States Patent
`Pasolini et al.
`
`(IO) Patent No.:
`(45) Date of Patent:
`
`US 7 ,463,997 B2
`Dec. 9, 2008
`
`(54) PEDOMETER DEVI℃EAND STEP
`DETE℃TION METHOD USING AN
`ALGORITHM FOR SELF-ADAPTIVE
`℃OMPUTATION OF A℃℃ELERATION
`THRESHOLDS
`
`(75)
`
`Inventors: Fabio Pasoli时， S Martino Siccomario
`(IT); Ivo Binda, Voghera (IT)
`
`(73) Assignee: STMicroelectronics S.r.1., Agrate
`Brianza (IT)
`
`( * ) Notice:
`
`Subject to any disclaimer, the term ofthis
`patent is extended or a司justed under 35
`U.S.C. 154(b) by 3 days.
`
`(21) Appl. No.: 11/537,933
`
`(22) Filed:
`
`Oct. 2, 2006
`
`(65)
`
`Prior Publication Data
`
`US 2007/0143068 Al
`
`Jun. 21, 2007
`
`(30)
`
`Foreign Application Priority Data
`
`Oct. 3, 2005
`
`(EP)
`
`........….......…............. 05425683
`
`(51)
`
`Int. 。－
`(2006.01)
`GOJC 22100
`(52) U.S. Cl. ...................................................... 702/160
`( 58) Field of ℃lassification Search ................. 702/141,
`702/150--154, 158, 160; 600/595; 73/490,
`73/510
`See application 自le for complete search history.
`
`(56)
`
`References ℃ited
`
`U.S. PATENT DOCU肌1ENTS
`5,583,776 A
`12/1996 Levi et al. ................... 364/450
`
`412000 Gaudet et al ................ 702/160
`6,052,654 A
`10/2000 Richardson et al. ......... 600/300
`6,135,951 A
`6,826,477 B2 * 1112004 Ladetto et al. …........... 7011217
`6,898,550 Bl
`5/2005 Blackadar et al.
`.......... 702/182
`200610020177 Al * 1/2006 Seo et al.
`................... 600/300
`2007/0073514 Al* 3/2007 Nogimori et al.
`.......... 702/160
`200710143069 Al * 6/2007 Pas。lini et al. .............. 702/160
`2007/0198187 Al*
`8/2007 Pasolini et al. .............. 7011220
`
`FOREIGN PATENT DOCU肌1ENTS
`
`GB
`
`2 359 890
`
`9/2001
`
`* cited by examiner
`
`Primary Examiner Michael P Nghiem
`(74)Attorney, Age以 or Firm T .isa K. Jorgenson; Dennis M.
`de Guzman; Se巳d IP Law Group PLLC
`
`(57)
`
`ABSTRA℃ I
`
`In a pedometer device for detecting and counting steps of a
`user on foot, an accelerometer sensor detects a vertical accel(cid:173)
`eration generat巳d during the step. A processing unit, con(cid:173)
`nected to the accelerometer sensor, processes an acceleration
`signal relating to the acceleration in order to detect the occur(cid:173)
`rence of a step, and in particular compares the acceleration
`signal with a first reference threshold. The processing unit
`automatically adapts the first reference threshold as a func(cid:173)
`tion of the acceleration signal. In particular, the processing
`unit modifies the first reference threshold as a function of an
`envelope of the amplitude of the acceleration signal.
`
`30 ℃laims, 5 Drawing Sheets
`
`r-'
`
`PROCESSING UNIT
`
`SETTING
`
`3
`
`DISTANCE-CALCULATION
`FIRST COMPARATOR
`THRESHOLD-ADAPTATION I I SECOND COMPARATOR
`ENVELOPE CALCULATION I I MEAN-VALUE CALCULATION
`I I AXIS-DETERMINATION
`
`LENGTH-ESTIMATION
`
`4
`
`SAMSUNG EXHIBIT 1005
`
`Page 1 of 12
`
`

`

`U.S. Patent
`
`Dec. 9, 2008
`
`Sheet 1of5
`
`US 7,463,997 B2
`
`r-'
`
`PROCESSING UNIT
`
`SETTING
`
`3
`
`DISTANCE-CALCULATION
`FIRST COMPARATOR
`THRESHOLD-ADAPTATION I I SECOND COMPARATOR
`ENVELOPE CALCULATION I I MEAN-VALUE CALCULATION
`I I AXIS-DETERMINATION
`LENGTH-ESTIMATION
`
`DISPLAY
`
`I
`
`I INTERFACE
`
`4
`
`FIG. 1
`
`Page 2 of 12
`
`

`

`U.S. Patent
`
`Dec. 9, 2008
`
`Sheet 2 of 5
`
`US 7,463,997 B2
`
`「－－－「
`
`飞
`
`p 、
`’
`f
`
`I 11
`
`。
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`、
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`＼ν !
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`ν……··· Env+
`飞＼
`
`\
`
`二
`
`Fig.5
`
`Page 3 of 12
`
`

`

`U.S. Patent
`
`Dec. 9, 2008
`
`Sheet 3 of 5
`
`US 7,463,997 B2
`
`PARAMETER
`INITIALIZATI。N
`
`10
`
`DETERMINATION OF ACCELERATION DATUM
`CalAcc AND THRESHOLD ADAPTATION
`
`11
`
`NO
`
`12
`
`13
`
`14
`
`20
`
`STEP
`INCREMENT
`
`21
`
`STEP LENGTH
`
`DISTANCE
`INCREMENT
`
`INCREMENT OF CALORIE
`SPEED COMPUTATION
`
`Page 4 of 12
`
`

`

`U.S. Patent
`
`Dec. 9, 2008
`
`Sheet 4 of 5
`
`US 7,463,997 B2
`
`DETERMINATION OF ACCELERATION DATUM
`CalAcc AND THRESHOLD ADAPTATION
`
`11, 18
`
`ACQUISITION OF
`ACCELERATION SAMPLE Ace
`
`30
`
`ELIMINATION OF D.C. COMPONENT
`A .. I r \ l"'\r-甲.－ RMINATION OF CalAcc
`
`33
`
`36
`
`43
`
`1l
`VE
`+-
`
`nH巳E
`
`*-
`
`41
`
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`MW工
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`
`34
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`35
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`
`37
`
`Page 5 of 12
`
`

`

`U.S. Patent
`
`Dec. 9, 2008
`
`Sheet 5 of 5
`
`US 7,463,997 B2
`
`CalAcc
`
`[II lf'il 11\I Uil 阳 ur.111111\,
`
`Q叫onh－
`
`10
`
`Fig.6
`
`DETERMINATION OF ACCELERATION DATUM
`CalAcc AND THRESHOLD ADAPTATION
`
`POSITIVE PHASE DETECTION
`CalAcc> s+
`
`STEP INCREMENT
`
`STEP LENGTH ADAPTATION
`
`DISTANCE INCREMENT
`
`INCREMENT OF
`SPEED COMPUTATION
`
`Fig.7
`
`T 丁
`
`12
`
`13
`
`21
`22
`
`23
`
`。。。
`
`θ~Q
`Bσ 飞
`
`53
`
`52
`
`Fig.8
`
`Page 6 of 12
`
`

`

`US 7,463,997 B2
`
`1
`PEDOMETER DEVI℃E AND STEP
`DETE℃TION METHOD USING AN
`ALGORITHM FOR SELF-ADAPTIVE
`℃OMPUTATION OF A℃℃ELERATION
`THRESHOLDS
`
`2
`counted as steps; on the other hand, if the threshold is too
`high, some steps may not be detected.
`
`BRIEF SU肌f鸟也气RY OF THE INVENTION
`
`BACKGROUND OF THE INVENTION
`
`One embodiment of the present invention provides a
`p巳dometer device and a method for detecting and counting
`steps which will enable the aforesaid disadvantages and prob-
`!ems to be overcome.
`1. Field of the Invention
`One embodiment of the invention is a pedometer device for
`The present invention relates to a pedometer device and to 10
`a step detection method using an algorithm for self-adaptive
`detecting and counting the steps of a user. The device includes
`an accelerometer sensor configured to detect an acceleration
`computation of acceleration thresholds.
`generated during a step; and a processing unit connected to
`2. Description of the Related Art
`the accelerometer sensor, and configured to process an accel-
`Step-counting devices (referred to in general as pedom-
`eters) are known, which, being carried by a user, enable 15 eration signal relating to the acceleration to detect the occur-
`measurement of the number of steps made, and calculation of
`rence of a step. The processing unit includes a first compara-
`the distance traveled, as well as supplying of additional infor-
`tor configured to compare the acceleration signal with a first
`mation, such 邸， for example, the average speed, or the con-
`reference threshold, and a threshold-adaptation circuit con-
`sumption of calories.
`figured to modify the first reference threshold as a function of
`Pedometers are advantageously used in inertial navigation 20 the acceleration signal.
`systems (the so-called dead-reckoning systems) applied to
`One embodiment of the invention is a step detection
`human beings. Such systems trace the movements of a user,
`method for detecting steps in the gait of a user. The method
`by identifying and measuring his/her displacements starting
`includes producing an acceleration signal relating to an accel-
`from a known starting point, without resorting to the use of a
`eration generated during a step; and processing the accelera-
`Global Positioning System (GP时， or by acting as aid to a
`tion signal to detect the occurrence of the step. The processing
`GPS. In said systems, a compass supplies the information
`step includes comparing the acceleration signal with a first
`linked to the dir巳：ction of displacement, and the pedometer
`reference threshold, and modifying the first reference thresh-
`supplies the information linked to the amount of said dis-
`old as a function of the acceleration signal.
`placement. Pedometers are also used in a wide range of appli-
`cations in the clinical sector (for example, in rehabilitatio时，
`and in general in the field of fitness （扣r example, as instru(cid:173)
`ments for monitoring a physical activity).
`For a better understanding of the present invention, pre-
`In particular, pedometers are known that use integrated
`accelerometers of a MEMS (micro-electromechanical sys- 35 ferred embodiments thereof are now described, purely by
`tem) type for step detection. In particular, such pedometers
`way of non-limiting example and with reference to the
`have particularly compact dimensions, and can be advanta-
`attached drawings, wherein:
`FIG. 1 shows a block diagram of a pedometer device;
`geously integrated within portable devices, such as mobile
`phones, Mp3 readers, camcorders, etc.
`.
`FIG. 2 shows a graph corresponding to the pattern of an
`The aforesaid pedometers implement a step detect10n 40 acceleration signal during a step;
`method based upon the analysis of the pattern of a vertical
`FIG. 3 shows a flowchart corresponding to operations of
`acceleration, which is generated during the various phases of
`detection and counting of steps, executed by a processing unit
`the step by the contact of the foot to the ground, and which is
`of the pedometer device of FIG. 1;
`detected by an accelerometer fixed to the body of the user. In
`
`25
`
`30
`
`BRIEF DESCRIPTION OF THE SEVERAL
`VIEWS OF THE DRAWINGS
`
`：~~~：；~：~o~：口：：~~i：~ct！~~~~：~i：~ ~~~~~:i;a~~~~~ 45 比l~！~~；t:::w~~~~；~t~~~ c~7es:c0c~f！~~i~n op＝~~~~~d~~
`
`executed by the processing unit of the pedometer device of
`user’ s body. In particular, the occurrence of a step is deter-
`FIG.1;
`mined by identifying acceleration peaks that appear in the
`FIGS. 5-6 are graphs corresponding to the pattern of an
`acceleration signal, and said peaks are detected by comparing
`the acceleration signal with a given reference threshold, hav- 50 acceleration signal during a step and of reference thresholds
`ing a pre-set value.
`associated to the algorithm of FIG. 3;
`
`How巳V巳r V巳nthoughth巳 acc巳l巳削
`a
`an
`thatisr巳p巳atabl巳 at 巳achst巳p, its patt巳m (and, in particular, its
`FIG. 8 is a partially exploded schematic view of a portable
`amplitude and temporal extension) has a wide variability
`according to a number of factors that affect the gait, such as 55 device, in particular a mobile phone, incorporating the
`p巳dometer device of FIG. 1.
`the resting surface, the type of shoe worn (rigid sole or flex-
`ible sole, etc.), and the sp臼d of the gait (slow walking, fast
`walking, running, etc.). Furthermore, each individual user has
`given characteristics and peculiarities that affect the gait,
`differentiating it from that of other users.
`FIG. 1 is a schematic illustration of a pedometer device 1,
`It follows that a step detection based upon the comparison
`comprising an accelerometer 2, of a linear type and having a
`vertical detection axis z, and a processing unit 3, connected to
`of the value of the acceleration signal with a reference thresh-
`old having a pre-set value for the detection of acceleration
`the accelerometer 2. Advantageously, the accelerometer 2
`peaks, involves the occurrence of errors that may even be
`and the processing unit 3 are mounted on the same printed
`considerable in counting of the steps, and in the measurement 65 circuit, housed inside a casing of the pedometer device 1 (not
`of the distance traveled. In particular, if the threshold is too
`illustrated). The pedometer device 1 is carried by a user, for
`low, spurious signals, rebounds, or noise in general, may be
`ex缸口ple on his belt or on his shoulder, so as to be fix巳d to the
`
`DETAILED DESCRIPTION OF THE INVENTION
`
`60
`
`Page 7 of 12
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`

`

`US 7,463,997 B2
`
`3
`4
`rence of a ste抖， counting of the steps and measurement of the
`body of the user and be able to sense vertical accelerations
`that occur during the step, caused by the impact of the feet on
`total distance traveled are updated; otherwise, the algorithm
`returns to the initial condition of looking for a new positive
`the ground.
`phase of the step. In particular, the positive acceleration peaks
`The pedometer device 1 如rther comprises a display screen
`that occur within the pre-set time interval are ignored by the
`4, connected at an output of the processing unit 3, and an 5
`interface 5, connected at an input of the processing unit 3. The
`algorithm (in so far as they can be ascribed to phenomena of
`noise, such as impact, anomalous rebounds, etc.).
`display screen 4 displays information at output from the
`In detail, the algorithm starts with initialization, block 10,
`pedometer device 1, such as the number of steps, the distance
`of the values of the positive and negative reference thresholds
`traveled, etc. The interface 5, for example, including push-
`buttons, an alphanumeric keypad, communication ports, etc., 10 s+ and S , respectively, at a positive minimum value S1 and at
`a negative mini日ium value S2, the latter being smaller, in
`allows the user to communicate with the processing unit 3 （扣r
`example, by entering data).
`absolute value, than the positive minimum value S1. As will
`The accelerometer 2 is advantageously an integrated sen-
`be clarified, said minimum values represent limit values
`sor of semiconductor material, made using the MEMS tech-
`below which the reference thresholds are not allowed to drop.
`nology, of a known type and thus not describ巳d in detail 15 In addition, the values of a positive envelope Env+ and of a
`herein. In use, the accelerometer 2 detects the component
`negative envelope Env of the acceleration signal A (which
`along the detection axis z of the vertical acceleration gener-
`will subsequently be us巳d for modification of the reference
`thresholds) are initializ时， respectively, at the positive mini-
`ated during the step, and produces a corresponding accelera-
`ti on signal A.
`mum value S 1 and at the negative minimum value S2.
`As shown in FIG. 2, the pattern of the acceleration signal A 20
`Next, block 11, the processing unit 3 determines a first
`(with the d.c. component filtered out) in time t has a given
`acceleration datum CalAcc, and consequently modifies the
`acceleration profile which repeats at each step (indicat巳d by
`values of the reference thresholds (as will be described in
`detail hereina武er with reference to FIGS. 4 and 5).
`the dashed rectangle). In detail, the acceleration profile com-
`prises in succession: a positive phase, in which a positive-
`The algorithm then proceeds, block 12, with the search for
`acceleration peak occurs (i.e., directed upwards), due to con- 25 the positive phase of the step, by comparing the value of the
`tact and consequent impact of the foot with the ground; and a
`acceleration datum CalAcc with the positive reference thresh-
`negative phase in which a negative-acceleration peak occurs
`olds+, to detect a positive acceleration peak of the accelera-
`(i.e., directed downwards) due to rebound, having an absolute
`ti on signal A.
`value smaller than that of the positive-acceleration peak.
`Until a positive phase of the step is found, block 13, the
`The processing unit 3, comprising a microprocessor circuit 30 algorithm proce巳ds with acquisition of a new acceleration
`(for example, a microcontroller or DS凹， acquires at pre-set
`datm丑 CalAcc in block 11 (and corresponding modification
`intervals samples of the acceleration signal A generated by
`of the reference thresholds), and with the comparison of said
`the accelerometer 2, and executes appropriate processing
`n巳w acceleration datum with the positive reference threshold
`operations for counting the number of steps and measuring
`s+
`the distance traveled. As will be described in detail hereinaf- 35
`The positive phase is detected when the acceleration datum
`ter, the processing unit 3 compares the value of the accelera-
`exceeds the positive reference threshold s+ and then drops
`below the positive reference threshold, the instant of detec-
`tion signal A (with the d.c. component filtered out) with a
`positive reference thresholds+ and with a negative reference
`tion of the positive phase corresponding to the instant in
`threshold S , for identifying, respectively, the positive phase
`which the acceleration datum drops again below the positive
`(positive acceleration peak) and the negative phase (negative 40 reference thresholds+. At this instant, the processing unit 3
`stores the value assumed by the positive reference threshold
`acceleration peak) of the step.
`According to one embodiment of the present invention, the
`S+, which is a maximum value s+ max·
`values of the positive and negative reference thresholds s+, S
`After the positive phase detection, the algorithm proceeds
`with the search for the negative phase of the step, block 14,
`are not fixed and equal to a given pre-set value, but are
`calculated in a self-adaptive way (i.e., in a way that adapts 45 i.e., of a negative acceleration peak, by comparing the value
`of the acceleration datum CalAcc with the negative reference
`without any external intervention from a user) by the process-
`ing unit 3, based on the values assumed by the detected
`thresholds-. In particular, the search for the negative phase of
`acceleration. In particular, as will be clarifi巳d hereinafter, the
`the step is executed within a certain time interval Mask, the
`values of the positive and negative reference thresholds S+, S
`value of which must be lower than a maximum interval Max-
`are modified at each acquisition of a new sample of the 50 Mask from detection of the positive phase (corresponding to
`a certain number of samples, the value of which is determined
`acceleration signal A, as a function of the value of a positive
`and negative 缸口plitude envelope of the acceleration signal, in
`also as a function of the s缸口piing rate of the acceleration
`such a manner that the reference thresholds v町 with time
`data).
`approximately following said envelopes. The pedometer
`Until a n巳gative acceleration peak is detected, block 15,
`device 1 thus adapts to variations in the detection conditions 55 and as long as the time interval Mask is shorter than the
`（阻止 in particular, to different profiles of the acceleration
`maximum interval Max_Mask, block 16, the algorithm pro-
`signal, in terms of amplitude and duration），巾， for example,
`ceeds with the search for the negative phase of the step. In
`to a different type of terrain, or to an increase in the speed of
`detail, thetime interval Mask is incremented, block 17, a new
`acceleration datum CalAcc is acquired (and the values of the
`the gait.
`The algorithm implement巳d by the processing unit 3 for 60 reference thresholds are modified accordingly), block 18
`per扣rming, among other things, the operations of step count-
`(which is equivalent to block 11 ), and the algorithm returns to
`ing and of traveled distance measurement is now described,
`block 14. Ifno negative phase of the step has been identified
`with reference to FIG. 3. Said algorithm envisages the analy-
`after expiry of the maximum interval Max Mask, block 16,
`sis of the acceleration signal A in order to look for a positive
`the algorithm returns to block 11 in order to look for a new
`phase of the step followed by a negative phase within a pre-set 65 potential positive phase of the step.
`time interval from the occurrence of the positive phase. In the
`On the contrary, if the negative phase is identi自己d within
`case where said sequence occurs (which indicates the occur-
`the maximum interval Max_Mask (i.e., the acceleration
`
`Page 8 of 12
`
`

`

`US 7,463,997 B2
`
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`Page 9 of 12
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`

`

`US 7,463,997 B2
`
`8
`7
`threshold s ~ and as long as the acceleration datum CalAcc
`positive acceleration peak). In this case, the algorithm uses a
`single reference threshold, in particular the positive reference
`increases, the positive acceleration threshold s+ follows, in a
`thresholds+, which is modifi巳d as a function of the value of
`“ damped” way, the increase of the acceleration datum CalAcc
`the positive envelope Env+, in a way altogether similar to
`(see, in particular, FIG. 5). Next, the acceleration datum
`CalAcc starts to decrease, and, along with it, the positive 5 what has been described previously. Said simplified algo-
`acceleration thresholds+, which, as long as the acceleration
`rithm, although computationally less burdensome for the pro-
`cessing unit 3, has, however, the disadvantage of being more
`datum CalAcc decreases, assumes a decreasing pattern (with-
`sensitive to noise. In fact, the lack of check on the presence of
`out, however, dropping below the positive minimum value
`S1). In particular, at the end of the positive phase of the step,
`the negative phase, a武er the positive phase, renders false
`the maximum value s+ maχis stored. The positive reference 10 detection and counting errors more likely.
`thresholds+ returns to the positive minimum value S1 when
`The accelerometer 2 could be equipped with a number of
`the user comes to a halt. A similar pattern (in absolute value)
`axes of measurement, for example thr臼 mutually orthogonal
`is showed by the negative acceleration threshold S , with the
`axes of measurement, and be built, for ex缸口ple, as described
`difference that the d巳crease (in absolute value) of the negative
`in “ 3-axis Digital Output Accelerometer For FutureAutomo-
`acceleration thresholds- is different, in particular faster. Said 15 tive Applications”, B. Vigna et al., A鸟也包气 2004. In this case,
`according to one embodiment of the present invention, the
`difference is due to the different conformation of the negative
`algorithm implemented by the processing unit 3 envisages
`acceleration peak, which has a smaller amplitude and a longer
`duration as compared to the positive acceleration peak, so that
`identifying the main vertical axis to be used for step detection
`an excessively long decrease time could lead to the peak not
`as the axis of detection that has the highest mean acceleration
`being detected. The difference, in absolute value, of the posi- 20 value Accm (on account of gravity). For example, the main
`vertical axis can be identi自己d at each acquisition of a new
`tive minimum value S 1 and of the negative minimum value S2
`is due to the same reason.
`acceleration sample, block 30 of FIG. 4, so as to take into
`According to one embodiment of the present invention, the
`account variations in the orientation of the pedometer device
`1, and cons叫uently of the accelerometer 2 arranged inside it.
`positive minimum value S1 and the negative minimum value
`Instead of being integrated in the pedometer device 1, the
`S2 can be modified from outside, for example through the 25
`interface 5 in order to modify the sensitivity of the pedometer
`accelerometer 2 could be arranged outside the casing thereof,
`device 1. In particular, if said minimum values are decreased,
`and connected, in a wired or wireless way, to the detection
`the sensitivity of the device increases, in so far as acceleration
`unit 3. In this case, the accelerometer 2 could advantageously
`peaks of smaller amplitude (for example, due to a particularly
`be housed in a garment or accessory worn by the user, for
`slow gait or to a surface that is not very rigid) can be detected. 30 example a shoe, a belt, a watch, etc.
`As shown in FIG. 8, the pedometer device 1, due to its
`At the s缸口e time, however, the number of false positives
`detected increases, in so far as noise (external vibrations,
`reduced dimensions, may advantageously be housed inside a
`portable devic已， in particular a mobile phone 50 (or else an
`bumps, fast movements made by the user) is more likely to
`cause erroneous detections assimilat巳d to the phases of the
`Mp3 reader, a c缸丑era, a PDA, a g缸丑e console, etc.). In tl山
`step.
`35 case, the accelerometer 2, and the processing unit 3 are
`The advantages of the pedometer device and of the corre-
`mounted on a printed circuit board 52 fixed within a casing 53
`of the mobile phone 50. Advantageously, in this embodiment,
`sponding step detection method are clear from the foregoing
`the processing unit 3, in addition to implementing the algo-
`description.
`In any case, it is emphasized that the pedometer device 1 is
`rithms previously described, controls the operation of the
`able to adapt to changes in the acceleration profile, for 40 mobile phone 50. Lik巳wise, the display screen 4, which is
`obviously arranged so as to be visible from outside the casing
`example due to an increase in the walking speed, and so
`external interventions for resetting the acceleration thresh-
`53, shows both information corresponding to the pedometer
`device 1 and, more in general, information linked to operation
`olds necessary for step detection are not needed.
`of the mobile phone 50. The interface 5 in this case preferably
`The fact that the acceleration thresholds follow the enve-
`lopes of the acceleration signal (analogously to an electronic 45 comprises a communication port (of a known type, and not
`peak detector) enables said changes to be followed rapidly,
`shown), which can be interfaced with a personal computer.
`without any risk for any loss of steps and counting errors
`The interface 5 can therefore be used both for downloading
`occurring, and at the same time enables a good insensitivity to
`the data produced by the pedometer device 1 (among which at
`noise to be achieved. In particular, when the accelerations
`least the number of steps counted) and for uploading into the
`increase (in absolute value), for example because the walking so processing unit 3 operating parameters of the pedometer
`device 1, such as the positive and negative minimum values
`speed has increased, the reference thresholds increase rap-
`idly, so as to adapt rapidly to the new conditions. When,
`Sv S2.
`instead, the accelerations decrease, for example because the
`Finally, even though the entire description refers to a digital
`implementation of the pedometer device 1, it is evident that a
`user is slowing down, the reference thresholds also decrease,
`but slowly, and always remaining above a mini日mm value. In 55 similar version of an analog type (comprising, among other
`things, threshold comparators, a peak detector, amplifiers,
`this way, the device is able to follow closely a new increase in
`etc.) can be contemplated by making the appropriate obvious
`the acceleration values.
`Finally, it is clear that modifications and variations can be
`substitutions.
`All of the above U.S. pater山， U.S. patent applicatio叼ub-
`made to what is described and illustrated hereinγithout
`thereby departing 企om the ~cope of the present i盯entwn, as 60 lications, U.S. p旧时 applic瓜ions, foreign patents, foreign
`defined in the appended claims.
`patent applications and non-patent publications referred to in
`In particular, as shown in FIG. 7, in which the s缸m refer-
`this specification and/or listed in the Application Data Sheet,
`are incorporated herein by reference, in their entirety.
`ence numbers are used for designating blocks similar to the
`ones previously described, according to an alternative
`巳mbodiment of the present invention, the step detection algo- 65
`rithm can be simplified, and can be based exclusively upon
`the identification of the positive phase of the step (i.e., of the
`
`The invention claimed is:
`1. A pedometer device for detecting and counting steps of
`a user, the device comprising:
`
`Page 10 of 12
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`

`

`US 7,463,997 B2
`
`9
`10
`an accelerometer sensor configured to detect an accelera(cid:173)
`threshold-adaptation means for modifying said first ref(cid:173)
`erence threshold as a function of said acceleration
`tion generated during a step; and
`signal,
`a processing unit coupled to said accelerometer sensor, and
`wherein said first reference threshold has positive values,
`configured to process an acceleration signal relating to
`and wherein said processing unit further includes second
`said acceleration to detect an occurrence of the step, said 5
`comparator means for comparing said acceleration sig-
`processing unit including:
`nal with a second reference threshold having negative
`first comparator means for comparing said acceleration
`values; and wherein said threshold-adaptation means are
`signal with a first reference threshold, said processing
`unit being configured to detect the occurrence of the
`further for modifying automatically said s巳：cond refer-
`ence threshold as a function of an envelope of an ampli-
`step based on a result of said comparing between said 10
`tude of said acceleration signal.
`acceleration signal and said first reference threshold,
`10. The device according to claim 9, wherein said first and
`and
`second reference thresholds have, in absolute value, a respec-
`threshold-adaptation means for modifyi吨， at each
`tive lower-limit value, and wherein said processing unit fur-
`acquisition of a new sample of said acceleration sig-
`nal, said first reference threshold as a function of an 15 ther includes setting means for setting said lower-limit value.
`envelope of an amplitude of said acceleration signal.
`11. The device according to claim 9, wherein said process-
`2. The device according to claim 1, wherein said process-
`ing unit is configured to detect the occurrence of the step,
`ing unit further includes envelope-calculation means for cal-
`when said acceleration signal has a given relation with said
`culating said envelope of said 缸呻litude of said acceleration
`first reference threshold, and subsequently with said second
`signal, and wherein said threshold-adaptation means modi- 20 reference threshold within a given time interval.
`12. An electronic mobile phone, comprising:
`自己s automatically said first reference threshold as said func-
`tion of said envelope so that said first reference threshold
`a casing; and
`follows a variation of said envelope.
`a pedometer device housed in said casing to detect and
`3. The device according to claim 2, wherein said threshold-
`count steps of a user, the pedometer device including:
`adaptation means are configured to assign to said first refer- 25
`an accelerometer sensor configured to detect an accel-
`ence threshold a value equal to a fraction of a value of said
`eration generated during a step; and
`envelope, said fraction being smaller than 1.
`a processing unit coupled to said accelerometer sensor,
`4. The device according to claim 3, wherein said fraction is
`and configured to process an acceleration signal relat-
`approximately 0.65.
`ing to said acceleration to detect an occurrence of the
`step, said processing unit including:
`5. The device according to claim 3, wherein said process(cid:173)
`自rst comparator means for comparing said acceleration
`ing unit further includes:
`signal with a first reference threshold, said processing
`length-estimation means for determining an estimated step
`unit being con且gured to detect the occurrence of the
`length at each step detection, as a function of a maxi(cid:173)
`step based on a result of said comparing betw臼n said
`mum value of said first reference threshold; and
`acceleration signal and said first reference threshold,
`distance-calculation means for calculating a dist缸ice trav(cid:173)
`and
`eled by said user as a function of said estimated step
`threshold-adaptation m四ns for modifyi吨， at each
`length.
`acquisition of a new sample of said acceleration sig-
`6. The device according to claim 1, wherein said process-
`nal. said first reference threshold as a function of n
`en~elope of an amplitude of said acceleration 吨nal.
`ing unit further includes: mean-value calculation means for 40
`l3. The mobile phone according to claim 12, wherein said
`calculating a d.c. component of the acceleration detected by
`· d accelerometer sensor; for eliminating said d.c. com po-
`processing unit further includes envelope-calculation means
`nent from said acceleration; and for producing said accelera-
`for calculating said envelope of said 缸口plitude of said accel-
`tion signal.
`eration signal, and wherein said threshold-adaptaf
`7. The device according to. claim 1, wherein said acceler- 45 modifies automatically said first reference threshold as said
`ometer sensor includes a micro-electromechanical system
`function of said envelope so that said first reference threshold
`(MEMS）叩1sor, and said acceleration is directed along a
`follows a variation of said envelope.
`vertical axi