Contribuer au développement du code: Votre contribution au développement de l'application sera fortement appréciée ! Connectez-vous sur GitHub pour
cloner le projet :
-
+ https://github.com/Ifsttar/NoiseCapture
NoiseCapture App is an application dedicated
- to the evaluation of your noise
- environment. It allows to perform measurements and, thus, to give
- information on your noise exposure. In addition, you can contribute to the
- realization of collaborative (or community) noise maps by anonymously
- sharing your measurements.
NoiseCapture App is an application, made by experts,
- but do not forget that it will never replace a professional sonometer. If
- you need a professional assistance, please contact a specialist.
-
The quality of the measurement depend of the technical
- performance of the smartphone. Depending of the smartphone and the android
- version, some smartphone may produce bad estimation of the sound level.
- See section concerning the limits of noise
- measurement with a smartphone for more information.
NoiseCapture App is an application dedicated
+ to the evaluation of your noise
+ environment. It allows to perform measurements and, thus, to give
+ information on your noise exposure. In addition, you can contribute to the
+ realization of collaborative (or community) noise maps by anonymously
+ sharing your measurements.
NoiseCapture App is an application, made by experts,
+ but do not forget that it will never replace a professional sonometer. If
+ you need a professional assistance, please contact a specialist.
+
The quality of the measurement depend of the technical
+ performance of the smartphone. Depending of the smartphone and the android
+ version, some smartphone may produce bad estimation of the sound level.
+ See section concerning the limits of noise
+ measurement with a smartphone for more information.
+
Start a measurement
On the Measurement menu item, press the RECORD
- button to start a measurement. You can stop the measurement by
- pressing the STOP button.
+ button to start a measurement. You can stop the measurement by
+ pressing the STOP button.
You can pause/resume a measurement using the PAUSE
- button. Depending on the corresponding Settings
- value, when resuming the measurement, the last seconds of the measurement
- can be removed.
- What is displaying?
-
+ button. Depending on the corresponding Settings
+ value, when resuming the measurement, the last seconds of the measurement
+ can be removed.
+ What is displaying?
+
a horizontal level-meter and a numeric value showing the instantaneous
- sound level ('fast' level on 125ms) in dB(A) (A-weighted
- decibel). The color depend on the level range (each level range of 5dB
- is associated to a given color);
-
statistical sound levels in
- dB(A): minimum (Min), maximum (Max) and the mean (Mean) values of the
- fast sound level;
-
a chronometer that gives the
- measurement duration in second;
+ sound level ('fast' level on 125ms) in dB(A) (A-weighted
+ decibel). The color depend on the level range (each level range of 5dB
+ is associated to a given color);
+
statistical sound levels in
+ dB(A): minimum (Min), maximum (Max) and the mean (Mean) values of the
+ fast sound level;
+
a chronometer that gives the
+ measurement duration in second;
an information is given concerning the GPS
- localization accuracy;
-
a noise level spectrum,
- showing the instantaneous sound level for each third-octave band between
+ localization accuracy;
+
a noise level spectrum,
+ showing the instantaneous sound level for each third-octave band between
100Hz and 16kHz. If you tap on the spectrum, it displays a time-frequency
- representation of noise.
-
-
Give a description
-
On the Description menu item:
-
-
add a 'Description' , if needed;
-
add a 'Picture ', if needed;
-
evaluate the Pleasantness of the sound environment, by
- moving the cursor from 'Unpleasant' to 'Pleasant';
-
select one on more 'Tags' that correspond to your perception of the
- sound environment;
+ representation of noise.
+
+
Give a description
+
On the Description menu item:
+
+
add a 'Description' , if needed;
+
add a 'Picture ', if needed;
+
evaluate the Pleasantness of the sound environment, by
+ moving the cursor from 'Unpleasant' to 'Pleasant';
+
select one on more 'Tags' that correspond to your perception of the
+ sound environment;
valid the description by pressing the VALID
- button.
-
-
This step is optional but it could be useful to evaluate
- the noise environments, as well as for a research purpose. Your
- contribution will be highly appreciated. Only the anonymous elements
- 'Pleasantness' and 'Tags' are uploads. The 'Description', as well as, the
- 'Picture', are stored on your smartphone only and, thus, not uploaded.
-
Analyze results
-
On the Results menu item, you
- can access to several noise indicators.
-
While during measurements sound level are displayed in a 'fast' mode
- (125ms), final results are given in a 'slow' mode (1s), based on the 1s
- (one second) equivalent sound level (Leq,1s). Leq,1s is a standard
- environmental noise indicator, used for the evaluation of noise annoyance.
-
What is displaying?
-
-
statistical sound levels in
- dB(A): minimum (Min) and maximum (Max);
-
percentile noise levels in
- dB(A) over the whole measurement duration:
-
-
LA90: A-weighted noise level that is exceeded for 90% of the
- measurement period. LA90 is a useful descriptor to quantify the background noise level;
-
LA50: A-weighted noise level that is exceeded for 50% of the
+ button.
+
+
This step is optional but it could be useful to evaluate
+ the noise environments, as well as for a research purpose. Your
+ contribution will be highly appreciated. Only the anonymous elements
+ 'Pleasantness' and 'Tags' are uploads. The 'Description', as well as, the
+ 'Picture', are stored on your smartphone only and, thus, not uploaded.
+
Analyze results
+
On the Results menu item, you
+ can access to several noise indicators.
+
While during measurements sound level are displayed in a 'fast' mode
+ (125ms), final results are given in a 'slow' mode (1s), based on the 1s
+ (one second) equivalent sound level (Leq,1s). Leq,1s is a standard
+ environmental noise indicator, used for the evaluation of noise annoyance.
+
What is displaying?
+
+
statistical sound levels in
+ dB(A): minimum (Min) and maximum (Max);
+
percentile noise levels in
+ dB(A) over the whole measurement duration:
+
+
LA90: A-weighted noise level that is exceeded for 90% of the
+ measurement period. LA90 is a useful descriptor to quantify the background noise level;
+
LA50: A-weighted noise level that is exceeded for 50% of the
measurement period. LA50 is the median
- sound level;
-
LA10: A-weighted noise level that is exceeded for 10% of the
- measurement period. LA10 is a useful descriptor of road traffic
+ sound level;
+
LA10: A-weighted noise level that is exceeded for 10% of the
+ measurement period. LA10 is a useful descriptor of road traffic
noise, which is correlated with the noise
- annoyance;
-
-
-
equivalent noise level in
- dB(A), on the whole measurement duration [at the center of colored
- circle];
-
repartition of the noise exposure
- (RNE): this indicator represents the distribution over the time of your
- noise exposure. Each of the five colors correspond to a given noise
- level range.
-
a noise level spectrum,
- showing the sound level for each third-octave band between 100Hz and
- 16kHz.
-
-
Explore the map
-
On the Map menu item, users can
- access to a geo-referenced representation of the measurement that are
- stored in the smartphone memory. Users can choose to represent:
-
-
'Selected record', which corresponds to the last measurement or to a
- loaded previous measurement (see History
- for information);
-
'All records' stored in the smartphone memory;
-
'Community noise map': this noise map that is built using all data
- produced by all participating citizen. This noise map is stored on the
- web server and need an internet access to be displayed.
-
-
Explore the measurement history
-
On the History menu item, users
- can access to all measurements that are stored in the smartphone memory.
-
All measurement that are performed with the smartphone are archived in
- the history. You can access to the state of the measurement ('Upload' or
- 'Not upload' to the server) with the 'Cloud' symbol,
-
By tapping on item from the history, you can:
-
-
'Upload to the community': if the corresponding measurement has not be
- automatically uploaded to the server, you can process to a manual
- upload;
-
'Export result': using a given application (message, drive...), you
- can export/save a ZIP file that contains all the metadata of the
- measurement. See the README document in the ZIP file for the description
- of the metadata. This is the same ZIP file that is upload to the web
- server;
-
'Edit description': you can modify the description of the
- corresponding measurement (same as the Description
- menu item). If the item has been already uploaded to the server, you can
- only modify the text description and the picture;
-
'Show result': you can access to the results of corresponding
- measurement (same as the Results
- menu item);
-
'Show on map': you can access to the map for the spatial
- representation of corresponding measurement (same as the Map
- menu item);
-
'Delete': select this option if you want to remove the measurement
- from your smartphone.
-
-
If a measurement is removed from the history, but was
- previously transferred to the web server, it is not removed from the web
- server. Remember that all data that are uploaded to the server are
- anonymized; thus, be confident! (see Privacy)
-
Calibrate your smartphone
-
On the Calibration menu item,
- users have the opportunity to calibrate their smartphone.
-
-
+ annoyance;
+
+
+
equivalent noise level in
+ dB(A), on the whole measurement duration [at the center of colored
+ circle];
+
repartition of the noise exposure
+ (RNE): this indicator represents the distribution over the time of your
+ noise exposure. Each of the five colors correspond to a given noise
+ level range.
+
a noise level spectrum,
+ showing the sound level for each third-octave band between 100Hz and
+ 16kHz.
+
+
Explore the map
+
On the Map menu item, users can
+ access to a geo-referenced representation of the measurement that are
+ stored in the smartphone memory. Users can choose to represent:
+
+
'Selected record', which corresponds to the last measurement or to a
+ loaded previous measurement (see History
+ for information);
+
'All records' stored in the smartphone memory;
+
'Community noise map': this noise map that is built using all data
+ produced by all participating citizen. This noise map is stored on the
+ web server and need an internet access to be displayed.
+
+
Explore the measurement history
+
On the History menu item, users
+ can access to all measurements that are stored in the smartphone memory.
+
All measurement that are performed with the smartphone are archived in
+ the history. You can access to the state of the measurement ('Upload' or
+ 'Not upload' to the server) with the 'Cloud' symbol,
+
By tapping on item from the history, you can:
+
+
'Upload to the community': if the corresponding measurement has not be
+ automatically uploaded to the server, you can process to a manual
+ upload;
+
'Export result': using a given application (message, drive...), you
+ can export/save a ZIP file that contains all the metadata of the
+ measurement. See the README document in the ZIP file for the description
+ of the metadata. This is the same ZIP file that is upload to the web
+ server;
+
'Edit description': you can modify the description of the
+ corresponding measurement (same as the Description
+ menu item). If the item has been already uploaded to the server, you can
+ only modify the text description and the picture;
+
'Show result': you can access to the results of corresponding
+ measurement (same as the Results
+ menu item);
+
'Show on map': you can access to the map for the spatial
+ representation of corresponding measurement (same as the Map
+ menu item);
+
'Delete': select this option if you want to remove the measurement
+ from your smartphone.
+
+
If a measurement is removed from the history, but was
+ previously transferred to the web server, it is not removed from the web
+ server. Remember that all data that are uploaded to the server are
+ anonymized; thus, be confident! (see Privacy)
+
Calibrate your smartphone
+
On the Calibration menu item,
+ users have the opportunity to calibrate their smartphone.
+
+
The methodology is based on the knowledge of a Reference
- value for the equivalent noise level Leq (in dB, not in dB(A))
- for a given duration, from a reference device (an acoustic calibrator, a
- calibrated smartphone, a sound level meter).
-
Depending on the calibration method, the calibration can be performed
- for a given frequency band or for the full range (global value).
-
This Reference value is then
- compared to the Measured Leq
- (in dB) using the smartphone. The difference between these two values
- gives a correction factor (i.e.
- the signal gain) that will be applied to the input signal.
-
-
- Several calibration methods are available:
-
-
The smartphone calibration is a crucial and necessary
- step. Without calibration, you can be sure that the measured data will be
- wrong!
-
The correction factor is applied for the whole signal.
- Multi-frequency calibration is not possible for now.
-
The calibration is carried out with dB values, not
- dB(A).
-
-
-
-
The correction factor can also be set manually in the
- Settings menu.
-
When using a 'Global' value for the calibration, make sure
- that the Reference value will be
- obtained using the same frequency range that your smartphone.
-
The 'Calibration warm-up time' and the 'Calibration
- duration' can be modified in the Settings.
-
During calibration, the smartphone and the reference device
- must be used in a similar way.
-
-
Calibration from a reference device
-
+ value for the equivalent noise level Leq (in dB, not in dB(A))
+ for a given duration, from a reference device (an acoustic calibrator, a
+ calibrated smartphone, a sound level meter).
+
Depending on the calibration method, the calibration can be performed
+ for a given frequency band or for the full range (global value).
+
This Reference value is then
+ compared to the Measured Leq
+ (in dB) using the smartphone. The difference between these two values
+ gives a correction factor (i.e.
+ the signal gain) that will be applied to the input signal.
+
+
+ Several calibration methods are available:
+
+
The smartphone calibration is a crucial and necessary
+ step. Without calibration, you can be sure that the measured data will be
+ wrong!
+
The correction factor is applied for the whole signal.
+ Multi-frequency calibration is not possible for now.
+
The calibration is carried out with dB values, not
+ dB(A).
+
+
+
+
The correction factor can also be set manually in the
+ Settings menu.
+
When using a 'Global' value for the calibration, make sure
+ that the Reference value will be
+ obtained using the same frequency range that your smartphone.
+
The 'Calibration warm-up time' and the 'Calibration
+ duration' can be modified in the Settings.
+
During calibration, the smartphone and the reference device
+ must be used in a similar way.
+
+
Calibration from a reference device
+
Performing
- the calibration:
-
-
In the 'Calibration mode' list, choose the frequency on which you
- want perform the calibration. You can also choose 'Global' from
- the list to calibrate over the entire measurement spectrum. In the
- latter case, remember to configure the reference device to perform a
- measurement in the same frequency band as your smartphone.
-
Press the START button.
-
-
Before calibration starts, you have a warm-up time that can
- help you to prepare your calibration (prepare to turn on the
- reference device, if necessary).
-
Then, the calibration measurement starts for a given duration.
- For a better accuracy, the measurement duration should be the
- same both for the smartphone and for the reference device.
-
-
+ the calibration:
+
+
In the 'Calibration mode' list, choose the frequency on which you
+ want perform the calibration. You can also choose 'Global' from
+ the list to calibrate over the entire measurement spectrum. In the
+ latter case, remember to configure the reference device to perform a
+ measurement in the same frequency band as your smartphone.
+
Press the START button.
+
+
Before calibration starts, you have a warm-up time that can
+ help you to prepare your calibration (prepare to turn on the
+ reference device, if necessary).
+
Then, the calibration measurement starts for a given duration.
+ For a better accuracy, the measurement duration should be the
+ same both for the smartphone and for the reference device.
+
+
Once the measurement is done, enter the Reference
- value (from the reference device) in the edit box and press
- the APPLY button.
-
If you do not want to apply the correction factor, you can press
- the RESET button to perform
- a new calibration or you can leave the Calibration activity.
-
-
-
-
-
Testing
- the calibration:
-
-
Once a correction factor is applied, you can test the calibration
- by checking the box 'Test gain'.
-
Press the START button
- for performing a new measurement and turn on (if necessary) the
- reference device.
-
At the end of the measurement, the Measured
- Leq should be equal or quite similar to the reference
- device.
-
Given the procedure and equipment involved, you may consider
- acceptable a difference up to 0.5dB between the two values. If the
- difference is not accetable, restart the Calibration procédure.
- After several attempts, if you can not calibrate your smartphone
- phone with a difference of less than 0.5dB, you can restart with an
- error of 1dB.
-
-
-
-
Calibration with a calibrator
-
To apply this calibration procedure, you need an acoustic calibrator and an external microphone. The diameter
- of the microphone should be compatible with the calibrator.
-
-
Performing
- the calibration:
-
-
In the 'Calibration mode' list, choose the frequency on which you
- want perform the calibration.
-
Press the START button.
-
-
Before calibration starts, you have a warm-up time that can
- help you to prepare your calibration.
-
Then, the calibration measurement starts for a given duration.
- For a better accuracy, the measurement duration should be the
- same both for the smartphone and for the reference device.
-
-
-
Once the measurement is done, enter the Reference
- value (from the reference device) in the edit box and press
- the APPLY button.
-
If you do not want to apply the correction factor, you can press
- the RESET button to perform
- a new calibration or you can leave the Calibration activity.
-
-
-
-
+ value (from the reference device) in the edit box and press
+ the APPLY button.
+
If you do not want to apply the correction factor, you can press
+ the RESET button to perform
+ a new calibration or you can leave the Calibration activity.
+
+
+
+
Testing
- the calibration:
-
-
Once a correction factor is applied, you can test the calibration
- by checking the box 'Test gain'.
-
Press the START button
- for performing a new measurement and turn on (if necessary) the
- calibrator.
+ the calibration:
+
+
Once a correction factor is applied, you can test the calibration
+ by checking the box 'Test gain'.
+
Press the START button
+ for performing a new measurement and turn on (if necessary) the
+ reference device.
At the end of the measurement, the Measured
- Leq should be equal or quite similar to the reference
- device.
-
Given the procedure and equipment involved, you may consider
- acceptable a difference up to 0.5dB between the two values. If the
- difference is not accetable, restart the Calibration procédure.
- After several attempts, if you can not calibrate your smartphone
- phone with a difference of less than 0.5dB, you can restart with an
- error of 1dB.
-
-
-
-
Automatic calibration from a calibrated
- smartphone
-
In this method, a smartphone already calibrated with NoiseCapture, can calibrate one or more smartphones. On the side of the microphones to
- be calibrated, the procedure is fully automatic. The entire system is
- controlled by the reference smartphone.
-
+ Leq should be equal or quite similar to the reference
+ device.
+
Given the procedure and equipment involved, you may consider
+ acceptable a difference up to 0.5dB between the two values. If the
+ difference is not accetable, restart the Calibration procédure.
+ After several attempts, if you can not calibrate your smartphone
+ phone with a difference of less than 0.5dB, you can restart with an
+ error of 1dB.
+
+
+
+
Calibration with a calibrator
+
To apply this calibration procedure, you need an acoustic calibrator and an external microphone. The diameter
+ of the microphone should be compatible with the calibrator.
+
Performing
- the calibration:
-
-
-
-
The reference smartphone must be in "transmitter" mode.
-
The smartphones to be calibrated must be in "receiver" mode.
-
On the reference smartphone:
-
-
Select the source signal:
-
-
"Pink noise": in this case, the smartphone generates a reference
- signal. It is necessary to use a sound source connected wirelessly
- with the reference smartphone, the source being at equal distance
- from all smartphones;
-
"Ambient noise": Environmental noise is used for calibration. The
- sound level must be sufficiently high and the sound field must be
- relatively "diffuse".
-
-
Press Start; the rest of the procedure is automatic. You can
- cancel the current calibration with the Cancel button.
-
-
-
What are the limits of noise
- measurement with a smartphone
-
Device requirements for Android
- compatibility
+ the calibration:
+
+
In the 'Calibration mode' list, choose the frequency on which you
+ want perform the calibration.
+
Press the START button.
+
+
Before calibration starts, you have a warm-up time that can
+ help you to prepare your calibration.
+
Then, the calibration measurement starts for a given duration.
+ For a better accuracy, the measurement duration should be the
+ same both for the smartphone and for the reference device.
+
+
+
Once the measurement is done, enter the Reference
+ value (from the reference device) in the edit box and press
+ the APPLY button.
+
If you do not want to apply the correction factor, you can press
+ the RESET button to perform
+ a new calibration or you can leave the Calibration activity.
+
+
+
+
+
Testing
+ the calibration:
+
+
Once a correction factor is applied, you can test the calibration
+ by checking the box 'Test gain'.
+
Press the START button
+ for performing a new measurement and turn on (if necessary) the
+ calibrator.
+
At the end of the measurement, the Measured
+ Leq should be equal or quite similar to the reference
+ device.
+
Given the procedure and equipment involved, you may consider
+ acceptable a difference up to 0.5dB between the two values. If the
+ difference is not accetable, restart the Calibration procédure.
+ After several attempts, if you can not calibrate your smartphone
+ phone with a difference of less than 0.5dB, you can restart with an
+ error of 1dB.
+
+
+
+
Automatic calibration from a calibrated
+ smartphone
+
In this method, a smartphone already calibrated with NoiseCapture, can calibrate one or more smartphones. On the side of the microphones to
+ be calibrated, the procedure is fully automatic. The entire system is
+ controlled by the reference smartphone.
+
+
Performing
+ the calibration:
+
+
+
+
The reference smartphone must be in "transmitter" mode.
+
The smartphones to be calibrated must be in "receiver" mode.
+
On the reference smartphone:
+
+
Select the source signal:
+
+
"Pink noise": in this case, the smartphone generates a reference
+ signal. It is necessary to use a sound source connected wirelessly
+ with the reference smartphone, the source being at equal distance
+ from all smartphones;
+
"Ambient noise": Environmental noise is used for calibration. The
+ sound level must be sufficiently high and the sound field must be
+ relatively "diffuse".
+
+
Press Start; the rest of the procedure is automatic. You can
+ cancel the current calibration with the Cancel button.
+
+
+
What are the limits of noise
+ measurement with a smartphone
+
Device requirements for Android
+ compatibility
The Android
- Compatibility Definition Document (CDD)"enumerates the
- requirements that must be met in order for devices to be compatible with
- the latest version of Android. To be considered compatible with Android,
- device implementations MUST meet the requirements presented in this
+ Compatibility Definition Document (CDD) "enumerates the
+ requirements that must be met in order for devices to be compatible with
+ the latest version of Android. To be considered compatible with Android,
+ device implementations MUST meet the requirements presented in this
Compatibility Definition" ( text
- from Android 5.1 CDD).
-
According to the CDD:
-
-
The device SHOULD exhibit approximately flat amplitude versus
- frequency characteristics: specifically, ±3dB, from 100Hz to 4000Hz.
-
Audio input sensitivity SHOULD be set such that a 90dB sound power
- level (SPL) source at 1000Hz yields RMS of 2500 for 16-bit samples.
-
PCM amplitude levels SHOULD linearly track input SPL changes over at
- least a 30dB range from -18dB to +12dB re 90 dB SPL at the microphone.
-
Total harmonic distortion SHOULD be less than 1% for 1kHz at 90dB SPL
- input level at the microphone.
-
-
In addition, it is specified that " While some of the requirements
- outlined in this section are stated as SHOULD since Android 4.3, the
- Compatibility Definition for a future version is planned to change these
- to MUST. Existing and new Android devices are very strongly encouraged
- to meet these requirements, or they will not be able to attain Android
- compatibility when upgraded to the future version."
-
What does it theoretically means?
-
- Thus, the quality of the noise measurement:
-
-
depends both of the device and of the Android version.
-
should be quite verified between 100Hz and 4000Hz (frequency
- response).
-
should be quite linear (amplitude response) in a range from -18dB to
- +12dB relatively to 90dB (Sound Pressure Level).
-
-
In conclusion, in the current situation,
- even after a rigorous calibration and without any further correction, it
- is not possible to ensure the quality of the measurement for low and
- high noise levels, as well as, beyond 4000Hz, whatever the device and
- the Android version. One can however assume that next smartphone
- generations should ensure a better measurement quality.
-
-
Best practice for the best noise
- measurement
-
In order to perform a correct noise
- measurement:
-
-
The smartphone must be calibrated
- (see Calibration);
-
The smartphone must be outside the
- clothing pockets;
-
The smartphone has to be in the hand;
-
The smartphone microphone must not
- to be masked;
-
If possible, uses an external
- omnidirectional microphone.
-
- In addition, if you want to produce noise
- measurements that will be very useful for producing collaborative
- (outdoor) noise maps, please check these points:
-
-
The measurement must be performed
- outside buildings;
+ from Android 5.1 CDD).
+
According to the CDD:
+
+
The device SHOULD exhibit approximately flat amplitude versus
+ frequency characteristics: specifically, ±3dB, from 100Hz to 4000Hz.
+
Audio input sensitivity SHOULD be set such that a 90dB sound power
+ level (SPL) source at 1000Hz yields RMS of 2500 for 16-bit samples.
+
PCM amplitude levels SHOULD linearly track input SPL changes over at
+ least a 30dB range from -18dB to +12dB re 90 dB SPL at the microphone.
+
Total harmonic distortion SHOULD be less than 1% for 1kHz at 90dB SPL
+ input level at the microphone.
+
+
In addition, it is specified that " While some of the requirements
+ outlined in this section are stated as SHOULD since Android 4.3, the
+ Compatibility Definition for a future version is planned to change these
+ to MUST. Existing and new Android devices are very strongly encouraged
+ to meet these requirements, or they will not be able to attain Android
+ compatibility when upgraded to the future version."
+
What does it theoretically means?
+
+ Thus, the quality of the noise measurement:
+
+
depends both of the device and of the Android version.
+
should be quite verified between 100Hz and 4000Hz (frequency
+ response).
+
should be quite linear (amplitude response) in a range from -18dB to
+ +12dB relatively to 90dB (Sound Pressure Level).
+
+
In conclusion, in the current situation,
+ even after a rigorous calibration and without any further correction, it
+ is not possible to ensure the quality of the measurement for low and
+ high noise levels, as well as, beyond 4000Hz, whatever the device and
+ the Android version. One can however assume that next smartphone
+ generations should ensure a better measurement quality.
+
+
Best practice for the best noise
+ measurement
+
In order to perform a correct noise
+ measurement:
+
+
The smartphone must be calibrated
+ (see Calibration);
+
The smartphone must be outside the
+ clothing pockets;
+
The smartphone has to be in the hand;
+
The smartphone microphone must not
+ to be masked;
+
If possible, uses an external
+ omnidirectional microphone.
+
+ In addition, if you want to produce noise
+ measurements that will be very useful for producing collaborative
+ (outdoor) noise maps, please check these points:
+
+
The measurement must be performed
+ outside buildings;
The measurement must be done when the GPS
- signal is correct;
-
'Tags' must be specified
- when the measurement is complete (see Description).
-
-
Resources
-
+ signal is correct;
+
'Tags' must be specified
+ when the measurement is complete (see Description).
+
+
Resources
+
Acoustic
- Glossary: a very useful glossary in Acoustics and Vibration,
- maintained by Gracey & Associates;
-
Acoustics:
- the definition of 'Acoustics' in Wikipedia;
+ Glossary: a very useful glossary in Acoustics and Vibration,
+ maintained by Gracey & Associates;
+
Acoustics:
+ the definition of 'Acoustics' in Wikipedia;
Environmental
- noise: many official information about 'Noise' from the European
- Environment Agency.
-
-
-
+ noise: many official information about 'Noise' from the European
+ Environment Agency.
+
The device SHOULD exhibit approximately flat amplitude versus
- frequency characteristics: specifically, ±3dB, from 100Hz to 4000Hz.
-
Audio input sensitivity SHOULD be set such that a 90dB sound power
- level (SPL) source at 1000Hz yields RMS of 2500 for 16-bit samples.
-
PCM amplitude levels SHOULD linearly track input SPL changes over at
- least a 30dB range from -18dB to +12dB re 90 dB SPL at the microphone.
-
Total harmonic distortion SHOULD be less than 1% for 1kHz at 90dB SPL
- input level at the microphone.
-
-
In addition, it is specified that " While some of the requirements
- outlined in this section are stated as SHOULD since Android 4.3, the
- Compatibility Definition for a future version is planned to change these
- to MUST. Existing and new Android devices are very strongly encouraged
- to meet these requirements, or they will not be able to attain Android
- compatibility when upgraded to the future version."
The device SHOULD exhibit approximately flat amplitude versus
+ frequency characteristics: specifically, ±3dB, from 100Hz to 4000Hz.
+
Audio input sensitivity SHOULD be set such that a 90dB sound power
+ level (SPL) source at 1000Hz yields RMS of 2500 for 16-bit samples.
+
PCM amplitude levels SHOULD linearly track input SPL changes over at
+ least a 30dB range from -18dB to +12dB re 90 dB SPL at the microphone.
+
Total harmonic distortion SHOULD be less than 1% for 1kHz at 90dB SPL
+ input level at the microphone.
+
+
In addition, it is specified that " While some of the requirements
+ outlined in this section are stated as SHOULD since Android 4.3, the
+ Compatibility Definition for a future version is planned to change these
+ to MUST. Existing and new Android devices are very strongly encouraged
+ to meet these requirements, or they will not be able to attain Android
+ compatibility when upgraded to the future version."
NoiseCapture App Ăš un'applicazione studiata per la valutazione del tuo ambiente di rumore. L'app permette di effettuare misurazioni e quindi fornire informazioni sulla tua esposizione al rumore. Inoltre puoi contribuire alla realizzazione di mappe di rumore collaborative, condividendo le tue misurazioni in forma anonima.
Feel free to explore the code and to fork the project on GitHub:
https://github.com/Ifsttar/NoiseCapture
+ href="https://github.com/Universite-Gustave-Eiffel/NoiseCapture">https://github.com/Universite-Gustave-Eiffel/NoiseCapture
Votre contribution au développement de l'application sera fortement appréciée ! Connectez-vous sur GitHub pour
cloner le projet :
- https://github.com/Ifsttar/NoiseCapture