User Manual OT BioLab v3.0
User Manual OT BioLab v3.0
User Manual OT BioLab v3.0
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OT BioLab User manual v.3.0
INDEX
1. Introduction ......................................................................................................... pag. 5
2. OT BioLab Installation ......................................................................................... pag. 6
3. Driver Installation ................................................................................................ pag. 9
3.1 Driver removal procedure .............................................................................. pag. 9
3.2 Complete the driver installation ...................................................................... pag. 10
4. Signal Acquisition .................................................................................................. pag. 12
4.1 Setting the acquisition parameters .................................................................. pag. 12
4.2 Creating a Setup ............................................................................................ pag. 13
4.3 Entering Visualization Mode ............................................................................ pag. 14
4.4 Storing signals and accessory parameters ........................................................ pag. 17
4.5 Tracks options ............................................................................................... pag. 19
4.6 Feedback window .......................................................................................... pag. 22
4.7 Display window .............................................................................................. pag. 24
4.8 Real-Time Maps ............................................................................................. pag. 26
5. Signal review ......................................................................................................... pag. 30
5.1 File extensions ............................................................................................... pag. 29
5.2 Reviewing a signal ......................................................................................... pag. 30
5.3 Signal export ................................................................................................. pag. 34
6. Signal Processing .................................................................................................. pag. 38
6.1 Amplitude ...................................................................................................... pag. 39
6.2 Data Approximation ....................................................................................... pag. 39
6.3 Calibration ..................................................................................................... pag. 39
6.4 User Code ..................................................................................................... pag. 39
6.5 Conduction velocity estimation ........................................................................ pag. 40
6.6 Differential .................................................................................................... pag. 42
6.7 Envelope ....................................................................................................... pag. 42
6.8 FFT .............................................................................................................. pag. 43
6.9 Filtering ......................................................................................................... pag. 43
6.10 Frequency ................................................................................................... pag. 43
6.11 IZ Maps ....................................................................................................... pag. 45
6.12 Maps ........................................................................................................... pag. 47
6.13 Merge tracks ................................................................................................ pag. 49
6.14 PSD ............................................................................................................ pag. 48
6.15 Sum ............................................................................................................ pag. 50
7. PC requirements .................................................................................................... pag. 52
8. Problem Solving .................................................................................................... pag. 52
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OT BioLab User manual v.3.0
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OT BioLab User manual v.3.0
1. Introduction
OT BioLab is an acquisition and processing tool developed by OT Bioelettronica. It is a
freeware software downloadable at www.otbioelettronica.it in the Download section.
A flash version of the manual is also available at OT Bioelettronica web site.
OT BioLab allows to acquire, review and process bioelectrical signals detected using the
OT Bioelettronica devices listed below:
Using OT BioLab it is also possible to review and process any kind of signals stored in txt
format.
OT BioLab has been designed for Windows XP, Windows Vista, Windows 7, Windows 8
operating both with 32 or 64 bit.
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2. OT BioLab installation
OT BioLab installation procedure requires few minutes and allows to install the software
and preinstall the drivers for EMG-USB2, MEBA, SHAKEEG and EMG-USB. Extract and run
the OT BioLab setup file. The start-up window will appear (see Fig. 1), click Next to
continue.
Now, the license agreement window appears (see Fig. 2). Read carefully the license
condition and click Next to continue.
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The next step require to choose the folder where the program will be installed. It is
possible to browse the PC and select the desired folder (see Fig. 3). Again, click Next to
proceed.
It is possible to create a shortcut in the Start Menu folder (see Fig. 4).
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Installing OT BioLab it is also possible to pre-install the drivers (see Fig. 6).
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3. Driver installation
To properly install the OT BioLab drivers it is necessary to uninstall the previous version of
drivers in case they were installed together with Acquisition Software. Thus, it is
compulsory to remove from the PC the old drivers before to proceed the new drivers
installation. In case of doubt it is always possible to follow the driver removal procedure
before proceed with OT BioLab drivers installation.
Simply follow the instruction reported in the Driver Remover windows (see Fig. 8).
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The messages appearing in the following windows will be displayed in the language of the
operative system. In this manual the figures show the windows visualized by the Italian
operative system.
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In the first window of the procedure select Not now from the options list and then click
Next to proceed. The driver pre-installation performed during OT BioLab installation
allows to choose the option Install automatically in the second window of the procedure.
Figure 11 shows the last window displayed at the end of the drivers installation procedure.
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4. Signal Acquisition
Follow the next steps to perform a signal acquisition using OT BioLab:
a) Set the acquisition parameters
b) Create a setup
Channels: it selects the number of channels that will be transferred between the
device and the PC. This number can be lower than the physical channels provided
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by the device connected to the PC; moreover, possible options are different for
different devices. This number represents the number of channels that will be
transferred to the PC. Consider that when a large number of channels is
transferred, the PC workload increase. Note: the number of saved channels can be
lower than the transferred channels. Additionally to the selected channels, the
devices transfer to PC also the auxiliary (AUX-IN) channels. In particular, 8 auxiliary
channels are transferred when using the EMG-USB or MEBA, 16 channels when
using the EMG-USB2 and 4 channels when using SHAKEEG.
Sampling frequency: it sets the signals sampling rate. Available values are different
for different devices. When high sampling frequency is used could be useful to
reduce the number of channels transferred to the PC to reduce the PC workload.
Data Acquisition Path Folder: it sets the path folder of the acquired data. As
default the path folder is C:\Users\USER\Documents but it can be changed by the
browse folder button. In this folder the acquired data will be finally saved.
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The channel table is displayed in the left side of the Setup window. The table number of
rows reflects the transferred channels between the selected device and the PC. Each row
represents a physical channel of the amplifier (the number of transferred channels and the
device can be set in the Options window). The first table column indicates the inputs
associated to each channel. The different inputs are highlighted alternating the
background colour.
The last rows of this table (8 rows for EMG-USB and MEBA, 16 rows for EMG-USB2 and
EMG-USB2) are devoted to the AUX-IN channels.
In the right side of the Setup window, a series of buttons and drop down menu give the
possibility to build the setup
From top to bottom the drop down menus allow the user to:
- select the sensor type
Pictures of sensors and of adapters help the user to insert the correct setup. For each
sensor, one or more adapters are available.
There are different types of sensors and they are divided in five groups: AUX, EEG, iEMG,
MMG, sEMG. Restrictions are applied on the AUX sensors; they can only be associated to
the AUX IN channels. All the other channels can be assigned to any other sensor type, is
up to the user to know which amplifier channels can be used to manage a certain signal
type.
The software has been mainly designed for the acquisition and manipulation of EMG
signals. For this reason it is compulsory to associate a muscle for each channel. In case of
AUX in or EEG signals it is possible to select the Not a Muscle menu voice and the side
can be left undeclared.
Many of the available sensors can detect more than one signal (e.g. an EMG electrode
array). Each signal is amplified by an amplifier channel. When a sensor is inserted in the
setup, the correct number of channels is automatically occupied by the sensor.
The buttons on the right side of the Setup Editor window allow the user to:
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- insert a sensor (with associated muscle and side) into the selected line of the table,
all the necessary subsequent rows (i.e. channels of the amplifier) will be associated
and occupied by the sensor;
- replicate the sensor different times in case more sensors of the same type have to
be inserted;
- delete only the sensor associated to the selected row of the table;
- complete the setup and use the current setup for acquisition even if it has not
saved.
Please note that only the channels associated to a sensor will be stored on the PC during
an acquisition. This means that it is possible to acquire just the channels needed between
the channels transferred to the PC through the USB.
Two additional columns in the channels table, available only for the AUX-IN channels, give
to the user the possibility to display the values of desired channels in a pop-up window, or
to use the desired channels as biofeedback. Refer to Feedback Window and Display
Window sections for further details.
Finally a Warning Checkbox can be selected in the bottom of the Setup Editor (see Fig.13).
If it is checked as Warning Enabled, it allows show a window warning in case the sensor
selected with the corresponding adapter and the acquisition mode is not correct for the
setup choosen. The warning guides the user to select the right configuration. Only in this
case the acquisition will not start until the correct configuration is used of when the
checkbox will be set to Warning Disabled.
As default the checkbox is set to Warning Disabled.
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display in real time signals detected from the device and to store them. By default OT
BioLab is in Review Mode.
Stop Acquisition
Review Start Acquisition
Visualization Restart
Reset Saturation Freeze
Once the acquisition parameters have been set and the setup has been created it is
possible to switch from Review Mode to Visualization Mode and display signals in real time
by pressing the blue arrow on the toolbar or selecting from the main menu: Acquisition ->
Visualization. The signals are automatically updated on the screen every second by
displaying the data received from the USB port.
Different buttons are available in the toolbar in Visualization Mode (see Fig. 14), all the
function listed here are also available under the drop-down menu Acquisition:
- Visualization: it allows to switch from Review Mode to Visualization Mode.
- Freeze: during the visualization of the signal in real time it is possible to freeze
signals currently displayed on the screen, for example for a visual analysis. This
button has no effect on the signal stored if it is pressed during acquisition.
- Restart: when in the freeze phase, this button restarts the visualization of the real
time signals.
- Start Acquisition: this button starts the data storing of all signals associated to a
sensor in the setup in the PC hard drive.
- Stop Acquisition: when the acquisition is in progress, this button can be used to
stop the data storing and to close the file.
- Reset Saturation: each sensor has an indicator that changes from green to red
when one of the sensor signals is close to saturation (refer to the Advanced option
in Visualization Mode section). This button can be used to turn off the indicator.
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- End acquisition in: this check box allows to pre-define the duration of an
acquisition. When it is selected, and a given number of seconds is indicated in the
adjacent box, the acquisition automatically stops when the desired time is elapsed.
- Acquisition Time: it is an indicator that reports the acquisition time. The counter
starts when the Start Acquisition button is pressed.
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Fig. 15. Acquisition parameters window. It is displayed at the end of every acquisition and summarizes the
parameters related to the acquisition.
It is possible to proceed with signal file storing when the Keep acquisition button is
pressed. Next steps require to choose the subject from the database, write the place and
the protocol name (See Fig. 16).
In case the subject has not been previously inserted into the database, pressing the
Choose Subject button it is possible to have complete access to the database and to
introduce a new subject (refer to Subject Toolbar section).
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When all the fields have been filled, the OK button becomes available and it is possible to
proceed to the data storing.
The last window of the storing process asks the user to save the file in the folder
previously selected in the Tools -> Options Menu suggesting a file name for the .otb files.
The file name is an 18 character string in the format AANNSSPPYYMMDDMMSS.otb
composed by:
- two digits representing the amplifier identifier (AA)
- first 2 letters of First name (NN)
- first 2 letters of Family name (SS)
- first 2 letters of Place (PP)
- date: Year, Month and Day (YYMMDD)
- time: Minutes and Seconds (MMSS)
The filename coded in this way ensure the unique name for any acquired file and allows
the user with practice to recognize the files. In order to save the file after long acquisition
times two different types of files can be saved in OT Biolab. In case the raw file dimension
is lower than 400 MBytes, a single file .otb will be saved, otherwise a folder will be saved
in the same folder selected in the Tools->Options Menu with the same name of the .otb
file. In this folder three files will be saved: 1) the raw file (i.e. the binary data file) named
with the 18 character string with extension .sig, 2) an .xml file named with the 18
character string and 3) the abstract.xml file. These last two files contain all the information
about the recording. The .xml named with the 18 character string can be used to open the
recording in OT BioLab. The abstract.xml includes internal parameters and processing
options transparent to the user.
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button in the sensor name area. Moreover, all the tracks can by hided or displayed at the
same time using the Reduce/Expand button on the left upper corner of the visualization
area.
The vertical size of a track can be modified simply by moving the cursor close to the track
upper or lower border line, keep left mouse button pressed and move the border up or
down.
A G
The vertical scale area shows directly the signal amplitude in V at the end of the
amplification chain for single tracks, the enumeration of the signals associated to a sensor
for multiple tracks. The signals amplitude for multiple tracks can be indirectly estimated by
using the signal baseline distance as reference. Moving the cursor on the signal display
area, the signals amplitude values appears beside to the cursor. Moving the cursor on the
sensor display area, some information related to track will be displayed beside the cursor.
Every single or multiple track has an own saturation indicator. It is normally green and
becomes red when the signal (or one of the signals) is close to the saturation level ( 2.5
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V for almost all amplifiers). The indication can be intended as a suggestion to reduce the
gain for the sensor. The indicator can be reset, changing the colour from red to green,
using the Reset Saturation button (refer to the Entering Visualization Mode section).
Each sensor has different option that it is possible to access by right click in the sensor
name area. The sensors options in Visualization Mode are:
- Set Vertical Range: selecting this option a new window will appear. The window
is different for single and multiple tracks. For single track it is possible to insert the
minimum and maximum values for the vertical scale. For multiple tracks it is
possible to set the offset between two adjacent channel or superimpose the signals
(everyone will have the same baseline) and set the minimum and maximum values
for the vertical scale, as for the single tracks.
- Hide/Show last channel: only for multiple tracks, this option allows to hide the
last signal of a sensor (e.g. the last signals from an EMG array when differential
mode is used).
- Change Colour: this option allows to change the track colour. By default the
signals are black, the processing results are blue and the fitting curves are red
(refer to the Signal Processing section).
At the bottom of the left control window two buttons (+ or -) allows change the values of
the signal offset in case signals are grouped or to change the signal range in case are
ungrouped.
Some option can be applied to more than one track at the same time. It can be done by
selecting the desired tracks: left click on the sensor name area or CTRL + left click to add
additional tracks to selection. All the tracks in a range can be selected: select the first
desired track and then SHIFT + left click on the last desired track. When a group of tracks
is selected, changing one of the options: Set Vertical Range, Change Colour or change the
vertical track size, will be applied to the entire group of selected tracks.In the upper right
side of the toolbar (see Fig. 14) a Free Selection checkbox allows to freely select parts of
the signals with a start and end out of the epoch grid. When the Free Selection is
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selected, in the Start Time and End Time boxes it is also possible to choose the start
and the end times of the signal to analyze.
The feedback graph (Fig. 18) reported as a vertical bar represents the real time value of
the AUX-IN channel, or the mean of two channels, selected. The bar is blue when the
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signal level is lower than the target limits, is red when the signal level is greater than the
target limits and is green when the signal level is in between the target limits.
In the left side of the Feedback window some controls are available (Fig. 19):
Mode drop down selector. Select the operation mode: if the Absolute mode is chosen,
the feedback graph shows the raw input signal value. If the Relative mode is selected, the
feedback graph shows the value of the input signal as a percentage of the current MVC.
Target Value box. This box is used to select the target level. In Absolute mode the value
is assumed with the measurement unit selected (see section 10.4). In relative mode, the
level is defined as a percentage of the MVC value. In relative mode, the feedback full scale
is automatically changed when the target levels are lower than 45% MVC to maximize the
graph resolution.
Offset Null button. This button set the zero value by subtracting the amount of offset
detected when the button is press. The associated box shows the amount of offset
subtracted in the selected measurement units (see section 10.7). Please note that the
offset is removed by software, changing the saturation level of the feedback graph.
In the Feedback window left upper corner the red button starts Maximum Voluntary
Contraction (MVC) recording button and the Setup button open the Feedback Setup
window.
By clicking the Start MCV Recording button, for 10 s the software will look for the highest
value at the input of the AUX-IN channel used as biofeedback. During the recording the
warning Recording MVC blinks.
The feedback configuration window allows the user to set the biofeedback parameters as
desired. I particular, it is possible to set:
Range. This values indicate the biofeedback vertical visualization limits.
Conversion factor. Is the sensibility at the AUX-IN input, for example a value of 40,
when a force transducer is used, indicate that a signal with an amplitude of 1 V at the
AUX-IN input correspond to 40 kg of force applied to the sensor.
Measurement unit. Is the indication that will be used for the vertical axis.
Accuracy. Is the precision requested to the subject when holding a target level indicated
as a percentage of the full scale by two horizontals lines in the feedback graph.
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Consider the average of the signals. When two channels are selected for the
biofeedback, check this box to visualize the average of the two channels as a single bar or
uncheck the box to display them independently.
Invert signal from channel X. For both feedback channels it is possible to invert the
signal polarity by checking the corresponding check box.
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The Display window shows information about a signal at the AUX-IN channel input. The
current value, the minimum and maximum detected, the average from the beginning of
the session and the offset are displayed in Volts (See Fig. 20).
In the left side of the display window the following controls are available:
Remove Offset. Allows subtract by software the data value reported in the display.
When this button is clicked the value of the offset subtracted to the real time data will
been reported in the right bottom of the display window. If this button is clicked two
times, the offset value is reported to zero.
Reset. This button resets and set to zero the minimum, maximum and the average value
data during an acquisition.
Edit Preferences. With this button it is possible to open a new window in order to select
a different unit of measurements and the conversion factor between the old and the new
units (see Fig 21). Finally the new display window with the new units will be modified and
displayed.
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Fig. 22. OT Biolab main menu and the button used to launch the Real-Time maps highlighted.
When the real-time map button is pressed, a window with all the matrixes available for the
acquisition is shown. With the current software version, four 64 electrodes matrix are
available (ELSCH064RS3 10 mm IED, ELSCH064NM2 10 mm IED, ELSCH064NM3 8 mm
IED, ELSCH064-13x5-125 12.5 mm IED). After selecting the matrix, a window with the
map is shown (see Fig. 23). In this window the color-bar, the interpolation mode, the
rotation angle and the minimum and the maximum value of the RMS scale can be changed
(see pag. 44 of the Maps paragraph for details).
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to columns or rows of the matrix selecting the proper checkbox in the window matrix (see
Fig.25). The final result of the example reported in Fig. 25 is finally showed in Fig 26 with
the visualization of the selected signals.
It should be noted that also during the acquisition of signals is possible to use this option
but in any case all channels of the matrix will be stored at the end of the acquisition.
Fig.24. Signals of a matrix. In the upper left of the vertical control window the picture of the
corresponding matrix can be selected/ pressed to select only signals of one or more row/column of the
matrix.
Fig.25. Window that appears after the selection of the matrix picture.
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Fig.26. Example with signals after the selection of the first row of the matrix (as reported in Fig. 25).
5. Signal review
OT BioLab allows to open and review different file types. There are two methods to load a
file: using the Open function under the File menu or from the Menu toolbar, or using the
Import function under the same menu and toolbar. The Open method simply open a new
file and, in case other signals are currently opened, they will be closed (if they are not
saved a prompt will ask the user if the user want to save them). The Import method keep
the currently opened signals and adds the new ones under them. The Import function can
be particularly useful, for example, when signals recorded using more EMG-S devices
have to be managed.
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temp; otherwise the files are saved in the .otb format and the temp folder will
be deleted automatically
- .xml:
i) If the file data is larger than 400 Mbytes, due to large acquisition times, a
message at the end of the acquisition will inform the user that the file has been
saved in a different folder (see Fig. 27). This folder, as reported in Section 4.2, will
contain three files: 1) a .sig file, 2) the abstract.xml and 3) an .xml file named with
the same name used for the .sig file. In this case it is possible to visualize the data
using the OT BioLab Open menu window also selecting the .xml file format and
choosing this file named as the folder name.
ii) abstract.xml files are generated by an old generation software called Acquisition
Software. It does not contain signals but all the information related to the signals
acquisition and provide links to one or more .sig files containing the data. When
opening one abstract file .xml it is possible to open one or more related signal files.
Several files .xml are generated by OT BioLab, but the open function is reserved to
abstract file created by Acquisition Software.
- brx: files generated by bruxoff and containing two EMG signals and one ECG
signal.
- emg: files generated by EMG or EMG-S and containing a single EMG channel.
- txt: any text file containing data can be opened. To open it, OT BioLab require
some details regarding the format. For this reason a Text File Information window
appears asking the user to choose the decimal separator, the columns delimiter, the
time column or at least the time increment between subsequent lines. When all the
information are inserted it is possible to open the data.
All files, once opened, can be processed, manipulated and saved as .otb file.
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Fig. 27. Pop-up Window that appears after saving the data if files are larger than 400 Mbytes .
Fig. 28. Screen shot during signal review showing an example of signals.
Epochs
In Review Mode, the signals are segmented in epochs. The epoch size can be defined by
the user in the Set Epoch field, in the toolbar (see Fig. 29). The epoch segmentation is
necessary for several processing plug-in. The signals can be selected in two ways: a left
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click on the Sensor name area selects the entire signals, a drag through the desired epoch
while pressing the left mouse button selects a group of subsequent epochs.
Fig. 29. Toolbars available in Review mode. From left to right: Edit toolbar,
View toolbar, Subjects toolbar and Set Epoch field.
Edit Toolbar
When more signals have been detected from a single sensor, they are grouped together
by creating a multiple track. In Review Mode, it is possible to group and ungroup signals
as desired.
To ungroup signals select a multiple tracks and then press the minus green button on the
Edit toolbar or select Edit -> Ungroup Selected Tracks from the main menu bar. All the
signals related to the original sensor will be spitted in single tracks and moved under the
last signal, in the bottom part of the OT BioLab Review window. The name of single tracks
will be assigned automatically by keeping the enumeration of sensor channels.
To group together two or more signals select the desired signals and then press the plus
green button on the Edit toolbar or select Edit -> Group Selected Tracks from the main
menu bar. The new multiple track generated will be moved under the last signal, in the
bottom part of the OT BioLab Review window.
A given track can be deleted if desired, by selecting the track an pressing the Delete red
button on the Edit toolbar or selecting Edit -> Delete Selected Tracks from the main menu
bar. Even if the track and related signals are no longer displayed, in any case, the
originally acquired data is preserved in the otb file.
View Toolbar
The View toolbar (see Fig. 29) and the View menu include several options for the review
of signals. The available functions are:
- Zoom In: increases the time view resolution by reducing the time window
displayed. This function it is also accessible by using the mouse scroll wheel
together with the CTRL button.
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- Zoom Out: decreases the time view resolution by enlarging the time window
displayed. This function is also accessible by using the mouse scroll wheel together
with the CTRL button.
- Zoom to Selection: expand the time selection to fit the full screen.
- Abstract: displays the information contained in the abstract file associated to the
file opened. The abstract will be open with a template generated in Excel.
- Search for Abstract: search tool that allows to find a particular file by searching
for abstracts defined fields.
Subject Toolbar
Every signal acquired has to be stored together with subject details. For each subject it is
possible to create a record containing all the related data. The records are collected into a
database. OT BioLab give the user the possibility to manage different databases. This
feature can be useful for privacy aspects when more user use the same PC but they dont
want to share the subjects information.
By default one database is created by OT BioLab during installation in a folder managed
by the O.S. that the user cant access directly. If the user do not need more than one
database no operation are required, automatically the default database is used and all the
operation are performed on it. Alternatively, under Subjects -> Manage Database it is
possible to create a new database or select an existing one. The database created by the
user can be saved everywhere on the hard drive or external memory devices with the
desired filename. The extension, by default is .otdb. When a user database is selected, OT
BioLab keep memory of the database even when the software is restarted. In case file
.otd is removed, renamed or moved from the originally folder, by default the software
switch to the default database.
Subjects can be add to the database at the end of a recording, but it is also possible to
insert new subjects at any time. In particular, it is possible to add new subjects to the
database or find and edit the subjects record. Pressing the Add New Subject button in the
Subject toolbar, the Subject Editor window appears (see Fig. 30). All the information
related to a subject can be typed, few of them are compulsory, and then, pressing the OK
button, the subject is added to the database.
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In case some information related to one subject has to be modified, it is possible to search
the subject into the database, and then edit any desired field. The Find/Edit Subject
button on the Subject toolbar open the search window. Any parameter of a subject can be
used to find its record into the database.
Fig. 30. Subject Editor window. It allows to add a new subject to the database
or edit the information related to an existing subject.
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VAD 1000
xN [mV] [1]
2 ADRES Gain
where:
- VAD is the A/D converter input range in volts
- ADRES is the A/D converter resolution
- Gain is the gain used during the acquisition for the corresponding channel
- 1000 allow to obtain the result in mV.
For example, when using EMG-USB, EMG-USB2 and MEBA, the A/D converter input range
(VAD) is 5 V, the resolution (ADRES) is 12 bits and the Gain for each sensor can be find in
the abstract file. Note that the gain for AUX channels is 0.5 V/V since the inputs accept -5
5V dynamics, but the A/D converter input range is 0 5V.
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After the filename and the position has been selected the Export Settings window is
displayed (see Fig. 31) where it is possible to select the type of header and decimal
separator.
Fig. 31. Export Settings window. It allows to set the exporting options.
The data is exported with signals amplitude estimated by OT BioLab representing the
input signals at the amplifier inputs, taking into account the gain used during the
acquisition. By default the time columns is added and the measurement units are indicated
in the file header.
Note that it is not possible to export simultaneously different tracks if they has been
acquired with different sample frequencies.
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6. Signal Processing
OT BioLab allows to process any kind of signals managed by the software itself (refer to
the File Extension section). The processing tools are available in Review Mode. Processing
functions are accessible under the Processing menu.
There are processing plugins that can be only applied to single tracks and other
processing can be applied both to a single tracks or to a multiple tracks (refer to Track
Options section).
All the processing tools do not change the recorded signals but generate new tracks under
the last existing track.
6.1 Amplitude
This processing tool use two standard amplitude estimators to generate two new single
tracks containing the results. The estimators are the Average Rectified Value (ARV) and
the Root Mean Square (RMS). The two tracks generated are added under the last existing
track. In both cases a value for every epoch is calculated and displayed as a point in the
middle of each epoch. When the zoom is set to display more epochs, the points are
connected each other by displaying a line between each adjacent points.
The estimation of ARV (AARV) is obtained for the epoch i using the following formula:
1000 N
AARV (i ) xK
N K 1
[V] [2]
Where:
- N is the number of samples per epoch
- xK is the amplitude of the signal at the input of the amplifier in mV as obtained from [1]
- 1000 allows to obtain the result in V.
The estimation of RMS (ARMS) is obtained for the epoch i using the following formula:
N
1
ARMS (i ) 1000
N
x
K 1
2
K [V] [3]
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Where:
- N is the number of samples per epoch
- xK is the amplitude of the signal at the input of the amplifier in mV as obtained from [1]
- 1000 allow to obtain the result in V.
6.3 Calibration
This processing plugin can be used to calibrate a signal acquired for example using a load
cell to obtain the trace directly expressed in the correct measurement unit and with the
correct scale. Morover it is possible to remove an offset to obtain the correct zero level.
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Refer to Appendix A for further detail about the script editor and the provided scripts.
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This multichannel algorithm estimates the CV in the frequency domain. The algorithm is
described in the paper: Assessment of average muscle fiber conduction velocity from
surface EMG signals during fatiguing dynamic contractions. D. Farina et al, IEEE Trans
Biomed Eng. 2004 Aug;51(8):1383-93 and it provides an estimation of the CV from a set
of EMG signals in a time interval in which the mean square error (mse) between aligned
signals is minimized. The minimization of the mse function is performed in the frequency
domain, without limitation in the time resolution and with an iterative computationally
efficient procedure. The algorithm that is implemented in OT Biolab uses a rectangular
window with an amplitude of unity. This choice was adopted in order to minimize the
computational time of the algorithm. The CV is calculated for epochs as for the previous
algorithm. The track containing the results is added under the last existing track. The
value for every epoch is displayed as a point in the middle of each epochs (see Fig. 32).
The third plug-in is named Windowed conduction velocity and it allows to calculate the
CV at the center of a free selection. The signal is windowed in time domain by a Gaussian
function. The algorithm used is the same of the Multichannel CV, so three or more signals
can be selected. In this case it is necessary to group the tracks in which the user
calculates the CV. Using the free selection the plug-in calculates the CV at the center of
the selected time interval as reported in Fig. 33. When this plug-in is selected a window
will appear to select the desired sigma in milliseconds of the Gaussian window. The
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calculated value is reported in a new track at the center of the selected interval (see Fig.
33).
Fig. 33. Example of a windowed CV calculated with a Gaussian function (sigma of 30 ms).
6.6 Differential
This processing tool can be applied to a multiple track or to a pair of single tracks. Simply
it calculate, sample by sample, the difference between signals.
When applied to a multiple track it make the difference between adjacent channels and
retrieve a new multiple track with N-1 signals when the starting multiple track has N
signals. Typical application is the use with multiple tracks containing EMG signals from an
electrode array; the processing calculates the single differential signals when applied to
monopolar signals, or double differential signals when applied to single differential signals.
Be careful, this plugin when the number of signals selected is three or more, it works only
with grouped tracks.
In case a matrix is used for the calculation of differential signals, a window will appear to
ask the user to calculate differential data selecting the desired direction, horizontal or
vertical. As result the differential data are ordered with respect to rows or columns of the
matrix.
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6.7 Envelope
Extract the envelope from a single track and normalize it with respect to the envelop
maximum peak. The tool has been designed for EMG signals, the resulting signal is
obtained by rectifying the desired signal and applying a II order Butterworth low pass filter
with 5 Hz corner frequency to the rectified signal.
6.8 FFT
The FFT can be estimated from single or multiple tracks on the desired number of epochs.
After selecting the track a window will appear (Fig. 34a) for selecting the number of
samples that will be used to obtain an averaged FFT to reduce the noise in the estimated
power spectrum. A minimum of 256 samples for the averaged FFT is required. The
maximum number of samples is equal to the length of the data. From this menu the user
can select the window functions to apply to the time domain data for estimating the FFT
(rectangular, hanning, hamming, blackman). Samples used to obtain the averaged FFT
can be overlapped (50 % of overlap - Welchs method) or no overlapped (Barletts
method) selecting the options that appears on the bottom-right of the window menu. After
selecting these options a new window will display the result of the algorithm (Fig. 34b).
Details about the FFT algorithm can be found at http://sourceforge.net/projects/kissfft.
After the FFT has been estimated, keeping the left mouse button pressed a rectangular
window can be drawn to indicate the area that the user want to zoom in. When a right
click on the FFT window is done a menu appears close to the cursor. The options given by
this menu allows to copy, save or print the graph, to show the graph values at the cursor
position, to change manually the X and Y axis limits and to manage the zoom.
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a) b)
Fig. 34. Example of an FFT spectrum obtained from an EMG channel. In Fig. 34a the window menu for
selecting number of samples. In Fig.34b an FFT spectrum obtained averaging 1024 samples is shown.
6.9 Filtering
This processing tool can be applied both to single tracks and multiple tracks. When
running it, a request of filter type and corner frequencies is displayed. It is possible to
choose between different type of filters:
- Low pass
- Band pass
- High pass
- Stop band
Moreover, the corner frequencies are differently asked depending on the filter type
selected.
The signals generated by the filtering process are added as single or multiple track in the
review window leaving unaltered the starting signals.
All filter types are II order Butterworth filters.
6.10 Frequency
This processing tool uses two standard frequency estimators to generate two new single
tracks containing the results. The estimators are the Mean Frequency (MNF) and Median
Frequency (MDF). The two tracks generated are added under the last existing track. In
both cases a value for every epoch is calculated and displayed as a point in the middle of
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each epochs. When the zoom is set to display more epochs, the points are connected each
other by displaying a line between each adjacent points.
The estimation of MNF (fMNF) is obtained for the epoch i using the following formula:
I k fk
f MNF (i ) k 0
n
[Hz] [4]
I
k 0
k
Where:
- nis the number of frequency bins in the spectrum
- fk is the frequency of spectrum at bin k of n
- Ikis the Intensity of spectrum at bin k of n
The estimation of MDF (fMDF) is obtained bycomparing the total signal spectrum intensity
divided by two with the cumulative intensity (i.e. all the intensity values for frequencies
lower and including the focal intensity). The lowest frequency retrieving the cumulative
intensity bigger than the half total intensity is fMDF.
6.11 IZ Maps
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The value of the cross-correlation is normalized between 0 and 1. Finally this value is used
to plot on a 2D map the innervations zone (see Fig.36).
In order to localize the IZs in a proper way, the matrixes must be positioned with a
preferred direction along the direction of the muscle fibers. The directions used for these
matrixes are, respectively: the horizontal direction for the 8x8 channels ELSCH064NM3
matrix, the vertical direction for the ELSCH064RS3 matrix and the horizontal direction for
the ELSCH064NM2 matrix (see Fig.35).
In Fig. 36 are reported some examples for the localization of the IZ of the biceps muscle
for all the three matrixes.
Fig. 35. Directions that must be used to place the matrixes with respect to the directions of the muscle
fibers for localizing the IZs zone with the OTBiolab plugin IZ Maps.
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Fig. 36. Three examples of the IZs localization with three different matrixes. The red zones of the maps
represents the IZ zones of the brachii muscle.
6.12 Maps
Maps plugin allows show in a 2D plot the matrix signals of 64 electrodes or 16 electrodes
with different colour scales. After selecting 64 signals it is possible to choose the electrode
matrix used for the data acquisition (see Fig. 37).
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The maps plugin has been designed to process data acquired as MONOPOLAR signals.
After selecting the matrix type a new window will appear with the visualization of the
colour map. On the left side of this window, different options are available in order to
change the visualization of the map depending on the type of analysis that is chosen (see
Fig. 38).
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Fig. 38. Visualization of the colour map and of the menu with different options that can be modified.
From the menu map different mode of visualization can be selected: Monopolar,
Horizontal differential and Vertical differential. With the Monopolar mode, the plot is
generated from the original signals without additional processing. The Horizontal
differential mode allows to perform the difference between contiguous electrodes of the
monopolar signals from left to right of the matrix rows. The Vertical differential allows to
perform the difference between contiguous electrodes of the monopolar signals from top
to bottom columns of the matrix.
The maps can be displayed with two different options: RMS or RAW data.
Choosing the RMS option, the software estimate, for each signal, the root mean square
values over the epoch selected in the OT BioLab main window (e.g. 0.5 s in Fig. 39). A
cursor bar in the top of the visualization window can be moved to select the colour map at
a certain time. A Play button in the left side of this bar can be used to start an automatic
display of the maps during the acquisition time or to stop it.
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In the RAW option, the instant values over the acquisition time are used to generate each
map. With this option it is possible to display the acquired data by showing the
propagation of the action potential along the muscle fibers.
Three different colour bars are available: Jet, from blue to red, Heat, from black-red-
white and Bone, a modified grey scale with a blue colour.
The interpolation is the bicubic interpolation with three different resolutions: Low,
Medium and High.
Four different rotation angle can be chosen : 0, 90, 180 and 270 degrees with respect to
the orientation that is reported in the left-bottom side with a picture of the selected
matrix.
The minimum and the maximum value of the colour range is reported in V and can be
changed in the menu. These values are also updated and reported in the right side of the
colour bar.
The minimum and the maximum value can be changed only when the check box of the
autorange is un-checked. Selecting the check box of the autorange it is possible to
visualize the map with the minimum and the maximum values calculated during the
acquisition. The autorange values can be evaluated by pressing the Calculate button and
then selecting the check box. The calculation can take time, it depends on the acquisition
length. It is possible to calculate the autorange values only for the monopolar case, both
for the RMS and for RAW data mode.
6.14 PSD
The power spectral density (PSD) can be estimated from single or multiple tracks on the
desired number of epochs. As in the FFT plugin, after selecting the track a window will
appear for selecting the number of samples that will be used to obtain an averaged FFT to
reduce the noise (see FFT plugin for details), the window functions and the method
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(Welch or Barlett method). After selecting options of this menu two plots will show the
PSD of the signal in two different units: dB/Hz and mV2/Hz. As an example in Fig. 39a and
in Fig. 39b a PSD signal is shown in linear and in logarithmic scale, respectively. When the
PSD has been estimated, keeping the left mouse button pressed a rectangular window
can be drawn to indicate the area that the user want to zoom in. When a right click on the
PSD plot is done, a menu appears close to the cursor. The options given by this menu
allows to copy, save or print the graph, to show the graph values at the cursor position, to
change manually the X and Y axis limits and to manage the zoom.
a) b)
Fig. 39. Example of a PSD spectrum obtained averaging 1024 samples of an EMG channel. In Fig. 39a the
left side a PSD in linear scale is shown. In Fig.39b the plot is reported in logarithmic scale.
6.15 Sum
This processing tool can be applied to a multiple track or to, at least, a pair of single
tracks. Simply it calculates, sample by sample, the sum between signals.
When applied to a multiple track it calculates the sum between all channels associated to
the sensor selected and retrieve a new single track containing the sum.
Typical application is the use with signals from an electrode array; the processing
calculates the signals virtually obtained with multiple inter-electrodic distance.
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7. PC requirements
Operative system: Windows XP SP2 (Net framework 2.0) / Vista / 7
Processor: 2.8GHz Intel Pentium IV (or equivalent) and later.
Port: USB2.0
Hard Disk: 10 MBytes for software installation
Minimum RAM: 1 GBytes
The minimal PC requirements listed allows the proper acquisition of all 256 channels of
EMG-USB2 equipment (with max sampling frequency 10.240Hz) and a visualization of 16
channels simultaneously. The increase of the number of visualized channels can produce a
visualization latency or an intermittent visualization.
8. Problem Solving
A problem for the visualization of sensors in the Setup Editor can occur in case the old
version of the software has not been disinstalled before the installation of the new
software.
In order to install correctly the new version 2.0.XXXX.0, the old version of the software
should be disinstalled before, running the unins000.exe file located in C:\Program
Files\OTBioLab. If the problem remains after the installation of the new software, the
folder C:\ProgramData\OT Bioelettronica must be cancelled manually.
Usually C:\ProgramData\ folder is an hidden folder of the Windows operative system and
can be shown using the procedure of Windows Show hidden Folders.
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Appendix A - OT Connector
OT Connector is a tool integrated in OT BioLab who is completely transparent to the user.
It works in background and is automatically started when in visualization mode.
OT BioLab listens on port 31000 on all interfaces on the PC connected to the amplifier. If a
connection with this port is established it is possible to access the acquired data from a
different application running on the same PC or any other device on the same Ethernet
network - even with a different operative system.
The sequence of operations that has to be executed to access the data are:
- Open OT Biolab and configure your channel setup, sampling rate etc... Than start
the Visualization mode
- Establish the communication with the TCP socket on the port 31000. OT Connector
will answer with the string OT Biolab.
- Get the configuration (number of channels and sample rate) by sending the string
config. OT Connector will answer with 3 data words containing the sample rate,
the number of EMG channelsa nd the number of AUX channels. Gain, low pass and
high pass filters are also available for each channel.
- While in Visualization mode, start the data flow by sending the string start. OT
BioLab will start to transfer data on the connection.
An example is provided to access the data from the TCP socket using Matlab. In the OT
BioLab installation folder, in the subfolder OTConnectorClient, a set of files are installed
with the application. Two of them are java files used at the lower level to communicate
with the socket. The additional three matlab files are:
- OTClient.m is a class of functions that allows the interface between Matlab and
the TCP socket provided by OTBiolab. The methods available in this class allow the
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user to establish the connection with the socket, start/stop the data transmission
and close the communication. Consequently it encapsulates the TCP/IP protocol.
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Graphical interface
The provided graphical interface allows to create, edit and run the scripts.
It can assume two different layouts:
basic layout (Fig. 40), where the list of the existing scripts is presented, but the
corresponding code is not shown. This layout is particularly useful to use an
existing script
advanced layout, where, on the right side of the window, the code editor is shown
(Fig. 41).
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In order to switch from one layout to the other, use the blue arrow in the toolbar.
The toolbar button have the following functions (from left to right):
Execute the selected script
Show the properties of the selected script
Import a script from a file
Export a script to file
Change the current view (switching between list and detail view)
The Editor toolbar buttons have the following functions (from left to right):
Creates a new script
Delete the current script
Save the current script
Run the current script
Edit the properties of the current script
Script properties
For each script the following properties have to be defined through the Properties Dialog,
reported in Fig. 42:
Name: the name of the script
Author: the name of the author
Description: the description of the script
Input signals: if checked, a test is performed before the execution of the script to
verify that the allowed number of input signal were selected by the user
Code layout: allow to access the behind-the-scene wrapper generated by OT Biolab
when a new script is defined, thus allowing some more complex elaboration.
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Class OTBAutomation.OTBGraph
Description
This class is used to create stand alone windows with a graph
Methods
void Title(string title)
Set the title of the graph
void XLabel(string label)
Set the x-axis label
void YLabel(string label)
Set the y-axis label
void Plot(double[] x, double[] y, Color color)
Plot the provided data using the specified color. The two x and y vectors
must have the same number of elements.
Class OTBAutomation.OutputTrack
Description
This class is used to contain the results of the elaboration and return it to OT Biolab.
Methods
OutputTrack(InputTrack input)
Allocate an output signal, with the same description, units, title, and
sampling frequency (in Hz) as the provided in put signal
OutputTrack(int length, double samplingFrequency, string title)
OutputTrack(int length, double samplingFrequency, string title, string units)
OutputTrack(int length, double samplingFrequency, string title, string units,
string description)
Allocate an output signal, specifying the number of samples, the sampling
frequency (in Hz) and the title. Units and description, if missing, are
set to an empty string.
OutputTrack(double [] data, double samplingFrequency, string title, string
units)
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Use the array provided as first parameter to allocate a signal, usign the
passed sampling frequency (in Hz), title and units.
double[] Values
Get/Set the values of the signal elements.
string Description
Get/Set the textaul description of the signal. Default: empty string
string Units
Get/Set the units of the signal. Default: empty string
string Title
Get/Set the title of the signal. Default: empty string
double SamplingFrequency
Get/Set the sampling frequency, in Hz. Default: 1
Description
This class is used to access the OT Biolab data selected by the user before executing the
script.
Methods
double Value(int i)
Get the values of the signal elements. Remark: read only (that is, you
cannot change the values of an input signal).
string Units
Get the units of the signal.
string Title
Get the title of the signal.
int Length
Get the number of samples in the signal
double SamplingFrequency
Get the sampling frequency, in Hz.
bool IsSubsampled
Return true if the signal is subsampled, false otherwise
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Description
This class provides an easy way to perform some common numerical operation (sum,
maximum, etc.), interact with user, and allocate the memory.
Methods
OutputTrack[] AllocateOutput(int howmany)
Allocate the memory for the required number of output signals.
OutputTrack[] NoOutput()
Used to allocate the memory when no output signal is required. (this is
important because a script is always supposed to return a variable called
Output).
OTBGraph CreateGraph()
Create an instance of the OTBAutomation.OTBGraph, used to create a window
with a graph.
double AskUser(string Question, double defaultValue)
Allow to ask a numerical user input. The second parameter is the default
value suggested to the user
void Message(string text)
Show an informative message box with the specified text.
double[] Rand(int n)
Generates an n-elements random vector, whose samples are uniformily distri
buted between 0 and 1.
double Max(double []data)
Returns the maximum value of the elements stored in a vector.
double Min(double[] data)
Returns the minimum value of the elements stored in a vector.
double Mean(double[] data)
Returns the average value of the elements stored in a vector.
double Sum(double[] data)
Returns the sum of the elements stored in a vector.
double[] LinSpace(double from, double to, int n)
Returns a vector of n linearly spaced elements between from and to.
double[] Zeros(int n)
Returns a vector of n elements, all set to zero
bool FFT(double[] signal, out double[] FFTreal, out double[] FFTimag)
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Evaluate the FFT of the real signal passe in the first vector. The second
and third vectors will contain the real and imaginaty part of the FFT,
respectively.
double[] Copy(double[] data)
Generates a vector with the same size and the same elements as the one
passed as parameters
double[] Multiply(double val,double [] data)
Multiply the passed array by the supplied scalar.
double[] Multiply(double []data1, double[] data2)
Multiply together the elements of the two vectors. If they have a
different length, an empty (null) vector is returned.
double[] Add(double val, double[] data)
Add the supplied scalar to the passed array by.
double[] Add(double[] data1, double[] data2)
Add together the elements of the two vectors. If they have a different
length, an empty (null) vector is returned.
Important remarks
In every script the following variables are automatically defined:
Input, which is an array of InputTrack, and contains the currently selected
signal(s);
Output which is an array of OutputTrack, and will contain the signal(s) allocated by
the user.
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Script UserInput
Description
This script asks the user for a number N, generates a random sequence with N values and
plots it both in the signal pane and in a new graph
Code
//Ask a number to the user; the default value is 100
double N=OTBScriptHelper.AskUser("Please enter a number",100);
//Get the maximum value of the N elements just generated array, the minimum and
the average
double Max=OTBScriptHelper.Max(data);
double Min=OTBScriptHelper.Min(data);
double Mean=OTBScriptHelper.Mean(data);
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//plot in red the 1 to N sequence on the abscissa and the random number on the
ordinate
gr.Plot(x,data,Color.Red);
Script Sine
Description
This script generates a sinusoidal signal, with the same sampling frequency as the
selected signal
Code
//Allocate space for one output signal
Output=OTBScriptHelper.AllocateOutput(1);
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Output[0]= new
OutputTrack(numSamplesPerSignal,Input[0].SamplingFrequency,"Sine",Input[0].Units
);
Script SumSignals
Description
This script calculates the sum of all the selected signals
Code
//Allocate space for one output signal
Output=OTBScriptHelper.AllocateOutput(1);
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Output[0].Values[k]=0.0;
//add the contribution from each signal
for (int iSignals=0;iSignals<numSignals;iSignals++)
{
Output[0].Values[k]+=Input[iSignals].Value(k);
}
}
Script ProdSignals
Description
This script calculates the product of all the selected signals.
Code
//Allocate space for one output signal
Output=OTBScriptHelper.AllocateOutput(1);
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Script FFT2File
Description
This script calculates the Fourier Transform of a signal and save the resulting data to a
user specified file
Code
//No output is returned to OTBiolab
Output=OTBScriptHelper.NoOutput();
//Get the number of samples in the first original signal
int numSamplesPerSignal=Input[0].Length;
//allocate the space to copy the input signal samples in a temporary vector (to
compute the FFT)
double []data= new double [numSamplesPerSignal];
//copy the samples from the OTBiolab signal to the just allocated vector
for (int k=0;k<numSamplesPerSignal;k++)
{
data[k]=Input[0].Value(k);
}
//declare the variables that will host the real and imaginary part of the FFT
double []FFTReal;
double []FFTImag;
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//save each FFT sample to file (first the real then the imaginary part)
for(int k=0;k<numSamplesPerSignal;k++)
outfile.Write(string.Format("{0} {1}\r\n", FFTReal[k], FFTImag[k]));
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OT Bioelettronica
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