Questions tagged [sensor]

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6
votes
1answer
9k views

How to determine covariance matrix $Q$ and $R$ in Kalman-filter

I am implementing getting orientation from smartphone. I want to use Kalman filter and should determine process noise covariance matrix $Q$ and measurement noise covariance matrix $R$. (newbie to ...
5
votes
1answer
474 views

What type of low-pass filter to use for gyroscope filtering in control application?

I am using a gyroscope to generate a feedback signal that drives a motor to resist rotation, just as in a camera gimbal. The gyroscope is sampling at 32 KHz with a bandwidth of 8 KHz, and my control ...
5
votes
1answer
410 views

Finding dependence between two sparse signals

I am new to signal processing and would really appreciate your help. happy to provide more context/details. In my research, I have a system that has many sensors $X_1, \ldots, X_N$ and using this ...
3
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2answers
4k views

Detecting outliers/noise from sensor data

I am trying to detect outliers/noise as indicated on the diagram below from sensor data. Can anyone advice how to go about it? I can only do this in python, so are there libraries in python that I can ...
3
votes
1answer
425 views

How to interpret Allan Deviation plot for gyroscope?

Regions with different slopes correspond to different types of noises in Allan Deviation plot of a steady gyroscope at steady temperature. My doubts are: What is significance of x axis in this plot, ...
3
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1answer
126 views

FFT of resultant of signals

If one has two signals (say, two acceleromters mounted perpendicularly) and a piece-wise resultant acceleration signal is determined, it appears that frequency content information cannot be determined ...
2
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3answers
203 views

Kalman Filter Sensor Processing

Kalman filter achieves convergence of state vector by using sensor observations. Assuming a sensor such like velocity sensor, giving two axis velocity information in X-axis as well as Y-axis(see edit ...
2
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2answers
172 views

Why do we assume zero mean noise in sensor data?

I am reading a paper on measuring respiratory patterns from video data. In defining the model, the authors formulate the problem mathematically as: $x_i(t)=h_i(t) \ast g(t) + n_i(t) $ Where $n_i(t)...
2
votes
3answers
376 views

Why is my laser beam intensity profile not Gaussian?

I am kind of new to laser physics and signal processing, I hope I am in the right place to ask this question. I am also sorry for my not-great English. I have been asked to study the transverse ...
2
votes
2answers
497 views

detect and distinguish driving maneuvers via smartphone sensors

I want to do some driving style analysis via smartphone. Therefore, I programmed an app that records a 2D acceleration (when accelerating/braking and turning left/right). The app calibrates itself in ...
2
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2answers
1k views

Measuring walking speed with iPhone accelerometer

As part of a research project, I have been tasked with determining gait speed (walking speed) for a subject using a handheld iPhone. The main constraint is that walking distances are very short (10-30 ...
2
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2answers
267 views

Compressed / Compressive Sensing - Sensor Placement

I have a beam fixed at one end and free at the other. It obviously results in vibrations due to the disturbances in the environment or when induced. This system can be represented using a differential ...
2
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0answers
191 views

Software based synchronizing of multiple data streams/sensors with slightly differing sampling rates

Situation: I try to synchronize the data streams of multiple sensors (ADXL372) of the same type but with different data output rates. The data sheet states all sensors should have the same sampling ...
2
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2answers
187 views

Detecting pattern from signal data by gaussian mixture model?

I'm a machine learning newbie. I have sensor data which is generated by several sensors. The data is a series of 'time's. (it is not labeled, in other words, I cannot know which sensor generates ...
2
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0answers
150 views

Vibration signal analysis of non-stationary movement

my task is to develop a condition monitoring system of a machine module. For that I am using the vibration sensors placed on the machine housing. I want to focus on only one module of the machine, a ...
2
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0answers
34 views

How to determine load cell response to arbitrary temperature changes with known step response(s)

We have a loadcell, the output of which is (naturally) temperature dependent. Under static load conditions, we have observed a dynamic response to temperature changes. Therefore, we did a step ...
2
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0answers
83 views

Obtaining n values from n-1 sensors

As the questions states, lets consider we have 3 gas sensors giving me data for: A B C Note that only sensors for A and B give absolute values, yet we need the absolute values for all four species:...
2
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0answers
135 views

Open source GPS+IMU sensor fusion?

Are there any Open source implementations of GPS+IMU sensor fusion (loosely coupled; i.e. using GPS module output and 9 degree of freedom IMU sensors)? -- kalman filtering based or otherwise I see a ...
2
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0answers
858 views

Analyzing accelerometer data: appropriate use of rotation matrices?

I'm working on a project in which a rod is attached at one end to a rotating shaft. So, as the shaft rotates from 0 to ~100 degrees back-and-forth (in the xy plane), so does the rod. I mounted a 3-...
2
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0answers
7k views

Horizontal banding (flickering) due to electronic rolling shutters

It is a well-known artifact that in CMOS cameras with electronic rolling shutter, horizontal banding (flickering), i.e. brightness intensity variations, are observed when the image is recorded under ...
1
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3answers
490 views

Digital filter selection for sensor

I am having a LM35 sensor which gives $10\textrm{ mV}$ signal per degree rise of temperature. Now I have one question, which digital filter will be the best for this ? This sensor will be use in very ...
1
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1answer
89 views

Signal recovery from multiple noisy sensors

I'm working on detecting signals buried under the sensor noise using a multiple sensor system and using some technique (correlation?) to take what is common to all the sensors and cancel out the ...
1
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1answer
2k views

Using Kalman Filter to fuse two sensor readings of the same type

I have always used Kalman Filter to smooth a signal comes from one sensor only. I would like to know if Kalman Filter could be used to fuse data coming from two different sensors that provide the ...
1
vote
1answer
807 views

Filtering an acceleration signal

I have a triaxial accelerometer giving me acceleration along x, y, and z. I then combine the 3 axes by calculating magnitude of acceleration over all time points (details in my question here) I'm ...
1
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1answer
91 views

Combination of accelation signals from two devices

I have $x_A$, $y_A$, and $z_A$ acceleration signals collected from a smartphone and I call it: set $A$ and I also have $x_B$, $y_B$, and $z_B$ same acceleration signals from smartwatch: let's call ...
1
vote
1answer
1k views

Triaxial accelerometer to single signal

I have some smartphone recorded accelerometer data, so I have acceleration along 3 axes: $$a_{x}, a_{y}, a_{z}$$ The accelerometer data was collected by securing a phone to a walking subject. I'm ...
1
vote
1answer
293 views

Frequency measurement from acoustic emission sensor data(VDC RMS)

Currently, I am facing a problem about understanding FFT concept and getting exact frequency with acoustic emission sensor data(VDC RMS data). I want to measure the sound frequency from the acoustic ...
1
vote
1answer
250 views

How to remove ADC-induced noise from voltage measurement data?

I am measuring the various voltages involved in a solar energy system, but the recorded values vary by quite a bit, most of which is caused by the ADC in the Arduino Nano I am using to take the ...
1
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1answer
1k views

Accelerometer - coordinate system transformation

I'm getting some accelerometer readings from an Android phone, but it comes in on the phone's coordinate system. I want to apply a transformation to put the acceleration in the world coordinate system ...
1
vote
2answers
360 views

Multiple cheap IMUs vs one expensive IMUs

In my project, there is a possibility of either buying one expensive IMU or 5 cheaper IMUs. They have to be cheaper due to budget limitations, and the idea is to use them in order to be able to do "...
1
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0answers
36 views

How to draw a smooth spectrum from a discrete array of measurements at selected frequencies?

I have a AS7265x triad spectroscopy sensor from SparkFun (link) which gives me measurements at 18 individual light wavelengths between 410nm and 940nm. The datasheet says that the FWHM of each sensor ...
1
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0answers
42 views

Rocketry : Combine two accelerometers to reduce noise?

I am designing an IMU for an experimental rocket. I'll be using the BN055 9DOF that has sensor fusion - orientation quaternion - and gravity compensation. My main goal is speed computation, and I was ...
1
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1answer
33 views

Is there a closed form solution for a temporal calibration of two different signals?

Given two signals $f_1(t),f_2(t+dt)$ where $t$ is time and $dt$ is the time delay between the two signals, is there any closed-form solution with respect to $dt$? what are the efficient global ...
1
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0answers
41 views

Interpretation of steady state sensor signal

I try to understand some measurement results of an accelerometer MEMS sensor. I used a mikrocontroller which is sampling an accelerometer's analog signal with the built in analog-digital-converter. ...
1
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0answers
46 views

Source localization in 3d

Let's say I have a 4-sensor square-shaped array in 3d space, with sensors at $$ s_1 = [1 \ 0 \ 1] \\ s_2 = [2 \ 0 \ 1] \\ s_3 = [1 \ 0 \ 2] \\ s_4 = [2 \ 0 \ 2] \\ $$ And a single source somewhere ...
1
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0answers
217 views

How to convert magnetometer readings into orientation?

I have a magnetometer sensor, obtaining the reading with $50$Hz rate. Unfortunately, the data is not labeled: I just know that these are $x$,$y$,$z$ axes, and that the reading are in $\mu$T (micro ...
1
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0answers
123 views

Interpretation of minimum discernible signal (MDS) in sonar equation

I am working on modelling and simulations of synthetic aperture sonar at component/subsystem level. I have started with standard sonar equations for calculating detection ranges for different ...
1
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1answer
2k views

Choosing correct filter parameters for IMU sensor datas

I have a IMU sensor breakoutboard using ITG3701, LSM303D LinkProduct. This involves accelerometer, gyroscope and magnetometer. I have connected the sensors to a Arduino and sending the datas to ...
1
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0answers
161 views

sensor fusion on GPS/IMU

can anyone gives any link or explained to me on how sensor fusion works on GPS/IMU. as of now, i have gain learn few of the algorithms on Kalman Filter. Currently, im using an arduino Uno as my data ...
1
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0answers
95 views

Sensor Data Fusion with Orientation Sensors in 3D Euclidian Space

Preconditions For measuring the position of a mobile device in 3D space, I utilize two sensors with different characteristics that measure device orientation. Sensor A (a combined sensor of ...
0
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2answers
41 views

Minimum sample frequency of IMU accelerometer and gyroscope

I was wondering how I would justify a sampling rate of 125 Hz for accelerometer and gyroscope data from wearable sensors. This is a rate used in a lot of biomechanics literature, but I can't seem to ...
0
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1answer
94 views

Bias instability in Gyroscopes : AVER / ADEV

I am attempting to implement allan variance to determine the amount of bias that is shown in my IMU's gyroscope ( BMI160 ). I am doing this with the following formula, that was captured in the ...
0
votes
2answers
345 views

Oversampled Binary Image Sensor vs Active Pixel Sensor(CMOS)

I am a beginner in the field of Image processing.I was designing a camera sensor when I came across these two type of sensors: CMOS(Active Pixel Sensor) Oversampled Binary Image Sensor. Now, I can ...
0
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1answer
74 views

What type of sensors have complex Gaussian noise?

What type of sensors have complex Gaussian noise? Do strain gauges also exhibit such noise?
0
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1answer
23 views

Inverting Sensor Transfer Functions?

When you see software packages that read in data from sensing equipment, does the software do something to inverse the transfer function? Correct me if I'm wrong in my understanding, but this is how ...
0
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1answer
62 views

Kalman Filter - How to combine data from sensors with different measurement rates?

I'm trying to implement a Kalman filter for tracking the position of a vehicle with the help of position data from GPS and Odometry measurements. The GPS data (WGS84 format collected from an app on an ...
0
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1answer
73 views

Handling a number of simultaneous measurements in Extended Kalman Filter?

If I have a number of sensors whose measurements arrive at the same time - how can I handle them properly in the Kalman filter? P.S. The measurements are not necessarily taken at the same time but I ...
0
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1answer
5k views

What is sensor drift?

From Wikipedia: If the output signal slowly changes independent of the measured property, this is defined as drift So my question is, if I have a gyroscope with sensor drift does that mean that $E\...
0
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1answer
87 views

Techniques Used To Process Accelerometer Recordings [closed]

I'm currently working on a project which involves using Accelerometer data. Having searched the internet for techniques in processing the data, I am unable to find simple techniques. Is there any ...
0
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1answer
3k views

How to get relative rotation matrix from two orientation values in android?

Following http://www.codeproject.com/Articles/729759/Android-Sensor-Fusion-Tutorial , I get two orientation values. Then, I transform those values to rotation matrices R1, R2. I think the relative ...