Questions tagged [sensor]
The sensor tag has no usage guidance.
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Calibration/Filtering Order
Let's suppose we have a stream of data from a 3-axis sensor like a MEMS magnetometer. Each of the sensor's axes have an output bias, gain, and misalignment (all axes should be orthogonal). ...
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Parameter value in bias instability modeling
In IMU error modeling, bias instability/flicker noise is often modeled by a first order Gauss-Markov process whose standard deviation is equal to the given BI coefficient [1, p.185][2, p.31]. Because ...
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Estimator of accelerometer offset
I would like to estimate the offset of my accelerometer without using anything but measurements of the sensor. Is there any estimator for this? Averaging all the data points would probably do the ...
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Estimate bits per pixel from RAW photo
Nowadays many consumer products like smartphones or action cameras support RAW photos. Typically, they spit out a DNG/TIFF file with 16 bit values. However, the actual bit depth of the A/D is rather ...
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How to sync two similar lists/waveforms with differently populated data in python?
I have two lists of sizes L1 - 22400(865*26) and L2 - 79000 with measurements of some environmental data. Data of both the lists are measured simultaneously. The L2 is a continuous measurement for ...
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Upsampling realtime data for sensor fusion
I am doing a real-time sensor fusion of gps and imu streams using a Kalman filter. Both streams are obtained independently (with geolocation and accl-gyro values) in real time. I am doing this in ...
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215
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Gyroscope sensor drift problem at speed
I have an iPhone mounted on a bike to measure the slope of the road in real-time. This works pretty well at first but as soon as I speed up, the reported pitch starts to drift. I'm using CoreMotion ...
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Minimum amount of data needed for low pass filter on real time sensor data
I need to apply a low pass filter up to a period of 10 hours to my data. My sensor has a sampling rate of 1 sample every 5 minutes. I need to know how much data I at least need to have to be allowed ...
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Correcting Drift and Stepped Pattern in Pressure Sensor Data
I’m observing drift and a stepped pattern in data from a piezoelectric pressure sensor measuring constant atmospheric pressure. the results are the following:
The data should ideally be a flat line ...
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Would an image sensor with photosites arranged irregularly to reduce aliasing be feasible?
I’m guessing it’ll be more computationally complex considering the irregularly sampled image would have to be converted to a regularly sampled one and probably a different demosaicing algorithm would ...
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Is movesense magnetometer in NED or ENU reference frame? / How to determine magnetometer reference frame
I can't find an axis diagram for the movesense sensor, nor does it say on the spec sheet on the website - Is the magnetometer in the NED or ENU reference frame? On SO there is an answer that doesn't ...
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Accelerometer beacon as game controller lag
As part of our product, we use a sensor/beacon to measure the inclination/angle of the product. We do this with a KKM 3-axis accelerometer (model: https://www.kkmcn.com/long-range-beacon-k5p). However,...
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Modelling MEMS accelerometer noise
I am trying to compare two MEMS accelerometers in terms of their noise for ground motion monitoring applications. I would like to take some "clean" data (recorded by good quality ...
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Detecting camera raw image saturation/clipping level
I'm looking for a fast but robust algorithm to detect whether a camera raw image has clipped/saturated highlights and, if so, compute the level at which saturation occurs. This saturation/clipping ...
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Line sensor data generating data array
I have a line sensor with a $n$ number of detector elements, pixels.
This line sensor should be used to capture data while moving so that later from the captured data images can be generated. The ...
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Sampling Frequency of a Rotational Sensor
In the picture above you can see a sensor I've been dealing with, called a "Caliper". This sensor arm simply passes over the pits or bumps on a disk rotating with a constant angular velocity ...
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Kalman filter in data fusion
I am very new to Kalman filter. I am doing a project using one sensor the track the sensor's position. I developed 2 methods to solve the position, one in better accuracy and one is less accurate.
I ...
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Sensor Fusion of Two Same Type of Data
I have an object moving with sinusoidal motion. I estimate the position of the object using lidar and camera separately. Then I want to fuse these two estimation data in the optimal way. For example I ...
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What's the best way of modeling 3d target motion with only 2d angle observations?
A maneuvering target is flying in 3d cartesian space, but a sensor (passive infrared or mic array, etc.) can only observe it in polar coordinate with 2d orientations
(azimuth, elevation). For ...
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Distribution of Sensor Uncertaintiy/Error in Datasheets
In a typical sensor datasheet, there is a range of uncertainty for a given parameter. For example, there are min, typ and max values for the sensor sensitivity. In general, the datasheets do not ...
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Determining location of moved sensor in near field array processing
I have a situation where a linear array of sensors monitoring near field sources has had one of the sensors bumped so that the sensor position is off by a smallish amount and is not in its original ...
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538
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Get IMU acceleration of a direction when tilted
I have an IMU that is placed on the body. My goal is to calculate the position data of the vertical upward movement. Since the sensor is never perfectly aligned and will always have a little tilt, I ...
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Understanding shifts and superpositions in vibration sensor data
I’m looking at some measurements for elevator door vibrations from this dataset (a cleaned version of what is available here, as I understand it) and, if I plot the series of measurements, I get the ...
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getting a smoother real-time frequency estimate using the phase for a triangle wave
I'm using a phototransistor and an optical chopper to measure the angular velocity of a wheel, much like how mechanical mice used to work. The signal looks like a triangle wave with some noise in it, ...
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Detecting bullet holes using Python with camera or sensors
I am trying to build a system to detect bullet holes in paper. I've read many StackOverflow threads but not a single one satisfied me. Current methods, which I am using, are good but not perfect and ...
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Minimizing Integration Error in an Accelerometer
I am trying to use an accelerometer in an IMU (ISM330DHCX) (integrating to get position). To do this I need to fix the calibration error. Ideally the integral of the accelerometer values while static ...
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Adaptive Particle Filter: unknown process Equation
In my design and implementation of a SIR particle Filter, I don't have the state process equation of the actual system, which would have given a very good estimation of the real signal. I was ...
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What sensors can be fused using the Kalman Filter framework
I was recently introduced to the concept of Kalman filtering in the context of projectile tracking. A classmate recommended this to me, and what intrigued me most was its ability to fuse different ...
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SNR estimation from a radar sensor signal
I am using a radar sensor for human activity monitoring which works on 3.18GHz. The received signal by the receiver of the sensor depends on the movements in its area of observation. All the activity ...
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Kalman Filter Motion model with moving sensors
Suppose I have an object that I am tracking with moving sensors using a basic Kalman Filter (for example, think of a ship being tracked by satellites). In the simplest case where the sensors are ...
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Clustering FFT frequency bins from sensor time series data
I am trying to analyse multivariate time series data sets. I have 6 signals for each event, representing 3 linear accelerations and 3 rotational velocities for a 40ms window. I am trying to find a way ...
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sensor data windowing and normalization
I am getting up to speed with working with sensor accelerometer data. I am looking to conduct a FFT on this signal. I found that the signal being non periodic is causing issues so I have tried to look ...
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Kalman filter for heading estimation with magnetometerv + gyroscope only considers magnetometer
I implemented a Kalman filter to estimate the heading of a robot that is moving in 2D, given the measurements coming from a magnetometer (X, Y) and a gyroscope (Z). The code is the following:
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Using lock-in amp to measure pulsed signal
I am working on a design of an acoustic resonator for sensing application,
I use an excitation field at a certain frequency (a), and measure the response of the sensor (b), for my application, I only ...
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Time-frequency analysis of a nonlinear system
I have empirically developed a sensor failure detection system which works fine. The system receives inputs from different types of sensors. Because of noise characteristics, I use low pass filters on ...
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How to determine sampling rate of a lock-in amplifier?
I am trying to figure out the sampling rate of a lock-in amplifier and how it is related to the time constant. For example, imagine measuring sinusoidal waves at $1$, $5$, $10$, and $50$ Hz ...
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How do I turn my sensor samples into a cleaner, more useful curve?
This is for one of my fish tanks, which has dimmable LED lights. It's a bit of an experiment where I'd like to see what'll happen if the "sun" above the tank "rises" and "sets&...
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Trying to do frequency analysis of an accelerometer output
I am new to signal processing. I have a 3 axis MEMS accelerometer. I have read its output into $\mbox{Matlab}^{\tt TM}$.
My problem is that the signal I am trying to isolate has a frequency of about 0....
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FFT requirements of real time signal from sensors
I have an electrical current sensor which generates measurements every second. I want to calculate the FFT of this signal. Since my real-time values are received every second, I think that the fastest ...
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Kalman filter with multiple sensors
I have been reading more about EKF and I am a bit confused on how you handle predictions with multiple sensors.
Ex, I have IMU, GPS, Odom and Stereo Camera.
Each can be used to predict location, how ...
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How to get a depth map from a Kinect 360 depth sensor?
I'm trying to understand how Kinect 360 depth sensor works. At the moment, I know that this sensor is composed by an infrared pattern generator and a infrared camera. IR camera gets the pattern ...
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Accelerometer drift: What hardware-level signal conditioning operations are being performed under the hood of a MEMS accelerometer chip?
I'm in a debate with a peer who says that filtering accelerometer signals at the chip-level has nothing to do with mitigating the problem of drift
Often, additional software-level filtering is ...
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Speed from Depth/Pressure sensors
I have a pressure based Depth sensor. For reference, MS5837-02BA.
All depth measurements I've been able to read are very accurate (±1cm)
I tried experimenting to find out the speed of the body by ...
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Averaging data from 2 sensors
Suppose we take a reading of a single rotating axis using 2 identical sensors. Intuitively, I think that averaging the outputs of both sensors will yield a less noisy result. But what if sensor A has ...
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Using a Kalman filter to clean acceleration data
I am collecting acceleration, gyroscope and magnetometer data in all 3 directions. I would like to filter noise from the accelerometer using a Kalman filter. I am not trying to esimate orientatoin or ...
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How significant is the time lag between inertial IMU data in a inertial analisys?
I'm working on a MCU system that use an IMU (ICM-20948) which has two different chip inside: one provides accelerometer and gyroscope data at $1125$ Hz (configurable at $125$ Hz), the other one ...
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Finding Minimum SNR or Minimum Detectable Signal Based on Noise Spectral Density
Imagine I have an $n$-bit sensor, whose noise spectral density is $V/\sqrt{Hz}$. $V$ is an exemplary measurement unit. The desired measurement bandwidth is also known. Is there a mathematical way to ...
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Accelerometer Inference from power spectrum
I have 3d accelerometer data sampled as 60hz. When I am looking at the power spectrum in all three accelerations (x,y,z). I am noticing a trend with a negative slope. I trying to figure a few things ...
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What is the driving Voltage?
While I was looking into ultrasonic transducer in order to transmit and receive a beam, I came across specification of a transducer stating driving voltage as 20Vrms. I am not sure what actually does ...
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Equalization of ultrasonic transducer [duplicate]
I am working with ultrasonic transducers with frequencies 100 kHz, one for transmission one for reception. The transmitted signals are chirps. I would like to measure the time of flight between ...
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