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Signal Processing

Questions tagged [real-time]

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real-time refers to processing done with a strict set of time constraints in a deterministic manner.

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41 views

FFT algorithm for real-time analysis

In a project, I have real-time voice audio being delivered in buffers of around 128 samples at a time. I want to calculate the autocovariance of the signal and use it to control an AR filter. To do ...
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34 views

Is the whole data needed for the fast fourier transform with an ongoing signal?

I sample an signal with around 840k values a second, to check the spectrum around <400kHz. But i can't save the whole data as it is just to much for my microcontroller. I know that for the ...
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207 views

Using Wavelet Transform on a 1D signal while updating the values

I'm working on a NN that uses Wavlet Transformed signals (with different wavelets and levels) and combines them with an additional Statistical Features input (input_4) to provide one step ahead ...
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0answers
82 views

How do audiobook players manage to quickly speedup/slowdown playback speed without using more memory?

Many audiobook player apps on Android have a reading speed slider which lets us choose the reading speed e.g. 0.5x 0.75x 1.00x 1.25x 1.50x. This is time-stretching ...
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1answer
22 views

Implementing echo on adsp 21262 [closed]

I'm working on an echo implementation on the board adsp 21262. I've added a buffer to have more samples to work with. I end up then with 4 buffers of size 2048 each. The problem is that I need to ...
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1answer
246 views

How to find correlation/cross-correlation of two signals in real time?

Considering there are two signals and the signals are real time in nature. Visibly when one signal does up the other signal does down and vice versa. Sometimes both the signals moved towards the same ...
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1answer
133 views

Are there DC removal techniques that do not introduce a filtering transient?

I have an application in which I need to remove DC components from a sampled signal in real time (basically the same constraints of ECG, but it has nothing to do with the brain). My measured signal in ...
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1answer
122 views

Implementing real-time signal processing filters

I’m currently working on my capstone for school, and I’m looking for some guidance/tips when it comes to real-time filtering. The nature of the project is to monitor breathing patterns, send the ...
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1answer
113 views

FFT of a $N$-length real sequence via FFT of a N/2-length complex sequence

I would like to optimise FFT algorithm by only using a FFT of size $N/2$ to transform a real sequence of length $N$. There are already many questions and many excellent answers on the matter (here for ...
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2answers
56 views

What fps can be considered as a hardline for real-time performance? Is there any academic paper that describes this?

I am trying to design a deep learning based inferencing solution for security applications. My deployed program achieves an FPS of 15fps for classification. Can it be considered real-time?
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1answer
34 views

Question on Levinson's proposed discrete form of Wiener filter

The whole foundation of Levinson's discrete version of Wiener filter is based on the assumption of stationarity of a time series, and aims to predict a value based on the past observed values. Now, if ...
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2answers
57 views

How can I calculate what a recording would sound like if it was played through my speakers and mic?

I am trying to isolate the sound of someone speaking while music plays back in a noisy environment. I have multiple speakers and a microphone in my system. I am able to play back just music and ...
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1answer
82 views

Perform overlap add with available FFT size smaller than filter coefficients

I would like to process 12 to 20 seconds of incoming audio at a sample rate of 44100. I must process this audio in real time in an STM embedded kit (perhaps also an Android Smartphone). I'm trying to ...
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1answer
69 views

How can i record 1 MHz signal and do a real-time processing in a PC? [closed]

I have a 1 MHz signal from transducer that needs to be analyzed in real-time condition, so the sampling needs to be more than 2 MHz. It consists of digital filtering, turn into spectogram and feed ...
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1answer
50 views

What are some efficient algorithms for real-time calculation of eigenvalues?

I need to calculate eigenvalues of a square matrix for a real-time implementation using microcontrollers or dSPACE. Obviously, I can find the eigenvalues of a 2by2 matrix analytically. I am wondering ...
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1answer
1k views

Matlab code for wigner ville distribution [closed]

I wanna to have a wigner ville distribution spec.and need code in matlab
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1answer
175 views

Real-time modulated IIR filter

I've been learning to implement an IIR filter for a synthesizer project. It is now more or less stable when the parameters are constant, but ultimately I want the parameters to be arbitrarily ...
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43 views

DSP Hardware recommendation or is it even needed?

I'm new in embedded programming. Trying to choose a dsp, they seem very feature rich for my planned usage. I want to analyze 18 signals (simultaneously or near simultaneously) real time. I want to do ...
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2answers
935 views

Do all real-time filters introduce phase lag, or can there be such a thing as “lag-less” or “zero lag” real time filters?

Do all real-time filters introduce phase lag? I once heard of "lagless filters", but I don't think they can be used real-time (ie: on live data streaming in for a control system, for example, ...
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135 views

Real-time implementation of cascaded all-pass filters from given transfer function

I am working on real-time implementation of spring reverb based on scientific paper called Parametric Spring Reverberation Effect by Välimäki, Vesa; Parker, Julian; Abel, Jonathan S. One block of ...
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1answer
561 views

Real-time wavelet decomposition and reconstruction for ECG feature extraction

I need to locate R-peaks in an ECG signal. I'm using wavelets to extract QRS complexes: First, I decompose the signal using a maximal overlap discrete wavelet transform with the Symlet 4 wavelet. This ...
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1answer
102 views

Finding good feedback coefficients for basic reverb

I'm currently working on some reverb algorithm code for the Gamebody Advance to get a bit of that ambient feeling for the music instead of having plain dull sound. A few challanging restrictions are ...
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0answers
30 views

Efficient format for 2D signal?

I'm trying to solve the following problem. I got a "low frequency" input 2D signal over a square region. I'll collect a few samples, somewhere around 10-30 maybe, the exact sample count will be ...
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1answer
46 views

Buffering block and filter length in real-time processing

I have a signal sampled at 256 Hz, which I want to filter with a 50 taps long FIR filter in real time. Would it be a problem, if my data block size is only 32 samples? And should I then concatenate 3 ...
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3answers
2k views

what is the difference between buffering and queuing?

I've some problems with definition of queuing and buffering so what is the difference between buffering and queuing ?
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1answer
1k views

How to find Leq for a WAV audio file like an SPL Meter would?

Given an audio file (WAV), I need to find the $\rm L_{A_{eq}}$ (continuous A-weighted equivalent sound pressure level) of the audio file. For this purpose, I am following this workflow: Get a frame ...
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2answers
381 views

Two real time signals convolving

This might be a stupid question but is it possible to convolve two real-time signals together? I know that generally for running convolution you have the IR and the block of the real time signal and ...
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0answers
69 views

Pose-invariant face detection and recognition

I would like to detect faces and later apply recognition algorithms to surveillance videos. Ideally, the application should run in real-time (or near real-time) and transfer the data first to an ...
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0answers
82 views

Dot or point pattern recognition for Braille Paper

we are very new to image processing field. We are gonna do a study about braille to text conversion, by the way braille is a method of writing for blind. !(https://fryemuseum.org/images/...
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3answers
414 views

IIR biquad real-time filter just output noises

I've implemented a IIR filter but it outputs only noise (like FM radio out of tuning) and I can't see what's wrong. This is the processing function: ...
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1answer
688 views

Guitar pitch detection [duplicate]

I try to develop a guitar game in android platform. And I need to do the real-time pitch detection of guitar chord. I will get the input from the microphone, and then analyze the input (the input ...
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1answer
127 views

Matching guitar signal with tablature, near real-time algorithms?

I'm looking for candidate algorithms that might work for a use-case comparable to Rocksmith's analysis system. To compare a clean electric guitar signal with a tablature reference. A higher latency ...
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0answers
74 views

Which is faster: image segmentation or line detection?

Some papers use image segmentation techniques and others use edge detection. I need to know which one is faster. update: I need to do semantic segmentation for outdoor sense and the data is optical ...
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1answer
83 views

Rollercoaster: determining subject position from inertial data?

I have inertial data (accelerometer, gyroscope, magnetometer) from phones of human subjects riding a single rollercoaster repeatedly. The ride has temporal variance (ex. sometimes getting from A to B ...
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1answer
65 views

Does it make sense to recompute Parks-Mccellan on a per sample basis?

I'm thinking of using Parks-Mccellan for my equalization needs, but since I require that the filter be variable (gain, Q etc.) then does it make sense to recompute Parks-Mccellan on a per sample basis?...
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108 views

Fast greyscale image segmentation on 16x16 image

I have a 8-bit greyscale 16x16 image where I want to extract coherent shapes with a more or less consistent pixel arrangement if possible (like: a rectangle, staircase, line). Currently, I'm doing ...
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1answer
365 views

Determining the covariance of point clouds in real-time

So basically I have a set of multidimensional data that I need to determine the covariance of between dimensions in real-time. Each point that comes in is a vector. I have gotten the mean and variance ...
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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 ...
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0answers
96 views

Sample-By-Sample Linear Prediction

As I understand it and have it currently implemented, linear prediction [via Burg's method or the autocorrelation method] is a block algorithm. Hence, there will be latency involved because one must ...
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2answers
738 views

Play IQ data in the soundcard

I have short-wave digital receiver that send RP packets with IQ components over network depend of the RF frequency and passband. I need to work with the telephone passband (0.3 - 3.4 kHz). The task is:...
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2answers
7k views

Can deep neural networks achieve real-time video analysis?

Recently, convolutional neural network based, deep architectures (DNN) such as AlexNet and VGGnet have been very successful in image classification challenges (e.g. ImageNet) and action recognition/...
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1answer
9k views

What is Typical RTP Packet size for H.264 video transmission

I am encoding my video using JM reference software. The encoded file is divided into RTP packets. I can set a RTP packet size in bytes using configuration file. But i am unable to find what should be ...
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1answer
130 views

Multichannel input/output evaluation board

I'm working on a project at school and the first step is to choose a dsp/evaluation board but I'm having trouble. The project is to create a system that can be used for a variety of audio applications ...
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1answer
1k views

Real-time delay between signals

I currently have a real-time noise suppression algorithm based on two inputs from different microphones. It has passed most tests that I have thrown at it, however when the signal I am trying to ...
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3answers
423 views

Filter Design - Step Response

I'm looking for a tool\method which allows me to design a filter without involving the frequency response at all. Specifically, I'm trying to design a simple FIR smoothing filter for an emmbedded ...
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2answers
9k views

Filtering a digital signal online in real-time using python

I am currently trying to apply a bandpass filter to a signal in real-time. There are samples coming in with a constant sampling rate and i would like to calculate the corresponding bandpass filtered ...
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2answers
83 views

Computes velocity from sampled position

My system is : A step by step wheel returns its position each 150ms. I want to pilot an horizontal infinite scroll bar with the wheel. The scroll bar needs velocity as input to move. Moreover the ...
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0answers
43 views

Is there a way to go from a set of (F/D)FT values to FIR coefficients?

I'm not yet well educated on the DSP subject, but I've initiated a project where I will do some audio filtering. My intuition tells me that there is a link between the coefficients of a FIR filter and ...
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1answer
248 views

Cascaded one-pole sections and relationship to time constant

I have implemented a typical one-pole lowpass filter to smooth out some control signals. The form of the filter is: $$ y1 = x0 + b1\centerdot(y1 - x0) $$ x0 is the current input sample. y1 is the past ...
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59 views

Estimating the power consumption of an arbitrary, real-time DSP algorithm

Consider a digital signal processing algorithm that operates over a block of $L$ [samples], with a real-time constraint $\tau$ [s] (i.e. its throughput must be $L/\tau$ [samples/s]). The theoretical ...

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