Questions tagged [algorithms]

Algorithm is a method expressed in a finite list of steps of well-defined instructions to process a signal.

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1answer
57 views

FFT algorithm gives wrong signs on my output numbers

I was told from another stack exchange (stackoverflow and computer science stack exchange) to post here - so hopefully now i can get some help from people who understand the algorithm, but if this is ...
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17 views

Is my implementation of Generlized Pencil-of-Function correct?

I have a time-series data that should be of the form $$ f(t) = \sum_nA_n(e^{\alpha_n t}+e^{-\alpha_n(T-t)});\;\alpha_n=\eta_n+i\omega_n;\;i=\sqrt{-1} $$ and I want to find parameters $A_n$, $\eta_n$, ...
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29 views

Asymmetry In The Mirroring Of An FFT Of A Sinusoidal Signal

I am trying to implement a Cooley-Tukey FFT algorithm in its iterative version. Specifically, I am implementing this Wikipedia pseudocode (please look at the section Data reordering, bit reversal, and ...
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1answer
52 views

Clear examples of Fixed Point Algorithm Specification Block Diagram for FPGA Implementer

I have been working on converting a simple, floating point algorithm to fixed point and need to create a block diagram to help the guy who will implement this on an FPGA. As often is the case, the ...
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120 views

Algorithm that Fills the White Holes Within the Character Image

I have this degraded image : Using paintbucket tool in Paint.NET Windows application, I fill the character image black. My ...
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19 views

Remove background, keep black characters

I use ID scanner machine (link) to remove the background. The result is the gray image below. It seems that the scanner uses IR to do that. Is there any algorithms to obtain the same result? Thanks in ...
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1answer
57 views

Discrete Wavelet Transform output: coefficients or FIR-filtered signals?

I have a theoretical question about the calculation of the Discrete Wavelet Transform, using MATLAB specifically. According to this video-tutorial on the MATLAB lagorithm: https://it.mathworks.com/...
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1answer
13 views

Implementing an L-System conversion from R2 to R1 for symmetric, square matrices

I have been reading for some time about L-Systems, and specifically the Hilbert Space filling curve. I am interested in writing a function to convert upper-triangular matrix coordinates into an ...
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1answer
49 views

Upsampling implementation

I have problem with upsampling implementation in the following way: My code: ...
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0answers
69 views

Mapping ring asteroids in Elite Dangerous by image processing

In the game Elite Dangerous, which is an online spaceflight-based sandbox game set in a procedurally-generated galaxy, one of the most profitable in-game occupations is mining commodities from ...
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1answer
71 views

Algorithm to Count Zeros Outside Unit Circle for FIR Filter

As detailed in this post Can I set a constraint on the first tap of an FIR filter such that its inverse is stable? I show how Cauchy's Argument Principle can be used to easily confirm if an FIR filter ...
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1answer
51 views

What is the difference between time complexity and sample complexity?

What is the the difference between time complexity and sample complexity in the context of algorithm development? I'm currently studying the sparse Fourier transform and this idea of sample ...
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26 views

What is the technical term to join two signals with different phases?

there is a name for this: If I have two signals with a discontinuity, arrange the phases of one signal to fit the other and not see the discontinuity.
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21 views

Why does the griffin lim algorithm work?

the griffin lim algorithm works to reconstruct audio from a magnitude spectrogram, but i don't understand how reusing the same spectrogram every iteration with noise can produce decent sound How from ...
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11 views

Question regarding the implementation of the guided random walks algorithm

I'm working on the implementation of the paper: Segmentation by retrieval with guided random walks: Application to left ventricle segmentation in MRI. I tried to modify the weights functions mentioned ...
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0answers
38 views

Is there a FFT algorithm which is both in-place and constant geometry?

I work in crypto where the NTT (Number Theoretical Transform) which is just a FFT in finite fields is used. I wanted to know if there exists an implementation of the FFT which is both in-place and ...
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1answer
57 views

RF signal identification algorithms

There exist many, many analog and digital data transmission protocols. It is often difficult to tell which mode one listens to and tedious to do for many signals. In Ham Radio, a Reed-Solomon ...
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1answer
48 views

How to compute an old style shore line drawing?

I wish to represent a shore line, old-style, as in the following image (city on the left, water on the right): UPDATE: new image for another example of what I'm after, namely the thin lines (given ...
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1answer
70 views

How CDMA receiver extract it's corresponding data from the receiving modulated & superposition-ed signal?

I have difficulty understanding CDMA. I have read all those PN/walsh code things, and understand orthogonality very well. But none of the resources I found demonstrate how a receiver end extract ...
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24 views

Reconstract the image from the modulus of its Fourier transform

In Reference, it is shown than one can recover the image by using only the modulus of its Fourier transform. It provides two iterative algorithm which is really similar to Gerchberg–Saxton method. ...
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3answers
257 views

Best Approach to Rank Complex Magnitude Comparision Problem

This is in reference to the responses for an efficient algorithm for the comparison of bounded fixed point complex numbers at this post. Efficient Magnitude Comparison for Complex Numbers See the ...
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1answer
198 views

The selection of the amplitude of the signal, consisting of rectangular pulses, at different frequencies

I already asked a similar question, but did not receive an answer and did not find a solution, I want to make another attempt to get to the bottom of the truth. There is a signal consisting of ...
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9answers
1k views

Efficient Magnitude Comparison for Complex Numbers

Is there a more efficient algorithm (or what is the most efficient known algorithm) to select the larger of two complex numbers given as $I + jQ$ without having to compute the squared magnitude as $$...
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1answer
135 views

Separation of signals without loss of information about the signals themselves

There is a signal that contains: Rectangular pulses on frequency of 1 kHz Rectangular pulses on frequency of 1.4 kHz Other noises. Required: Separate 1kHz pulses from everything else and measure ...
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14 views

Smooth Cross-Fading [duplicate]

I want to cross-fade from one signal smoothly to another signal. Example: Signal1 = 5 Signal2 = 1 I already looked for algorithms/ procedures but could not find anything helpful. As I am not that ...
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16 views

Finding Duplicate Pixel/Objects along Image seams

I have a seam of two photos joined by a seam alignment algorithm that on occasion generates duplicated pixels/objects/artifacts on both sides of the seam in the final, aligned photo. The images are ...
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2answers
253 views

Understanding Voss-McCartney pink noise generation algorithm

I'm implementing the Voss-McCartney pink noise generation algorithm. If you follow the link above, you can read: from James McCartney 2 Sep 1999 21:00:30 -0600: The top end of the ...
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2answers
94 views

how a signal for which calculate RMS can be filtered and have a fast settling time?

i designed a sinusoidal pwm amplifier (3KHz to 20KHz) that regulates its output voltage reading the RMS value of output current. The RMS is obtained squaring the signal sampled by AD converter @...
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1answer
76 views

One Too Many Non-Zero Eigenvalues in MUSIC DF Algorithm

I'm working on simulating the MUSIC algorithm in MATLAB to determine the azimuth angle of arrival of a simulated signal. My virtual antenna array consists of 4 antennas arranged in a plane. While I ...
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21 views

decouple signal from environmental effect

Sensor signal depends on environmental factors such as temperature, relative humidity. Temperature compensation is relatively straightforward. But I am not entirely sure how to model the effect of ...
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0answers
75 views

Space-Time coding uses large amount of block codes to acheive maximum spectral efficiency

Assume I have a MIMO system with $M=8$ transmit antennas, and an arbitrary number of receive antennas. This MIMO systems uses space-time coding. the block codes (matrices) transmitted are part of a ...
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1answer
117 views

Understanding Fourier Transforms in abstract math terms

I am having a hard time implementing a method that computes Fourier transform coefficients for the complex form using the trapezoid rule. I have floated questions in the math and stackoverflow ...
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1answer
66 views

Fuse two sources of linear acceleration with a Kalman filter

How would I fuse two different sources of linear acceleration with a Kalman filter (perhaps linear acceleration readings from an IMU and from a dedicated accelerometer)? My state is defined by ...
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45 views

Range Migration Algorithm in FMCW MIMO radar

I’m using a FMCW MIMO radar [77-79 GHz] with a virtual linear array made of 48 channels. I’m wondering if the adaptation of the range migration algorithm (typically used in SAR processing) is ...
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0answers
31 views

Hot to generate image through Delay and Sum algorithm

I want to generate image through Delay and Sum algorithm. The list of the formula are attached, I have calculated rij(t) which is nothing but signals in time domain (1xn matrices), and the tij(x,y) (...
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62 views

State of the art for automatic rhythm analysis

What are the currently most used and less error prone algorithms in the field of music information retrieval for beat detection and tracking?
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2answers
81 views

Idea for Noise Level Estimation / Automatic Thresholding in the Presence of Peaks

I have the fft of some signal, and want a rough estimate of the noise level in order to choose an appropriate threshold for our peak detection algorithm. In general, the fft contains mostly noise with ...
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1answer
220 views

Understanding a lowpass - comb filter implementation

I try to understand the implementation of the low-pass comb filter of the Freeverb reverberation algorithm: https://ccrma.stanford.edu/~jos/pasp/Lowpass_Feedback_Comb_Filter.html The original ...
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1answer
223 views

Need Help with Time-Stretching WSOLA Algorithm

I’m having problems implementing time-stretching using the Wave Similarity Overlap Add (WSOLA) algorithm. I got the basic OLA algorithm working first and then added wave alignment using cross-...
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1answer
132 views

Baseband signal processing algorithms [closed]

What is one exactly referring to when you say "baseband signal processing algorithms"? Can anyone give a few (common) examples.
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1answer
58 views

Is it possible to estimate the DOA from real samples only?

I'm sampling a ULA with a scope after transmitting a CW. I'm wondering if I can estimate the DOA assuming I'm interested only in the range [0,90] [deg] and not the full [-90,90] [deg]. The first issue ...
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1answer
60 views

How to automatically identify a surge in a periodic signal

Say I have a periodic signal i.e. Sine wave, which sometimes can have spikes that are 100% larger than the peak value. These spikes can be periodic as well. I'm trying to find an algorithm that could ...
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27 views

Extracting 'structure' post permutation

I have particle activity as shown in the left pane of animation below. The activity is clustered and it moves slowly. Sometimes these clusters merges together. On the right side of it, its shuffled ...
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1answer
62 views

What do these values in the freeverb diagram mean?

I am implementing a reverb based on the Freeverb implementation detailed here. There is also a more in-depth description of the LBCF in question here, but I am not able to find the information I want ...
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1answer
60 views

Goertzel derivation

Referring to this link, about Goertzel,I am confused about the final equation after N iterations Where does real = (q1 - q2 * cosine) and ...
2
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1answer
59 views

Are there any efficient algorithm to detect circular shape of arbitrary size in an image?

I have images that are 1278 by 1024. They are pictures of a certain product that is rectangular in shape and are about 25mm by 20mm. As a part of a quality inspection process using computer vision, ...
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80 views

Robust peak detection taylored for spectroscopy

i need a algorithm for peak detection in raman spectroscopy. I tried this one, but it did not give me satisfying results. Spectrums may look like this: In professional software, i think they use the ...
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0answers
17 views

Partitioning data for minima detection

I am working with signals that consist of consecutive equidistant dips. I am trying to write an algorithm that finds the absolute lowest (minimum) point in each of the dips. We don't know the ...
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1answer
104 views

Is it possible to do better than Cramér Rao lower bound for different estimation methods

I’m new to learning about the Cramér Rao lower bound. Does the calculation of the CRLB imply that only particular estimation algorithms can be used (e.g. estimating delay and Doppler from a complex ...
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1answer
129 views

Maximum likelihood estimation complexity computation

I have a basic question about maximum likelihood (ML) estimator and its implementation. I am trying to simulate a communication system, while using ML at the receiver side to find the transmit ...

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