Python is a high-level interpreted general programming language. Python has popular numerical and scientific libraries/packages, most notably numpy and scipy. The scipy.signal package is a powerful signal processing software collection. This tag covers the use of numpy, scipy, and other Python ...
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1answer
95 views
What do I do with the result of an FFT?
So I am working on a project using digital signal processing, which I am not familiar with at all, and a lot of this is all new to me. I am using SciPy\NumPy to play around with code to understand the ...
2
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0answers
79 views
Ricean Multipath channel model implementation
I'm trying to implement a multipath ricean channel model. I had found several resources but I'm kind of lost with too much information. What I have from now is the following step:
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3
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2answers
70 views
Fixed point channel model for OFDM system
I'm testing an OFDM system implemented in fixed point. The data format is Q11. My system work's fine but I need to test it under some channel for evaluation of the design before field testing. The ...
2
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1answer
127 views
Apply AWGN noise to QPSK-OFDM symbol
I'm working on an OFDM-QPSK based system and I'm having some trouble to match the BER of my system with the theoretical curve. My OFDM implementation fills all the subcarriers and have t_symbol s ...
2
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0answers
34 views
How to find the group delay of IIR filters in Python/SciPy
I sent a square wave signal (red) through a IIR filter (butterworth in this case), to make it more "realistic". Then there's a slight group delay in my output signal (blue). Is there a way to find out ...
4
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1answer
131 views
What is the phase and magnitude response of white noise?
I would like to create white noise in the frequency domain, and then transform it to the time domain using python. To understand the problem, I simply generated white noise in the time domain, and ...
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1answer
47 views
Amplitude calculation
I've got an array of different values representing the y-values in a plot:
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4
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2answers
154 views
Simulating analog filter using convolution or converting with fft
My task is simple; I want to simulate analog low-pass filtering of an input signal, using Python. Note that the input signal is an array of values, not an analytical function.
My first question is if ...
2
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1answer
91 views
Deconvolution in Python
I'm trying to use and understand SciPy's deconvolve for a project I'm working on. I'm having some trouble understanding how to use it.
What I would like to do is to take two PMFs from discrete ...
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1answer
144 views
How can i measure shape elongation feature in matlab or python opencv?
How can i measure shape elongation faeture in matlab or python opencv?
There is a function library or i have to implement to my own?
In case there is no function, i found this definition:
"The ...
2
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1answer
145 views
Working backwards from PSD to possible signal
I have been trying to reconstruct a random signal from its PSD and am running into trouble. I know that many different signals in the time or spatial domains can result in the same PSD-- I am ...
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0answers
32 views
There are other shape properties scale-rotation invariant except HuMoment?
There are other shape properties scale-rotation invariant except HuMoment?
There are example that show me how can i implement them?
I find this example in c++ ...
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1answer
65 views
All-pass filter implementation in numpy
I'm playing with Python & numpy to filter audio. It is relatively straightforward to design and us low-high-bandpass/stop FIR and IIR filters, stuff can be done in a couple of lines.
I'm ...
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1answer
147 views
Failed to implement Goertzel algorithm in Python
After some questioning on stackoverflow, I tried to implement a Goertzel algorithm in Python. But it doesn't work : https://gist.github.com/4128537
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0answers
103 views
Use fourier transform to calculate image pixelation coef in python
I want to calculate a coef of image pixelation to remove bad pictures from a bunch of files.
Some pictures results from bad compression and we can see a lot of pixelation on them like img a here: ...
2
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1answer
215 views
Half Subcarrier spacing in LTE Uplink
First post here, trying to make it as good as possible. Do not know how to make the Python code look nice - any tips? :) Anywho - to the main problem:
I am currently working on simulating the uplink ...
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3answers
546 views
What's wrong with this code for tomographic reconstruction by the Fourier method?
I've been playing around with tomographic reconstruction algorithms recently. I already have nice working implementations of FBP, ART, a SIRT/SART-like iterative scheme and even using straight linear ...
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5answers
560 views
Finding squares in Image
I need to find the squares in an image using OpenCV (no problem in matlab or any other, generally what i expect are some ideas).
Consider the test image below :
I need to find those coloured ...
5
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3answers
659 views
Is it correct to subtract a low-pass filtered signal from the original signal and use the result as a “high-pass”?
I am having a hard time trying to find documentation to implement band-pass or high-pass filter with python/scipy/numpy.
I can easily create and apply a low-pass filter, though, so I ask:
Would it ...
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2answers
1k views
Picking the correct filter for accelerometer data
I am fairly new to DSP, and have done some research on possible filters for smoothing accelerometer data in python. An example of the type of data Ill be experiencing can be seen in the following ...
4
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3answers
1k views
Beginner Attempting FFT Signal Filtering With Numpy
I've tried looking around for information on this, but I'm really out of my league here. I'm a guy who likes to fool around with Python, and I wanted to make a program that would filter an audio file. ...
7
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1answer
124 views
Recognizing data clustered into shapes
I am working on a project in Python to detect and classify some bird song, and I have found myself in a position where I need to convert a wave file into frequency vs. time data. This hasn't been too ...
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5answers
2k views
How to write lowpass filter for sampled signal in Python?
Sorry for question that may be trivial, but I am new in signal processing, and I didn't find python code with good explanation. So I will be glad to get explanation for dummy :)
I have some signal ...
3
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1answer
98 views
How to remove color cast from HSV information
I have hue, saturation and value of a color (HSV color-space). The color has to be set on a device that displays them incorrectly. If I specify white it displays light magenta. However, if you specify ...
3
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0answers
337 views
Scipy - Audio Processing
I looking for good tool for Audio signal processing. e.g Speech & music analysis, identification.
Does scipy provide functions for audio processing? Is this a good tool for Audio Signal ...
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2answers
362 views
Complex impulse response functions?
I think I must have misunderstood something regarding the relation between impulse and frequency responses.
I have calculated the Impulse Response Function, IRF, from the Frequency Response ...
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4answers
492 views
Counting the number of groups of 1s in a boolean map of numpy.array
I am right now dealing with some image processing in Python via PIL (Python Image Library). My main aim is counting the number of colored cells in an immunohistochemistry image. I know that there are ...
3
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2answers
231 views
What is the best method for merging time lapsed photos? Accessable from python(PIL)
I have numerous photos from a still image camera that I would like to merge into one photo to allow for easy spotting of motion or new objects. There is a bit of noise across the photos but not very ...
3
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2answers
748 views
How to remove the boundary effects arising due to zero padding in scipy/numpy fft?
I have made a python code to smoothen a given signal using the Weierstrass transform, which is basically the convolution of a normalised gaussian with a signal.
The code is as follows:
...
11
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2answers
2k views
Improving spectrogram resolution in Python?
I'm using the specgram() function in matplotlib to generate spectrograms of speech wave files in Python, but the output is ...
6
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2answers
252 views
How can I detect buttons in a GUI of an app with pattern detection using python?
I will explain taking as example the GUI of the Calculator app in windows.
Given this Calculator application open and focused, I need to find a way of detecting all the buttons.I can only use ...
10
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2answers
352 views
Fail to separate sound signals by FastICA on real-world recording
I have written a program to perform FastICA on a stereo WAV file using the code on Python MDP FastICA Example
With the audio examples I get very good results.
Then I try to do real world recording ...
12
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1answer
9k views
low pass filter and FFT for beginners with Python
I am new to signal processing and especially to FFT, hence I am not sure if I am doing the correct thing here and I am a bit confused with the result.
I have a discrete real function (measurement ...
