Questions related to implementation of various algorithms under software environments and programming languages.
1
vote
1answer
72 views
What is the most efficient type of software bandpass filter?
I'm writing a C++ application to extract four modulated carrier signals at four separate frequencies, from a single input signal. I've designed four FIR filters at t-filter.appspot.com but they run ...
1
vote
1answer
47 views
Amplitude calculation
I've got an array of different values representing the y-values in a plot:
...
4
votes
1answer
103 views
How does filter bank work in image processing?
I read a paper about directional filter bank in image processing and I don't understand clearly about the process. It says they use '2-band structure' like this image:
could someone here please ...
3
votes
0answers
82 views
Qualitative Evaluation of Interest-Point-Detectors and Descriptors in Computer Vision
I'm writing on a qualitative evaluation study of interest-point-detectors and descriptors. I've read all Mikolajczyk papers as well as most of the surves from Datta et al. etc. Now I'm implementing an ...
5
votes
5answers
304 views
When to consider double (64 bit) floating point for Audio
When synthesizing and processing audio on modern processors, when would one consider using something other than single precision (32 bit) floating point? Obviously, the audio coming in and going out ...
7
votes
1answer
132 views
Convolution involving turning each pixel value to the most represented pixel value of the neighbourhood
In order to correct gradual changes of intensities in the background of grey-scales images, I have been blurring them and then subtracting the original images from the convolved one.
In some cases, I ...
3
votes
1answer
850 views
How do I implement the Structure tensor (in Matlab)?
I am trying to figure out the details on how to implement the structure tensor in Matlab and need some advice!
For an image $\ I(x,y) $ the structure tensor S is given by:
$$ S=\begin{pmatrix}
W ...
4
votes
2answers
169 views
Is it possible to transmit and/or receive multiple types of signals at the same time?
Using an inexpensive SDR (such as the USRP or Per Vices Phi), I want to process two or more communication protocols at the same time (e.g. WiFi and GSM). Is it possible to Tx (or Rx) both at the same ...
3
votes
3answers
291 views
Demodulation of a BFSK frequency hopping signal using FFT
I am not very familiar with DSP techniques, and I am currently working on my research project to develop the firmware of a DSP processor, using C/Linux. It involves the modulation and demodulation of ...
2
votes
0answers
82 views
What is EAQUAL ? How does it relate to PEAQ?
This wiki post on wiki.hydrogenaudio.org says that it is very similar to PEAQ and also a part of ITU-R BS.1387 recommendation ? How reliable it is for determining audio quality.
Are there any other ...
4
votes
1answer
345 views
Why can Quadrature Demodulation demod a Frequency Modulated Signal?
I use a Quadrature Demodulator in my SDR application, which is defined as:
$\angle (S_n, S_{n+1})=arctan(S_{n+1}*\overline{S_{n}})$
So practically its amplitude is the angle between two Samples ...
4
votes
1answer
456 views
Help with equations for exponential ADSR envelope
With application code, I have implemented a linear ADSR envelope for shaping the amplitude of an oscillator's output. The parameters for attack, decay and release duration as well as sustain level ...
7
votes
1answer
578 views
Tutorial on 2nd generation wavelets (with lifting)?
For some denoising and deconvolution experiments, I'd like to apply a 2nd generation wavelet transform (using lifting steps) to images.
I know that there are several implementations available, but ...
5
votes
1answer
149 views
Help with algorithm for modulating oscillator pitch using LFO
I am developing a software emulation of an analog synthesizer. I am trying to modulate the pitch of an oscillator using an LFO. For each sample fed to the computer's sound system, I am calculating ...
5
votes
2answers
360 views
How can I break a filter down into second order sections?
This is a follow-up question of How do I apply a Chebishev filter? I designed a filter in Scipy:
...
1
vote
1answer
108 views
How to calculate the gain in a bivariate fft in R?
In Statistica gain is defined as follows:
Gain. The gain value is computed by dividing the cross-amplitude value
by the spectrum density estimates for one of the two series in the
analysis. ...
6
votes
2answers
263 views
How do I apply a Chebishev filter?
I read a paper about a brain-computer interface. In this paper the authors reported "each signal has been filtered with an 8-order band-pass Chebishev Type I filter which cut-off frequencies are 0.1 ...
-3
votes
2answers
719 views
how to extract features from this image ? what are the suitable features to be selected?
I have this image:
After many preprocessing operations, I obtained this image
my goal is implementing one to many matching on my images for recognition purpose,i have 250 image for 50 persons (5 ...
7
votes
2answers
770 views
“Low-pass filter” in non-EE, software API contexts
I am an experienced software engineer and am working on smartphone sensors. I've taken fundamental EE classes in DSP and am trying to apply my knowledge. I believe that I understand convolution, ...
6
votes
1answer
320 views
System identification packages
I've been hunting around for an alternative to Matlab's System Identification Toolbox, but the commonality of the terms "system" and "identification" are confounding the search.
Are there any ...
4
votes
2answers
2k views
How does MATLAB handle IIR filters?
MATLAB has a butter, which constructs a Butterworth filter given an order and relative cutoff frequency. The filter created can be used to ...
12
votes
1answer
475 views
Removing Glare from Image
Disclaimer: I am in NO way engaged in signal processing. Just very curious...
Ny question is, very simply: is it possible to apply software processing to an image to remove or reduce headlight ...
10
votes
2answers
416 views
How to implement a digital oscillator?
I have a floating-point digital signal processing system that operates at a fixed sample rate of $f_s = 32768$ samples per second implemented using an x86-64 processor. Assuming that the DSP system ...
10
votes
3answers
976 views
Where can I get an open source implementation of the Parks-McClellan optimal FIR filter design algorithm?
Background:
Often times I am doing some sort of signal processing task that requires a unique filter. Usually at this point I go to Matlab and generate a new unique filter using firpm(). The Matlab ...
14
votes
2answers
676 views
Are there any standard implementation forms for tunable Butterworth filters?
One of the standard ways to implement a Butterworth filter is with a cascade of second-order sections, each corresponding to a pair of complex-conjugate poles. For a fourth-order filter, for example, ...
