All Questions

9
votes
0answers
556 views

Will an Unscented Kalman Filter Be “As Good” as Other Optimization Algorithms for This Problem?

I want to calibrate a tri-axis magnetometer when a tri-axis gyroscope is also available. I am fairly certain I can solve this problem using various optimisation algorithms, but I would prefer to use ...
9
votes
0answers
1k views

Ensemble learning, multiple classifier system

I am trying to use a MCS (Multi classifier system) to do some better work on limited data i.e become more accurate. I am using K-means clustering at the moment but may choose to go with FCM (Fuzzy c-...
8
votes
0answers
223 views

What is the normalization factor for the quincunx lattice wavelet transform, and how do you find it?

On pages 57-60 (preview was available last I checked, images here in case), there is a quincunx lattice transform described. Lattice: ...
7
votes
0answers
1k views

Help in Retraining a HOG Descriptor using SVMLight

I am currently trying to count cars using OpenCV 2.4.4 with a HOG descriptor. Because a model for car detection is not available in OpenCV, I am creating my own model using SVMLight and a dataset of ...
6
votes
0answers
166 views

EWMA based differential that is strictly positive on strictly increasing irregular time series?

Let's say I have a time series $ \{t_i, x_i\} $ where the $x_i$ are strictly increasing and the $t_i$ are not regularly spaced. I can define a differential operator as $$ \Delta_i = \frac{x_i-x_{i-1}...
5
votes
0answers
145 views

Distribution of the output of AWGN channel

$$\mathbf{Y}=\mathbf{X}+\mathbf{W}$$ $\mathbf{X}$ is input, an $n$-dimension equiprobable vector in a finite subset of complex space $\mathcal{A}^n \subset \mathbb{C}^n$ with norm $\sqrt{\rho n}$ (...
5
votes
0answers
199 views

What's the similarities and differences between Wigner transform and wavelet transform?

Wigner transform and continuous wavelet transform are both some kind of time-frequency representation of a signal. What are the similarities and differences between them? Could you give some ...
5
votes
0answers
161 views

Stochastic process inference from partial observations

Consider a set $U$. My signal is a piece-wise constant "function" $Sig: t \mapsto s$, i.e. the signal at time $t$ equals to some subset $s \subset U$. One can see $Sig(t)$ as a stochastic process. ...
5
votes
0answers
452 views

Zero-padding of MFCC coefficients

I am trying to implement speech recognition using backpropagation algorithm, and I have been following this paper. I have followed it all the way, except that it tells me to zero-pad the coefficients ...
5
votes
0answers
549 views

fit theoretical spectrum to simulated one

I have a bunch of simulated time series, for which I can compute the power spectrum. Generally, the simulated power spectrum can be sketched as follows: I now aim to calculate the features of the ...
5
votes
0answers
139 views

Filtering Corners Detected on Multiple Scales

I made a multi-scale Harris corner detector (inspired by MOPS) which is simply a Harris corner detector performed on several scales (i.e. subsampled versions of the same image). This effectively make ...
5
votes
0answers
2k views

Jacobian Matrix of a Quaternion $q$ respect to Angular Velocity $\omega$

In the context of visual tracking and video processing I need to estimate variations of the orientation related to the angular velocity. I am trying to calculate the Jacobian matrix of a quaternion $\...
5
votes
0answers
538 views

Spread-spectrum systems and multipath fading

I didn't find a suitable tag for this, but figured it would fit under "Frequency spectrum". Which of the Spread-spectrum systems listed here are most resistant to multipath fading? Please, briefly ...
4
votes
0answers
65 views

Eigenvalues of a product of matrices with specific structures

I'm working on a multichannel feedback system with open-loop frequency response $\mathbf{A}(\omega) = \mathbf{B}(\omega)(\mathbf{C}(\omega)-\mathbf{D}(\omega))$. The time-domain convolution matrices ...
4
votes
0answers
83 views

Finding the parameters and endpoints of a sinusoid

Suppose I have some signal $$ s(t) = n(t) + \left\{\begin{aligned} &0 &&: t < t_0\\ &A e^{i (2 \pi f t + \theta_0)} &&: t_0 \le t \le t_1\\ &0 &&: t > t_1 \...
4
votes
0answers
118 views

Unbiased estimation of square in presence of Gaussian noise

I have a single scalar observation, $y$, of a scalar parameter $x$ in presence of additive Gaussian noise. That is $y = x + n$ where $n$ is the Gaussian noise. The variance $n$ is known to be $\sigma^...
4
votes
0answers
528 views

Correct Fish Eye camera Radial Distortion and blurry effect at the image edges

There are a lot of questions regarding this topic ,but I am trying to get a more clear picture from these questions. I am trying to calibrate a fish eye camera and I am using OpenCV omnidir class ...
4
votes
0answers
290 views

Symbol timing recovery design

I am trying to design the Symbol timing recovery(#STR) block of #DVBS Receiver. These are the specifications Symbol rate ($f_s$) = $2\textrm{ MHz}$ Acquisition range = $10\%$ of Symbol rate ...
4
votes
0answers
330 views

Implementing blind deconvolution in MATLAB

I want to implement blind deconvolution for the signal $ r(n) = h(n) \star s(n) + a(n)$ in MATLAB where $r(n)$ is the recorded speech $h(n)$ is impulse response of room acoustics $s(n)$ is desired ...
4
votes
0answers
109 views

How to replace color in an image without changing its texture/shades or brightness?

I want to replace color in an image from another color: For that sample image is below I want to replace color such that it becomes I know it can be easily done in Photoshop but I am looking for an ...
4
votes
0answers
3k views

Verifying MFCC Final Result

I have created a Octave code for MFCC calculation for speech recognition, which takes a wav file as input and then gives the MFCC as the output. But the final results are a bit confusing, so I am ...
4
votes
0answers
294 views

Design Nonlinear (Arbitrary) Phase FIR Filter using Iterative Reweighted Least Squares (IRLS)?

How would you use the MATLAB function below to create a FIR filter with a custom magnitude and phase response? It is from the Statistical Modeling and Inference MATLAB Toolbox ...
4
votes
0answers
416 views

Attempting to use the trapezoidal rule to form a difference equation representing a circuit

I have a differential equation that has been proven to be correct. The transfer function obtained by Laplace domain analysis and Matlab freqs match up and all is well. The problem is somewhere in ...
4
votes
0answers
190 views

Digital control: Exercise solution

Can you help me (show me how) to solve the following exercise? For the process with transfer function $G(s)=e^{-2s}/(s+1)$ design a digital controller with sampling time $T_{s} = 1$ that meets the ...
4
votes
0answers
323 views

Extra 'fingers' found in graph after applying FFT in MATLAB

I am currently working on the FFT function in MATLAB. In this function, i require a 1024 number of data Time Domain plot and produce a 400 number of data Frequency domain plot. After applying the FFT ...
4
votes
0answers
893 views

STFT overlap add method - What am i doing wrong?

i am trying to implement a short time fourier transform of an audio signal to do some filtering (subtract another stft signal using spectral subtraction). I am using a hamming window function with 50% ...
4
votes
0answers
471 views

How to construct descriptors for irregularly shaped image patches

As hinted in this answer, Perceptual hashing is a way to ascribe comparable measures (hashes) to images (rectangular patches). The images do not need to be the same size, and can be slightly distorted,...
4
votes
0answers
105 views

Relative beat detection for two audio recordings

I'm trying to synchronize (overlap) two audio recordings of the same song: a complete HQ version, and an incomplete, noisy version (phone recording for example). The noisy recording may have had its ...
4
votes
0answers
2k views

Demodulation of noisy AFSK signal

I'm trying to implement a software audio modem with FSK to transmit and receive short digital data between two devices (e.g. a PC and an iPhone) so I'm simulating simple cases study using Scilab/...
4
votes
0answers
304 views

Blind 1D equalization/deconvolution with some knowledge of filter kernel

Let $s_{\rm out}[n]$ be the 1D output signal of a system, $s[n]$ be the input, and $k[n,q]$ be the filter kernel for an element $n$ and for fixed value $q$. Then: $s_{\rm out}[n] = s[n] \ast k[n,q]$ ...
4
votes
0answers
1k views

OpenCV face recognition: Finding a best match

I am working on OpenCV2.4.2 C++ interface for face recognition functionality. The face recognition feature seems to be working fine on standard databases. (AT&T, Face Recognition Data, University ...
4
votes
0answers
102 views

How to evaluate performance of a simulated system

I have created a database (DB) of amplitde vs time delay of UWB pulses originating from various (known) points in a certain (known) "region" in a space. This DB also stores region name, since there ...
4
votes
0answers
542 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
0answers
106 views

Capacity of channels with pilots?

Question is about "channel capacity" http://en.wikipedia.org/wiki/Channel_capacity I guess it is pretty elementary for experts, however I have not seen it discussed in e.g. Proakis book or Tse "...
4
votes
0answers
140 views

Discrete-time model of 2-user CDMA system, recovered information at receiver using polarity detection?

I have discrete-time model of 2-user CDMA system with: $b_1=-1, b_2=+1, \alpha_1, \alpha_2, s_1, s_2$ and $n$ white noise. What are the recovered infromation bits for user 1 and user 2 respectively ...
3
votes
0answers
35 views

The tail of scipy deconvolve

I have a dataset for the function $g(t) = \int_{0}^{\infty}f(t-\tau)h(\tau)d\tau$ I would like to deconvolve. My assumptions are The signal $f(t) = 0$ before the start of observation, that is for $t &...
3
votes
0answers
46 views

Convolution of signals sampled on a logarithmic grid

Is there a practical accelerated algorithm or a theoretical discrete (Fourier) transform based method to convolve discrete-time signals sampled on a logarithmic grid? What I mean is representing a ...
3
votes
0answers
45 views

Solving the PDE of a signal in an optical fiber

Disclaimer Please let me know if this is not the right place to ask this question. Disclaimer Part 2 I have no background in signals. My focus is in mathematics. In my programming class, we are ...
3
votes
0answers
76 views

Input and Output SNR Calculation in AM receiver input and output

For the FOM calculation of an AM receiver, the input and output signal powers are respectively, $$P_{in} = \frac{A_c^2(1 + k_a^2P_m)}{2}$$ $$P_{out} = k_a^2A_c^2P_m$$ These are obtained from the input ...
3
votes
0answers
60 views

How to implement the RLS for matrices

I need to implement the RLS algorithm but it's for matrices instead for vectors, I have made the below code, but still something wrong is not working well, EDIT: The code should be done as below, ...
3
votes
0answers
51 views

Physical significance of Power spectral density of sum of correlated random processes

For two processes $X(t)$ and $Y(t)$, PSD of $Z(t) = X(t) + Y(t)$ is $S_Z(\omega) =S_x(\omega)+ S_Y(\omega) + S_{XY}(\omega)+S_{YX}(\omega) $. If $X(t)$ and $Y(t)$ are orthogonal, PSD of the sum ...
3
votes
0answers
27 views

Proper way to implement a decimation

I have an input signal with bandwidth 2.5 MHz. Let's say it's filtered using analog Butterworth low-pass filter. I would like to sample the signal using AD9203 10-bit 40 Msps ADC. If I understand ...
3
votes
0answers
67 views

Designing a fast linear operator with $\pm 1$ entries with low condition number and low Hamming distance between consecutive rows

I need to design a matrix for compressive imaging where each row represents an $N$-pixel filter in a focal plane through which light is masked, summed, and measured (think of Rice's single-pixel ...
3
votes
0answers
70 views

Synchronization of BPSK with variable-length symbols (ISO 14443)

Does anyone have an idea how one would perform BPSK symbol synchronization if symbol length is allowed to vary? As dumb as that sounds, this is not a theretical question.The "Proximity" Type B NFC ...
3
votes
0answers
78 views

Multilateration of Sound in 3D Space

TL:DR - How can you find the 3D coordinates of a emitter than transmits an impulse signal? STORY: I'm working on something to improve my bird-watching. I've got a camera that can take pictures of ...
3
votes
0answers
53 views

wavelet reconstruction

I am doing mtech project now. Actually I am working on discrete wavelet transform.I have done till wavelet decomposition. I have been stuck in reconstructing the signal back to original .please help ...
3
votes
0answers
67 views

Energy Detection in Presence of Colored Gaussian Noise

Before asking my question, let me introduce the context: For spectrum sensing based on energy detection, which has been widely studied in presence of AWGN, the optimal detection threshold is computed ...
3
votes
0answers
63 views

Selection of transforms, windows, wavelets for current signal analysis

I am new to this topic but I already read about the propperties of different signal analysis methods. I am stuck with the obvious advantages of FFT, STFT and Wavelet transforms but can't find good ...
3
votes
0answers
4k views

Discrete wavelet transform: visualizing relation between decomposed detail coefficients and signal

I'm trying to directly visualize the relation between discrete wavelet transform (DWT) detail coefficients and the original signal/its reconstruction. The goal is to show their relation in an ...
3
votes
0answers
40 views

Hardware selection for acquiring signal in digital form

I want to it clear that I am a mechanical engineer and so my knowledge on electronics and signal processing is limited. I am working in a hydrophone system. My job is to find the position of an ...

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