is a mathematical object to be recorded in a [usually] rectangular array of elements of ring or field, which (table) is a set of rows and columns are located at the intersection of its elements. The number of rows and columns specify the size of the matrix.

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1answer
22 views

involutory transformations - why are they not so much used in signal processing? [on hold]

We generally prefer orthogonal transformations/matrices in signal processing as the transpose of the matrix is the inverse and you do not need to find inverse transform separately. But involutory ...
0
votes
1answer
42 views

Calculating covariance matrix for MVDR beamforming

I am trying to calculate the covariance matrix that is required for the calculation of an MVDR beamformer. I am getting confused as to how to calculate it. I have an array of 3 microphones each with a ...
0
votes
1answer
19 views

How is the matrix $\mathbf R_x$ not Toeplitz in case of a signal missing one term?

I am solving a question that says if we have sequence $x(n)$ of a signal missing one term then we have to find autocorrelation matrix $R_x$ as follows: $$R_x = E\{\mathbf {xx^H}\}$$ Now if I take $...
0
votes
0answers
34 views

Accelerometer - coordinate system transformation

I'm getting some accelerometer readings from an Android phone, but it comes in on the phone's coordinate system. I want to apply a transformation to put the acceleration in the world coordinate system ...
0
votes
0answers
26 views

How to generate Golay sequence?

I am trying to follow the 25.213 3GPP spec point 5.2.3.1 to generate Golay sequence for the P-SCH channel. I was able to do it recursively for Hadamard sequences, but I am unsure of what golay ...
0
votes
0answers
17 views

Why do we assume the matrix of impulse responses to be a Toeplitz matrix during deconvolution

$y(n)$ = output signal $x(n)$ = input signal $\mathbf H$ = system response as a toeplitz matrix $$\mathbf H = \begin{bmatrix}h(0)&&&\\h(1)&h(0)&&\\h(2)&h(1)&h(0)&\...
0
votes
2answers
142 views

How is the sound converted to matrix in Matlab?

I am using the audioread(filename,y,Fs) function of Matlab and it converts an audio file to a matrix. I want to know how is each value of that matrix generated. Is ...
0
votes
1answer
34 views

Hessian Matrix. Second partial derivative test

I have a question about the hessian matrix / determinant of the hessian matrix. For the Hessian matrix, one is able to determine the local curvature around a point. And with the Second partial ...
0
votes
1answer
44 views

what is happening when i run this code line? [closed]

I have the following MATLAB code: x=[1 2 3; 4 5 6; 7 8 9;]; u=(0:255)/(255-1).^1.05; x2=u(x+1) when I run this code I get the following as a result in ...
0
votes
0answers
45 views

Multiplying two large sparse matrices

I am having two big large sparse matrices A, B, suppose M=256, ...
0
votes
0answers
244 views

How to calculate the scale, rotation angle and translation between 2 images if we know the homography result matrix?result

I got the result of findHomorgraphy in OpenCv. As below: Homography transform matrix: [-1.1534205416542787 0.7834287271121142 527.9064589440736 -0.2415444621693116 0.16412191792642924 ...
1
vote
2answers
81 views

Maximising each element in a matlab array

Is it possible to construct an array A, without looping, where A(i,j) = max(B(i),C(j)) and B ...
1
vote
0answers
22 views

Emulate signal loss of a pixellated detector in Python?

I have a matrix 64x64 where each cell represents the pixel of a pixellated detector. The spacial response of this detector decreases by going further from its center (that is, coordinates "31,31" or "...
0
votes
0answers
43 views

Compute gradient and divergence within region (subdomain)

I want to compute gradient and divergence within specific region in a image. For the gradient, I use forward difference and for the divergence, I use backward difference. In matlab, I set the mask ...
2
votes
1answer
65 views

What does “kernel based” mean?

In my thesis I try to explain what kernel based methods are, especially the meaning for object detection. I know kernel based methods like Mean- and CamShift and I know how to use them. I understand ...
0
votes
0answers
19 views

Internal constaint of essential matrix

I work on visual odometry program and I use EmguCV. I use calibrated camera to detect features from current frame with SURF, and match them with previous using Knn. Because I have calibrated camera I ...
0
votes
1answer
50 views

Mat and int are incompatible? [closed]

anybody knows what this is? Mat mat = (Mat_<double>(3, 4) << 0, 0, width, width, 0, height, height, 0, 1, 1, 1, 1); I dont know what mat would be in ...
1
vote
0answers
38 views

Sensor Data Fusion with Orientation Sensors in 3D Euclidian Space

Preconditions For measuring the position of a mobile device in 3D space, I utilize two sensors with different characteristics that measure device orientation. Sensor A (a combined sensor of ...
0
votes
0answers
21 views

Find similarity rating in trajectories

I've got trajectories encoded in black and white. These are stored in a matrix with dimensions 150x150 (i.e. black = 1, white = 0). An example of two trajectories below (plotted): My objective is ...
0
votes
0answers
103 views

Generating Wavelet family matrixes

We have unnormalized Haar matrix which, is for example, H4=[1 1 1 1;1 1 -1 -1;1 -1 0 0;0 0 1 -1] After normalizing it, we use for haar transform. I know how to ...
3
votes
1answer
107 views

5.1 Rear To 5.1 Side mixing matrix

I am searching for a matrix definition for converting a audio signal (5.1 with rear) to a audio signal (5.1 with side). Currently I am using the definitions from: https://msdn.microsoft.com/en-us/...
1
vote
0answers
29 views

Matrix expansion into bases

I have an image (that is a matrix), let's say of dimensions NxN. I then want to expand this matrix into M basis matrices (for the moment I'm still unsure how many M of these basis matrices I should ...
0
votes
1answer
66 views

Is there a way to perform 2-D image rotation by matrix multiplication?

In my understanding, unlike shifting and scaling, image rotation actually rotates the coordinates whereby interpolating the pixels at discrete positions. It is like a projection that discrete values ...
2
votes
0answers
68 views

Distribution of a signal covariance matrix

A common estimation problem in signal processing assumes the following signal model \begin{equation} \mathbf{r} = \sum_{i=1}^{Q}\alpha_i\mathbf{s}\left(w_i\right)+\mathbf{n} \end{equation} where $\...
0
votes
0answers
21 views

Are there condition numbers associated with the STFT, DWT?

Recently I learned that the DFT has good numerical stability since it can be represented as an orthogonal matrix, which has a condition number of 1. Is it possible to represent the STFT and DWT as ...
0
votes
1answer
690 views

How to get relative rotation matrix from two orientation values in android?

Following http://www.codeproject.com/Articles/729759/Android-Sensor-Fusion-Tutorial , I get two orientation values. Then, I transform those values to rotation matrices R1, R2. I think the relative ...
0
votes
1answer
330 views

Convert a 1D array into a 'rotated' 2D matrix

simply put, let's say I have this array - [1 2 1] I want to try and get this output in Matlab [1 1 1 1 2 1 1 1 1] It's like my array was 'rotated' ...
0
votes
1answer
717 views

PSNR of two images of different size in matlab

I performed bicubic interpolation on a 256*256 image(img) dest = interp2(img,'bicubic') and i got a 511 * 511 image.I want to compute PSNR of a 512 * 512 image(...
-1
votes
1answer
301 views

Difference between correlation/convolution and matrix multiplication

Can anyone please clarify the difference between correlation/convolution and matrix multiplication? As I thought either convolution or correlation is similar to matrix multiplication. I read this ...
1
vote
0answers
70 views

How to replace Hadamard Product and Column wise addition with new Matrix operation?

Let $$ A= \begin{bmatrix} a_{1,1} & a_{1,2} & a_{1,3}\\ a_{2,1} & a_{2,2} & a_{2,3}\\ a_{3,1} & a_{3,2} & a_{3,3}\\ \end{bmatrix} $$ and $$ B= \begin{...
2
votes
1answer
201 views

What is a covariance matrix?

Suppose you have k samples from each of the N elements of a uniform linear array (ULA) of sensors: What is the physical meaning of a covariance matrix? How do you form a covariance matrix with the ...
1
vote
0answers
46 views

Solving an array signal processing estimation problem based on the Rayleigh quotient

The Rayleigh quotient for a covariance matrix $\mathbf{C}$ and a non-zero steering vector $\mathbf{a}$ is given by $$ R(\mathbf{C},\mathbf{a}) := \frac{\mathbf{a}^H\mathbf{C}\mathbf{a}}{\mathbf{a}^H\...
2
votes
0answers
97 views

Least Angle without matrix inversion?

Sorry if this is too damned long. I did what I could to abbreviate it. I'm new to numerical work with matrices. I believe I have a way to compute Least Angle without explicit matrix inversion. I'm ...
1
vote
3answers
127 views

How to compute regions of matrix

Let's say we have the following matrix: 0 0 0 0 0 0 0 1 0 0 0 0 1 1 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 0 0 1 1 0 0 0 0 0 0 I want to calculate the ...
0
votes
0answers
85 views

Matching 2 undirected weighted graph in matlab

Consider 2 undirected weighted graph as shown in figure.Consider first graph as G1 and second graph as G2.Graph G1 consist of vertices V={F1,F2,F3,F4,F5} and Graph G2 consist of vertices V={N1,N2,N3,...
1
vote
0answers
159 views

How to understand energy function in thin plate splines?

guys! I have carried out some experiments using matlab warp tools from here. But the results are not good, so I decide to read its original paper Principal Warps: Thin-Plate Splines and the ...
0
votes
1answer
857 views

reconstruction of time series in SSA

i am trying to reconstruct time series from SSA ,because according to this link http://en.wikipedia.org/wiki/Singular_spectrum_analysis there is procedure ...
0
votes
0answers
41 views

How to calculate the freedom of projection matrix?

I learned projection matrix from textbook. It says that the 9th is redundant, so it has 8 freedom. But I can not know the reason clearly. Following the equations. I can not understand why i does ...
0
votes
1answer
54 views

Expectation of product of hermitian matrix

Let $\textbf{h} \in \mathbb{C}^{N\times 1}$, $\textbf{a} \in \mathbb{C}^{N\times 1}$, $\textbf{b} \in \mathbb{C}^{N\times 1}$ and $\textbf{c} \in \mathbb{C}^{N\times 1}$. The variable $h_i$ is defined ...
0
votes
1answer
51 views

Matrix form of STFT

IS there a Matrix form of the STFT that could be applied to a signal directly, as in the case of DFT? We know the matrix structure of the DFT Matrix. Can we derive that somehow for a STFT Transform? ...
0
votes
0answers
195 views

How to Prevent overflow/saturation in fixed point implementation of Fast Data Projection Algorithm

I am trying to implement an algorithm in real-time on a Fixed point DSP (The Blackfin from Analog Devices). The algorithm does a lot of stuff, but in the middle it performs an algorithm called "Fast ...
0
votes
1answer
140 views

Incoherence: Compressed Sensing (CS) vs Matrix Completion (MC)

I am seeking a clarification of the concept of Incoherence within the MC framework. Specifically, 1) the literature mentions the application of a "strong incoherence" given a set of assumptions. ...
0
votes
1answer
124 views

how to calculate cross correlation of transient signal?

there. Let me have a noisy speech signal $y(k)$ as below. $$ y(k) = x(k) + v(k) $$ where, $k$ is the discrete-time index, $x(k)$ is clean speech signal, $v(k)$ is a zero-mean random process, ...
0
votes
0answers
413 views

3 Band Wavelet Transform In MATLAB

I am currently working on an audio watermarking project in MATLAB. I currently have a code I am using to construct a nxn 3 Band Wavelet Transform matrix. However, when I try to construct a matrix that ...
2
votes
1answer
116 views

A good Digital Image Processing environment

i'm looking for a free/opensource solution for digital image processing with reasonable performances processing quite large images (e.g. actual smartphones have resolutions of 8-10Mpx) and being ready ...
1
vote
2answers
438 views

Covariance matrix explanation

I am trying to understand and visualize the concept of a covariance matrix. Suppose I have a matrix: $A = \begin{pmatrix} 2 & 3 & 4\\ 5 & 5 & 6 \end{pmatrix}$ how do I calculate its ...
2
votes
0answers
82 views

Can Cholesky outer product version result in negative square roots?

Say A is symmetric positive definite matrix , which means one necessary condition is diagonal entries of A are positive. If I do cholesky factorisation using outer product form, Can there be any ...
2
votes
1answer
6k views

understanding FFT2 function of Matlab

I am trying to understand what happen when we take FFT2 of a matrix in a matlab. first have a look at this simple example, a=ones(8); %8x8 Matrix of Ones fft2(a) ...
2
votes
1answer
116 views

Reflection Rotation matrix

I'm doing a rigid body between point clouds using SVD. Sometimes the routine produces an incorrect rotation matrix with a Determinant=-1, ie a reflection matrix. Any idea why ? Is there a valid way ...
0
votes
2answers
613 views

Matlab BOC (binary offset carrier)

I am trying to implement a binary offset carrier (BOC) direct sequence spread spectrum scheme in MATLAB. In that scheme, a code $c(t)$ (a binary vector which repeats after a certain number of zeros ...