# All Questions

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### matlab coding to combine FIR and IIR filters [on hold]

Design filter using IIR highpass filter with cutoff frequency, fc1 = 20 Hz and FIR bandpass filter with cutoff frequency fc2 = 10 Hz and fc3 = 15 Hz. What is your designed ...
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### How to use Matlab's 512 element lookup table array in OpenCV?

I am designing morphological operations in OpenCV. I am trying to mimic the functions remove and bridge in Matlab's bwmorph. To do this I referred to the function definition of bwmorph.m, there I ...
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### tooth isolation code [on hold]

I am currently working with dental images and I need to separate each tooth from the image. I find difficult to do it so.
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### Generate 3D image from multiple 2D images

If we're to capture an image of a body using four (4) WebCam with a 16 megapixel (1 in the front, 1 in the back and 2 sides(left and right)). Is it possible to make a 3D out of it using image ...
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### MATLAB : $\tt imwarp$ allots too much space [on hold]

I'm finding the projective transform from some set of correspondences. I'm using this as input to imwarp along with an image. My computer freezes at times. I have ...
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### Loop bandwidth for symbol timing recovery

I am trying to design the Symbol timing recovery (STR) block of DVBS Receiver. How should I chose the loop bandwidth and damping ratio for determining the loop filter coefficients $k_1$ and $k_2$? ...
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### What is a filter bank?

I have three Gabor filters. I am applying them to an image serially. Is this the correct concept of a Filter Bank? What if I want to apply the filter in parallel? I am using Accord.NET framework. ...
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### What are various types of Gabor Filters?

Gabor Filter has 4 types of kernels: Real Imaginary Complex Magnitude Squared Magnitude What do they actually mean? NB. Please, supply me any resource for further study.
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### Why do digital filters work?

So I just started reading on FIR and IIR filters and am amazed by how "simple" the theory seems, so far. But what confuses me is, why does filtering work by creating a weighted sum of previous ...
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### Upsampling with FIR filter causing discontinuity at start of new buffer

I have implemented an oversampling algorithm for an audio signal in C++ which is producing a distortion of the signal at the start of a buffer. The algorithm is wrapped in a class with methods for up ...
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### Amplitude transfer function

Given a LTI-system $$y[n]=x[n]-2x[n-1]+y[n-1]- \frac{8}{9}y[n-2]$$ The transfer function $H(z)$ is: $$H(z) = \frac{1-2z^{-1}}{1-z^{-1}+ \frac{8}{9} z^{-2}}$$ How do I calculate the amplitude ...
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### Measuring the open loop transfer function in closed loop: what's the better approach?

Considering the closed loop system; $C$,$G$, and $H$ all linear and stable transfer functions, If I chose to excite $\bf r$ and measure $\bf e$, I get the Sensitivity Function, $S$ ...
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### Periodicity of transfer function of FIR filter proof (Parks and Burrus, Digital Filter Design)

In Digital Filter Design by Parks and Burrus, p. 19. The transfer function of an FIR filter is given by the $\mathcal Z$-transform of $h(n)$ as: $$H(z)=\sum_{n=0}^{N-1}h(n)z^{-n}$$ (where $h$ is ...
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### Limitations of inter-sample cross-correlation in time-shift detection

I wish to find the time shift value of a (noisy) signal to the highest degree of precision that is possible. The amount of time shift is not an integer amount of samples. First, calculating the ...
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### Basic tools for digital filter design?

What tools to use for practicing elementary filter design? Is Matlab all there is? Do I need some specific tool boxes? What functions do I need? I'm starting from the ground up in digital filter ...
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### Spectral plot shows more notes than there really should be

I was experimenting with sound analysis lately and from what I see when I plot spectral data of an audio file is that apart from notes that were actually picked there are some other notes with quite ...
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### what is the disadvantages of the following [on hold]

Wavelet Stft Dft Frequency response Mann and morison technique Mux A/D converter Also what is ment by aliasing problem and watch dog property Recursive and non recursive
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### Soft question: Seeking compressive sensing imaging demo in MATLAB

I am looking to experiment in MATLAB with image restoration/reconstruction using compressed sensing. I am relatively new to compressive sensing, and was inspired by the following Wired article to ...
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### Artifacts in sub-sample delay

There are at least two ways of achieving sub-sample delay. One is to simply over-sample the signal and then delay it by the wanted sub-sample amount. The over-sampling is equivalent to creating new ...
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### How to identify a similar voice audio? [on hold]

I want to implement an application where given an audio containing a speech as query,it returns the most similar audio that was already submitted by an other user. Here two audio are similar if they ...
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### Difference between $\tt rand()$ and $\tt randn()$ in MATLAB

rand() is for "Uniformly distributed pseudorandom numbers" I generate two rand arrays, and then use the cross-correlation ...
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### How to derive the transmitted signal from a constellation diagram

Let us assume we have $16$ symbols to transmit. We can represent these $16$ symbols by $16$ unique signals and transmit. If at the receiver we can identify these $16$ signals correctly, we have ...
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### Projector image subtraction

Imagine you have a projector and camera pointed at a wall, with people walking in front of the wall (between projector and wall). Is there a standard way to robustly obtain silhouettes of the people ...
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### Where and how do an Image and a complex number meet?

I am trying to implement a Gabor Filter bank. Gabor Filter uses a complex function. How do the filters like Gabor Filter operate on an Image? Does a complex number represent an entire Image or only ...
57 views

### Method of reconstructing a band-limited signal from discrete samples

I understand current cell phones use digital communications. Given that this industry brings in billions of dollars each year, there is much incentive to get the best performance possible. So what ...
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### Different results for different orders of estimating AR model using Yule-Walker equations

I'm trying to use MATLAB to estimate the AR parameters to the following filter: $$H(z) = \frac{1}{1-0.5z^{-1}+0.25z^{-2} -0.25z^{-4}}$$ As I can see, the process at the output of this filter depends ...
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### Exponential power delay/decay channel

If I want my channel gain to resemble an exponential power delay profile is it enough to define h= [1 0.66] if I have two channel taps (i.e memory length of ...
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### How to hide the number on the constellation points in matlab? [migrated]

This is how you plot a constellation: hMod = comm.RectangularQAMModulator('ModulationOrder',32, ... 'SymbolMapping','binary'); constellation(hMod) but how do ...
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### Poster detection in OpenCV?

I'm really new in image processing, so please sorry I'm a newbie. I tried to use the squares.cpp for detecting posters (since they usually are rectangles) without using expensive feature detectors ...
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### Why noise canceling headphones do not attenuate the signal itself?

Noise canceling headphones use a microphone to capture noise in order to cancel it. How is it guaranteed that the microphone will not record the actual signal and attenuate it?
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### Hyperspectral vs Multispectral Imaging

I understand that the difference between the two are the number and width of the bands. Given a hyperspectral image, is it possible to 'convert' it to multispectral ? In this paper for example, the ...
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### Time recovery - GNU Radio

I read about Time recovery (as an example, the Mueller&Muller algorithm); it is linked to when you should sample your signal. I am currently working on a project with GNU Radio and there is ...
50 views

### Conversion into the Q31 Format

I have a Setup, where I receive 24-bit ADC samples in the two's complement in 8-bit chunks. Usually I just "converted" them into a signed 32-bit integer like this: ...
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### Why are some JPEG files of the same scene much larger than others? [on hold]

I'm using a Foscam FI8910W ip camera to view a static scene under constant lighting conditions. When I pull back a frame grab, it's about 35 KB in size. I can do this over and over and it's always ...
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### Why SEs (symbol error) are not same?

I simulated 16 QAM in MATLAB using binary and Gray coding. In both cases SE should be same even though bit error (BE) will be less in case of Gray coding. I wrote the following MATLAB program to ...
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### Difference between a digital lock-in amplifier and a FFT when extracting phase of a signal?

I am trying to measure the relative phase of a sine wave fixed at a particular frequency in a noisy environment. My initial approach is to simply collect $N$ samples, take an FFT, and then just ...
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### Why Auto-regressive model is considered closed loop while Moving-average model is considered open loop? [on hold]

In AR(2) I use the previous two readings to predict the present reading. then I use the present and the reading before to predict the future reading. This seems an open loop to me! It seems to me as a ...
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### how to find nonzero numbers in Error? [on hold]

i have my orignial signal X and recovered signal X_re i want find nonzero number in my Error ...
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### Image retrieval approach

I have a good understanding of 'normal' Machine Learning, I'm pretty good at Python and have decided to start a Raspberry Pi project, however my knowledge of Image Retrieval is limited. I'm trying to ...
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### steady state - calculate [on hold]

$$x[n]=10 \cos⁡(0.4nπ+45°)+20 \cos⁡(0.5nπ+30°)$$ That is a steady state input. I think that to solve and join them in one, we must apply this formula: $$cos⁡(x)+cos⁡(y)=2cos((x+y)/2)cos((x-y)/2)$$ ...
Structure Tensor is a matrix in form: $S=\begin{pmatrix} W \ast I_x^2 & W \ast (I_xI_y)\\ W \ast (I_xI_y) & W \ast I_y^2 \end{pmatrix}$ where $W$ is a smoothing kernel (e.g a Gaussian ...