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I'm currently studying FIR filter and am having trouble understand how the following equation works, and it's implication.
$$ y[n] = h[n] * z^n = H(z) \cdot z^n $$
I don't really understand how this works given that
$$ y[n] = h[n] * x[n] $$
$$ Y(z) = H(z) \cdot X(z) $$
It seems to me that $ x[n] = X(z) = z^n $. What's... |
I recently stumbled across some notes on the "Waterbed effect" in some notes by A. Megretski for an MIT course on "multivariate control systems". Here's an excerpt:
A common effect, usually associated with unstable zeroes and poles of the open loop plant, makes it theoretically impossible to make certain closed loop t... |
I have the input image :
and the output of vein detection for the leaf using a Gabor filter, but the output is really noisy:
I tried using Total variation denoising however the results are not good:
However I don't want to loose the fine details in the leaf's veins, so a median filter won't suit my problem
|
I want to downsample images to arbitrary sizes using supersampling to avoid aliasing effect.
The only two good explanations I found were on Wikipedia and everything2.com, but there are still gaps. For example:
The image should be upsampled before supersampling. But how much? Is there any special filter to be used for ... |
there are n derivative filters: $f_i$, and denote $f_i^r$ as $f_i$'s reverse filter such that
$$f_i(x,y)=f_i^r(-x, -y)$$
$r_i, f_i$ given, to find $r$ from the equations:
$$f_i * r = r_i, (1 \leq i \leq n)$$
Professor Weiss recovers $r$ using the following method:
$$r = g * \left(\sum_{i=1}^n f_i^r*r_i\right)$$ and $g$... |
Welch's method has been my go-to algorithm for computing power spectral density (PSD) of evenly-sampled timeseries. I noticed that there are many other methods for computing PSD. For example, in Matlab I see:
PSD using Burg method
PSD using covariance method
PSD using periodogram
PSD using modified covariance method... |
I am trying to learn about inverse filtering of images and am trying it out on a test image in MATLAB.
The test image is an 8x8 checkerboard, with 64x64 pixels, generated by the MATLAB code:
g = checkerboard(8);
I am using a 3x3 averaging filter, h, and convolving it with the test image.
I am not adding noise and I wa... |
Background: I'm trying to make a system that tracks a number of bubbles in a video
I'm implementing the bubble detection in the single image case using the Circular Hough Transform. Due to occlusion, blur and other factors, this detection will never be 100% accurate. I am tuning the detection procedure for high recall,... |
So while answering how to design a PI controller for a first order time delayed system (Question Here )
Here is the closed loop equation to a control system:
$$
G_C(s) = \frac{\frac{K}{T}(1-sT)(s)} { s^3 + (\frac{1}{T} + a - KK_p)s^2 + (\frac{a}{T} + \frac{KK_P}{T} +K_I)s+\frac{KK_I}{T}}
$$
Question: How do you de... |
I understand (mostly) how independent component analysis (ICA) works on a set of signals from one population, but I am failing to make it work if my observations (X matrix) includes signals from two different populations (having different means) and I am wondering if it is an inherent limitation of ICA or if I can reso... |
This is a detector problem I believe:
I am being stumped by what appears to be a simple problem. Basically, I have a band of interest. If signal energies exist within this band of interest, then I perform operation X on my signal.
My problem is that I am not sure exactly how to go about 'deciding' if a signal exists o... |
Let's say that the point spread function, h, is known for a blurred image B.
If we want to apply an inverse filtering method (eg. Direct Inverse Filtering for noiseless images, Wiener Filter, Constrained Least Squares, etc.), can/do we pad the blurred image B in order to divide H (DFT of h)? (The dimensions of H would ... |
I want to compare a bunch of depth images coming from Kinect and eliminate the similar ones. Those images present posture of a single user sitting on the chair (depicted in).
My idea is to create a function which will return the difference in range [0,1] between two postures. This means, I want to compare only a postu... |
The Gabor wavelet is a kind of the Gaussian modulated sinusoidal wave (source)
Gabor wavelets are formed from two components, a complex sinusoidal carrier and a Gaussian envelope. (source)
and
In fact, the wavelet shown in Figure 2a (called the Morlet wavelet) is nothing more than a Sine wave (green curve in ... |
I have an auto-correlation function that was generated from a signal, and I am trying to extract its 'repetition rate' in order to calculate the dominant frequency of the pulse, but I am not exactly clear how to do this.
Here are two cases, labelled 'good' and 'bad' to mark best/worst case scenarios. What methodologie... |
I've got a sliding DFT implementation that appears to be working (judging from an output plot). I would like to be able to invert this implementation using the standard tricks of swapping the real and imaginary components or conjugating my data. However, when I attempt this my output looks nothing like the original. I ... |
I just need some clarification of some very basic aspects of creating a frequency analyzer. I am writing a c++ program, so far it is just a media player, with a custom explorer. You can make playlists, shuffle, repeat etc.
But my goal is to continue to add functionality. So far, I just have a signal level meter, a... |
I need to do a FFT on an image for noise reduction, but the problem is that I do not need the complete image, but only a circle in the middle. The borders are a fixed rig, thus I am not interested in what it displays, but it has an impact on the result of the FFT.
Is there any way to just cut out a circular part and us... |
I'm trying to automatically detect some medical defined anatomical landmarks in a CT reconstructed volume. Medical doctors use these landmarks to measure some patient specific parameters.
I have attempted to use the SIFT feature descriptor, since these anatomical landmarks are kind of "keypoints". This did not work ver... |
I've been looking into marker detection algorithms to use with a kinect based application, and the majority of the work I've been able to find is obviously focused on feature detection in 'normal' images.
However, the kinect hardware provides (essentially, once you've adjusted) an 11-bit depth value per pixel.
This dep... |
(I'm just learning a little about system identification so apologies in advance if this question is badly worded)
How do you go about choosing drive signals for system identification? I've seen PRBS signals used but it seems like that's going to work well for frequencies around the chip rate but not really low frequenc... |
I am trying to implement the generalized Hough transform in matlab. The algorithm requires the gradient direction at each point in the shape. How can I measure $ \phi $ as shown in the figure below?
|
I want to perform 2D haar discrete wavelet transform and inverse DWT on an image.Will you please explain 2D haar discrete wavelet transform and inverse DWT in a simple language and an algorithm using which I can write the code for 2D haar dwt?The information given in google was too technical.I understood the basic thin... |
Consider the wireless channel. It is mult-path - means that signal is sum of sent signals with some delay and fadings.
The standard models for "impulse response" for multi-path channel in wireless is:
$ h(t) = c_1 \delta(t - t_1) + c_2 \delta(t - t_2) + ... + c_N \delta(t - t_N) $,
where $t_i$ are path-delays and $c_i$... |
In image processing, what does it mean when a filter is called non-linear?
Does it mean the equation of the filter contains derivatives and if it didn't, it would have been called linear?
|
I've been told that the point spread function of a pixel is its distribution of intensity, while the sampling aperture of a pixel is its distribution of sensitivity. I'm a little unsure of what the difference between intensity and sensitivity is. It sounds like the former deals with how a pixel is displayed, while the ... |
Can someone point me towards a good book or survey article on adaptive/self-tuning of PI controllers?
All I can find online are articles which are either vague or heavy on theory.
|
I am doing some 'extreme' eq for spectral mangling type effects with audio. Im using brick wall filters, and very narrow band pass and reject filters (vst plugins), and I'd like to know if there's anything I can do about the pre/post 'ring' with the linear phase /minimal phase filters Im using. Unfortunately I must us... |
I'm using digital filters to apply spectral mangling-type special effects to audio.
When using a digital filter (vsts/standalone DSP programs/outboard digital filter, etc.), especially when using narrow transition bands/brickwall filters, are there any effective ways to remove ringing artifacts introduced by the filter... |
In my foray into detections, I am trying to understand how best to generate receiver operating characteristic (ROC) curves, and some questions have come up.
In my studies, I have found out that ROC curve generation is simply the plot of true-positive rate (TPR) versus false-positive rate (FPR). Naturally one wants TPR... |
I have a stochastic process completely uncorrelated. Why the autocorrelation function has a delta of dirac in the origin?
Which is the reason of that?
$R_{XX}({\tau})=A{\delta(\tau)}$
where $R_{XX}$ is the autocorrelation function of $X$ process and $A$ is a constant dependent by process spectrum
|
The Fourier transform takes a signal and splits it into a series of sine and cosine waves.
I am told that it's supposed to be possible to split a signal into some other set of functions. My question is: How do you do this?
I'm presuming that the set of functions you use would have to have certain properties for this to... |
why if I lose 80% power in the output of a system, Does it mean that I had lost 10×log10(0.2) = -7dB ?
|
I'm experimenting with applying unusual 'spectral mangling' type special effects to audio.
1) What DSP techniques can be used to change the timbre of a complex tone, such as that produced by the voice, or a musical instrument?
Are there any ways to manipulate the level of specific frequencies in the spectral p... |
I see that there are different ways to write an AR model into a state-space representation, so that we can apply Kalman filter to estimate the signal. See Example 1, 2 and 3 here.
I wonder what differences are between the different state-space representations on the estimation by Kalman filter?
Thanks!
|
I am developing software that calculates the response of a system by comparing the FFT of input and output signals. The input and output signals are divided into windows and, for each window, the signals are median-subtracted and multiplied by a Hann function. The instrument response for that window is then the ratio... |
I do work with computer graphics and am dipping my toes into ray tracing. That field involves a good number of the subjects covered in DSP (Fourier transform, time vs frequency space, etc) but I was hoping to find a book in the realm that didn't also deal with, say, digital devices or electrical engineering-- not that... |
Let's have an image (gray-scale or even binary) as shown on the following figure at the left hand side, the goal is to generate a list of points i.e., coordinates in the form of (x,y) for each pack of the dark pixels in the image.
What are the proper image processing tools to do this and where are they available?
Up... |
Is there a known technique for estimating how close a human speaker is to a single microphone? I'm hoping that there is a known technique that can analyze an incoming audio signal that contains a human voice with typical ambient room noise, and give a rough estimate of how close the speaker is to the microphone. Is the... |
I am trying to understand the mechanism of finding the transfer function for a Wiener function.
|Rxx(0) Rxx(-1) ...... Rxx(1-N)| | h(0) | | Ryx(0) |
|Rxx(1) Rxx(0) ...... Rxx(2-N)| | h(1) | = | Ryx(1) |
|...... ...... ...... ...... | | .....| |....... |
|Rxx(N-1) Rxx(N-2) ...... Rxx(0) | |h(N-1)| |Ryx(N... |
I'm trying to replicate the ideas from the Eigenface page on wikipedia. From a hundred sample images represented by a data matrix $\bf X$ (where each image flattened to a vector of length $n$, thus $\bf X$ is a $100$ by $n$ matrix), I've computed a SVD decomposition:
\begin{equation}
\bf X = U \Sigma V^{T}
\end{equatio... |
I am trying to formalize my understanding of how best to measure the performance of a binary detector. (See previous question here). I had looked into ROC curves for doing this however based on previous research and feedback here I think ROC curves are too simplistic. Here is the problem I face:
Context:
I have a micro... |
As we know there are two kinds of signals: analog signals and digital signals.
And there are two common techniques for multiplexing the signals: Time Division Multiplexing (TDM) and Frequency Division Multiplexing (FDM).
As I understand it, FDM is commonly used to multiples analog signals, while TDM is commonly used t... |
Is there something like an anti-filter in image processing?
Say for instance, I am filtering an image using the following 13 tap symmetric filter:
{0, 0, 5, -6, -10, 37, 76, 37, -10, -6, 5, 0, 0} / 128
Each pixel is changed by this filtering process. My question is can we get back the original image by doing some mathe... |
What is the true meaning of a minimum phase system? Reading the Wikipedia article and Oppenheim is some help, in that, we understand that for an LTI system, minimum phase means the inverse is causal and stable. (So that means zeros and poles are inside the unit circle), but what does "phase" and "minimum" have to do wi... |
Can you suggest any good introductory resources on ridgelets and/or curvelets for image processing purposes?
I'm considering buying Sparse Image and Signal Processing: Wavelets, Curvelets, Morphological Diversity (more). Is there anyone who can recommend for or against it?
|
I have this image
I would like to remove the shadow from the image. I know a lot of different methods like certain morphological operations have been used to remove shadows:
I have created this mask for the same image
Are there some other methods I could try using this mask that I have created?
EDIT:
input image and... |
The literature on this method seems scarce, but I know that it has been used on radar systems to 'get away with' not having to sample nearly as fast as Nyquist would otherwise dictate, (at the cost of additional time). Or so I think.
So, how does "Equivalent Time Sampling" work, and where can it be used? How does it s... |
How do I digitize an analog telephone recording and filter it with a Chebyshev filter?
|
I have a function that performs gaussian blur on image for some specific $\sigma$ (the standard deviation).
It first computes kernel of size $\lceil 3\sigma \rceil$ and then performs convolution with that kernel.
However, I would like to specify blurring radius in pixels rather than $\sigma$.
I suppose that the blur ra... |
The term non-lossy codec means the coding thing having no compression lost, more here. I need such format to process the audio, without destroying the quality. Wikipedia mentions in the context of lossy compression:
Ogg Vorbis (noted for its lack of patent restrictions)
Speex (noted for its lack of patent restrictions)... |
Not sure if this is the right place to ask, feel free to move it if any other site suits this better.
Anyway I am referring to QAM modulation used in US Cable TV. I know it comes under Annex B which is related to FEC.
I know that 64 QAM has a symbol rate ~= 5057000 Symbols/s and 256 QAM 5360000Symbols/s
I would like t... |
According to CIE color space and relation of RGB with XYZ, we can express
$$
R = \int_0^\infty I(\lambda)r(\lambda)d\lambda
$$$$
G = \int_0^\infty I(\lambda)g(\lambda)d\lambda
$$$$
B = \int_0^\infty I(\lambda)b(\lambda)d\lambda
$$
where $r(\lambda),g(\lambda),$ and $b(\lambda)$ are the corresponding color matching fun... |
What does the expression 'combine signals coherently' imply?
|
I'm using an FFT to analyze what is essentially the power envelope of a signal (see here for info on the containing project), and, since power numbers are always positive, to eliminate the DC component I'd like to use a window function that is 50/50 positive and negative, vs the usual all-positive function.
I've taken... |
I am wondering what techniques might be available for 'de-noising' the following example time-frequency image that was created using Welch's method. The following plot was created from a robotic sensor. (This is NOT a color image - it is a greyscale image - colors added for visual purposes only).
Goal:
My goal ultima... |
I'm trying to decipher what exactly this statement means. So if I have a signal which has no pure sinusoidal components, does that mean I can't decompose my signal completely into sine-waves which may be amplitude/phase/period shifted? And so I would conclude that there is also like a saw-tooth component or a square-... |
When the signal is modulated onto the carrier in the electromagnetic spectrum,
that signal occupies the small portion of the spectrum surrounding the carrier frequency. It also cause sidebands to be generated at frequencies above and below the carrier frequency.
But how and why are those sidebands generated in AM and ... |
I'd like to find the "best" fit of an ellipse to contiguous, possibly concave shapes such as:
What have I tried?
I thought that one could assign the direction of the major and minor axes $\vec a, \vec b$ of the ellipse by mapping the pixel values to coordinates, mean subtracting, and saving the largest two eigenvector... |
I'm applying Matlab's median filter to a data sequence and I'm trying to figure out what filter co-efficients of a linear filter this corresponds to.
Would the normal time-frequency relationship that exists for linear filters maintain itself for the median filter?
|
So let's say I'm given a sequence of samples of a continuous time signal and I take the $FFT$ of that at 64 points. And so I have my frequency graph which is interpolated along those 64 points. So basically that's a vector $X$ of length 64, and so applying a linear filter to that is essentially performing coordinate-... |
Given a desired filter magnitude response, plus acceptable linear phase and minimum phase FIR filter approximations, how can one design a filter with the given response and a delay specification of some value between minimum phase and linear phase?
|
Here is my code for a two-toned signal, where I use a stop-band to remove the higher tone and then plotted the before (in blue) and after (in red) in the frequency domain after convolving my signal with the filter coefficients.
If you put this code into Matlab you can clearly see that the higher frequency has been succ... |
When using a phase vocoder to alter the spectral envelope of a signal, the input signal is split up into many (often hundreds of) bands. With many phase vocoders, the output levels these individual bands are often controllable by the user.
What artifacts are caused by filtering these individual bands in a phase vocode... |
What kind of analysis might be used on sets of 2D monochrome image matrices or bitmaps to estimate or compare their relative quality of being "in focus"? Is there an efficient way of computing a scalar metric on something like overall contrast, luminance sparsity, or other artifacts produced from out-of-focus blurring... |
What are the differences between classical low-pass filtering (with an IIR or FIR), and "smoothing" by localized Nth degree polynomial regression and/or interpolation (in the case of upsampling), specifically in the case where N is greater than 1 but less than the local number of points used in the regression fit.
|
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 much movement (Cameras are focused on areas that do not expect much to change).
If you were to merge these photos into on... |
MIT has been making a bit of noise lately about a new algorithm that is touted as a faster Fourier transform that works on particular kinds of signals, for instance: "Faster Fourier transform named one of world’s most important emerging technologies". The MIT Technology Review magazine says:
With the new algorithm, ca... |
Consider a simple case where two signals from two different sensors are cross-correlated, and the time-delay-of-arrival computed from the absissa of the peak of their cross-correlation function.
Now let us further assume that due to the dimensionality constraints of both antennas and the constraints on maximum possibl... |
How does the signal look when we don't use the Nyquist rate to remove aliasing from a signal during sampling?
Let's suppose the signal is sinusoidal, with a frequency of 500 Hz and an amplitude of 2.
signal = 2*cos(2*pi*500*t)
If I sample it, (replacing t=nTs , Ts = sampling period and n represent number of samples) a... |
I am wondering what would be the right approach to extract top and bottom fields from a YUV 4:2:0 frame.
In the YUV 4:2:0 representation, Luma and Chroma samples are located as shown below:
Y Y Y Y Y Y Y Y
c c c c
Y Y Y Y Y Y Y Y
Y Y Y Y Y Y Y Y
c c c c
Y Y Y Y Y Y Y Y
Hence, one needs to be caref... |
Common non-rectangular window functions all seem to be symmetric. Is there ever a case when one would want to use a non-symmetric window function before an FFT? (Say if the data on one side of the FFT aperture were considered a bit more important than data on the other, or less noisy, etc.)
If so, what kinds of asy... |
I have an $n \times n$ asymmetric convolution kernel, $k(t_1,t_2)$. $k$ is zero everywhere except for in small regions near the corners.
I also have an $n \times n$ image, $f$.
Let $*$ denote circular convolution so that the convolution operator, $K(f) = k*f$, returns an $n \times n$ image.
What is a formula for the tr... |
What 'exactly' is power spectral density for discrete signal?
I was always under the assumption that taking the Fourier transform of the signal, and then the ratio of desired frequency range magnitude over the entire frequency range gives the power ratio for that frequency range which is the same as power spectral dens... |
The Kalman filter algorithm works as follows
Initialize $ \hat{\textbf{x}}_{0|0}$ and $\textbf{P}_{0|0}$.
At each iteration $k=1,\dots,n$
Predict
Predicted (a priori) state estimate $$ \hat{\textbf{x}}_{k|k-1} =
\textbf{F}_{k}\hat{\textbf{x}}_{k-1|k-1} + \textbf{B}_{k}
\textbf{u}_{k} $$
Predicted (a priori... |
What is the relationship, if any, between Kalman filtering and (repeated, if necessary) least squares polynomial regression?
|
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 the frequency to be input into the main oscillator like this (pseudocode):
osc_frequency = note_frequency * (1 + tuning) ... |
I have two spectra of the same astronomical object. The essential question is this: How can I calculate the relative shift between these spectra and get an accurate error on that shift?
Some more details if you are still with me. Each spectrum will be an array with an x value (wavelength), y value (flux), and error. Th... |
I am currently learning about least-squares (and other) estimations for regression, and from what I am also reading in some adaptive algorithm literatures, often times the phrase "... and since the error surface is convex..." appears and any depth as to why it is convex to begin with is no where to be found.
...So what... |
I'm using a version of "KISS FFT" by Mark Borgerding. It accepts an array of 16-bit fixed-point input values and produces a 32-bit float result array.
I've discovered that if the input amplitudes are low many of the float result values come out zero, but if I simply scale the inputs (by, say, the factor 16) then fewer... |
So lets say I have a transfer function for an FIR filter $H(z) = (z-a)...(z-n)$ where $a,...,n$ are points along the unit circle. But what about other points along the unit circle that correspond to frequencies we want to leave alone? Won't we end up multiplying these frequencies by random complex numbers? when we wo... |
I'm trying to wrap my head around the proper use of a Wiener or error-prediction filter for filtering data. It seems to me that it is only a whitening filter, so how is it used when the data you want to recover isn't an AWGN signal?
For instance, I have a signal that has several distint interfering signals - I can see ... |
I have a little karaoke-style app where a user sings 4 lines of a song, with a one second gap between each line. There is no backing music, so it's voice only, hopefully making the problem easier to solve.
I am looking for the most robust way to detect exactly where in my recording the user starts and ends singing l... |
Beyond the raw equation for calculating mutual information, what does it mean in physical terms?
For example:
From Information Theory, we know that entropy is the smallest loss-less compression scheme that we can use on a alphabet with a specific probability distribution.
What would that mean in terms of Mutual Inform... |
I am trying use the FFT in a different way then most people ask about. I want to be able to take a picture of a graph with regular repeating vertical lines, and to process the image to determine how far in pixels the lines are apart on average. I have tried canny edge detection and hough line detection and I don't thin... |
I'm trying to implement a modified version of the otsu binarization algorithm. I'm trying to binarize document images. But in the binarization procedure I want the object (in this case the text) to retain its original grayscale value while the background takes the value of 255; that is, white. I'm posting a sample imag... |
I have an RGB image with various signs. My main goal is to count the signs that are in contact with the image borders.
Approach and problem
I started by loading the image [Fig. 1], then converted it to grayscale and applied a median filter to get rid of some noise [Fig. 2]. Then I binarized it with a threshold of 0.2, ... |
Can anyone please help me understand the 2D equation of DCT?I find it hard to understand it in terms of how to apply the equation.
For example if I have an 8x8 image and I will apply 2D-DCT to every block of that image where will I start the application from left to right, top to bottom, or after left to right, top to ... |
As follow up to my previous question I was wondering if there are any speech detection libraries in existence. By speech detection I mean passing in an audio buffer and getting back an index of where speech starts and stops. So if I have 10 seconds of audio sampling at 44kHz, I would expect an array of numbers such as:... |
Equation (4) of a recent paper (An improved peak-frequency-shift method for Q estimation) shows how to generate a wavelet using a zero-phase Ricker wavelet.
$|B_1(f)| = |B_0(f)|\exp(-\pi t f / Q)$
In the above, $|B_1(f)|$ is the amplitude spectra of the wavelet that I want to calculate, $|B_0(f)|$ is the amplitude spec... |
Let $Y$ be a measured (noisy) image $Y= X+ noise$, where $X$ is an image contains $0$(Background) and $200$(object). I need to create a decision rule that determines whether the true pixel value was $0$ or $200$ given the image $Y$.
the noise is Gaussian with mean=0 and standard deviation=sigma
I_true = [zeros(50,140);... |
I know that you can calculate the gain of a low-pass filter by summing the filter coefficients. I don't know how to calculate the gain of an arbitrary matched filter.
For instance, I have created a matched filter for an 802.11a long training symbol (for the purposes of this question that detail doesn't matter- just th... |
Assume you have a signal, and within it, some pulses are present. A pulse is a simple tone. You know the pulses' duration and shape. (Let us assume that a pulse is made of a couple of cycles, and then to which all those cycles are multiplied by a hamming window. So the final pulse may look like the blue plot below:
... |
Both linear regression and Kalman filtering can be used to estimate and then predict from a time domain sequence of data (given some assumptions about the model behind the data).
What methods, if any, might be applicable to do prediction using frequency domain data? (e.g. predict a future step, using the output from... |
From what I have heard, compressed sensing can only be utilized for a sparse signal. Is this correct?
If that is the case, how can a sparse signal be distinguished from any bandlimited signal? Every signal can be expanded to include a sparse or zero-coefficient signal part. Does it become a sparse signal in that case?... |
I'd like to take pictures of labels on a jar of food, and be able to transform them so the label is flat, with the right and left side resized to be even with the center of the image.
Ideally, I'd like to use the contrast between the label and the background in order to find the edges and apply the correction. Otherwi... |
I am looking at a hardware based platform for surveillance class of applications. I want to identify faces of people as they appear in the scene.
I don't intend to really apply face recognition (then or later). Also orientation of faces can be assumed straight for practical purposes. Face detected once needs no furthe... |
Adaptive thresholding has been discussed in a few questions earlier:
Adaptive Thresholding for liver segmentation using Matlab
What are the best algorithms for document image thresholding in this example?
Of course, there are many algorithms for Adaptive thresholding. I want to know which ones you have found most effec... |
This is a side-trip from my snoring app.
I had a crack at producing an autocorrelation of the audio signal, to see if that "correlates" with snoring/breathing very well. I have a simple algorithm going (produces 1.0 as the zeroth element, which is a good sign), but I'm wondering how to evaluate the result to determine... |
Is there a more optimal peak location estimator specifically for triangle waves in AGWN, compared with peak estimation for generic waveforms?
For a "smooth" waveform in noise, a common peak locator method might involve a linear-phase low-pass filter or an overdetermined polynomial curve fit (by regression, et.al.), fol... |
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