# Questions tagged [algorithms]

Algorithm is a method expressed in a finite list of steps of well-defined instructions to process a signal.

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### is it possible to matching b / w images without feature extraction steps? if possible which algorithm may be more suitable?

these are example of my image i have a 245 images similar to it ,i obtained these b/w images after preprocessing stage , i want to use them for recognition persons(not verification) in matlab. can i ...
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### Matlab video processing of Contracting tissues. how to analyze movement?

I'm trying to write a code The helps me in my biology work. Concept of code is to analyze a video file of contracting cells in a tissue Example 1 Example 2: youtube.com/watch?v=uG_WOdGw6Rk And ...
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### Binary robust independent elementary features ("BRIEF") understanding

How are the descriptors in the BRIEF algorithm matched to each other? How is the template image found in the another image? How do we compare the descriptors? I have read that article but didn't ...
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### Programming a Vocoder

I'm want to program my own vocoder synthesizer like "Songify" but I can't find a simple of vocoder algorithm. Maybe you can explain or tell where to look for information on how vocoder works.
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### Fit piecewise linear data

What is a robust way to fit piecewise linear but noisy data? I'm measuring a signal, which consists of several almost linear segments. I'd like to atomatically fit several lines to the data to ...
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### How Can I practically implement the FFT with size unequal to a power of two?

Can anybody explain how I can implement the Fast Fourier Transform (FFT) of length unequal to a power of two in hardware, e.g. FPGA? What is the algorithm for this implementation? Does anybody know ...
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### Iris recognition using filters?

I am implementing an iris recognition system in matlab and have performed the following steps according to an algorithm proposed in a paper Initial image Median filtering For each row in the ...
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1 vote
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### Open Source Implementation of 3D Thinning algorithm

I am looking for open source implementation of thinning algorithm in 3D. Thinning algorithm: Convert binary shapes to 1-pixel wide lines, without shortening it or breaking it apart. For example, ...
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### main direction in 2D map of data

It may be a very simple question. We would appreciate any comments, guide or complete solution. We prefer however incomplete solutions but novel practical ideas. - How to find the main direction of ...
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### Detecting drum bpm in a noisy .wav file

I am looking for algorithm(s) to solve the following problem: Given a noisy .wav sound capture (some wind + friction noise on the microphone), how to detect the BPM of a soft drum beat? I have ...
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### Detecting a fixed template image out of a semi-constant frame of video

There are a number of videos that I'm looking to process of different video games to detect various "states" in them. The first game that I am tackling is any edition of Super Street Fighter 4. In ...
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### Which are the steps to extract contours/shapes from depth videos?

I am trying to create a histogram of the depth videos (converted to grayscale first) in order to apply a threshold to keep only highest values, and then do some dilation in order to extract contours. ...
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### Frequency Modulation Synthesis Algorithm

Based on what I read, I've made an algorithm for FM sound synthesis. I'm not sure if I did it right. When creating a software synth instrument a function is used to generate an oscillator and a ...
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### Contours matching - finding contours displacement

I found contours on two images with same object and I want to find displacement and rotation of this object. I've tried with rotated bounding boxes of this contours and then its angles and center ...
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### What Is the Algorithm Behind Photoshop's "Black and White" Adjustment Layer?

Can someone explain the algorithm behind the "Black and White" adjustment layer in photoshop? I have to reproduce it using C++ for an application that emphasizes non-red/magenta(ish) pixels ...
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### How do I implement an adaptive thresholding algorithm for underwater sonar

I want to implement an adaptive thresholding algorithm in MATLAB for filtering data received by an underwater sonar receiver. The data received has an interactive noise component resulting from ...
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### Bitmap alpha bevel algorithm?

I am looking to create an algorithm which adds a bevel effect to a bitmap using it's alpha as a bump map. How would I go doing something like this? I have tried specular lighting but I only get the ...
• 309
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### Bitmap border/stroke alogirthm?

I am looking for an algorithm that adds borders to a bitmap image(very much like the photoshop stroke effect) but one that will also have antialiasing to the borders(or one that copies alpha from the ...
• 309
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### Applying A-weighting

I want to calculate the loudness of a given signal and I've come across this thread. I'm slightly confused about the A-Weighting aspect of it. I can't post images, but I think this site has the ...
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### Autocorrelation in audio analysis

I'm reading up on Autocorrelation, but I'm not sure I understand exactly how it works and what output I should expect. Am I right in thinking that I should input my signal to the AC function and have ...
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### Data decomposition method invariant to small shift and scale?

Is there a data decomposition method similar to eigenvalue that estimates projection matrix to reduce dimensionality but does not project similar vectors too far away in euclidian distance terms from ...
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### Is there an algorithm to compare several pictures?

I'm looking for an algorithm to store small dimensions of some pictures and later search on the stored data for matches similar to a new picture. Maybe something with Self Organizing Map in machine ...
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### Am I handling offline FFT correctly?

I need some help clarifying FFTs and what they represent. I have a buffer containing compressed audio. Due to limitations, I can't handle the full uncompressed audio but can decompress small segments ...
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### Recognizing math functions within songs

I'm new to DSP, and just discovered this StackExchange, so apologies if this isn't the right place to post this question. Is there a resource that describes genres in a more mathematical terms? For ...
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### How is a "good" or "bad" singer defined in signal processing terms?

I was watching the American and Indian idol auditions on youtube earlier in the day. I watched both successful and failed contestants and I was able to distinguish the really bad from the good singers ...
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### Fastest Algorithm for Distance Transform

I am looking for the fastest available algorithm for distance transform. According to Image Processing Learning Resources - HIPR 2 (HYPERMEDIA IMAGE PROCESSING REFERENCE) - Morphology - Distance ...
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### What is the difference between Remez exchange and Parks-McClellan filter design?

A question recently came up regarding Parks-McClellan and some of the comments point out that the wikipedia article on Parks-McClellan states, ...the Parks-McClellan algorithm is a variation of ...
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### Skel to infinity morphological operations on 3D volume

I have a 3D volume image that consists of 2D tomographic images. In MatLab, for 2D images, we can use bwmorph and call for 'skel' operation to infinity to get a pixel thick overall outline of the ...
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### Calculating the PDF of a waveform from its samples

A while ago I was trying different ways to draw digital waveforms, and one of the things I tried was, instead of the standard silhouette of the amplitude envelope, to display it more like an ...
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### Estimating onset time of a tone burst in noise?

What techniques might one use to estimate the onset time of a sinusoidal tone burst in a noisy signal? Assume the tone burst has a known fixed frequency (but unknown phase) and a very sharp rise ...
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### What factors should I consider in choosing an edge detection algorithm?

I've learned about a number of edge detection algorithms, including algorithms like Sobel, Laplacian, and Canny methods. It seems to me the most popular edge detector is a Canny edge detector, but is ...
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