4 votes
Accepted

GPS Coarse Acquisition PRN Codes

I have a PRN generator that I have validated with live captured signals that is available on the Mathworks Exchange site at this address and equally runs in Octave (Update: I also pasted the core of ...
Dan Boschen's user avatar
  • 51.1k
4 votes
Accepted

GPS CA Signal Acquisition

What's the maximum residual frequency offset allowable when doing the despreading of the CA code? 500 Hz? Or, what's the SNR loss due as a function of frequency missmatch due to residual Doppler? The ...
Dan Boschen's user avatar
  • 51.1k
2 votes

Scale invariant template matching

To increase the speed, I think the dimensionality of the feature descriptors should be reduced. SIFT feature descriptor is of 128 dimensions. So you can try PCA-SIFT which reduces the descriptor ...
Debasish Jana's user avatar
2 votes
Accepted

Difference between Generalized Hough Transform and Cross-correlation Feature Matching

There is a big difference: The Hough Transform maps the input space to a parameter space, where the search takes place. This way, the run-time of the algorithm is independent of the degree of the ...
Tolga Birdal's user avatar
  • 5,465
2 votes

Algorithm for Scale Invariant Template Matching

Just wanted to give a little bit of modern answer to this question. In the 'machine learning' sense. Such matching problems are (maybe a little unfortunately) rebranded as one-shot object detection or ...
Tolga Birdal's user avatar
  • 5,465
2 votes
Accepted

Feature matching of images without corners

I have referred to Stage I.D of this tutorial. Hope this helps. http://www.robots.ox.ac.uk/~vgg/practicals/instance-recognition/index.html#stage-id-improving-sift-matching-using-a-geometric-...
Arka Sadhu's user avatar
1 vote

Algorithm to detect tapping-events in an XYZ-signal of an accelerometer

Please consider the following, if you are not familiar with some of the techniques you described A simple vectorial amplitude + detrend + threshold would be enough to catch most of the taps over a ...
Brethlosze's user avatar
  • 1,430
1 vote

Identify and remove repeated audio chunks

What I'd do: Transform data into a representation that maximizes "similarity" of chunks that are otherwise "alike" but have large Euclidean distance in terms of raw waveforms ...
OverLordGoldDragon's user avatar
1 vote

How to find a noisy line in a picture

What about an algorithm in image domain? For every pixel, check into the direction you desire to know (up-down in your images above, I guess) if there is a pixel with "the same" value (i.e. a value ...
M529's user avatar
  • 1,736
1 vote

Algorithm for Scale Invariant Template Matching

I believe Haar Cascades(used by Viola-Jones) are inherently scale-invariant. Also severely deprecated by modern Neural Networks, but I know nothing about those. It also doesn't do any OCR - if you ...
Vorac's user avatar
  • 233
1 vote
Accepted

Algorithm for Scale Invariant Template Matching

If your templates are all based on some kind of text you may use some kind of OCR to match the text itself and not only by features. Regarding features, you may read: A Comparative Analysis of SIFT, ...
Royi's user avatar
  • 19.6k
1 vote

Detect when signal starts oscillating

As far as I can tell from the graph, the variance of the signal goes up substantially under "oscillation" conditions. So, monitor the variance over a rolling window. High variance indicates ...
Dave Kielpinski's user avatar
1 vote

Matching guitar signal with tablature, near real-time algorithms?

Assuming that the tablature is well defined; let's say it's a MIDI file complete with pitch bend commands. you can make a synthesizer where each note is actually a tracking comb filter tuned to the ...
robert bristow-johnson's user avatar
1 vote

Detecting which digital number an image represents

You already converted to binary - if that proves to work well, then you can do a shrinkage operation (I'm quite sure there should be such in OpenCV but not completely) until you get one point per ...
mathreadler's user avatar

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