# Unanswered Questions

0answers
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### Real-valued ringing when zero-padding odd-length FFT

So I'm trying to write a frequency-domain interpolator that zero-pads the frequency response of a signal and inverse transforms. There's two cases I have to deal with: Even-length response - have ...
1answer
325 views

### Kalman Filter - best way to handle “derived” measurements?

Ie, if you have as state variables position (p) and velocity (v), and I make low-frequency measurements of p, this also indirectly gives me information about v (since it's the derivative of p). What ...
1answer
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2answers
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### Calculating a homography based on detected lines

I know you can calculate homographies from image to camera plane using correspondence points between a "perfect model" and the image points. I'm doing it for a football pitch/field, and have used ...
0answers
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### Estimating the input to a system from a system state using EKF

[ Cross-posted from: http://math.stackexchange.com/questions/164169/estimating-the-input-to-a-system-from-a-system-state ] I have a system for which I have obtained a non-linear time-varying ...
2answers
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### STFT and DWT (Wavelets)

STFT can be successfully used on sound data (with a .wav soundfile for example) in order to do some frequency-domain modifications (example : noise removal). With ...
0answers
603 views

### Ensemble learning, multiple classifier system

I am trying to use a MCS (Multi classifier system) to do some better work on limited data i.e become more accurate. I am using K-means clustering at the moment but may choose to go with FCM (Fuzzy ...
2answers
316 views

### Conditions for precoding matrix to preserve complex conjugate symmetry on DFT vector

Suppose there is a DFT vector $\mathbf{X}$ with length N, which presents complex conjugate symmetry around its middle point, i.e., $X(1) = X(N-1)^*$, $X(2) = X(N - 2)^*$ and so forth. $X(0)$ and ...
0answers
491 views

### Help in Retraining a HOG Descriptor using SVMLight

I am currently trying to count cars using OpenCV 2.4.4 with a HOG descriptor. Because a model for car detection is not available in OpenCV, I am creating my own model using SVMLight and a dataset of ...
1answer
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### How to find the lower eyelid in an image?

I have an image of 480x360 px that contains eye portion only i.e., sclera iris, pupil, eyebrows etc. Now I have to find the lower eyelid in the image. What I've done till now is that cut the image ...
0answers
131 views

### What is the normalization factor for the quincunx lattice wavelet transform, and how do you find it?

On pages 57-60 (preview was available last I checked, images here in case), there is a quincunx lattice transform described. Lattice: ...
0answers
277 views

### How do you choose the optimal number of taps in a windowed image scaling filter?

I'm attempting to use a filter to scale an image and for the most part, I have something that appears to work. But now I want to be able to generate a filter with an optimal number of taps. I know ...
1answer
763 views

### Implementing a Matlab filter to cancel cross talk between two sensors

I have two sensors that have a cross talk between them. I would like to cancel the cross talk. For this I recorded two tracks, where sensor no.1 (called x1) has some input, and sensor no.2 (called x2) ...

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