Unanswered Questions
12
votes
0answers
947 views
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 to ...
9
votes
2answers
393 views
Log-Polar DFT Based Scale-Invariant Image Registration
I'm trying to do image registration using phase correlation as described in the Reddy Chatterji paper. In my case, the images may be scaled and translated relative to each other.
The algorithm for ...
8
votes
0answers
982 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 c-...
7
votes
2answers
402 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 $X(N/...
7
votes
1answer
466 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 ...
6
votes
0answers
78 views
Decoding raw data from the Terra satellite
I have a raw data from a demodulator, received from the Terra scientific satellite (The target is MODIS data). As far as I know, the data is encoded by a Convolution error-correction code. The ...
6
votes
1answer
106 views
Why are some JPEG files of the same scene much larger than others?
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 ...
6
votes
0answers
212 views
Will an unscented Kalman filter be “as good” as other optimisation algorithms for this problem?
I want to calibrate a tri-axis magnetometer when a tri-axis gyroscope is also available.
I am fairly certain I can solve this problem using various optimisation algorithms, but I would prefer to use ...
6
votes
0answers
868 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 ...
6
votes
0answers
177 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:
...
6
votes
1answer
109 views
DFT - Removing window effect in spectral domain with convolution
I was thinking about the DFT windowing subject and a thought came to my mind. A DFT will yield the spectrum of a signal convoluted with spectrum of the window used, therefore having a main lobes and ...
6
votes
1answer
403 views
How to choose a windowing function when performing a Chirp $\mathcal Z$-transform?
I've got some data sampled at 32 Hz. The only interesting stuff is happening between about 0-8 Hz and I've got to do real time batch processing and detect events with a delay of no more than a second. ...
5
votes
0answers
65 views
Regarding the choice of cost function in adaptive control - squared error vs absolute error
I did search the question database regarding this question, and although one or two questions came close, they didn't really address my specific question.
In adaptive control based on minimizing ...
5
votes
1answer
143 views
For a discrete LTI system, does “bounded memory” imply “rational transfer function?”
Every LTI system with a $\mathcal Z$-domain transfer function that is a rational function - aka a quotient of two polynomials in $z$ - can be implemented using a bounded amount of memory.
Is the ...
5
votes
1answer
71 views
Expanding piecewise polynomial using Daubechies wavelet
What is the best Daubechies wavelet (i.e. the number of vanishing moment) to expand a signal $\boldsymbol{x} \in \mathbb{R}^n$?
$\boldsymbol{x}$ consists of $m$ pieces of polynomial with $d$ degree. ...
