## Top new questions this week:

### Is a high-passed signal the same as a signal minus a low-passed signal?

My question is, if I want to high-pass a signal, is it the same as low-passing a signal and subtracting it from the signal? Is it theoretically the same? Is it practically the same? I have searched ...

matlab filter-design lowpass-filter highpass-filter digital-filters

### Removing unwanted square-wave noise from a signal

I have a signal, s, given at the end of this message. I need to remove the square wave shape from it. The desired signal is actually very small and it has been contaminated by a strong square-shape ...

signal-analysis noise wave

### Weighted Nuclear Norm Minimization for Image Denoising

Recently, I saw new published papers like this paper about denoising images using Weighted Nuclear Norm Minimization (WNNM) approach and I am wondering what is the physical intuition behind it. The ...

image-processing denoising linear-algebra optimization

### Removal of noise from vibration recordings

Problem I am analyzing accelerometer recordings that are contaminated by 'spikes' caused by issues in the digital circuitry. The spikes are problematic, because I wish to determine the peak-amplitude ...

matlab filters denoising highpass-filter

### FFT Result - which bins are useful

Which bins of FFT result are useful? For example I made FFT on 1024 real samples, and it produced result with 1024 complex samples. I read somewhere, the only half of that result is useful if input ...

fft

### What is the minimum sampling duration to capture a given frequency?

Due to the Nyquist rate, you need to sample twice as fast as the highest frequency you want to measure. Then when you do a FFT the number of samples determines the number of bins and thus the ...

fft frequency nyquist

### How to find orthonormal basis function in the following digital communication problem?

I'm trying to express the following set of signals on orthonormal basis functions. These signals are to be transmitted using a 4-ary modulation scheme.How do i write ψ1(t)and ψ2(t) for the same. Also ...

digital-communications orthornormal

## Greatest hits from previous weeks:

### Filtering 50Hz using a notch filter in MATLAB

I've read up a lot about this, but haven't been able to piece everything together successfully, so I'm looking for some help. I need to filter 50 Hz from a signal. It looks like the best options are ...

matlab filters

### Algorithm(s) to mix audio signals without clipping

I'd like to mix two or more PCM audio channels (eg recorded samples) digitally in an acoustically-faithful manner, preferably in near-real-time (meaning little or no peek-ahead). The physically ...

audio algorithms distortion

### Aligning frames with common elements

I am new to image processing and had the following question: I have take some 512-px grayscale images. The images were take in such a way that all images were of the same spot, but there was some ...

image-processing signal-analysis image-segmentation

### Efficient Hessian-Laplace blob detector implementation

As it is mentioned in a paper for SURF, it is possible to approximate hessian determinant using integral images. If I want to implement Hessian-Laplace detector, is it feasible to also approximate ...

image-processing computer-vision opencv local-features
I am trying to get equivalent of this system using the Noble Identities: $$x[n] \rightarrow \boxed{H(z^L)} \rightarrow \boxed{\uparrow L} \rightarrow y[n]$$ my answer is x[n] \rightarrow ...