Questions tagged [resolution]

Resolution is a term used in Image Processing. It is an umbrella term that describes the detail an image holds.

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How to emulate lower resolution digitized data (higher step-size)

I am a statistician by training, and I am very new to signal processing, but I would appreciate some help and patience! Suppose I have a digitized signal measured at a given frequency, range, ...
5 votes
4 answers
177 views

FFT with High Time and Frequency Resolution

Can anyone describe in a bit more detail or provide references to the techniques for simultaneous enhancements to time and frequency resolution described in a high level in this video? Can anyone ...
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2 votes
4 answers
336 views

Methods to increase FFT time resolution without lowering FFT size

It is known that in FFT time and frequency resolution are inversely related if FFT resolution is increased then time resolution will decrease. However is it possible to overcome issues in time ...
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1 vote
1 answer
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Resolution of phase measurement using cross Correlation

The setup is the following: I am using a RedPitaya board to measure the phase shift of two input signals. These input signals will sweep logarithmically from 1kHz to 100 kHz in 10 seconds. Currently, ...
1 vote
2 answers
649 views

Relation of zero-padding and frequency resolution

Consider simple rectangular pulse and FFT of it in Python: ...
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1 answer
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Effect of downsizing on perceived sharpness

Suppose an $N\times M$ image of an object is downsized to a $N'\times M'$ image using a standard algorithm such as bilinear. How does that downsized image compare in sharpness to an image of the same ...
0 votes
1 answer
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How to increase the frequency resolution in FFT?

I'm still learning. I have checked many questions on here similar to mine, but have not found an answer. I'm analyzing the oscillation of a train catenary system. Due to bad sampling frequency and ...
1 vote
1 answer
100 views

Measurement resolution for an accelerometer

This may be a trivial question but I don't have a strong background in signal processing and measurements. I have a piezoelectric accelerometer with a sampling frequency of 10 kHz (sensitivity $102 \; ...
2 votes
1 answer
138 views

Alias free-range extent and range resolution formula proof

I've consulted many books about radar working principle. The well known formula of the resolution and alias free range extent (unambiguous range) appear referred to FMCW radar,ie $$ \delta R = c/(2B) $...
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1 answer
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Understanding the units of wavelet time & frequency resolution

While using a continuous wavelet transform for my research project, I came up with some questions. Having a set of equations for a Morlet wavelet, $\psi(t)=\sqrt{\frac{2}{\pi}}e^{-t^2/2}e^{i6t}$ $\...
2 votes
1 answer
558 views

What is the effect of a larger window size on "temporal resolution"?

I guess my question boils down to what "temporal resolution" means? I'm taking a signal processing class right now and we're learning about DFT and windowing at the moment. We've learned ...
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1 vote
1 answer
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Quantization error of SAR-ADCs

My question is related to the quantization error and the functionality of SAR-ADCs. In general, the quantization error of an ADC is defined as +-0.5LSB. If this concept is correct a voltage that ...
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4 votes
1 answer
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The effects of frequency resolution in FFT on the frequency spectrum

This is a section for the parameter study of my thesis (basically: why and how I did what I did in the experiments). Currently, I have to choose the fit bandwidth and FFT lines combination for the ...
6 votes
2 answers
489 views

Using oversampling to increase resolution of a DC-signal as input

Currently I'm working on a project which uses oversampling to increase the resolution of a 12 bit ADC to a maximum of 16 bits. My goal is to fully understand the theory behind oversampling and why it ...
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1 answer
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Is it worth recording 4K resolution from a 1080p camera input?

I work with this as a recording setup: Canon 5D3 into an ATEM MINI recorder into Ecamm Live (primarily for the sake of bypassing the 30 minute limit at present, not for live-streaming), but eventually ...
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0 answers
84 views

Should A/D resolution affect EEG signal properties and how?

I encounter a curious situation wherein the recording device of my EEG data appears to affect how many transients of definition "x" I find, especially strange since the amplitude criterion is relative ...
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Estimation of Power Spectral Density

I'm learning some basic signal processing to use in my research. So I'm trying to solve this combined signal: $x(t)= \text{sin}⁡(60\pi t+\theta)+ 0.5 \text{sin}⁡(120\pi t+\theta)+ 0.3 \text{sin}⁡(...
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1 answer
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How can I improve the resolution of a spectrogram of a low-frequency signal with high sampling frequency (Python)?

Imagine you have signals $x_1(t)$ and $x_2(t)$ that contain a limited number of periods of low frequency oscillations and are sampled at 44100Hz (coming from an external source) and you want to obtain ...
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Weird resampling artifacts of a periodic signal

I am trying to grab time series data from a database storing data on a propritary format. When i chose a resolution which is not a multiple of the power of two of the sampling resolution i get these ...
1 vote
2 answers
598 views

Multi Resolution STFT for audio

I am looking at trying to achieve a multi resolution STFT analysis on a log sine sweep audio measurement. I have an impulse, and I would like to perform two different windowed length FFTs on the ...
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1 vote
1 answer
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Separability vs. Resolution - Synonymous terms?

In terms of discrete representation of a variable, let's say time measurements in absolute values in [seconds], is there a difference between separability and resolution? When do speak of either ...
0 votes
1 answer
263 views

Effective Nyquist frequency / signal resolution for overlapping time averaged signal samples

Say that I have a continuous signal. If I sample the signal at sampling rate f_sample, then the highest signal frequency that I can resolve without worrying about ...
0 votes
2 answers
4k views

How to increase resolution of FFT?

I have an input signal in the ( 0 - 20 kHz ) frequency range . When i sample this signal maximum sampling frequency is around 40 kHz . When i calculate the FFT using 1024 points i got resolution of ...
1 vote
1 answer
66 views

How do I add more resolution / taps to an analog -> digital filter?

(I am trying to create an IIR audio filter that adds reverb to an initial sample) Say I designed an analog filter to model acoustic attenuation based on the following mathematical model: $$ I = I_0 ...
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1 answer
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THD requirement for generated sine

I need to generate a sine signal using a DAC with a certain THD specification, say 0.1% @ 1KHz. As a first approach I’m considering it to be an ideal DAC along with an ideal LPF for aliasing removal ...
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1 vote
2 answers
3k views

How to increase the spectral resolution?

My question is about the spectral resolution of a discrete signal. Each sample of my signal is made up with 2^n frames sampled at 44.1 kHz. So, when I want to know the spectral resolution, I ...
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2 votes
1 answer
123 views

FFT radix-2 in audio - resolution issues - logarithmic scale - sample rate VS buffer size

I would like to ask how to deal with audio DSP. Is FFT good at all to deal with audio? I am working on an app, that generates a single impulse, rout it to an EQ plugin, and the output of the plugin is ...
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1 vote
2 answers
2k views

Basic difference between Multi-scale and Multi-resolution images

While working on Convolutional Neural Network (CNN) I saw many research articles working on the Multi-scale images. In the literature of image processing I saw there is also Multi-resolution analysis ...
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1 answer
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Most natural interpolation to simulate increasing distance?

Background: I'm generating multiple datasets with varying scales of resolution to simulate taking pictures from varying distances and then comparing image classification performances. For example ...
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2 answers
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Origin of brightness artifacts in intensity resolution compressed images

when compressing this image (It corresponds to Fig2.20 from the book Digital Image Processing by Gonzalez and Woods and the original .tif document can be downloaded through this link By reducing ...
3 votes
1 answer
790 views

Minimum length of windows and separable signals

I created a signal with lets say $\omega_1$ that is fixed at 1 bin in the FFT: $$A_1\cos(\omega_1t)$$ I was asked to find the closest $\omega_2$ to $\omega_1$ so that the signals $A_1\cos(\omega_1t)$...
1 vote
1 answer
63 views

Resize High Resolution Camera Capture to Low Resolution Camera Capture?

Say, you captured a high-res image of a scene and a low-res image of the same scene, using a lower-res camera, ensuring that the lower-res camera is using the same technologies, except for the image ...
0 votes
1 answer
217 views

fast fourier transform frequency limit [closed]

I'm a french student in engineering and I'm given a kind of mandatory technical project to work out on until February. I must investigate the following article : https://www.osapublishing.org/...
4 votes
1 answer
3k views

Uncertainty principle - Duration bandwidth principle

In one of NPTEL courses about time-frequency analysis, the professor said that the duration bandwidth principle is $\sigma_t^2 \sigma_\omega^2 \ge \frac{1}{4}$. He added that the formula making use ...
19 votes
2 answers
18k views

What are advantages of having higher sampling rate of a signal?

Being a non signal processing science student I have limited understanding of the concepts. I have a continuous periodic bearing faulty signal (with time amplitudes) which are sampled at $12\textrm{ ...
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2 votes
1 answer
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Deciding on the FFT length for water waves in flume (wave facility)

Soon I'll be conducting experiments in a wave facility (flume) for my MSc thesis. And I would like to analyse wave spectra (amplitude and energy density). The time step (or 'accuracy') of the wave ...
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1 vote
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Where can I find more information about this formula relating a window's time and frequency size?

I remember having seen a formula of the form $C=\frac{B}{L}$ that relates a duration $L$(s) of a window to its width $C$(Hz) in the spectrum (defined at -3dB or so). The constant $B$ would be ...
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3 votes
1 answer
336 views

Reduce the number of frequencies after FFT

I have a long signal (1 day sampled at 500 Hz), which results in many frequencies if I calculate the amplitude spectrum (see e.g. here). However, I am only interested in the "big picture", let's say ...
1 vote
2 answers
274 views

FFT Resolution Inference

Let's say I have an audio clip of $N$ samples. I want to describe every $10$ ms of audio with an FFT of size $1024$, without information bleeding over from other $10$ ms windows. Given that the ...
0 votes
2 answers
629 views

How do I get the Time information after STFT?

I'm tring to code a STFT program in Matlab. I got results but I'm confused a bit. I have a audio signal of 900000 pts sampled at 1000Hz (15 min signal). I've taken fft with following parameters => ...
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6 votes
1 answer
139 views

How to Increase the Resolution of a Video from a Sequence of Photos?

I have a video filmed in a relatively low quality and resolution and a sequence of photos of higher quality taken of the same scene at the rate of about one image every two seconds or so. Could those ...
0 votes
0 answers
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Invertible multi-resolution representation of audio/speech signals

What are the invertible (preferably linear) representations of an audio/speech signal which captures the essence of signal in different resolutions and details. Basically, I am looking for Laplacian/...
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0 votes
1 answer
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Sensitiviy and Resolution in Windowing Functions

When I read the article Windowing Functions, there are two terms that are does not understanding them well, sensitiviy and resolution. I looked for this two terms on the web, And I conclude that ...
1 vote
1 answer
489 views

WFM SDR and Audio resolution

How does SDR resolution translate to audio resolution when using FM demodulation? For example: using a 8-bit/2.048 Mhz IQ stream, what is the maximum audio sample rate and bit depth that can be ...
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3 votes
5 answers
2k views

Selectively improve the frequency resolution of FFT (DFT)

I have a digitally sampled signal(sampling frequency = 4000 Hz) which contains analog frequencies from 0 to 1000 Hz. I wish to have a frequency resolution of 100 Hz(like 0,100,200,300 Hz .. 1000 Hz) ...
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2 votes
5 answers
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Doppler Frequency Resolution for Radar

Doppler frequency is calculated by the formula $f_{d} = 2*v_{r}/\lambda$, where $v_{r}$ is the radial velocity and $\lambda$ is the radar wavelength. Normally FFT is used to detect the doppler ...
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3 answers
304 views

Does perceived ADC resolution, range and precision depend on fixed point format? What is the best way to deal with this for signal processing?

I am working on a system that is implementing a digital filter that was designed for another system that had an FPU and a 12bit ADC. The system that I am working on is using the same filter without an ...
0 votes
2 answers
176 views

Signal Resolution

I have a question. Suppose we have a signal $x(n)$, length (samples) $N=400$ which have been sampled with $f_s=8000 \mathtt{Hz}$. Also suppose $X(k)$ - the DFT transform of this signal. How many ...
0 votes
1 answer
552 views

Time-bandwidth product and uncertainty on harmonics

For a signal that is not corrupted with noise, how is the time-bandwidth product affecting the uncertainty or error introduced when extracting the fundamental frequency ? I mean, instead of choosing ...
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1 answer
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Image processing and Camera Calibration

I have several related questions about camera resolutions. If I calibrate my camera to a particular resolution say 640x360, can I use it for another resolution like 1024x768? Also, I want to know as ...
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