Questions tagged [measurement]

The tag has no usage guidance.

23 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
4
votes
3answers
658 views

Measuring non-planar objects in image

I'm working on a computer vision application (using openCV) and the goal is to measure the width of an object before/after it falls on a container. So after the fall its position will be random, ...
3
votes
0answers
2k views

How to convert raw pulse sensor data into actual pulse?

I've built a simple device, which sends readings from a pulse sensor to a PC. I get these data: What technique or algorithm can I use in order to calculate the pulse rate (beats per minute) from ...
2
votes
1answer
51 views

Is fft2 in MATLAB unitary? Some differences happen

I meet a problem when implementing fft2 in MATLAB. The question is I try to simulate the realistic measurements $Y = |FCXF^H|^2$ - the intensity of Fourier domain of object $X$, where $F$ denotes ...
2
votes
0answers
154 views

Digital filter for sharp impulse in data

I am looking for an algorithm or a filter to remove sharp peaks from my data. I am collecting raw data after every 1 second from an sensor through an ADC. The ADC has an internal FIR filter. I use ...
1
vote
0answers
40 views

How to draw a smooth spectrum from a discrete array of measurements at selected frequencies?

I have a AS7265x triad spectroscopy sensor from SparkFun (link) which gives me measurements at 18 individual light wavelengths between 410nm and 940nm. The datasheet says that the FWHM of each sensor ...
1
vote
0answers
81 views

Calculating Transfer Functions From Harmonic Distortion Percentage

Hi I am working on emulating a piece of analog audio equipment and would like to be able to create a transfer function based on the measured percentages of harmonic distortion. I know that harmonic ...
1
vote
0answers
46 views

How does the error in azimuth angle vary as one moves away from the boresight direction of a radar

My question is basically same as the title. I am trying to find a mathematical model which provides the error, $d\theta$, in azimuth angle($\theta$) as one moves away from the boresight direction of ...
1
vote
0answers
44 views

Parameter estimation from a measure

I'm doing an exercise where, given a data sample taken from a physical measure, I have to estimate the parameters of the measure where samples $x_i$ are described by the equation: $$ x_i = A \sin(2\pi ...
1
vote
0answers
70 views

Why is the term deconvolution used more for signals and not so much (or at all) for systems?

Wikipedia defines mathematical deconvolution here, and with the examples given and my experience, what I've read over the years is that deconvolution is used to determine an input signal provided a ...
1
vote
0answers
472 views

Sampling and zero crossing

I am sampling a sine wave of 50Hz(stepped down from 230V) at the rate of 500KHz. For identifying disturbances in the wave, i was thinking of comparing a cycle of incoming sine values with reference ...
1
vote
0answers
17 views

How is per-class rate defined?

I've recently read the following For our pixel labeling, consistent with [20], we report the number of pixels correctly classified (per-pixel rate) and the average of per-class rates. The per-...
1
vote
0answers
147 views

Image objects dispersion and diversity measures

I have images like below: I want to find some measures describing black spots dispersion and diversity. First measures I use are mass center off all black spots, mean area of spot, stdev of area ...
0
votes
0answers
19 views

Dirty Image Quality Assesment Measure

I was looking for a way to measure how dirty is the document in image processing. Example images below: a. Dirty Backgrounds b. Dirty Backgrounds with Text Can someone give me an initial idea to ...
0
votes
0answers
9 views

Measure that Compares an Actual Old Document from a Synthetic Old Document

I have collected dirty background images, below is the sample: I have also a collection of an actual image of a dirty document with text on it, just like below: My problem with my actual image of a ...
0
votes
0answers
16 views

IEC fast RMS measurement

I'm looking how to implement fast RMS measurement according to the IEC 61000-4-30 class A and I would appreciate some advice or guideline, as I'm having some doubts. IEC goes with zero crossing for ...
0
votes
0answers
36 views

Face image quality assessment

I'm trying to filter out bad face images (with artifacts) generated by StyleGAN. Is there a good image quality measurement mechanism in python for doing this? I've tried using BRISQUE but it is not ...
0
votes
2answers
70 views

Phase measurement with FFT for DMM Keithley 7510

I am currenly working on a measurement driver for the DMM Keithley 7510. I implemented a harmonics measurement using FFT (from MathNet library). First I simply sample my input voltage signal and ...
0
votes
0answers
30 views

Methodology for log some sweep audio measurement impulse response

I am trying to implement a method for measuring the response of a loudspeaker in a room using a log sine sweep stimulus. To check my method: 1. I create the stimulus using: Make recording length ...
0
votes
0answers
39 views

Log Sine Sweep Acoustic Measurements

I am currently trying to understand the Sine Sweep Method for taking acoustic measurements. I am following this paper: https://www.thinksrs.com/downloads/pdfs/applicationnotes/SR1_SweptSine.pdf I ...
0
votes
0answers
146 views

White noise sound vs harmonic sound reverb

I use a microphone array to localise a sound source in a small lecture theatre. I tested it with white noise and a bird noise source. I found out that the white noise source give very good results. ...
0
votes
0answers
82 views

Get the distinctive deltas of quite noisy and very variable / dynamic measurement values

for my thesis I need to point out the distinctive deltas of my measurements for further use. The jumps can occur with different heights over different time slots. And the absolute base values can ...
0
votes
0answers
27 views

If a signal is added to another in the freq. domain, how to filter it out?

I have two signals, $x$ and $y$. I know that $F(x)=F(s)+F(n)$ and $F(y)=F(n)$, where $s$ is the 'clean' signal, $n$ is the added noise and $F$ donate Fourier Transform. To obtain the clean signal, I ...
-1
votes
1answer
77 views

SNR problem with different sampling rates using innerproduct

I'm trying to measure the amplitude of a sinusoidal component in a noisy signal. Since the signal frequency is known beforehand, I'm calculating scalar product with a sine and cosine base function ...