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Questions tagged [signal-detection]

Signal Detection Theory (SDT) explains how a receiver detects a signal in noise as a function of the receiver's sensitivity to the signal & the receiver's bias or tendency to assert the presence of the signal whether it is there or not.

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Combining Data from Multiple Participants for Statistical Analysis of a Facial Expression Memory Task

Context of the Query: I am working on a project involving a memory task for facial expressions, consisting of two phases: Encoding Phase: In this phase, participants are exposed to 8 virtual ...
Clémentine Pouliot's user avatar
5 votes
3 answers
444 views

Hypothesis testing for detecting a (damped) sinusoidal signal in noise

I have a signal in white noise that has the following form: \begin{equation} r[t_i] = A e^{-t_i/\tau} \sin{(\omega t_i + \phi)} + n[t_i] \end{equation} I would like to test whether the signal (1st ...
P. Egli's user avatar
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2 votes
1 answer
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For discrete $X_n$ if $X_n \stackrel{d}{\to} U$, does $P_e \to 1$ where $P_e$ is optimal Bayes error and $U$ is uniform

Consider the following setting. Let $ \{X_n\}_{n=1}^\infty \subseteq [-1,1] $ be a discrete random variables that converges to a continuous uniform random variable in distribution. Let $Y_n = X_n +...
Boby's user avatar
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0 answers
24 views

Signal detection in the presence of both theoretical and experimental uncertainty

I am wondering what the best way to go about the following situation is. I will try to frame it in a clear way but please leave a comment if something can be clarified. I suspect this type of thing is ...
gabe's user avatar
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1 vote
0 answers
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Can I fit a Poisson distribution to a continuous variable to apply event detection algorithm?

Preprocessing: I have a time series of number of tweets per 10 minutes time interval that are all taken from a given discussion on a specific topic in a specific region. I preprocessed the data by ...
Mim_Tauch's user avatar
1 vote
0 answers
24 views

Gaussian white noise model in application

I am interested in applications (to data) of non-parametric statistics, and my question concerned the Gaussian white noise model defined by, $$ X_{t_1, \ldots, t_d}=f\left(t_1, \ldots, t_d\right) d ...
BabaUtah's user avatar
3 votes
0 answers
39 views

Why do popular ML and statistical packages simply ignore classical estimation and detection algorithms for statistical signal processing? [closed]

For those who had a hard time to study and understand classical estimation and detection algorithms, and unfortunately realized that these algorithms are simply ignored by many packages that have the ...
Rubem Pacelli's user avatar
1 vote
0 answers
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Is there a sense in which collections of probability distributions with the same matrix of Bhattacharyya coefficients are "essentially the same"?

A popular measure of "closeness" between probability distributions $\vec{p_1}$, $\vec{p_2}$ is the Bhattacharyya coefficient $\sum_j \sqrt{p_{1,j} p_{2,j}}$. Consider two statistical models $...
user386365's user avatar
0 votes
1 answer
532 views

Do calculate SNR based on mean and stdev need normalization?

How to calculate Signal to Noise Ratio? Is the mean to stdev ratio valid to be used as the basis for calculating SNR? What if a dataset or sample has a value of 0 all then add 1 random value other ...
Muhammad Ikhwan Perwira's user avatar
0 votes
0 answers
108 views

Visualizing signal detection indices in r

I was wondering if any of you could help with how I can somehow plot result from a signal detection analysis in r? I have used the psycho package and calculated dprime, beta, aprime, bppd and c for ...
Ronja's user avatar
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Calculate probability of alarm and the posterior probability of this alarm being false over different frequencies of output

I have the following information for an automatic detection system that output a warning when a signal is detected: Specificity: .99 (i.e. a false positive rate $FP = .01$) Sensitivity: .9 (i.e. a ...
fednem's user avatar
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3 votes
2 answers
263 views

Measuring response bias from a confusion matrix

Given a confusion matrix of a binary classifier, what are the best measures of response bias towards one of the classes? One idea that comes to mind is Signal Detection Theory's criterion, but this ...
Trisoloriansunscreen's user avatar
1 vote
0 answers
29 views

What is the probability that multiple spectral lines are just noise?

In spectroscopy spectral line emissions are related to each other, with fixed widths and heights that correlate with all lines based on fixed physical conditions. If I detect one spectral line at a 3 ...
Loperh's user avatar
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Uncovering which frequencies two systems are communicating on by observing reoccurring time correlated signals and their frequencies

Suppose you have a set of communication systems {A, B, C, D}, which speak with each other as well as other systems not contained in the set. Our concern is how they speak with each other. They ...
Michael's user avatar
1 vote
1 answer
70 views

What are the effects on signal detection metrics when a base rate matching strategy is used?

Assume that: We have two groups of observers The base rate of the signal being present is 97% Knowledge of this base rate is provided to observers in the second group Group descriptions... tends to ...
russellpierce's user avatar
1 vote
2 answers
40 views

Periods of High Activity Detection

So I have some sensor data (time series) of heart rate of some users. I want to detect the times they start and finish exercising. The data is sensor readings of heart rate every second, it's ...
Mohamed Gamal Hamed's user avatar
2 votes
1 answer
289 views

Hypothesis testing for detecting signal in Gaussian noise

I have the following two hypotheses: $\hspace{5cm}\mathcal{H}_0: y=w\\\hspace{5cm}\mathcal{H}_1: y=\sum_{i=1}^{N}h_ix_i+w$ Here $w\sim \mathcal{N}(0,1)$ represents Gaussian noise. $x_i \sim Bern(p), \...
wanderer's user avatar
  • 214
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0 answers
147 views

How to Add two white random gaussian noises from different noise sources?

I have generated two different white gaussian random noises in MATLAB using two different seeds. For example: Asn1 = sqrt(noisepow1/2)* (randn(size(As))+1i*(randn(size(As)))); Asn2 = sqrt(...
Arin Dutta's user avatar
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0 answers
17 views

Track peaks of two or more moving pulse generators

I want to disentangle the signals of two or more moving pulse sources using recordings of these pulses (see pictures). Example plots (4 panels per example to stretch the x axis a bit, the peaks of ...
Stefan Mucha's user avatar
1 vote
0 answers
43 views

Detect regularity in arrival times

I am working with series of arrival times. My typical dataset is made of 20-100 samples. I would like to detect regularity in the arrival time. By regularity, I mean that the inter-arrival times may ...
Gospadi's user avatar
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3 votes
1 answer
519 views

ROC curve as predictive tool in human performance--relationship between $\beta$, $X_C$, and signal probability

I am taking an engineering psychology course in which we are using ROC curves to evaluate human performance in signal detection. Many of the questions on this site about ROC curves are using them as a ...
Max's user avatar
  • 281
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0 answers
88 views

How can I "remove" variability in my data that is due to periodic signals, such as Temperature, RH and Solar radiation?

I have a measured signal that I know is affected by some periodic signals, such as Temperature, RH and Solar radiation. Is there a way that I can "remove" their influence from my measured ...
iditbela's user avatar
  • 127
1 vote
0 answers
30 views

What are the parameters in signal recovery? Whether source of these parameters are the sampling property of impulse response?

I was reading the following book: Juditsky, Anatoli, and Arkadi Nemirovski. Statistical Inference via Convex Optimization. Vol. 69. Princeton University Press, 2020. Here, I could not visualize the ...
Lakshman's user avatar
3 votes
2 answers
144 views

Negative correlation between d' and hit rates?

I have data from a relatively easy task where subjects had to detect a signal in noise. I computed the hit and false alarm rates (HR, FAR), and then proceeded to compute d' using the standard formula, ...
z8080's user avatar
  • 2,362
2 votes
1 answer
91 views

Minimum number of specimens for a medical experiment

Could someone validate the following - for the minimum number of specimens required. A pathogen has 8 different forms. Laboratory specimens (small organisms) are infected with the pathogen. For ...
arny's user avatar
  • 21
1 vote
0 answers
157 views

How to identify the frequencies of periodic peak signals in a noisy time series? (with R)

Suppose to have two time series with peak signals at different frequencies, like these two: ...
Raffaele Giannella's user avatar
0 votes
1 answer
37 views

Fourier analysis to retrieve components of individual spectra

I have a basic, simple question, I am a physics student, and searching internet gives me a lot of signal processing theory but couldn't find this basic answer, which I plan to implement in my speech ...
Ayan Mitra's user avatar
38 votes
3 answers
10k views

What percentage of a population needs a test in order to estimate prevalence of a disease? Say, COVID-19

A group of us got to discussing what percentage of a population needs to be tested for COVID-19 in order to estimate the true prevalence of the disease. It got complicated, and we ended the night (...
Industrademic's user avatar
1 vote
0 answers
33 views

Finding z score, based on knowing relative size of tails

(source: duckduckgo.com) This is based on my looking into signal detection, which deals with two distributions, one "positive," in this case, people who have a certain disease, and one ...
orb's user avatar
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1 vote
0 answers
258 views

ROC curve, d' A' - assumption-free?

In my research I want to know how reliably certain feature of a sentence indicates the class that sentence belongs to. So, according to that feature (=how many elements X they contain), the ...
Leandra's user avatar
  • 63
3 votes
1 answer
507 views

Finding exponential decay in noisy vibration signal

I have to analyse vibrational signals for which the general assumption is that there is one dominant excitation and an exponential decay in amplitude thereafter. I have created smoothened envelopes ...
lineInk's user avatar
  • 31
1 vote
1 answer
169 views

How to deal with differently skewed biological data?

I have a single-cell data set with around 40 variables per cell (protein expression, all variables are measured simultaneously). The expression distributions for the single channels look quite ...
tebiwankenebi's user avatar
0 votes
1 answer
239 views

Is signal detection theory a Bayesian approach?

Signal detection theory can be applied to modeling perception thresholds for defined stimuli, for example the detection of the presence of a specific signal. It is assumed both the stimulus intensity ...
Jonas Schwarz's user avatar
0 votes
0 answers
88 views

Signal Detection Theory: correct rejections - what underlying processes?

Suppose we have a word recognition task, on the basis of which we compute the four rates defined in Signal Detection Theory as Hits, False Alarms, Correct Rejections, and Misses (HR, FAR, CRR, MR). ...
Tasha's user avatar
  • 47
2 votes
1 answer
72 views

Chance&ceiling performance when using non-standardised hit&false-alarm rates

What is lost/missed out on if defining d', the sensitivity index from Signal Detection Theory, based on non-standardised rates? For example, Patel et al. 2008, for a task where normal and anomalous ...
z8080's user avatar
  • 2,362
2 votes
1 answer
639 views

What are the correct rejection- and miss-rate used for?

Say we have a two-alternative forced choice task on the basis of which we compute the four rates defined in signal detection theory, relating to hits, false alarms, correct rejections, and misses (HR, ...
z8080's user avatar
  • 2,362
2 votes
0 answers
305 views

How does d-prime calculation relate to binomial mixed models with probit link?

for a study I tested participants in a same-different task (1AFC) about melodies. There were 3 versions of each melody (within-subjects factor "version"). So d-prime seems the natural response/...
Federspiel's user avatar
2 votes
2 answers
2k views

How do I calculate d' from experimental data?

In Signal Detection Theory, d' is defined by the z-scores of Hits and False Alarms: d' = z(Hits) - z(False Alarms). Say the task is to detect if a certain object is present in a series of pictures, ...
user avatar
1 vote
0 answers
380 views

Pointwise Mutual Information (PMI) and Information Component (IC)

Pointwise Mutual Information (PMI) and the Information Component (IC) formula (https://link.springer.com/article/10.2165/00002018-200225060-00002) seem to be the same, PMI is mainly used in natural ...
Tina's user avatar
  • 11
0 votes
1 answer
26 views

Proving that a maximum exists when finding the optimal criterion in SDT

When deriving that there is an optimal criterion in the Signal Detection Theory literature that maximizes Proportion Correct (PC), we usually arrive at the following expression by setting the first ...
Mecasickle's user avatar
1 vote
1 answer
653 views

Is there an accepted way to interpret d' (d-prime) for evidence of detection

I have run a learning experiment, with a yes-no familiarity test at the end, and computed d' across various conditions. Is there some rule of thumb (perhaps dependent on sample size) as to how d' ...
Henry Brice's user avatar
3 votes
1 answer
447 views

Why does d-prime of average hit and false alarm rates differ from the average d-prime of individual cases?

I'm reporting d-prime for a set of IDs. After setting a dprime() function, I use it to compute d-prime for each ID based on their hit and false alarm rates, saved ...
cmbudgerigar's user avatar
3 votes
0 answers
879 views

A' (A prime) for extreme Hit rates and False Alarms

I am trying to compute the non parametric measure of sensitivity A' according to the following formula reported by Stanislav & Todorov (1999): $$ A'= .5+sign(H-F)*((H-F)^2+abs(H-F))/(4*max(H,F)-4*...
Elio Balestrieri's user avatar
1 vote
1 answer
660 views

HMM depmixS4 using a vector of known states to fit model

I am using the depmixS4 package to fit HMMs to RNAseq count data. My workflow is as follows: Stack reads into a 'stack' vector which looks like this: ...
DOOP's user avatar
  • 11
0 votes
1 answer
11 views

What is a technique for extracting the data pattern from experimental replicates?

I collect the data of air pollution over the year. The data is 2D where the first axis is discrete scale (mass of pollutants in integer; 50, 51, 52...) and another axis is continuous scale (intensity)....
Jan's user avatar
  • 171
3 votes
1 answer
96 views

Hit-&false-alarm-rates: cases of undefined denominator

I wish to apply SDT for an experiment whereby, while listening to a piece of music, subjects were asked to press a key when detecting a certain cue in the music. Based on the parts of the piece where ...
z8080's user avatar
  • 2,362
3 votes
1 answer
2k views

Computing z-scores for hit & false-alarm rates in Signal Detection Theory

For each subject in my sample, I need to compute a sensitivity index, d-prime, defined in Signal Detection Theory as d' = z(HR) - z(FAR) where HR and FAR are the ...
z8080's user avatar
  • 2,362
1 vote
0 answers
88 views

Building Neyman-Pearson test in 2D-space having only data for $H_0$ and $H_1$

Suppose we have some statistical data which is points in 2D-space. More precise sample space is upper right quarter of $\mathbb{R^2}$: $$\Omega = \{X | X=(x_1, x_2),\, x_1, x_2\in \mathbb{R_+}\}$$ ...
LRDPRDX's user avatar
  • 183
1 vote
0 answers
49 views

How can I best determine the Signal/Noise of a pulsed signal?

I have this pulsed signal, and I would like to quantify the signal to noise ratio. Is there a preferred way to do this? My current approach is to filter the points that are obviously part of the ...
user668074's user avatar
0 votes
0 answers
24 views

How to obtain a signal/noise measurement from a video without a background control

I have a video with a periodic process that can be seen as a change in brightness of the frame. I am measuring the process by calculating the average brightness value of the frame and plotting it over ...
user668074's user avatar