# 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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### 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: ...
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### 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)....
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### 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 ...
354 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 ...
64 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 $\mathbb{R^2}$: $$\Omega = \{X | X=(x_1, x_2),\, x_1, x_2\in \mathbb{R_+}\}$$ ...
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### 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 ...
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### 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 ...
724 views

### Negative D-prime values; use absolute values?

I have calculated D-prime measurements for for a memory performance task. Subjects viewed images that were either old or new and had to indicate their response via a button press. Thus, their response ...
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### Kurtosis to detect non-random signals in a spectrum

I have a spectrum that was created from a time series using the FFT. The spectrum has several man-made "channels" in it; some of these are one-bin wide, some are several adjacent bins wide (larger ...
59 views

### EEG waves measuring statistical significance of an event

I have recently gotten into a problem with EEG activity measurement. I need to prove (or disprove) that certain event triggered a statistically significant reaction in EEG activity. I know exactly at ...
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### What is the distribution of $d'$?

In my experiment, repeated measures of $d'$ (computed from hit and false alarm rates) are computed for a small number of subjects (<10) under multiple (10) conditions. Primarily, I am interested to ...
546 views

### Confusion between true negatives and false positives (double negation?!)

Given the below term definitions ..my question is: why is the logical negation (opposite) of a false negative not a true negative? This would imply 1-α=β, which does not have to be the case. And ...
204 views

### Detecting a tremor given accelerometer data

I'm trying to figure out what technique to use in order to detect a tremor in accelerometer data. I have the acceleration in the x, y and z coordinates. I've plotted 4 graphs of this data below with ...
524 views

### Neural networks and signal-to-noise ratio

My guess is that neural networks do not work very well in noisy environments, i.e. the lower the signal-to-noise ratio, the worse the result of a neural network, if compared to other statistical ...
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### Signal Extraction

I have following problem to show: let scalar valued signal $X_t$ be transmitted at time $t$ and received $Y_t = X_t + \epsilon_t$. Where $\epsilon_t$'s are zero mean noise. Suppose $E[X_t]=0$ for all ...
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### Proportion of variance explained, prediction accuracy, and noisy criterion variables

A given criterion measure is corrupted by noise such that only 60% of its variance is attributable to a true signal. This noisy measure of outcome is regressed against some number of predictors and a ...
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### Test for fractional Brownian motion in Matlab

Is there a test in Matlab if a time series satisfies properties of being a fractional Brownian motion?
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### periodicity within Signal [closed]

I am actually measuring the current of a dc motor, it takes values between, and I want to be able to find periodic peaks within my signal. My motor is connected to a spindel, the goal is to detect any ...
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### What should I use to establish a threshold to detect threshold crossings?

I have data graphed in green here: I want to detect the peaks but I don't know how to define the threshold values. The blue lines are mean ± standard deviation. Using that, I would miss the three ...
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### Statistical analysis of fourier transform of a 2D image (freaking AMAZING)

I'm a statistics grad student, and I just started getting into Digital-Image-Processing (an analogy for processing super-large contingency tables). In the book "Digital Image Processing" by Gonzalez ...
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### Interpretation of diagonal detail for a 2D (Haar) Wavelet Transform

I am a statistics grad student, and I have just began exploring the topic of wavelet regression (specifically, Haar wavelets for discrete functions). I understand the generalization from a one ...
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### What is the two alternative forced choice paradigm

Is a two alternative forced choice paradigm (2AFC) an experimental design?
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### CNN localizing object?

For classying images/objects CNNs are one possible or even the state-of-the-art solution but what if one wants to localize an object in an image? I thought if I use only convolutional layers without (...
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### How to determine what % of variance is due to noise (with limited data)

this is a difficult question and perhaps not answerable without further data. I have a list of staff that get monthly scores that are averages of customer ratings. (95%, 75%, 89%) So, the most ...