Initial experimental data

daccordeon / gravexplain

Continuous gravitational wave searches in a table-top experiment

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Initial experimental data #6

Closed daccordeon closed 4 years ago

daccordeon commented 4 years ago

set-up and tune the interferometer
capture 10s video and apply pipeline (i.e. track to get time-series then get fourier spectrum)
add in piezo with low frequency AC source and repeat above

daccordeon commented 4 years ago

capture longer video, bin into 10s chunks, apply pipeline
apply viterbi to fourier frequency vs time

daccordeon commented 4 years ago

expt_0.pdf

initial time series generated, tracker jumps in one ring, then back out

daccordeon commented 4 years ago

more videos taken and tracked overall, tracking is very poor at high frequencies, and requires very slow and low amplitude oscillations note: frequency resolution is fps/total_frames expt_1.pdf expt_2.pdf expt_3.pdf

still to do:

add in piezo driven at low frequency
apply viterbi to binned long capture

daccordeon commented 4 years ago

also:

use external webcam to obtain better image

hannahm8 commented 4 years ago

we could also try recording the intensity at the centre of the interference pattern to see if this can get high frequencies better than tracking

daccordeon commented 4 years ago

centre measurement provides similar results at low frequencies at high frequencies is unclear if significantly better than tracker note: likely that human driven high frequencies are very inconsistent, which might explain dips in signal and lack of signal in spectrum

expt_0_centre.pdf expt_3_centre.pdf

going to the labs:

external webcam to USB
low voltage piezo with wires, e.g. PA1CEW or PA2JEW
function generator

eventually:

apply viterbi to binned long capture

edit: formatting and edit tag

daccordeon commented 4 years ago

adding in budget webcam and speaker driven by function generator produces very sharp results note: expt_4_xxyy, driving frequency to speaker is xx.yy Hz

expt_4_0209_centre.pdf expt_4_0580_centre.pdf expt_4_2014_centre.pdf

first milestone by end of tomorrow:

apply viterbi to binned long capture

edit: formatting

daccordeon commented 4 years ago

viterbi successful on long 5/10 minute captures scanning_range, the amount that the viterbi path is allowed to change frequency in one long timestep is better left low at around 3-5 bins

expt_ngrid_5_slow.pdf expt_viterbi_path_5_slow.pdf

all that's left for this issue:

revise and document code
convert to script

edit: formatting

daccordeon commented 4 years ago

also, although this is likely hard:

find point of lip of inner circle to measure instead of the video centre

daccordeon commented 4 years ago

see experiment_viterbi.py and .ipynb

closing this issue, open a new issue for further extensions