Consider a two-column matrix representing possible regions of interest of a 45-sample random signal. Extract the signal samples corresponding to the regions of interest.
Consider a set of temperature data collected by a thermometer inside an office building for four months. The device takes a reading every half hour. The sample rate is thus 48 measurements/day. Convert the temperature to degrees Celsius and plot the data.
Consider a two-column matrix representing possible regions of interest of a 45-sample random signal. Extract the signal samples corresponding to the regions of interest. Concatenate the samples into a single vector.
Plot the signal and highlight the regions of interest.
plot(x)
y = NaN(size(x));
for kj = 1:size(roilims,1)
roi = roilims(kj,1):roilims(kj,2);
y(roi) = sigroi(1:length(roi));
sigroi(1:length(roi)) = [];
end
hold on
plot(y)
hold off
Extract and Concatenate Regions of Interest From Data Set
Consider a set of temperature data collected by a thermometer inside an office building for four months. The device takes a reading every half hour. The sample rate is thus 48 measurements/day. Convert the temperature to degrees Celsius.
load officetemp
tempC = (temp-32)*5/9;
fs = 48;
Create region-of-interest (ROI) limits that correspond to five random two-week periods separated by at least 24 hours. Temperature readings on these days are audited.
r = 5;
w = 14*fs;
s = 1*fs;
hq = histcounts(randi(r+1,1,length(tempC)-r*w-(r-1)*s),(1:r+2)-1/2);
t = (1 + (0:r-1)*(w+s) + cumsum(hq(1:r)))';
roilims = [t t+w-1];
Extract the regions of interest. Compute the mean temperature of each audited region of interest and display the values.
Example: chirp(0:1/1e3:1,25,1,50) specifies a chirp sampled at 1
kHz.
Data Types: single | double Complex Number Support: Yes
roilims — Region-of-interest limits two-column matrix of positive integers
Region-of-interest limits, specified as a two-column matrix of positive integers. The
ith row of roilims contains nondecreasing
indices corresponding to the beginning and end samples of the ith
region of interest of a signal.
Example: [5 8; 12 20; 18 25] specifies a two-column region-of-interest
matrix with three regions.
sigroi — Signal regions of interest cell array | vector
Signal regions of interest, returned as a cell array or a vector.
If concat is set to false,
sigroi is a cell array. The ith cell of
sigroi contains the signal samples corresponding to the
ith region of interest specified in
roilims.
If concat is set to true,
sigroi is a vector that concatenates all extracted signal
samples.
Extended Capabilities
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