function [BeatQ, r] = jSQI(features, onset, abp)
% JSQI ABP waveform signal quality index.
% [BEATQ, R] = JSQI(FEATURES, ONSET, ABP) returns a binary signal quality
% assessment of each beat in ABP. This algorithm relies on detecting
% abnormalities of numeric values in FEATURES and ONSET.
%
% In: FEATURES <mx12> --- features extracted from ABP using abpfeature.m
% ONSET <nx1> --- onset times of ABP using wabp.m
% ABP <px1> --- arterial blood pressure waveform (125Hz sampled)
%
% Out: BEATQ <nx10> --- SQI of each beat: 0=good, 1=bad
% Col 1: logical OR of cols 2 thru 10
% 2: P not physiologic (<20 or >300 mmHg)
% 3: MAP not physiologic (<30 or >200 mmHg)
% 4: HR not physiologic (<20 or >200 bpm)
% 5: PP not physiologic (<30 mmHg)
% 6: abnormal Psys (beat-to-beat change > 20 mmHg)
% 7: abnormal Pdias (beat-to-beat change > 20 mmHg)
% 8: abnormal period (beat-to-beat change > 1/2 sec)
% 9: abnormal P(onset) (beat-to-beat change > 20 mmHg)
% 10: noisy beat (mean of negative dP < -3)
% R <1x1> fraction of good beats in ABP
%
% Usage:
% - FEATURES must be obtained using abpfeature.m
% - ONSET must be obtained using wabp.m
%
% Written by James Sun (xinsun@mit.edu) on Nov 19, 2005.
% - v2.0 - 1/18/06 - thresholds updated to reduce false positives
% - v3.0 - 2/10/06 - added "..101..." detection - see lines 92-96
if length(onset)<30
BeatQ = [];
r = [];
return
end
% thresholds
rangeP = [20 300]; % mmHg
rangeMAP = [30 200]; % mmHg
rangeHR = [20 200]; % bpm
rangePP = [20 inf]; % mmHg
dPsys = 20;
dPdias = 20;
dPeriod = 62.5; % 62.5 samples = 1/2 second
dPOnset = 20;
noise = -3;
% get ABP features
Psys = features(:,2);
Pdias = features(:,4);
PP = features(:,5);
MAP = features(:,6);
BeatPeriod = features(:,7);
mean_dyneg = features(:,8);
HR = 60*125./BeatPeriod;
% absolute thresholding (flag unphysiologic beats)
badP = find(Pdias < rangeP(1) | Psys > rangeP(2));
badMAP = find(MAP < rangeMAP(1) | MAP > rangeMAP(2));
badHR = find(HR < rangeHR(1) | HR > rangeHR(2));
badPP = find(PP < rangePP(1));
% first difference thresholding (flag beat-to-beat variations)
jerkPsys = 1 + find(abs(diff(Psys)) > dPsys);
jerkPdias = find(abs(diff(Pdias)) > dPdias);
jerkPeriod = 1 + find(abs(diff(BeatPeriod)) > dPeriod);
jerkPOnset = find(abs(diff(abp(onset))) > dPOnset);
% noise detector
noisy = find(mean_dyneg < noise);
% SQI final
bq = zeros(length(onset),10);
bq(badP, 2) = 1;
bq(badMAP, 3) = 1;
bq(badHR, 4) = 1;
bq(badPP, 5) = 1;
bq(jerkPsys, 6) = 1;
bq(jerkPdias, 7) = 1;
bq(jerkPeriod, 8) = 1;
bq(jerkPOnset, 9) = 1;
bq(noisy, 10) = 1;
bq(:,1) = bq(:,2)|bq(:,3)|bq(:,4)|bq(:,5)|bq(:,6)|bq(:,7)|bq(:,8)|bq(:,9)|bq(:,10);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% make all "...101..." into "...111..."
y = bq(:,1);
y(find(diff(y,2)==2)+1)=1;
bq(:,1)=y;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
BeatQ = logical(bq);
% fraction of good beats overall
r = length(find(bq(:,1)==0))/length(onset);