Source Code - Analysis

Filtering

trans = fft(throw_az)

stem(trans)

plot(throw_az)

n=[-20:20]; 

wc=pi/300; %cut-off frequency (chosen arbitrarily to make data look clean)

h=wc/pi*sinc(wc*n/pi); 

filt_az=conv(throw_az,h); %filtered z-acceleration

filt_az=filt_az(1:length(throw_az),1)

plot(throw_az)

plot(filt_az)

Visualization 

clf

throw_ax = (ax(1178:1286)-mean(ax(1:100)))*9.8;

throw_ay = (ay(1178:1286)-mean(ay(1:100)))*9.8;

throw_az = (az(1178:1286)-mean(az(1:100)))*9.8

throw_t = t(1178:1286)/1000;

throw_gx = gx(1178:1286)-mean(gx(1:100));

throw_gy = gy(1178:1286)-mean(gy(1:100));

throw_gz = gz(1178:1286)-mean(gz(1:100));

clf

theta = cumtrapz(throw_t,throw_gz)'/16.4;

plot(throw_t,theta)

a_room = zeros(3, 109);

for i=1:length(throw_gx)

    R = [cos(theta(:,i)) sin(theta(:,i)) 0; -sin(theta(:,i)) cos(theta(:,i)) 0; 0 0 1];

    a_room(:, i) = R*[throw_ax(i,:); throw_ay(i,:); filt_az(i,:)];

end

a_room = a_room'

vx = cumtrapz(throw_t, a_room(:,1));

vy = cumtrapz(throw_t, a_room(:,2));

vz = cumtrapz(throw_t, a_room(:,3));

clf

sx = cumtrapz(throw_t, vx);

sy = cumtrapz(throw_t, vy);

sz = cumtrapz(throw_t, vz);

axis equal

for i=1:length(throw_t)

    scatter3(sx(i,:), sy(i,:), -sz(i,:))

    hold on

    axis([0 .2 0 .2 0 .2])

end