How can I filter data plotted on my UIAxes?

Hi everyone,

I´m programming a GUI on MatLab for a class of mine. The intention is to plot data read, and previously saved, from a sensor on the UIAxes. I have 3 UIAxes, each of them for one variable (Acceleration, Magnetic Field and Rates). On all 3, the X-Axe is Time.

The noisy data displays on the UIAxes and when I flter it, it gets filtered but the noisy data disappears.

I would like to display both the noisy and the filtered data on my UIAxes so I can compare them.

I already tried it using a 'Filter' Button or a Slider, but it doesn´t work. The original data always gets replaced by the filtered one.

How can I display both the unflitered and filtered at once, using either the 'Filter' Button or the Slider? Since I´m a rookie, I really have no idea how to fix it. Below you will find the codes I wrote and the file. Thank you in advance.

The code for the plotting is:

File = evalin('base','File');

Directory2 = evalin('base','Directory2');

S = load([Directory2,File]);

app.Accel = [S.accel];

app.Time = [S.time];

plot(app.UIAxes, [S.time],[S.accel]);

S = load([Directory2,File]);

app.Mag_field = [S.mag_field];

app.Time = [S.time];

plot(app.UIAxes2, [S.time],[S.mag_field]);

app.Mag_field = S;

S = load([Directory2,File]);

app.Rates = [S.rates];

app.Time = [S.time];

plot(app.UIAxes3, [S.time],[S.rates]);

app.Rates = S;

The code for the 'Filter' Button is

windowSize = 5;

b = (1/windowSize)*ones(1,windowSize);

a = 1;

for i=1:numel(app.UIAxes.Children)

app.UIAxes.Children(i).YData = filter(b, a, app.UIAxes.Children(i).YData);

end

And for the Slider

value = event.Value;

smoothingdata = smooth(app.Time, app.Accel, value);

plot(app.UIAxes, app.Accel, app.Time);

hold(app.UIAxes, "on");

plot(app.UIAxes, app.Accel, smoothingdata);

hold(app.UIAxes, "off");

Answer 1

[Pratyush Swain]

Hi Miguel,

I understand you have issues showing filtered and unfiltered data simultaneously on your app designer's UI windows. We need to make the following modifications:

1- For the filter button:

Instead of directly modifying the "YData" of the plotted lines, create new lines for the filtered data and add them to the axes.

windowSize = 200; 
b = (1/windowSize)*ones(1,windowSize);
a = 1;

% Plot original data
plot(app.UIAxes, app.Time, app.Accel);

% Plot filtered data
filtered_data = filter(b, a, app.Accel);
hold(app.UIAxes, 'on');
plot(app.UIAxes, app.Time, filtered_data);
hold(app.UIAxes, 'off');

2- For the Slider:

Similar to the Filter Button, create new lines for the smoothed data and add them to the axes.

value = event.Value;
smoothingdata = smooth(app.Time, app.Accel, value);

% Plot original data
plot(app.UIAxes, app.Time, app.Accel);

% Plot smoothed data
hold(app.UIAxes, 'on');
plot(app.UIAxes, app.Time, smoothingdata);
hold(app.UIAxes, 'off');

Also,earlier in the slider call back function, the axes were in the wrong order - "plot(app.UIAxes, app.Accel, app.Time)". I made the modifications in the app and tested it on sample data, here is the output:

I have attached the app designer file and sample data for your reference. For more information on appdesigner, please refer to https://www.mathworks.com/help/matlab/app-designer.html

Hope this helps.