Does the EI platform perform an interpolation on our data?

Hello

I’m trying to develop a event detection like single tap, double tap, directional tap (left to right, right to left) using EI plataform. Basically I’m sampling data from an accelerometer at 100Hz. I loaded the samples into the EI plataform, split the events I want to classify manually (set time windows of 100ms, so I’ll have 10 samples per window) and then I trained the model. I got a training result of 92% and a test result of 89%. I loaded the model onto my hardware and basically I have a circular buffer being loaded with samples at 100Hz and when an event occurs I center the event in a 10 sample buffer (100ms window) to feed the EI model but not I am getting the desired results.

And here comes my question: visually the accelerometer signal on the EI looks “smooth” when in fact a 100ms window only has 10 samples. Is the EI doing any interpolation on the data before training it?

Cause on hardware I’m not performing any interpolation. I just feed the model with 100ms of information i.e., 10 samples when an event occurs.

Hello @gabriel.brito,

Could you share your project ID please? So I can check if everything is properly setup.

You should have for each of your window (100ms) one occurence of your event.
So if in your 1 sec window you split it in 10 but if any (or more) of the 10 samples do not contain your event, you will train your model on something that is different from the reality.

Also what have you set for your window increase? Usually for event detection, the window increase value should be the same as your window size. Otherwise you might miss some events. You can have more information here: Impulse design - Edge Impulse Documentation

I am not 100% sure about the smoothing effect but I believe it is only for visualisation.

Best,

Louis

Hi

Thanks for you answer. The Project ID is 122069.

Hello @gabriel.brito,

Indeed your window increase seems off. Can you use 100ms, train and deploy again to see if you have better results?

Best,

Louis