Green ppg is equal to 0

[MalcolmMielle]

In Nemcova's method, the green ppg signal is used. However, when extracting the green ppg signal, the signal is flat and 0. We need to investigate if there is a bug in the method or if it's an expected behavior.

[gianlucatruda]

@MalcolmMielle I think that it's only with sample_data/ and not with nemcova_data. When I constructed the sample data, I named the video files with that PC000000n convention, so I'm pretty sure that clip is from my data.

This is what I get when processing sample 3 from preprocessed_data/nemcova_data/nemcova_test.csv:

And when I process sample 3 from preprocessed_data/sample_data/sample_data.csv:

And my best PPG curve so far comes from nemcova sample 14 (if I recall correctly):

[gianlucatruda]

@MalcolmMielle I think that it's only with sample_data/ and not with nemcova_data. When I constructed the sample data, I named the video files with that PC000000n convention, so I'm pretty sure that clip is from my data.

This is what I get when processing sample 3 from preprocessed_data/nemcova_data/nemcova_test.csv:

And when I process sample 3 from preprocessed_data/sample_data/sample_data.csv:

And my best PPG curve so far comes from nemcova sample 14 (if I recall correctly):

[MalcolmMielle]

So that means that when you recorded the video you got no green in the image at all?
I feel like that would influence the results quite a lot then. That will be good to investigate if that has to do with iPhone or if there is another underlying reason.

Thanks for chekcing it out!

[gianlucatruda]

@MalcolmMielle It's present in some of my sample_data/ clips. For instance, this is sample_id== 2.

But I just did a full check and only 1 of the 11 clips that I shot has legit data in the green channel. That's very odd.

[MalcolmMielle]

Did press too hard on the camera? Could that have an influence?

[gianlucatruda]

Did press too hard on the camera? Could that have an influence?

It's possible. I did the recording by placing my hand on the table and placing the phone on top. So the only pressure would have been the weight of the phone.

[MalcolmMielle]

Then it's probably not that hahah