Algorithm to Discriminate Noise Term and Select a Channel Automatically

[yosukeT]

Hello.

I have some questions.

I have created a system that evaluate R-R interval, and Heart Rate Variability automatically with non-contact heart-rate signal measurement system.

However I have two problems.

①I can't discriminate noise term from normal term contained in heart-rate signal automatically.

the noise term and normal term are defined as blow.

・normal term

　the waveform is periodic, have recogizable pattern.

・noise term

  the waveform is non-periodic, and the amplitude is too big.

For exemple in this case,figure 1, there is noise term clearly.

In noise term, the waveform seems random.

    figure1

②the system output 4 types of heart-rate signal.Thus I get 4 signal channels.

Then I have to select the well suited channel which the waveform is periodic, and there isn't noise term automatically.

For example in this case, figure 2, I should select channel2.

Because the waveform have very recogizable pattern and very clear peak . 

However I have no idea that select the channel automatically.

    figure2

If  you know sollution method,please advise me.

Thank you

yosukeT