[Homer-users] questions about application of CW5

[zhouyuan at nlpr.ia.ac.cn]

Hi,
   I have several questions about the application of CW5 system (TechEn Inc.). Could do you please answer them?
   1.The first is about motion artifact. In initial review, one of the advantages of NIRS is insensitive to head motion. However, in our experiments, we noticed NIRS was in fact sensitive to head motion. Some researchers, who are the users of  ETG-100 (Hitachi) or similar system, used certain method to correct short-term motion in their articles. Then how do you treat with and solve the artifact problem? Is it appropriate to take the same measure?
   2.The second is about the data processing. Because the baseline is sometimes unstable, some researchers used some methods to correct the baseline,e.g. linear fitting. Frankly,I don't completely understand  the method. However, I think it's an important question in data processing. So I want to know how you treat with this problem.
   3.As you know, it isn't easy to collect perfect data because of poor contaction. Usually, some channels have a lower SNR (signal-to-noise ratio). So they have to be excluded to further analysis. It's pity! Are there methods to improve the quality of signal by data processing. And what's the criterion of low SNR, i.e. is there quantitative criterion to exclude the low SNR channel?
   Thanks for your time and energy to read my e-mail.

Best regards,

Yuan Zhou