Why not use nomalization in CHROM methond?

[wang-tf]

Thanks a lot about your work! This is a very usefull framwork about rPPG.

In my opinion, the author of CHROM used normalization $\frac{C_i}{\mu(C_i)}$ before CHROM method. But in config file, there was a BPFILTER. Is it better than author's method ?

pyVHR/results/cfg/UBFC2_holistic.cfg

Lines 104 to 109 in 485f962

	[CHROM]
	path = None
	name = cpu_CHROM
	device_type = cpu
	params = {}
	pre_filtering = ['BPFILTER']