Hello all,

I am a student studying signal fingerprints and relating them to existing databases.

What I can hardly find any information about is the following (I may not be looking the right way) :

1. How does VIS and NIR differ in terms of characteristics? What are they reflecting? If VIS is reflecting colour (as we can perceive) what is NIR reflecting?

2. If two signals have a linear relationship in the VIS region when mixed does that mean they are also linear in the NIR region?

I greatly appreciate any insight especially if it can be sourced.