"Tint" colour type on background of the video at night is common to most CMOS sensors. It is sort of characteristics ( footprint ) of CMOS sensor how it processes video if firmware tuned up to a maximum night performance of reading a background details. In order to separate two dark objects at night ( especially in pitch dark ), - need some "tint"-effect.
Sony Exmor has violet / purple or blue tint effect. OV( OmniVision ) has light brown tint, Aptina AR0330 has dark brown tint.
Yes, it is possible to tune up firmware the way that you have no or minimum tint effect to have it more natural look, but the more natural you go - the less background details you can read. You win in one thing, but you losing in other.
Just to understand in more details what I said, below is comparison from two Panorama ( same hardware, but different firmware )
http://dashcamtalk.com/forum/thread...-12-03-vs-v1-12-06-day-night-comparison.5396/
You see there, one model tuned up to produce natural colours at night, but because of this background details reading are reduced compare to model which has purple tint.
Closest to most natural colour look, but at same good background details reading at night ( pitch dark ) I find now have Transcend DrivePro, however it also have slight "tint", kinda green-brown effect.
http://dashcamtalk.com/forum/threads/night-panorama-v1-12-03-vs-transcend-drivepro-200-v1-19.6446/