While Aras thesis is good, it is not a nice introduction to the topic, especially mathematical foundation. If you know a particular resource that delves into the topic of why signed distance fields work from a mathematical perspective, that would be great.

Thank you for the answer. Well, I was trying to compute hue and saturation from Cb and Cr values. I read hue = atan2(Cr/Cb) and saturation is sqrt(Cr^2+ Cb^2). Saturation I see is nearly 0.5. Same for hue, for Red color it turns out to be 108 degrees when measured from X axis or 18 degrees when measured along Y-axis anticlockwise. Not 0 in any case.