What are the Cartesian sign conventions for a spherical mirror?

Explanation

(i) The Incident light is taken from left to right ray.(i.e. object on the left of mirror).
(ii) All the distances are measured from the pole of the mirror (pole is taken as origin).
(iii) The distances measured to the right of pole along the principal axis are taken as positive.
(iv) The distances measured to the left of pole along the principal axis are taken as negative.
(v) Heights measured in the upward perpendicular direction to the principal axis are taken as positive.
(vi) Heights measured in the downward perpendicular direction to the principal axis, are taken as negative.