符号法则 meaning in English

sign convention
sign rule

Discussion on geometrical optics symbolic
几何光学符号法则探析
This paper makes analysis and comparison of the symbolic rules in different optical books , and brings to light the internal relations and integrity of the superiorest symbolic rule with the law of light propagation and imaging
本文对不同光学书上采用的符号法则进行了分析比较，揭示出了表观上最优的符号法则与光的传播及成象规律的内在联系及统一性