directrix

n.

准线；

1. Based on the geometry characteristics of Bertrand surfaces, the complicated surface conjugation issue can be discussed with their directrix line.
   基于白川德曲面的几何特征，将复杂的曲面共轭问题归结到准线上来讨论。
2. The surface generated by a straight line,the generator,passing through a fixed point,the vertex,and moving along a fixed curve,the directrix.
   锥面由一条直线，即母线，通过一固定点，即顶点，沿一给定曲线，即准线，连续移动而产生的平面。

A Single Directrix Quasi-Minimal Model for Paper-Like Surfaces
Dux illa directrixque artium: Rudolph Agricola's dialectical system
A guidance directrix approach to vision-based vehicle guidance systems.
Computing Hironaka's invariants: Ridge and Directrix
A Robust Procedure to Obtain a Guidance Directrix for Vision-Based Vehicle Guidance Systems
An Algorithm for Computer Vision Sensing of a Row Crop Guidance Directrix
Research Development of Vision-based Guidance Directrix Recognition for Agriculture Vehicles
Algorithm Based on Image Processing Technology to Generate Navigation Directrix in Orchard
Dispersion Curves for Harmonic Waves Propagating Along the Directrix of a Cylindrical Shell Reinforced with Rings
High-frequency asymptotic solutions for backscattering by cylinders with conic section directrixes