仿射透视三点问题
Affine Perspective-Three-Point Problem
为弱透视/准透视相机下的 P3P 位姿估计提供闭式解，并用少量迭代把仿射解升级为精确解，可直接用于小深度变化场景的快速绝对位姿求解与 RANSAC 内点估计。
原文依据 we further propose an iterative correction that upgrades the affine solution to the exact P3P solution
摘要译文
由模型翻译 · 术语统一 · 请对照原文核对关键结论本文研究仿射相机模型下的透视三点（P3P）问题。我们为弱透视与准透视这两种具有代表性的仿射相机模型推导了直接的闭式求解器。仿射 P3P 的解可归结为一个双二次方程。与需要求解三次或四次方程的精确 P3P 求解器不同，它能够利用二次求根公式简单而稳定地计算出实解。由于仿射近似仅在场景深度变化较小时成立，我们进一步提出一种迭代修正方法，将仿射解升级为精确 P3P 解。通过在合成数据与公开数据集上进行大量比较，我们证明经过两次升级迭代的仿射 P3P 求解器可达到与最优 P3P 求解器基本相当的性能。
英文原文摘要 851 字符
This paper addresses the Perspective-Three-Point (P3P) problem under affine camera models. We derive direct closed-form solvers for weak perspective and para perspective, which are representative affine camera models. The affine P3P solution reduces to a bi-quadratic equation. Unlike exact P3P solvers that require a cubic or quartic equation, it allows for the simple and stable calculation of real solutions using the quadratic formula. Since affine approximations are valid only when scene depth variation is small, we further propose an iterative correction that upgrades the affine solution to the exact P3P solution. Through extensive comparisons using synthetic data and public datasets, we demonstrate that affine P3P solvers with two upgrade iterations achieve performance substantially comparable to that of the state-of-the-art P3P solver.