点阵图形的矢量化是计算机图形学的经典问题，最小二乘法是点阵图短量化的主要方法，它用拟合误差是澡在阈值之内来判别矢量化结果的正确性，因而阈值的确定是关键，本文分析了用最小二乘法将理想点阵图形识别为矢量图的误差，科学地确定了阈值，提出了评价识别结果的判别式，为自动实现矢量化，还提出了点阵图形矢量化的新方法-双向滚动最小二第六识别法，导出递推公式，本文给出的评判式科学准确。提出的矢量化方法快捷高效，具有通用性。

The vecorization of dot matrix image is a classical question of computer graphics. The least-square algorithm, which distinguishes the result of vectorization right or not by defining whether the fitting errors is in the range of threshold or not, is a main method of vectorization of dot matrix image. So how to define the threshold is a key. These errors are analyzed while dot matrix image is recognized as vector diagram by the least-square algorithm, the threshold is defined scientifically, and the judgement formulas to evaluate recognition resul are put forward to in this thesis. In order to complete vectorization automatically, a new method of the vectorization of dot matrix image--the double direction roll least-square algorithm is presented, and some recurence formulas are deduced. The judgement formulas are scientific and accurate, the mothod of the vectorization is rapid and efficient. The formulas and the method are all quite well and universal.