针对字符预分类问题，提出基于广义可信度阈值判别的规则和多分辨率方向梯度直方图特征，证明该规则具有“错误率”和“平均候选类别数”的最优折衷.基于梯度图像高斯金字塔，提取了多分辨率方向梯度直方图特征.实验结果表明，该规则和特征具有一定的优越性.

 For character preclassification, a generalized confidence threshold determination rule and multi-resolution histograms of oriented gradients feature are proposed. It is shown that an optimal tradeoff between “error rate”and “average candidate number” can be obtained based on the proposed rule. From the Gaussian pyramid of a gradient image,multi-resolution histograms of oriented gradients are extracted. Experimental results indicate superior performance of the proposed rule and features. 