身份证底卡扫描图像自动纠偏方法

针对高拍仪拍摄的身份证底卡图像,首先抽取版面字符轮廓,然后计算轮廓的最小外接多边形的重心点来表示字符的位置;并通过随机Hough变换检测重心点形成的候选直线;最后根据最小二乘法拟合的直线与水平方向的夹角来旋转图像,从而实现底卡图像的自动纠偏功能。实验证明方法对图像的形状和噪声不敏感,并在身份证底卡扫描与识别系统中取得了良好的效果。

Automatic Correction Method of Scanned Image for Archived ID Card

In this paper,firstly it extracts the contours of the characters in the scanned image for archived ID card, and then calculates the center-of-gravity point of the minimum bounding polygon to indicate the position of the character, with the the center-of-gravity points it formed the straight line candidates by random hough transform, finally with the angle intersected between the horizontal line and the straight line deteced by generalized least squares to rotate the image,experiments show that the method is not sensitive to the shape of the image and the noise, and achieved results in the ID card scanning and recognition system.