平面物体在曲面状态下扫描仪图像的校正实验

Experiment of distortion correction for scanner image of twisted plane object

平面物体在曲面状态下经扫描仪扫描后,其图像将发生复杂的畸变。提出了用椭圆柱面加平面模型来描述实际扭曲的情况。基于二元曲面模型的投影畸变和成像畸变数字校正理论,推导了具体的畸变校正公式,并给出了确定成像畸变系数的实用方法。实验结果表明,经校正后投影畸变能够从最大的56%降低到2 5%;成像畸变能够从最大的8 4%降低到0 3%;投影畸变和成像畸变的组合畸变能够从最大的70%降低到3 1%。图像灰度直方图标准偏差的误差可从491%降低到6 5%。

The image of plane object obtained by scanner in situations of curved surface will produce complicated distortions. Elliptical cylinder plus plane surface is suggested to describe actual deformation. The practical method to determine the coefficient of imaging distortion is also presented. Based on the digital correction theory of projection distortion and imaging distortion for twodimensional curved surface distortion model, the formulas of correction for distortion are deduced. After correction, the projection distortion is reduced from 56 to 2.5 percent, the imaging distortion is reduced from 8.4 to 0.3 percent, the combination distortion (projection distortion and imaging distortion) is reduced from 70 to 3.1 percent. In addition, the standard error of the image's histogram is reduced from 491 to 6.5 percent.