【摘要】 傅里叶变换轮廓术(FTP)复原三维形貌时,用来提取基频成分的带通滤波器对测量精度有很大影响。传统二维滤波器如汉宁窗或高斯窗为对称滤波器,其截止频率的大小受条纹空间频率即基频与零频间的距离所限,经常会导致基频成分提取不完整,有用信息缺失。为解决此问题,在二维汉宁滤波器基础上,提出一种椭圆形底部形状的二维非对称滤波器,在不同频率方向上具有不同的频率响应和截止频率,可提取出更为完整的基频成分。台阶和阵列物体的模拟实验表明,二维非对称滤波器对2个物体的复原精度相比于传统汉宁滤波器分别提高了39.5%和55.6%。更多还原

【Abstract】 In the Fourier transforms profilometry(FTP), the band-pass filter that extracts the fundamental frequency component has a significant influence on the reconstructed accuracy of the 3 D profile. For traditional 2 D symmetrical filters such as Hanning window or Gaussian window, their cut-off frequencies are limited by the spatial frequency of projection fringe, namely the distance between the fundamental frequency and the zero frequency. This often leads to the incomplete extraction of fundamental frequency components and the loss of useful information. To solve this problem,we designed a 2 D asymmetric filter with the elliptical bottom shape on the basis of 2 D Hanning filter. It holds different frequency response and cut-off frequency towards different frequency directions and thus one can extract more complete fundamental frequency component. The simulation experiments of step object and array object show that the reconstructed accuracy of the proposed 2 D asymmetric filter improves respectively by 39.5% and 55.6% for these two objects compared with traditional Hanning filter.更多还原