在移相干涉技术的相位计算中,周期函数arctan的相位值分布在[-π,π]之间,相位值分布的跃变形成了被压包后的波面。理想无噪声和边界形状规则的压包波面可以直接通过条纹扫描法进行解包。例如当被测物边界形状不规则和存在噪声(灰尘脏点)时,会导致干涉图上出现无效区域,必须采用不依赖于边界形状,能自动绕过无效区域的算法。采用区域生长法对这类干涉图进行了解包。通过编程计算表明,这种解包算法能解决光学检测中的几乎所有的干涉图处理问题。
In phase calculate of phase-shifting interference technique, Because of the periodicity of function arctan, all the phase values are ranged over -π to π. The transitions of phase values form wrapped wavefront. If a wrapped wavefront is free of noise and has a regular shape of edge, it can be unwrapped directly by the method of fringe scanning. However, irregular shape of edge or even any unexpected dust may bring some invalid regions into the normal interferogram. A new arithmetic must be introduced which independent on any shape of edge and can automatically grow round any bad effect of the invalid region. The method of region growing is adopted to unwrap" interferogram, according to program calculate, this method can calculate most of interferograrns in optical test.