针对散斑干涉中的相位差提取问题，在四步相移的基础上提出了一种求解相位差的新方法．该方法通过采集物体变形前后的各4 幅图像，从理论上推导出相位差的一种新的数学表达式，避免了一般四步相移法求解相位差时出现的高频噪声问题和得不到真实的相位差包裹值问题．用该方法进行周边固定中心加载的圆盘模型实验，并与一般的四步相移法作比较．结果表明，文中提出的相位差求解新方法较一般的四步相移法在消除高频噪声、提高图像质量方面具有明显的效果，既抑制了噪声又能保持条纹的特征．

Aiming at the phase difference extraction in speckle pattern interferometry,a novel method is proposed based on the four-step phase shifting. In this method,by collecting the four interferometric patterns respectively before and after the object deforming,a novel mathematical expression of the phase difference is theoretically derived,which avoids the high-frequency noise and the false wrapped phase difference of the general four-step phase-shifting method. The proposed method is then tested by using a circumferentially-fixed disk model with a point loading at the centre and is compared with the general four-step phase-shifting method. The results show that the proposed method is significantly superior to the general one in terms of high-frequency noise elimination and image quality improvement,and that it can not only suppress the noise but also maintain the stripe features.