Diffraction limit is usually a thorny problem in an optical inspection system. In this investigation, a model-based deconvolution technique was developed to recover diffraction-limited images, where images with sizes smaller than the diffraction limit could be recognized. Experiments were carried out with a traditional microscope at 200× magnification coupled with a halogen light source for a series of line width samples. The point spread function of the imaging optics was first obtained from an estimated model and then combined with a nonlinear deconvolution algorithm to calculate the full width at half maximum and reconstruct the line widths. Experimental results indicate that a measurement error below one pixel size of the measurement system is achievable. Accordingly, the target of nanoscale line width inspection based on a low cost and real-time image processing technique can be fulfilled, which greatly increases the ability of nanoscaling on optical microscopes.

中文翻译：

---

用于在光学显微镜上测量衍射极限图像的迭代解卷积技术

衍射极限通常是光学检测系统中的棘手问题。在这项研究中，开发了一种基于模型的反卷积技术来恢复衍射极限图像，其中可以识别尺寸小于衍射极限的图像。使用放大倍数为 200 倍的传统显微镜和卤素光源对一系列线宽样品进行实验。首先从估计模型中获得成像光学器件的点扩散函数，然后结合非线性反卷积算法计算半高全宽并重建线宽。实验结果表明，低于测量系统一个像素大小的测量误差是可以实现的。因此，