A confocal measurement method based on superresolution image restoration and shaped annular beam

A new confocal measurement method based on superresolution image restoration and shaped annular beam is proposed. Firstly, we employ a binary optical element (BOE) to shape a Gaussian beam into an annular beam which preliminarily improves the lateral resolution of a confocal microscopy system, then we use a superresolution image restoration technique based on the theory of maximum likelihood estimate (MLE) to retrieve the lost high frequency information of the testing image, which further enhances the lateral resolution. The experimental results indicate that a lateral resolution of better than 0.1 μm is achieved when λ = 632.8 nm and N. A. = 0.85. In addition to the distinct superresolution effect, the proposed method also has the advantage of low cost, therefore, it provides a novel technical way to improve the lateral resolution of a confocal microscopy system.