基于二代小波算法的数字全息显微成像自动对焦方法

Autofocus method for digital holographic microscopic imaging based on second generation wavelet

摘要:

针对传统数字全息显微重建方法难以获取最佳重建距离，且依赖于传统PC平台难以便携化等问题，设计了一种嵌入式数字全息显微自动对焦系统。该系统不仅能方便的完成数字全息显微成像的自动对焦，获取最佳重建效果，而且具有便携化的特点。该系统采用同轴全息光路配合图像传感器获取全息图，利用优化后的角谱算法实现全息重建，再结合二代小波算法对重建结果进行图像质量评价，根据评价结果找到最佳重建距离，同时获取最佳重建结果，完成自动对焦。利用该系统采集一批分辨率板全息图进行自动对焦测试。实验表明，系统的重建速度为0.6s，分辨率为3.48um，自动对焦准确率达到90%以上，实验结果验证了系统的有效性。

Abstract:

Aiming at the problem that the traditional digital holographic microscopic reconstruction method is difficult to obtain the best reconstruction distance and it is difficult to be portable on the traditional PC platform, an embedded autofocus system for digital holographic microscopy is designed. The system can not only realize the autofocus of digital holographic microscopic imaging, but also achieve the best reconstruction effect, and has the characteristics of portability. The system adopts coaxial optical path configuration with image sensor to acquire holograms, and uses the optimized angular spectrum algorithm to perform holographic reconstruction. Combined with the second generation wavelet algorithm to evaluate the reconstruction results, the proposed system finds the best reconstruction distance according to the evaluation results, and obtain the best reconstruction results at the same time. The system is used to collect a batch of resolution plate holograms for autofocus test to verify the feasibility of the proposed method. Experiments show that the reconstruction speed of the system is 0.6s, the resolution is 3.48um, and the autofocus accuracy rate is over 90%. The experimental results verify the effectiveness of the system.