Shape from focus based on combination of spatial and frequency domains

The single focus evaluation function has the disadvantages of poor resolution and low reconstruction accuracy. To solve this problem, a focusing topography restoration method combining spatial domain and frequency domain was proposed. Firstly, the spatial Laplacian operator and frequency domain non-subsampled wavelet transform were used to evaluate the image focus, and the non-subsampled wavelet transform focus evaluation value was used as the weight factor to correct the Laplacian evaluation value. The initial depth map was obtained by using modified focused evaluation to reconstruct the surface topography. Then the depth map based on Laplacian operator was calculated, and the depth map was used as the guide map to guide the initial depth map and filter the final depth map. Simulation and experimental verification show that the proposed method has good results in both simulation and experiment. The resolution of evaluation curve is obviously improved, and the reconstruction of simulation model has lower root-mean-square error and higher correlation coefficient. In the experiment, the error between the 3D reconstructed model and the real object is smaller, which can effectively improve the accuracy.