Estimating Depth of Layered Structure Based on Multispectral Speckle Correlation

Some objects have layered structures in which a dynamic region is covered by a static layer. In this paper, we propose a new experiment for estimating the depth of the dynamic region using speckle analysis. The speckle is caused by the mutual interference of a coherence laser. We use two characteristics of the speckle. One is the temporal stability of the speckle pattern and the other is the wavelength dependency of the transmittance of the laser. We estimate the depth by computing correlations of speckle patterns using multispectral lasers. Experimental results using a simulated skin show that multispectral speckle correlation can be used for analyzing a layered structure.