Uniform illumination for large area digital speckle pattern interferometry using multibeam

Abstract

Using Digital Speckle Pattern Interferometry (DSPI) method measuring the large object in practice, the primarily problem is uniform illumination. This paper presents a method that using multiple laser beams to enlarge the illumination area and analysis the non-uniform illumination influences for interferogram. We design an illumination model using 10 semiconductor lasers for interferometer, and corresponding experiment shows that this method is suitable for industrial measurement in large area detection.

The application of DOE in uniform illumination for large area digital speckle pattern interferometry

“…Multiple laser diodes have been used in such non-damaged detection for large area illumination. But it has some defects such as large number of used diodes, coherent superposition of light field, wavelength shifting, etc [3] . To overcome these defects this paper presents a way that by using DOE(diffractive optical element) the flattened Gaussian beam could be achieved and fewer FGBs are necessary to get the uniform illumination of large area at a certain distance.…”