Multi-factor fusion index assessment of digital speckle interferometry images quality under dynamic environment

Abstract

When digital speckle pattern interferometry (DSPI) is applied to dynamic environmental, it is often accompanied by severe speckle de-correlation, which severely limits the application and detection accuracy of DSPI. Currently, the existing speckle image quality evaluation methods only consider the contrast of the speckle image or the morphology of speckle particles, which results in these methods unapplicable to dynamic environments. For this reason, this paper proposes a new evaluation method for laser speckle image, namely dynamic multi-factor fusion index (DMFFI), which combines evaluation of four aspects: speckle stability, speckle resolution, uniformity of gray distribution, and contrast. And then, the DMFFI method is compared with the traditional evaluation methods including mean gray gradient and second order derivative of mean gray gradient. The experimental results show that DMFFI has a better ability to evaluate the quality of laser speckle images under dynamic environment compared with the traditional evaluation methods. Finally, a comparison test under different environments is conducted, and the effects of environments on the quality of speckle images are analyzed and discussed, and a guideline for speckle image acquisition in DSPI technique is proposed, which have great significance and value for the application of DSPI technique to dynamic environment detection.