DSPI Filtering Evaluation Method Based on Sobel Operator and Image Entropy

Evaluating the filtering process of the digital speckle pattern interferometry (DSPI) of a single image by the traditional methods can result in under- or over-filtering. To solve this problem, this paper proposes an image-filtering evaluation method based on the Sobel operator and image entropy. First, the Sobel operator is introduced to convolute a filtered image to obtain a gradient image of a DSPI. Then, by analyzing the gradient image, image entropy is calculated according to the characteristics of the gradient map. Finally, the proposed method is verified by experiments. The experimental results show that the proposed method can quantitatively evaluate the filtering process of the DSPI.