PIV image preprocessing method based on particle feature retrieval

Abstract

The invention discloses a PIV image preprocessing method based on particle feature retrieval. The method comprises the following steps: observing a PIV image, analyzing the characteristics of particles, including a gray value g of a particle boundary pixel point, a difference value between the gray value of the particle boundary pixel point and the gray value of a pixel point where background noise is located, and the number d of pixels occupied by the particles in the transverse direction or the longitudinal direction, and setting thresholds for the three characteristics; scanning a gray matrix of the image, performing threshold segmentation on the image by using the threshold conditions of the three features, dividing all pixels in the image into two categories of PIV particles and background noise; carrying out gray value attenuation on the pixel point which is judged to be background or noise, and keeping the original gray value of the pixel where the particle is located to obtaina preprocessed image. According to the method provided by the invention, the effective information in the image is accurately identified starting from the characteristic difference between the effective information and the interference information, and then the interference information is processed in a targeted manner and the effective information is reserved.

Description

technical field [0001] The invention belongs to the field of image processing of fluid mechanics experiments, and in particular relates to a PIV image preprocessing method based on particle feature retrieval. Background technique [0002] In many engineering environments where PIV experiments are applied, due to the complex interference of test equipment, defects in the information acquisition system, and other interference factors, the finally acquired PIV images are often accompanied by complex and diverse noise interference, which is superimposed with effective particle information. After that, it will have adverse effects on the later data processing. Such images need to undergo certain preprocessing before effective flow field calculation can be performed. [0003] E.g, figure 1 , figure 2 is the first frame image of two groups of original PIV particle images selected arbitrarily, figure 1 The middle white box marks the area to be tested. It can be seen that the i...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a PIV image preprocessing method based on particle feature retrieval, to solve the problem that the processing effect of strong background interference in the prior art is relatively limited, and in engineering applications, Many PIV images containing noise interference obtained in the experiment could not be solved to obtain ideal results and had to be discarded, resulting in a large amount of data waste and repeated experiments

Images