Speckle interference image noise reduction method and device

Abstract

The invention discloses a speckle interference image noise reduction method and device. The method comprises the steps of converting a discontinuous original phase diagram into a continuous sine phasediagram and a cosine phase diagram through sine transformation and cosine transformation; performing noise reduction processing on the sine phase diagram and the cosine phase diagram by using stationary wavelet transform to obtain a sine noise reduction phase diagram and a cosine noise reduction phase diagram; and determining a target noise reduction phase diagram according to the sine noise reduction phase diagram and the cosine noise reduction phase diagram. According to the invention, the noise in the speckle interference image can be effectively and quickly filtered.

Description

technical field [0001] The present application relates to the technical field of digital speckle interference, in particular to a noise reduction method and device for a speckle interference image. Background technique [0002] The speckle interferometry technology records the speckle field generated by the interference between the reference light and the object light reflected from the rough surface of the object. According to the change of the phase map of the speckle field before and after the deformation of the object, the slight deformation of the object surface can be calculated. Due to the advantages of full-field, non-contact, and high-resolution speckle interferometry, it has been widely used in engineering measurements such as strain measurement, three-dimensional deformation measurement, and vibration evaluation. In the digital speckle interferometry technique, the speckle phase related to the deformation of the object is modulated in the [0, 2π] interval, which a...

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Problems solved by technology

[0003] In recent decades, the noise reduction methods for speckle interference images mainly include: first, the mean value filter of sin and cosine, which realizes denoising by mean filtering the phase image of sin and cosine, which is simple and effective, and is widely used. The average denoising effect is closely related to the number of filters. The denoising effect of one denoising process is not good, and it often takes 20 to 40 times. The more denoising times, the slower the filtering speed; the second is the windowed Fourier transform filter, which Denoising is achieved by discarding small window Fourier coefficients in the 2D window Fourier transform domain. The noise reduction ability is strong, but the filtering effect is affected by the window size and takes a long time.

[0004] To sum up, the currently commonly used noise reduction methods for two types of speckle interference images are difficult to achieve good results in both noise reduction ability and noise reduction speed.

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