A method for super-resolution based on sparse high-frequency ultrasonic microscopic imaging of tiny defects

Abstract

The invention belongs to the field of spare super-resolution detection and discloses a super-resolution method based on sparse small defect high-frequency ultrasonic micro-imaging. The method includes: executing an oversampling high-frequency ultrasonic microscopy C-scanning imaging; calculating a probe point spread function k according to the sampling step length and ultrasonic probe resolution; calculating sparse super resolution according to the point spread function to obtain a final high-resolution image. The method has the advantages that high-frequency micro-imaging is used to perform super-resolution micro-imaging on small defects, image signal-to-noise ratio and resolution are enhanced, the detection accuracy of the small defects is increased, the method is significant to the detection of the small defects, and reliable development of micro-devices is promoted effectively.

Description

Technical field [0001] The invention belongs to the field of sparse super-resolution detection, and more specifically, relates to a super-resolution method based on sparse micro-defects in high-frequency ultrasonic microscopy. Background technique [0002] With the development of modern advanced manufacturing technology to the micro-scale, the overall size of the device is getting smaller and smaller, and the micro-defects in the device become not negligible. The most commonly used methods for micro-defect detection include acoustic microscopy (AMI), X-ray and infrared thermal imaging. Among them, ultrasound microscopy imaging technology, also known as scanning acoustic imaging microscope (SAM), has the advantages of clear results, easy analysis and harmless to the human body, and is widely used. It is very sensitive to small defects such as delamination, interface voids and microbubbles. . [0003] The resolution capability of AMI for small defects mainly depends on the frequenc...

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Problems solved by technology

However, the penetration depth of the GHz probe is shallow (not exceeding 100 μm), the price is very expensive and easy to damage, and it requires personnel with a certain professional technical level to operate

Therefore, the high-frequency ultrasonic probe whose frequency does not exceed 300MHz is still widely used at present, and its resolution is generally 20-100μm, which is for the overall size of 10μm. 2 The resolution ability is seriously insufficient for tiny defects in the order of μm; Guangming Zhang et al. (G. Zhang; C. Zhang; D.M. Harvey. Sparse signal representation and its applications in ultrasonic NDE, Ultrasonics 2012, 3, 351-363.) This paper summarizes the signal super-resolution recognition technology currently applied in ultrasonic microscopic imaging technology. Almost all researches focus on the super-resolution reconstruction of ultrasonic echo signals, and identify the position and size of the echo, so as to be able to detect in multi-layer structures. However, none of these methods involve super-resolution reconstruction of ultrasound images.

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