Real-time detection method of digital image correlation method based on SIFT improvement

Abstract

The invention discloses a real-time detection method of a digital image correlation method based on SIFT improvement, and relates to a deformation detection method. The method comprises the following steps: 1, obtaining gray level images before and after deformation; 2, calculating sub-pixel curved surface fitting; 3, calculating a sub-pixel interpolation; 4, establishing different Gaussian scale spaces to construct a continuous scale image pyramid; 5, searching and screening feature points from the continuous scale space; 6, constructing analysis sub-regions in combination with the selected feature points; 7, calculating the displacement of the deformation sub-region; and 8, using a displacement feature vector to represent deformation. According to the method, the continuity of the displacement field is ensured, the adjustment of the calculation speed and precision is more concise and convenient, the two parameters are balanced, the improved algorithm does not increase the calculation complexity, the pretreatment time is saved, the method has better adaptability to complex boundaries, and higher calculation precision can be achieved under the condition of the same calculation speed.

Description

technical field [0001] The invention relates to a deformation detection method, in particular to a real-time detection method based on a SIFT-improved digital image correlation method. Background technique [0002] Civil engineering materials such as sand, concrete, rock, etc. are mixed with various materials. These different materials are very easy to form rough and uneven surfaces. These surfaces will have certain differences in the reflection effect of light, and these differences are random and non-uniform. Therefore, capturing these differences can be described in the digital image correlation method A characteristic of the surface of a material. [0003] The current geotechnical material deformation monitoring methods generally use the sensor method, ultrasonic method, etc., and the sensor method is more common. Paste or embed many transformers on the surface or inside of the stress test pieces, such as buildings and experimental materials, and monitor the voltage ch...

AI Technical Summary

Problems solved by technology

Bond the strain gauge to the surface of the component under test. When the force deforms, the strain gauge deforms along with the component. At this time, the resistance value of the strain gauge changes accordingly. The resistance change in the strain gauge is measured and converted by the resistance strain gauge. The instruments used to measure strain mainly include linear displacement sensors and extensometers, etc., but the circuits of the measuring instruments are complicated and can only be used for single-point one-way measurement and precise devices are required before obtaining complete results

Since the strain gauges commonly used to measure strain need to be patched and deployed in advance, and the measurement is often the average strain in a certain area, it is not suitable for some occasions where direct contact is not possible

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