A Method for Correcting the Influence of Thermal Air Flow on the Measurement Accuracy of Digital Image Correlation

Abstract

The invention discloses a method for correcting influence of thermal current on the related measuring precision of a digital image. A circular identification point array before and after that influence of thermal current is stabilized is identified, a 3D-DIC algorithm is used to solve displacement of a test piece sprayed with speckled along directions x, y and z, a parameter matrix in which the influence of thermal current causes a virtual displacement field of circular identification points is used to correct the displacement along the directions x, y and z, and thus, a more accurate surfacedisplacement field of the tested piece under influence of the thermal current is obtained. According to the method, a measuring device is simple, realization is easy, use is convenient and effective,the relative cost is lower, the influence of the thermal current on system imaging is reduced effectively, and the influence of thermal current on related measurement precision of the digital image can be corrected effectively.

Description

technical field [0001] The invention belongs to the field of optical measurement, and relates to a method for correcting strain caused by hot air flow by using digital image processing technology and camera calibration technology. Background technique [0002] With the continuous development of optical equipment and image processing technology, optical measurement technology is widely used in industrial measurement, geodetic mapping and other fields. Using optical methods to measure high-temperature deformation is a topic worthy of further research in the development and application of experimental mechanics. Materials used in high-temperature environments, such as structural materials for high-speed aerospace vehicles and high-temperature-resistant alloys in aero-engines, are all Field high-temperature deformation measurements are especially important for determining the thermophysical and mechanical properties of these materials used in high-temperature environments. Ther...

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Problems solved by technology

However, these evaluation mechanisms have their own limitations, because the various elements in the thermal environment are mutually restricted and influenced by each other, and it is difficult to comprehensively and systematically evaluate the degree of distortion of the strain map caused by the thermal air flow by using a single criterion to measure each influencing factor.

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