In the condition of oblique photographic angle or defective camera lens, the pictorial location of test model could contain slant or distorted deviation, which could further affect the accuracy of photogrammetry. In the aim of reducing the effect of slant and distorted deviation on photogrammetry, the relationship between two dimensional model coordinate and image coordinate was derived according to perspective principle. Furthermore, an image correction method was established by introducing image distorted deviation into perspective transformation. Intrinsic parameters of digital camera were calibrated by photogrammetry of a standard grid, which also showed that this method could achieve a metrical precision of 2‰. The method was applied to image calibration and displacement measurement of a geotechnical centrifuge model test, and the deviation of calibrated coordinate was less than 1mm, and has 5% or less influence on the displacement measurement.
Key words
centrifuge model test /
photogrammetry /
image calibration /
perspective transformation /
displacement measurement
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References
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