在拍摄角度不佳或成像元件存在缺陷的情况下,试验模型在图像中的位置会产生倾斜失真或者畸变误差,从而影响摄影位移测量的精度。为了降低图像失真以及畸变对测量的影响,根据透视原理,对物像二维坐标关系进行了推导,同时引入图像畸变误差,建立了一种图像校正方法。通过对标准网格进行摄影测量,标定了数码相机的内参数,验证了校正方法可以达到2‰的测量精度。并将校正方法应用于离心模型试验的图像校正和位移测量,结果表明校正后的坐标误差在1 mm以内,对本次位移测量的影响<5%。
Abstract
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.
关键词
离心模型试验 /
摄影测量 /
图像校正 /
透视变换 /
位移测量
Key words
centrifuge model test /
photogrammetry /
image calibration /
perspective transformation /
displacement measurement
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基金
四川大学试验技术立项项目(2015-124)
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