Adaptive projection moire method for continuous surface

Abstract

An adaptive projection moire method for a continuous surface comprises the following steps: measuring a three-dimensional initial shape of an object by using a projection moire technology through a calibrated real projector and a camera; constructing a virtual projection moire model according to the three-dimensional preliminary morphology and internal parameters and external parameters obtained through calibration, simulating a grid line pitch meeting a projection requirement in a virtual environment through an adaptive iterative algorithm based on preset ideal moire parameters, and generating a numerical grid line graph to be projected; and finally, projecting the numerical grid line graph to the surface of a measured object through a real projector, and collecting uniformly distributed moire images, thereby obtaining the accurate three-dimensional shape of the to-be-measured object. According to the invention, corresponding non-uniform projection grid lines and ideal uniformly-distributed adaptive moire patterns are generated for any measured object with a continuous surface, so that the measurement precision of the whole field is improved, and the measurement error distribution of the whole field is more uniform; te method is suitable for high-precision and high-resolution measurement of large-curvature objects, has no additional requirements on hardware, is low in energy consumption during working, and is suitable for field testing.

Description

technical field [0001] The invention relates to a technology in the field of optical measurement, in particular to an adaptive projection moiré method for continuous surfaces. Background technique [0002] As a full-field optical measurement method, the projection moiré method forms a moiré grating with a lower density than the original projected grating, so it can amplify the phase change of the grating caused by surface deformation, thereby achieving a higher Phase resolution and measurement accuracy. However, the distribution of this moiré pattern is extremely uneven, and its non-sinusoidal phase error will be introduced in the area where the grid lines are dense, and the phase noise is relatively large in the area where the grid lines are sparse. The above two kinds of phase errors will make the measurement error in this area larger, so the measurement accuracy distribution of the whole field is uneven. Contents of the invention [0003] The present invention aims at...

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Problems solved by technology

[0003] The present invention aims at the extremely irregular distribution of the moiré patterns generated by the existing scanning projection moiré technology within the full-field measurement range, and the measurement error in areas where the moiré is too sparse and dense is larger than that in uniformly distributed areas, that is, the full-field measurement For the defects of poor performance, an adaptive projection moiré method for continuous surfaces is proposed. For any measured object with a continuous surface, corresponding non-uniform projection grid lines and ideal uniformly distributed adaptive moiré are generated. In this way, the measurement accuracy of the entire field is improved, and the measurement error distribution of the entire field is more uniform. It is suitable for high-precision and high-resolution measurement of objects with large curvature. At the same time, there are no additional requirements for hardware and low energy consumption during operation. It is suitable for on-site testing.

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