A Fitting Correction Method for Digital Projection Raster Image Based on Distortion Global Correction

Abstract

The invention discloses a digital projection raster image fitting correction method based on distortion global correction. The method is characterized in that a grating projection system is configuredto acquire a digital projection raster image; the grating projection system is used; an object to be tested is placed on a platform; a projector is connected to a computer; the projector and a cameraare placed on both sides over the object to be tested respectively; the lens of the projector and the lens of the camera are both oriented toward the object to be tested; the computer gives a signalfor inputting a raster mode, and inputs the signal into the projector to generate a raster pattern as a raster light source to irradiate the object to be tested and the platform; the camera acquires an image of the object to be tested and the platform irradiated by the raster light source as an output raster mode; and the input raster mode and the output raster mode are successively subjected to light intensity correction, pixel matching, and sinusoidal correction. The method of the invention improves the quality of the projection raster, improves the raster projection three-dimensional measurement accuracy based on a phase shift method, and can expand the adaptability of the digital raster projection device to a certain extent.

Description

technical field [0001] The invention relates to the technical field of active three-dimensional measurement, and mainly relates to a method for improving the sinusoidality of a digital projection grating, in particular to a method for fitting and correcting a digital projection grating image based on distortion global correction. Background technique [0002] In active optical measurement, the grating projection method is widely used in three-dimensional shape measurement because of its high measurement speed and measurement accuracy. In the grating projection method, the three-dimensional shape information is hidden in the spatial distribution of the grating field, and the height information of the object to be measured can be obtained by dephasing the grating field. It can be seen that the accuracy of the grating field directly affects the accuracy of the three-dimensional shape measurement, and improving the accuracy of the grating field is of great significance to the th...

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Problems solved by technology

[0006] The above methods mainly have the following problems: First, the method of directly correcting the output grating pattern is greatly affected by the measurement system, and may produce unpredictable additional errors during error compensation. Therefore, in order to avoid the generation of additional errors , it is more reasonable to take the input raster mode as the correction object

Second, among the methods that take the input grating pattern as the correction object, the method proposed by Gai Shaoyan et al. has a small sampling range for establishing correction alignment, and the correction effect has a large difference between groups, which may make the overall grating pattern The correction results are partially unsatisfactory; and the existing methods do not take into account the problem of global correction of distortion between the input grating mode and the output grating mode, and there are systematic errors in the correction

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