Projection area determining method and device

Abstract

The invention discloses a method and device for determining a projection area, belonging to the technical field of three-dimensional measurement. The method comprises the following steps: shooting a group of structured light in a shooting area to obtain a group of shot images, wherein the group of structured light comprises at least three frames of structured light; determining the waveform significance coefficient of each position point in the shooting area according to the group of shot images, wherein the waveform significance coefficient of any position point is used for indicating the quality of an image formed by structured light at any position point in the group of shot images; and determining a projection area in the shooting area according to the waveform significance coefficientof each position point in the shooting area. According to embodiments of the invention, the waveform significance coefficients are irrelevant to the absolute brightness values of the shot images, somisjudgment operation caused by the fact that the structured light of the projection area is reflected to the projection area is avoided, and the accuracy of determining the projection area is improved.

Description

technical field [0001] The invention relates to the technical field of three-dimensional measurement, in particular to a method and device for determining a projection area. Background technique [0002] Three-dimensional measurement is a high-tech that integrates optical, mechanical, electrical, and arithmetic (mathematics and computer) technologies. It is mainly used to scan the spatial shape and structure of the object to be measured to obtain the spatial coordinates of the surface of the object to be measured. Among them, three-dimensional measurement includes projectors, cameras and computers. The projector is used to project structured light, which can form a projected grating when the structured light is irradiated on the object to be measured. The camera is used to shoot the projected grating to obtain the projected grating image. The computer is used to obtain the spatial coordinates of the object to be measured based on the projected raster image. Since the proj...

AI Technical Summary

Problems solved by technology

[0004] Since the structured light (first structured light and / or second structured light) in the projection area may be reflected to the non-projection area, the brightness difference of some pixels in the non-projection area is also greater than the brightness change threshold, so that some non-projection areas The projection area is misidentified as the projection area, resulting in poor accuracy of the above method

Moreover, due to the different reflectance of the material of the object to be measured and the different projection distances between the projector and the object to be measured, it is difficult to find a brightness change threshold that is applicable to all projection areas, and the projection area is based on this fixed brightness change threshold. division, will further lead to poor accuracy

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