Four-step phase shifting method based on absolute phase recovery

Abstract

The invention discloses a four-step phase shifting method based on n absolute phase recovery, and belongs to the technical field of three-dimensional measurement. The method comprises the following steps of: generating a grating coding stripe image implied with absolute phase identifiers through a computer; projecting coding stripe patterns and acquiring a detected object image; distinguishing the absolute phase identifiers according to the modulation degree information; and solving the phases by using different phase solving methods inside and outside an identifier region respectively. Compared with other phase solving methods, the solution of the phases does not need to individually project additional absolute phase identifier images in the methods, and the number of the required images is few; the phase solving methods are not strict with the boundary requirements of the absolute phase identifier region, and have good stability of acquiring accurate absolute phases; and the implied absolute phase identifier characteristics are obvious, the contrast is strong, the extraction is convenient, the form is not limited, and different application requirements are met.

Description

Technical field [0001] A four-step phase shift method based on absolute phase recovery relates to the field of computer vision measurement, belongs to the field of three-dimensional measurement methods and instrument technology, and in particular relates to the structured light encoding technology and absolute phase acquisition technology of an optical three-dimensional measurement system. Background technique [0002] Optical-based non-contact three-dimensional object shape measurement technology has been greatly developed, and this technology has been widely used in product design and manufacturing, quality inspection and control, robot vision and other fields. In addition, with the advancement of digital projection technology, the three-dimensional measurement technology of structured light based on digital projection equipment has been rapidly expanded, occupying an increasingly important position in the entire field of optical three-dimensional measurement technology. I...

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Problems solved by technology

[0006] Aiming at the disadvantages of existing methods, such as many projected images, difficult extraction of absolute phase positions, high requirements on image quality, and susceptibility to noise, the present invention proposes a structured light form with stronger absolute phase information, which only needs four images, The position of the absolute phase pattern is simply obtained by using the method of demodulation, which does not require high image quality, is not sensitive to noise, and avoids the recovery operation of the covered phase

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