Improved geometrical model of fringe projection profilometry

Abstract

The accuracy performance of fringe projection profilometry (FPP) depends on accurate phase-to-height (PTH) mapping and system calibration. The existing PTH mapping is derived based on the condition that the plane formed by axes of camera and projector is perpendicular to the reference plane, and measurement error occurs when the condition is not met. In this paper, a new geometric model for FPP is presented to lift the condition, resulting in a new PTH mapping relationship. The new model involves seven parameters, and a new system calibration method is proposed to determine their values. Experiments are conducted to verify the performance of the proposed technique, showing a noticeable improvement in the accuracy of 3D shape measurement. Disciplines Engineering | Science and Technology Studies

Simplified Geometric Model for Generic Projector Application in Digital Fringe Profilometry

“…The DFP technique consists of four main components [3], namely a projector, a reference plane, a camera and a computer. A digital fringe image would be created in the computer and projected onto the object surface as a spatial marker.…”

“…Finally, the difference between the phase maps would then be converted into height map by triangulation. Triangulation is the process of calculating the surface height of every pixel of the fringe image based on the phase map differences and the geometrical relationship between the camera, object, projector and reference plane [3]. The configuration of the main components will affect the accuracy and ease of use of a DFP system [3].…”

“…In 2012, a different model was proposed which eliminated the need for locating both camera and projector optical centres at the same distance from the reference plane while also ensuring the camera optical axis were perpendicular to the reference plane [6]. In 2014, Huang et al proposed a model that was free from the all three conditions [3]. The placement of components and configuration of the reported models are shown in Figure 1.…”

Simplification of high order polynomial calibration model for fringe projection profilometry

“…When a narrow band of light is projected onto a curved surface, a line of illumination that appears distorted from other perspectives than that of the projector is produced. Such phenom enon is used to retrieve the shape of an object in the FPP system [6][7][8][9].…”