Rapid 3D measurement of colour objects based on three-channel sinusoidal fringe projection

A rapid 3D measurement method based on three-channel projection is proposed in this paper. Project a composite color fringe map and an all-white map to the object to be measured. Firstly, crosstalk correction is performed on the composite color fringe pattern collected by the camera then the reflectivity of fringe image is corrected by all-white image. Then, the background normalization principle is used to solve the spectrum aliasing problem when the Fourier transform obtains a truncated phase. Finally, the three-frequency heterodyne method is used for phase unwrapping to obtain the continuous phase and 3D shape. Compared with the traditional color fringe projection method, this method not only eliminates the spectrum aliasing problem but also solves the uneven fringe reflectivity problem when measuring color objects using an all-white map. This method only requires two images to achieve measurement of 3D color dynamic objects.