## 1 Introduction
By encoding the fringe pattern used in the binary-coded phase-shifting technique spatially, the fringe order can be identified unambiguously, even for spatially isolated objects or surfaces with large depth discontinuities. It can also distinguish fringe orders well even when the surface color or reflectivity varies periodically with the position. However, this methodology has high requirements for encoding images, and once there is a coding error, it will lead to a large error in the subsequent dephasing. [PERSON] et al. [10] proposed a multi-frequency projection fringe profilometry for measuring large-depth discontinuous objects. A fringe pattern with multiple spatial frequencies is projected onto the target object. The phase map of the package at different spatial frequencies is obtained by phase shifting. By finding the peak value of the parcel phase index and the peaks of different spatial frequencies, the height of each point on the object surface can be obtained independently. Several measurements on real objects are given. However, the surface topographies of some complex surfaces cannot be completely measured. [PERSON] et al. [1] proposed a methodology based on a three-stream neural network to reduce motion error and introduced a general dynamic scene dataset establishment methodology to complete the 3D shape measurement of a virtual fringe projection system. The model is optimized with a large amount of automatically generated data for various motion types. The three-step phase-shifting fringe map captured along the timeline is divided into three groups and processed by the trained three-stream neural network to generate an accurate phase map. However, this methodology is complex and difficult to implement. [PERSON] et al. [11] proposed a dynamic phase measurement profilometry (PMP) based on the principle of three-color binary fringe combination time division multiplexing. By combining red (R),green (G), and blue (B) stripes into a three-color stripe of the same width without any color overlap, it can be pre-fed into the flash memory of a high-speed digital optical projector (HDLP). Special time division multiplexing timing was designed to control the HDLP to project the three-color binary stripes stored in the flash memory to the dynamic object under test in sequence at 234 frames per second, and set the projected light source mode to monochromatic mode, that is, all RGB LEDs remain luminous. At the same time, it triggers a high frame rate monochrome camera synced with the HDLP to capture the corresponding anamorphic patterns in the R, G, and B channels. By filtering, an almost complete phase-shift sinusoidal deformation pattern can be extracted from the captured three-step PMP phase-shift sinusoidal deformation pattern. It is equivalent to 3D shape reconstruction of the dynamic object under test at 78 frames per second. Experimental results show that the methodology is feasible and effective. This methodology is effective for the measurement of dynamic objects and can effectively avoid color crosstalk. This methodology has certain feasibility, but the experimental steps proposed by this methodology are complicated and difficult to implement. [PERSON] et al. [12] proposed a new single 3D measurement methodology based on four-element grating projection. In traditional binary grating PMP, sinusoidal fringes are extracted from multi-step or color fringe patterns. In this methodology, grayscale is fourth order by using DLP4500's two-bit grayscale encoding mode. The three non-zero gray levels are arranged in a cycle of equal width, and the fourth gray value is zero, which is not encoded in the fringe pattern, but represents shadow information in the deformation pattern, where a fourth-order raster is encoded. When the DLP4500 projects the four-element grating onto the object under test, the charge-coupled device (CCD) synchronously captures the corresponding deformation pattern.