In the structured light 3D measurement system using the commercial projector as the source, all the encoding patterns are projected with the two-dimensional matrix form. The computer transmits the patterns to the projector, and the patterns are projected onto the scanned object by two-dimensional images. If the code is a striped pattern, the characteristics of stripe structured light coding that the gray information remains unchanged in the same line or in the same column are not considered. Therefore, according to the unidirectional characteristic of the fringe encoding, we present a design scheme of a special structure projector, which can automatically extend one-dimensional gray sequence into encoded structured light. One-dimensional coding sequence with all gray information and a designed pixel-extended circuit are used to expand the pixel of structured light coded image, in order to improve the projection efficiency of structured light 3D imaging. The experimental results show that the speed of projection is improved by about 71.8% compared with liquid crystal display projection method, and the order of magnitude of phase accuracy difference is 10 -3. The projection efficiency of dual encoded structured-light images in 3D measurement is effectively improved.