Design of diffractive optical element projector for a pseudorandom dot array by an improved encoding method

Here we achieved the structured light patterns of a pseudorandom dot array by a single diffractive optical element. The dot array can be applied to achieve three-dimensional imaging. First, the pseudorandom dot array was generated by the proposed improved encoding methods, which are an improved formula-method-based encoding algorithm and an improved enumeration-method-based encoding algorithm. Second, diffractive optical elements were designed as dot projectors to generate pseudorandom dots by the Gerchberg–Saxton algorithm. Pseudorandom dot arrays with different sizes were generated to validate the proposed encoding methods. A pseudorandom dot array with a maximal size of 713 × 449 was experimentally achieved. By analyzing the intensity distribution of the projecting pattern, the projected dots have a unique window of 7 × 7, and the dot array is distortion free. The proposed encoding methods, optimization algorithm, and applied fabrication technology have potential applications in three-dimensional imaging, three-dimensional sensing, shape measurement, and deformation measurement with high decoding speed.