Three-Dimensional Measurement Method for High Dynamic Range Surfaces Based on Adaptive Fringe Projection

As an optical measurement method, fringe projection three-dimensional (3D) measurement technology will have poor measurement effect due to overexposure or too dark of the fringes when measuring high dynamic range (HDR) surfaces. The adaptive fringe projection method is one of the effective methods to solve the HDR surfaces measurement, but pixel matching is the difficulty. The existing matching methods generally use phase for matching, which requires at least 24 additional patterns to be projected, seriously affecting the measurement efficiency. In order to solve these problems, an adaptive fringe projection measurement method using speckle pattern for pixel matching is proposed in this paper. First, two grayscale patterns are projected to calculate the adaptive projection intensity. Then a speckle pattern is projected to match the pixels of the captured pattern and the projected pattern. Finally, the adaptive fringe patterns are generated. Better than the methods before, only three additional patterns are needed to be projected to realize the measurement of the HDR surfaces. The experimental results show that the proposed method can reduce the number of projected patterns by more than 59.5% while achieving similar measurement accuracy, which greatly improves the measurement efficiency.