An automatic geometrical calibration approach has been developed to calibrate a multiprojector-type light field (LF) display automatically and accurately. The calibration framework based on image mapping is detailed, which transfers the calibration of three-dimensional (3-D) scene into the calibration of two-dimensional image in the diffuser interface. A multiprojectors-type LF display prototype is applied to implement the experimental calibration. Comparison results of the reconstructed 3-D scene before and after calibration show that a better overall performance is obtained through the proposed calibration approach.
Simultaneous measurement of the birefringence magnitude and direction using Wollaston prism is presented. The
sinusoidally modulated laser beam passes through a circular polarizer, the birefringence sample and is split by a
Wollaston prism. The measuring beam is then detected by a bi-cell detector and two alternating current signals are
detected. Then the Wollaston prism is rotated by 45°, and another two alternating current signals are obtained. By
processing the four signals, the birefringence magnitude and direction is resolved simultaneously. In experiments, a
wedge waveplate was laterally moved and measured at different birefringence magnitude. The measured birefringence
magnitude linearly increased as the wedge waveplate was laterally moved. The maximum standard deviation of the
birefringence magnitude and direction is 0.11° and 0.05°The usefulness of this method is verified.