Line scanning deflectometry using a laser pico projector

In our previous publications, we had successfully made a deflectometry measurement by using a portable laser projector. In this research, we propose the beam weighting centroid method rather than previous the phase shifting method for quantification of the angular direction of the testing beam in the tested optics entrance pupil. By projecting the angular sequential lines on tested optics entrance pupil, the wavefront aberration is reconstructed from two orthogonal directions measurements, in a similar way to the line scanning deflectometry. The limited gray scale problem of laser projector during the phase shifting measurement is therefore eliminated. The reconstructed wavefront is proven to yield a more accurate result than the phase shifting methods at the cost of more image frames and acquisition time.