Sijiong Zhang

Learn More
We present two methods for three-dimensional particle metrology from a single two-dimensional view. The techniques are based on wavefront sensing where the three-dimensional location of a particle is encoded into a single image plane. The first technique is based on multiplanar imaging, and the second produces three-dimensional location information via(More)
This paper proposes a modified Shack-Hartmann wavefront sensor for phase retrieval. The sensor is revamped by placing a detector at a defocused plane before the focal plane of the lenslet array of the Shack-Hartmann sensor. The algorithm for phase retrieval is an optimization with initial Zernike coefficients calculated by the conventional phase(More)
Online co-phasing of segmented telescopes by dual-wavelength digital holography is proposed. Two digital holograms (one hologram per wavelength) are employed to get the phase of the segmented telescope for a longer synthetic wavelength by the digital holographic approach. The holograms are recorded by a high-speed CCD camera using the point-diffraction(More)
Phase diversity is a phase-retrieval algorithm that uses a pair of intensity images taken symmetrically about the wave front to be determined. If these images are taken about the system input pupil this is equivalent to a curvature-sensing algorithm. Traditionally a defocus aberration kernel is used to produce the phase-diverse data. We present a(More)
  • 1