Biomedical subjects

Jianfeng Sun

Publications and source records attributed to Jianfeng Sun.

5 recordsLinked to original sources

PubMed2006

Analysis of optical systems with extended depth of field using the Wigner distribution function.

We describe the use of a Wigner distribution function approach for exploring the problem of extending the depth of field in a hybrid imaging system. The Wigner distribution function, in connection with the phase-space curve that formulates a joint phase-space description of an optical field, is employed as a tool to display and characterize the evolving behavior of the amplitude point spread function as a wave propagating along the optical axis. It provides a comprehensive exhibition of the characteristics for the hybrid imaging system in extending the depth of field from both wave optics and geometrical optics. We use it to analyze several well-known optical designs in extending the depth of field from a new viewpoint. The relationships between this approach and the earlier ambiguity function approach are also briefly investigated.

Journal Article↗

PubMed2006

Research on a scanner for tilting orthogonal double prisms.

The original scanner for tilting orthogonal double prisms is studied to test the tracking performance in intersatellite laser communications. With a reduction ratio of more than 100 times from the change rate of the angle of beam deviation to that of the tilting angle of each prism, the theoretical analysis performed, as well as the verification experiment, indicates that the scanner can meet the requirements of the scanning accuracy superior to 0.5 microrad with the scanning range greater than 500 microrad and can facilitate the mechanical structure design.

Journal Article↗

PubMed2005

Mutual alignment errors due to wave-front aberrations in intersatellite laser communications.

We analyze mutual alignment errors due to wave-front aberrations. To solve the central obscured problem, we introduce modified Zernike polynomials, which are a set of complete orthogonal polynomials. It is found that different aberrations have different effects on mutual alignment errors. Some aberrations influence only the line of sight, while some aberrations influence both the line of sight and the intensity distributions.

Journal Article↗

PubMed2005

Three-dimensional superresolution by three-zone complex pupil filters.

Complex pupil filters are introduced to improve the three-dimensional resolving power of an optical imaging system. Through the design of the essential parameters of such filters, the transmittance and radius of the first zone, three-dimensional superresolution is realized. The Strehl ratio and the transverse and axial gains of such filters are analyzed in detail. A series of simulation examples of such filters are also presented that prove that three-dimensional superresolution can be realized. The advantage of such filters is that it is easy to realize three-dimensional superresolution, and the disadvantage is that the sidelobes of the axial intensity distribution are too high. But this can be overcome by the application of a confocal system.

Algorithms↗

PubMed2004

Transverse or axial superresolution with radial birefringent filter.

The superresolution technique is well known for its ability to compress the central diffraction spot to a size that is smaller than the Airy diffraction spot. The radial birefringent filter, which consists of two parallel polarizers and a rotationally symmetric birefringent element, is introduced into the superresolution technology, and the pupil function of it is deduced. It is shown that such a filter can be adapted either for transverse superresolution or for axial superresolution simply by changing the angle between either of the two polarizers and the radial birefringent element. At the same time the superresolution parameters are discussed. The filter is relatively simple in construction as it requires no phase changes, and low-cost replication is possible.

Journal Article↗