Biomedical subjects

Qifeng Yu

Publications and source records attributed to Qifeng Yu.

4 recordsLinked to original sources

PubMed2006

[In vivo and in vitro studies on anode-oxidized titanium percutaneous implants].

In order to solve the problesm in biological sealing of load-bearing percutaneous implants for a fairly long time, we investigated titanium with bioactivated anodic oxidized surface(group A) through the animal tests in vivo and the epithelium cell culture in vitro. Smooth Ti (group B) was used as control. The animal tests results showed that there was no evident difference in the inflammory reaction between the group A implant tissues and the group B implant/tissues. The bioactivated Ti surface could keep the implant not only bonding with the bone firmly but also adhering to the soft tissue closely, thus contributing to the formation of calcium phosphate layer and its micropores. The cell culture results also demonstrated that the microporous surface of group A could clasp and fix the skin. So, it can be concluded that the surface modified method of anode oxidization may be one of the most effective methods to resolve the problem of durable biological sealing.

Animals↗

PubMed2005

Two improved algorithms with which to obtain contoured windows for fringe patterns generated by electronic speckle-pattern interferometry.

Fringe patterns generated by electronic speckle-pattern interferometry are full of high-spatial-frequency and high-contrast speckle noise. Filtering with contoured windows has proved to be an efficient approach to filtering out speckle noise while retaining the fringe patterns. Furthermore, with contoured windows the contoured correlation fringe pattern method can be used to derive smooth, normalized, consistent fringes. Contoured windows previously were determined by fringe orientation only, and this process generated accumulated errors. We propose two new algorithms with which to obtain the contoured windows according to the fringe intensity slope and the distance ratio to neighboring skeletons. These new techniques can determine contoured windows more precisely.

Algorithms↗

PubMed2004

Analytical method for camera calibration from a single image with four coplanar control lines.

An analytical method to calibrate a camera's extrinsic parameters and effective focal lengths is presented. We used a single image with four coplanar control lines. Unique solutions of the camera's extrinsic parameters and the two effective focal lengths are derived linearly and analytically. If the effective focal lengths are known, unique solutions of the extrinsic parameters can be derived more easily. Our method can easily be implemented and has better precision than the analogous method by use of control points. The results of simulated experiments are presented.

Journal Article↗

PubMed2002

Spin filtering with curve windows for interferometric fringe patterns.

Filtering off noise from fringe patterns is important for the processing and analysis of interferometric fringe patterns. Spin filters proposed by the author have been proven to be effective in filtering off noise without blurring and distortion to fringe patterns with small fringe curvature. But spin filters still have problems processing fringe patterns with large fringe curvature. We develop a new spin filtering with curve windows that is suitable for all kinds of fringe pattern regardless of fringe curvature. The experimental results show that the new spin filtering provides optimal results in filtering off noise without distortion of the fringe features, regardless of fringe curvature.

Journal Article↗