Li Shuyu

An automatic method of synthesizing panoramic radiograph by unwrapping dental CT image

Panoramic radiographs synthesized from dental CT images manifest high quality than conventional dental panoramic radiograph and have been used in clinical treatment, but some manual operations are needed in current synthesizing algorithms. This paper presents a new algorithm to synthesize panoramic radiographs from dental CT images automatically. Firstly, projection image of the horizontal CT image is generated by maximum intensity projection (MIP). Then, a modified Ostus threshold method is used to segment dental arch area in the projection images. After that, a reference curve is obtained by fitting the medial axis of dental arch area. Finally, the CT slices are unwrapped normal to the reference curve and the panoramic radiograph is generated by synthesizing the projection of unwrapped images in frontal axis. This algorithm is fully automatic and the panoramic radiograph synthesized from dental CT images with this algorithm shows less geometric distortion and blurring.

An ERP research on the cerebral functional regions correlated to stereoscopic perception

The binocular disparity is the prime of forming stereopsis. The researches were not focused on basic visual functional areas affecting stereoscopic perception induced by binocular disparity. In this paper, ERP technology was used to study the regulatory region in cerebral cortex which relates to stereoscopic perception induced by binocular disparity. We chose eight subjects to conduct the experiment by using images with different binocular disparities, and we found the stereoscopic perception resulted from binocular disparity evoked N2 wave on all of occipital lobe with large amplitude at 180ms. In addition, the amplitudes of N2 waves in the O channels were lower than those of other channels. It means the regulation of stereoscopic perception induced by binocular disparity needs basic and advanced visual functional areas work together. Meanwhile, it also means the principle areas are the advanced visual functional areas.

Three-Dimensional Reconstruction and Analysis of Human Central Sulcus Based on Visualization Toolkit

Quantitative shape analysis of human central sulcus (CS) is important to understand the structure-function relationship. However, shape analysis of CS is a tedious process, and there is no analysis software that can be used directly for 3D reconstruction and morphological analysis of CS. In this paper, we developed the software with the VTK technology for three-dimensional (3D) reconstruction and shape analysis of CS. The functions of this software included: constructing and displaying the 3D model of CS with VTK unstructured grid mesh; achieving detailed morphological information by interaction operation of cutting and picking; analyzing global and local morphological characteristics such as surface area, average curvature, degree of concave and so on; visualizing the calculated results using pseudocolor. With the developed software, 12 cases of CS were reconstructed, and the global and local features that describe CS were analyzed. The software developed in this paper will provide researchers more accurate information on morphology of CS, and will help them describe the structure-function relationships of CS more precisely and effectively.