Multiple transmission electron microscopic image stitching based on sift features / 南方医科大学学报

We proposed a new stitching method based on sift features to obtain an enlarged view of transmission electron microscopic (TEM) images with a high resolution. The sift features were extracted from the images, which were then combined with fitted polynomial correction field to correct the images, followed by image alignment based on the sift features. The image seams at the junction were finally removed by Poisson image editing to achieve seamless stitching, which was validated on 60 local glomerular TEM images with an image alignment error of 62.5 to 187.5 nm. Compared with 3 other stitching methods, the proposed method could effectively reduce image deformation and avoid artifacts to facilitate renal biopsy pathological diagnosis.

Structural analysis based on adaptive window for pulmonary nodule detection / 南方医科大学学报

Radiographic detection of pulmonary nodules based on three-dimensional Hessian matrix is highly sensitive but frequently produces false positive results in areas where blood vessels intersect. We propose a novel approach to pulmonary nodule detection using Hessian matrix-based adaptive window structure analysis, in which the structure coefficients is used to differentiate a voxel that belongs to a nodule or vascular structures, followed by construction of the 3D adaptive window to analyze the local structure characteristics; the nodules were then detected using the discrimination function. The experimental results on pulmonary CT images from 17 patients showed a 100% detection sensitivity for nodules of varying sizes and types, with also significantly reduced false positive results generated by the vessel junctions. This approach provides valuable assistance to follow-up positioning and segmentation of the pulmonary nodules.

Monte Carlo simulation and validation of the multi-leaf collimator of Varian 23EX accelerator / 南方医科大学学报

<p><b>OBJECTIVE</b>To simulate the multi-leaf collimator of Varian linear accelerator using Monte Carlo method.</p><p><b>METHODS</b>The multi-leaf collimator model was established using the DYNVMLC module of BEAMnrc and validated by comparison of Monte Carlo simulation and actual measurement results.</p><p><b>RESULTS</b>The simulation results were well consistent with the actual measurement results with a bias of less than 3%.</p><p><b>CONCLUSION</b>The multi-leaf collimator of Varian linear accelerator can be successfully modeled using Monte Carlo method for analysis of the impact of the geometric properties of the multi-leaf collimator on the dose distribution.</p>

Design and realization of an algorithm for capsule endoscope image recognition system / 南方医科大学学报

Discrimination of abnormal images from the numerous wireless capsule endoscope (WCE) video sequence images is laborious and time-consuming, so that a computer-based automatic image recognition system is desired for this task. We propose an algorithm to allow feature extraction from each image channel and decision fusion using multiple BP neural networks. The algorithm was tested and the results demonstrated its high efficiency and accuracy in identification of abnormalities in the WCE images.

A Novel Automatic Registration Method for Serial Brain Images / 中国医学物理学杂志

Registration of serial images plays an increasingly important role in medicine. A novel registration method used for serial images matching is proposed, which is based on the joint histogram. After thresholding the two images to be registered, the joint histogram is divided into four separate regions. Then the criterion function is defined as bin counting in a specific region of the joint histogram, which simplifies the computation of the criteria function greatly and speeds up the alignment process significantly. We choose the Powell optimization algorithm to calculate the registration parameters. The comparison of the results from both mutual information and our method shows that the new method based on segmentation and counting is a fast, simple, efficient and accurate registration method.

Study of 3D visualization methods on PACS workstation / 生物医学工程学杂志

Based on a discussion on PACS and the way its image workstation obtains scanned sequential images, this paper presented a method of 3D surface construction and visualization on PACS workstation. Guest/Server structure was used between PACS application entities. Image storing and transmission were realized by service classes established by DICOM standards. Relation database was used to arrange the stored sequential images. Image workstation transformed the sequential images obtained from PACS net into volume data field. 3D reconstruction and rendering results were obtained by using surface-rendering and volume-rendering methods, which made the 3D construction results acquire vivid 3D structure details of high fidelity and strong sense of reality. 3 sets of application results were also presented in this paper.

Medical image elastic registration smoothed by unconstrained optimized thin-plate spline / 生物医学工程学杂志

Elastic registration of medical image is an important subject in medical image processing. Previous work has concentrated on selecting the corresponding landmarks manually and then using thin-plate spline interpolating to gain the elastic transformation. However, the landmarks extraction is always prone to error, which will influence the registration results. Localizing the landmarks manually is also difficult and time-consuming. We the optimization theory to improve the thin-plate spline interpolation, and based on it, used an automatic method to extract the landmarks. Combining these two steps, we have proposed an automatic, exact and robust registration method and have gained satisfactory registration results.

Registration and 3D rendering of serial tissue section images / 生物医学工程学杂志

It is an important morphological research method to reconstruct the 3D imaging from serial section tissue images. Registration of serial images is a key step to 3D reconstruction. Firstly, an introduction to the segmentation-counting registration algorithm is presented, which is based on the joint histogram. After thresholding of the two images to be registered, the criterion function is defined as counting in a specific region of the joint histogram, which greatly speeds up the alignment process. Then, the method is used to conduct the serial tissue image matching task, and lies a solid foundation for 3D rendering. Finally, preliminary surface rendering results are presented.