Time-series 3D Research Articles

3D convolutional neural networks-based segmentation to acquire quantitative criteria of the nucleus during mouse embryogenesis

During embryogenesis, cells repeatedly divide and dynamically change their positions in three-dimensional (3D) space. A robust and accurate algorithm to acquire the 3D positions of the cells would help to reveal the mechanisms of embryogenesis. To acquire quantitative criteria of embryogenesis from time-series 3D microscopic images, image processing algorithms such as segmentation have been applied. Because the cells in embryos are considerably crowded, an algorithm to segment individual cells in detail and accurately is needed. To quantify the nuclear region of every cell from a time-series 3D fluorescence microscopic image of living cells, we developed QCANet, a convolutional neural network-based segmentation algorithm for 3D fluorescence bioimages. We demonstrated that QCANet outperformed 3D Mask R-CNN, which is currently considered as the best algorithm of instance segmentation. We showed that QCANet can be applied not only to developing mouse embryos but also to developing embryos of two other model species. Using QCANet, we were able to extract several quantitative criteria of embryogenesis from 11 early mouse embryos. We showed that the extracted criteria could be used to evaluate the differences between individual embryos. This study contributes to the development of fundamental approaches for assessing embryogenesis on the basis of extracted quantitative criteria.

Direct construction of a four-dimensional mesh model from a three-dimensional object with continuous rigid body movement

Abstract In the field of design and manufacturing, there are many problems with managing dynamic states of three-dimensional (3D) objects. In order to solve these problems, the four-dimensional (4D) mesh model and its modeling system have been proposed. The 4D mesh model is defined as a 4D object model that is bounded by tetrahedral cells, and can represent spatio-temporal changes of a 3D object continuously. The 4D mesh model helps to solve dynamic problems of 3D models as geometric problems. However, the construction of the 4D mesh model is limited on the time-series 3D voxel data based method. This method is memory-hogging and requires much computing time. In this research, we propose a new method of constructing the 4D mesh model that derives from the 3D mesh model with continuous rigid body movement. This method is realized by making a swept shape of a 3D mesh model in the fourth dimension and its tetrahe-dralization. Here, the rigid body movement is a screwed movement, which is a combination of translational and rotational movement.

2P1-R08 Mobile Mapping Systemによる道路視点からの東日本大震災被災地域調査 : 時系列三次元点群比較による道路周辺環境の変化域抽出(ITSとロボット・メカトロ技術)

2P1-R08 Mobile Mapping Systemによる道路視点からの東日本大震災被災地域調査 : 時系列三次元点群比較による道路周辺環境の変化域抽出(ITSとロボット・メカトロ技術)

Visualizing dynamic geosciences phenomena using an octree-based view-dependent LOD strategy within virtual globes

Geoscientists build dynamic models to simulate various natural phenomena for a better understanding of our planet. Interactive visualizations of these geoscience models and their outputs through virtual globes on the Internet can help the public understand the dynamic phenomena related to the Earth more intuitively. However, challenges arise when the volume of four-dimensional data (4D), 3D in space plus time, is huge for rendering. Datasets loaded from geographically distributed data servers require synchronization between ingesting and rendering data. Also the visualization capability of display clients varies significantly in such an online visualization environment; some may not have high-end graphic cards. To enhance the efficiency of visualizing dynamic volumetric data in virtual globes, this paper proposes a systematic framework, in which an octree-based multiresolution data structure is implemented to organize time series 3D geospatial data to be used in virtual globe environments. This framework includes a view-dependent continuous level of detail (LOD) strategy formulated as a synchronized part of the virtual globe rendering process. Through the octree-based data retrieval process, the LOD strategy enables the rendering of the 4D simulation at a consistent and acceptable frame rate. To demonstrate the capabilities of this framework, data of a simulated dust storm event are rendered in World Wind, an open source virtual globe. The rendering performances with and without the octree-based LOD strategy are compared. The experimental results show that using the proposed data structure and processing strategy significantly enhances the visualization performance when rendering dynamic geospatial phenomena in virtual globes.

Practical considerations for a method of rapid cardiac function analysis based on three-dimensional speckle tracking in a three-dimensional diagnostic ultrasound system.

The purpose of this study was to validate the accuracy of our novel 3D speckle tracking method by using numerical data, and to demonstrate the rapid processing of this method by using data obtained from human subjects. In order to create a method that can rapidly assess cardiac function in regional heart wall segments, a 3D speckle tracking algorithm was created that focuses on data quality and performance. Prototype application software based on this algorithm was written to evaluate cardiac wall motion and to calculate indices such as strain. Time series 3D image data were generated for artificial numerical models that simulate the shape of the left ventricle and exhibit various types of motion. We compared observed values returned by the algorithm with expected values yielded by the models. This software was also applied to volume data of the human heart acquired by a 3D ultrasound system. Measurement of the indices was evaluated by using an error ratio that was a residual between an expected value and estimated one divided by the expected value. The average error ratio of the time series volumes was less than 5% for all indices, and no individual error ratio was more than 10% for numerical models. The process was complete within 0.5s per frame for human heart volumes. This application software can provide good estimates of various wall motion indices. The results are similar to data from numerical models, and are provided quickly enough for routine clinical usage.