Yoshimitsu Aoki

Accurate extraction and measurement of fine cracks from concrete block surface image

Measurement and analysis of cracks on the surface of reinforced concrete can be an effective key for diagnosing quake-proofness of a construction or measuring material fatigue. The conventional method of diagnosis is to analyze cracks using a sketch manually produced by inspection engineers, however it takes a fairly long time and lacks quantitative objectivity. This paper proposes an automatic detection and analysis system for concrete block inspection. By employing a high-resolution camera, the cracks and displacement features are automatically extracted using an integrated image processing technique. Utilizing the proposed method, the crack scale can be measured with sub-pixel order accuracy. Automatic feature extraction and quantitative analysis of cracks are implemented to make the system efficient tool for assisting specialists in inspection procedures.

Three-dimensional analysis system for orthognathic surgery patients with jaw deformities

INTRODUCTIONnTraditionally, lateral and frontal cephalograms are used with facial photographs to evaluate a patients maxillofacial skeletal and facial soft-tissue morphology. However, the enlargement and distortion of 2-dimensional radiography made it difficult to accurately conceptualize the patients anatomy. The purpose of this article was to introduce a new method for comparing 3-dimensional (3D) standard values of the maxillofacial skeletal and facial soft-tissue morphology before and after orthognathic surgery.nnnMETHODSnNormative 3D standard values of the maxillofacial skeletal and facial soft-tissue morphology were calculated from normal women. The pre- and postoperative morphology of one woman who underwent orthognathic surgery was compared with the normative data.nnnRESULTSnThis 3D analysis has clinical value to evaluate patients before and after surgical treatment.nnnCONCLUSIONSnThis quantitative assessment of 3D maxillofacial morphology can evaluate the area and degree of displacement and rotation of the facial skeleton and facial soft tissues. This method is sufficiently useful for routine clinical applications.

A 3-dimensional method for analyzing the morphology of patients with maxillofacial deformities

INTRODUCTIONnTraditionally, cephalograms have been used to evaluate a patients maxillofacial skeleton and facial soft-tissue morphology. However, magnification and distortion of the cephalograms make detailed morphologic analysis difficult in patients with complex deformities. The purpose of this article was to introduce a new method for visualizing deformation and deviation of the maxillofacial skeleton and facial soft tissues.nnnMETHODSnStandard 3-dimensional Japanese head models were sized to match the sella-to-nasion distance obtained from 2 patients (1 man, 1 woman) maxillofacial skeletal images. Then, the scaled standard model was superimposed on each patients 3-dimensional computed tomography image.nnnRESULTSnThis system provided clear shape information independent of size and facilitated the visualization of shape variations in maxillofacial skeletal and facial soft-tissue morphology.nnnCONCLUSIONSnThis method will be useful for 3-dimensional morphologic analysis of patients with jaw deformities.

Four-dimensional analysis of stomatognathic function

Many researchers have attempted to clarify the complex relationships between stomatognathic function and craniofacial morphology. Most studies investigated the trajectories of incisal or condylar points and measured temporomandibular morphology projected onto 2-dimensional radiographic films. Although these methods provided valuable information, their diagnostic capabilities were limited. We introduce a new 4-dimensional (4D) analysis of stomatognathic function that combines the 3-dimensional (3D) computed tomography of the cranium and mandible, dental surface imaging with a noncontact 3D laser scanner, and mandibular movement data recorded with a 6 degrees of freedom jaw-movement analyzer. This method performs dynamic and precise simulations that can analyze and display condyle to fossa distances and occlusal contacts during mandibular function. These comprehensive relationships can be analyzed and displayed not only at intercuspal position, but also at any mandibular position during functional movements. We believe that our 4D analyzing system will be useful for diagnosing temporomandibular disorders of patients with jaw deformities and other malocclusions.

A 3-dimensional method for analyzing facial soft-tissue morphology of patients with jaw deformities.

INTRODUCTIONnTraditional cephalometric radiographs can analyze facial soft-tissues 2 dimensionally. Because they cannot provide information about the nose, lips, cheeks, and mouth, another method is needed to analyze these soft tissues. We introduce a new method for analyzing the 3-dimensional (3D) shape and size of facial soft-tissue morphology.nnnMETHODSnA 3D average face model was constructed based on 3D computed tomography images of Japanese male and female adult volunteers who had well-balanced faces and normal occlusions. To test the feasibility of evaluating the quantitative effects of surgery, preoperative and postoperative 3D computed tomography images of facial soft tissues of 1 man and 1 woman were superimposed on the average faces.nnnRESULTSnThis quantitative assessment provided a comprehensive evaluation of the characteristics that separate size and shape. It was possible to view the superimposed images from any desired angle on a personal computer.nnnCONCLUSIONSnThis method provides easy-to-understand information for patients and appears to be useful for clinical diagnosis and pretreatment and posttreatment soft-tissue morphologic evaluations of patients with jaw deformities.

Real-time vision system for autonomous mobile robot

In order to realize a vision system for an autonomous mobile robot used in a human living environment, it is necessary to observe human behaviors and to react to those actions. In this paper, we propose a real-time human tracking method based on vision system for an autonomous mobile robot. First, the system detects body parts as moving areas in the scene, and a face region or region specific to human is extracted in the detected area using color. Next, the facial gesture and head gesture are recognized. We implement the vision system on a mobile robot, and experimentally show the system can detect and track a human and his face in real-time.

Search for Survivors Buried in Rubble by Rescue Radar with Array Antennas - Extraction of Respiratory Fluctuation -

The authors have developed a Doppler-type ground penetrating radar (GPR) unit to find survivors buried in houses that have collapsed in an earthquake or other disaster. The purpose of this study is to improve the dynamic range of radar consisting of an array antenna so that it can quickly identify far-off survivors under rubble. The authors focused on time-variable elements from the respiration of a survivor awaiting rescue in order to remove clutter components, such as the rubble. A healthy individuals respiratory frequency varies from 0.2 Hz to 0.5 Hz, so the authors propose a signal processing method to extract these frequency elements in an effective manner. The authors also examine the effectiveness of this method experimentally.

Physical facial model based on 3D-CT data for facial image analysis and synthesis

The authors have proposed a physics-based facial model based on anatomical data and knowledge, which has a three dimensional structure for facial image analysis and synthesis. The skin and the skull models are constructed from 3D-CT scanned data, and the facial muscles were placed between them just like as a real human face. With regard to the skin and muscle models, spring frames are used to simulate the elastic dynamics of a real facial skin and muscles. Facial modification can be flexibly realized by two factors: the expansion and contraction of non-linear springs which simulate a skin and muscles, and the motion of the jaw part of the skull. Using the system, one can represent realistic facial animation and predict facial modifications under given conditions for muscles and the skull. Furthermore, the method is effective for analyzing the relationship between modification on the facial surface and the motion of muscles and the skull.

Automatic analysis for neuron by confocal laser scanning microscope

The aim of this study is to develop a system that recognizes both the macro- and microscopic configurations of nerve cells and automatically performs the necessary 3-D measurements and functional classification of spines. The acquisition of 3-D images of cranial nerves has been enabled by the use of a confocal laser scanning microscope, although the highly accurate 3-D measurements of the microscopic structures of cranial nerves and their classification based on their configurations have not yet been accomplished. In this study, in order to obtain highly accurate measurements of the microscopic structures of cranial nerves, existing positions of spines were predicted by the 2-D image processing of tomographic images. Next, based on the positions that were predicted on the 2-D images, the positions and configurations of the spines were determined more accurately by 3-D image processing of the volume data. We report the successful construction of an automatic analysis system that uses a coarse-to-fine technique to analyze the microscopic structures of cranial nerves with high speed and accuracy by combining 2-D and 3-D image analyses.

Simulation of postoperative 3D facial morphology using a physics-based head model

We propose a prototype of a facial surgery simulation system for surgical planning and the prediction of facial deformation. We use a physics-based human head model. Our head model has a 3D hierarchical structure that consists of soft tissue and the skull, constructed from the exact 3D CT patient data. Anatomic points measured on X-ray images from both frontal and side views are used to fire the model to the patients head.The purposes of this research is to analyze the relationship between changes of mandibular position and facial morphology after orthognathic surgery, and to simulate the exact postoperative 3D facial shape. In the experiment, we used our model to predict the facial shape after surgery for patients with mandibular prognathism. Comparing the simulation results and the actual facial images after the surgery shows that the proposed method is practical.