Katsuya Kondo

Transcranial ultrasonography system for visualizing skull and brain surface aided by fuzzy expert system

A conventional ultrasonography system can noninvasively provide human tissue and blood flow velocity information with real-time processing. In general, since the human skull prevents the disclosure of brain anatomy, we usually placed the sensor at the anterior and superior attachment site of the upper ear (the posterior temporal window) in adults. Due to this limitation, the conventional system cannot obtain transcranial information from arbitrary places in the skull. This paper describes a transcranial sonography system that can visualize the shape of the skull and brain surface from any point to examine skull fracture and brain disease such as cerebral atrophy and epidural or subdural hematoma. In this system, we develop anatomical knowledge of the human head, and we employ fuzzy inference to determine the skull and brain surface. To evaluate our method, three models are applied: the phantom model, the animal model with soft tissue, and the animal model with brain tissue. In all models, the shapes of the skull and the brain tissue surface are successfully determined. Next, the method is applied to two adults. As a result, we have determined the skin surface, skull surface, skull bottom, and brain tissue surface for the subjects foreheads. Consequently, our system can provide the skull and brain surface information using three-dimensional shapes.

Real-time position and pose tracking method of moving object using visual servo system

This paper proposes a real-time position and pose tracking method of a moving object. The conventional methods need a three-dimensional (3D) model data of the target object. By the proposed method, the 3D position and pose tracking can be achieved without the 3D model data. We set some landmarks to estimate the 3D position and pose of the object by a single camera. In addition, the trajectory of moving landmarks is estimated by a Kalman filter. The experimental results show that a stick with a diameter of 5.0 mm can be inserted in a moving pipe with a diameter of 30.0 mm in real-time.

Fuzzy ultrasonic array system for locating screw holes of intramedullary nail

In this paper, we describe an ultrasonography system for locating screw holes of intramedullary nail by one-direction freehand scanning using an ultrasonic array probe. Although conventional X-ray method can visualize the nail in the femur, it has serious problem of X-ray exposure. We propose a locating method of the nail screw holes by an ultrasonic array probe. We extract screw hole regions by calculating two fuzzy degrees: average of the intensity and variance of the intensity using fuzzy inference. Next, we do a registration between the obtained image with the true image, where the true image is the nail image obtained by scanning an array probe to the nail exactly. As the result, we could calculate the center distance of two screw holes within an error of 1.0 mm.

Dentistry Support Ultrasonic System for Root Canal Treatment Aided by Fuzzy Logic

This paper describes a dentistry support system for root canal treatment using ultrasonic. Presently, no complete method of root canal treatment has proposed. Dentist empirically removes the dental pulp using measures of length of root canal. Therefore, the support system for root canal treatment is required to precisely remove the dental pulp. This paper solves the problem in root canal treatment by our ultrasonic device and fuzzy logic techniques. We determine the dentin-dental pulp junction by calculating two fuzzy degrees of amplitude of the echo and approximate distance of the surface and the junction. As the result, our system can determine the thickness of dental pulp within error of 0.289 mm

Ultrasonography System Aided by Fuzzy Logic for Identifying Implant Position in Bone

We describe a new ultrasonography system, which can identify an implant position in bone. Although conventional X-ray fluoroscopy can visualize implants, it has the serious disadvantage of X-ray exposure. Therefore, we developed a system for orthopedic surgery that involves no X-ray exposure. Barriers to the development of the system were overcome using an ultrasonic instrument and fuzzy logic techniques. We located distal transverse screw holes in an intramedullary nail during surgery for femur fracture. The screw hole positions are identified by calculating two fuzzy degrees of intensity and the variance. Results allow this system to identify the screw hole positions within an error of 1.43 mm, an error ratio adequate for clinical surgical practice.

Fuzzy Ultrasonic Testing System with Columnar Rod

This paper describes an ultrasonic testing system with a columnar rod. The general ultrasonic probe is affected by transmission pulse for measurement using the direct contact method. However, if we use a columnar rod between an ultrasonic probe and a target object, we can measure without the transmission pulse. This paper describes the measurement system of the object thickness by the rod and fuzzy logic. The evaluation method consists of three stages. First, the surface echo position is determined from the acquisition ultrasonic wave. Second, the bottom echo position is decided by using fuzzy inference. Finally, the object thickness is calculated from the surface position and the bottom position. We applied our method to ten materials with different thickness. As the result, our method was able to evaluate the thickness of all materials within the error rate of 6.0%

Automated Gyrus Labeling Using Knowledge-based Fuzzy Inference Systems

Automated labeling of the cerebral gyri on the cerebral surface is a fundamental work for estimating the regional atrophy of the cerebrum. Estimating regional brain atrophy will help us to diagnose the cerebral diseases. This article proposes a fully automated method for labeling the cerebral gyri using 3D human brain magnetic resonance (MR) images. The proposed method is composed of two steps; (1) initializing a surface model, and (2) deforming the surface model. They are based on fuzzy pattern matching and fuzzy inference systems based on anatomical knowledge. This article also introduces a knowledge extraction system for constructing the systems. Comparison between the automatically labeled gyri and the manually labeled gyri showed that the automatically labeled gyri overlap with the manually labeled gyri well.

Arbitrary viewpoint image generation method of unknown objects in known environment using a single camera

In this paper, we propose a method to generate arbitrary viewpoint images of unknown objects using a single camera set in a known environment. In recent years, various methods for generating arbitrary viewpoint images have been proposed. These methods often use multiple cameras. When we can generate the arbitrary viewpoint images using only a single camera, we can apply the technique to more various fields. Therefore, we propose the arbitrary viewpoint image generation method by using a single camera and the information of the known environment (size of a room, and the relation between the room and the camera). We set the camera at the rectangular parallelepipeds room and unknown objects on the floor. We generate the arbitrary viewpoint images using the estimated three-dimensional (3D) information of the unknown objects and the known environment information. In the experimental results, we show that the proposed method can estimate the 3D information of the unknown objects and generate the arbitrary viewpoint images.

Fuzzy ultrasonic imaging system for visualizing brain surface under skull considering ultrasonic refraction

We propose an imaging system of brain surface and skull by considering the ultrasonic refraction of the skull. We do an experiment by using a cow scapula to imitate the skull bone and a biological phantom to imitate cerebral sulcus. We first visualize the shape of skull. We second calculate the thickness of the skull aided by fuzzy logic. Finally, we calculate the refractive angle of ultrasonic wave and visualize the image referring to the refraction of ultrasonic wave. In the result of applying this method, we can successfully visualize the phantom surface image.

Self-Location Estimation of a Moving Camera Using the Map of Feature Points and Edges of Environment

Applications as visual navigation of mobile robot with image sensor and mixed/augmented reality have been investigated actively. Many of these techniques require the localization of human or robot. In this report, we propose a novel method for estimating the position of a camera by using edge and feature point information in time-series of images. The technique can be applied to the indoor environment and the environment spatial model including feature points is obtained by tracking background feature points with the position of camera. The prediction model image is generated based on trajectory of the moving camera from the spatial model and the camera position is estimated by correction of model image from comparison with the input image.