Hiroshi Natori

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In this paper, we propose a hybrid method for tracking a bronchoscope that uses a combination of magnetic sensor tracking and image registration. The position of a magnetic sensor placed in the working channel of the bronchoscope is provided by a magnetic tracking system. Because of respiratory motion, the magnetic sensor provides only the approximate(More)
This paper describes a method for tracking the camera motion of a flexible endoscope, in particular a bronchoscope, using epipolar geometry analysis and intensity-based image registration. The method proposed here does not use a positional sensor attached to the endoscope. Instead, it tracks camera motion using real endoscopic (RE) video images obtained at(More)
We propose a selective method of measurement for computing image similarities based on characteristic structure extraction and demonstrate its application to flexible endoscope navigation, in particular to a bronchoscope navigation system. Camera motion tracking is a fundamental function required for image-guided treatment or therapy systems. In recent(More)
This paper presents new image similarity measure for bronchoscope tracking based on image registration between real and virtual endoscopic images. A function for bronchoscope tracking is one of the fundamental functions in a bronchoscope navigation system. Since it is difficult to attach a positional sensor at the tip of the bronchoscope due to the space(More)
Pulmonary nodules may indicate the early stage of lung cancer, and the progress of lung cancer causes associated changes in the shape and number of pulmonary blood vessels. The automatic segmentation of pulmonary nodules and blood vessels is desirable for chest computer-aided diagnosis (CAD) systems. Since pulmonary nodules and blood vessels are often(More)
BACKGROUND Quantitative assessment of left ventricular ejection fraction (LVEF) is technically difficult in patients with poor image quality (IQ). Mitral annulus velocity assessed by pulsed tissue Doppler imaging (TDI) and mitral annulus motion assessed by M-mode echocardiography has been shown to correlate with LVEF. Furthermore, mitral annulus sites are(More)
This paper presents a method for the automated anatomical labeling of bronchial branches extracted from 3D CT images based on machine learning and combination optimization. We also show applications of anatomical labeling on a bronchoscopy guidance system. This paper performs automated labeling by using machine learning and combination optimization. The(More)
Human erythrocyte pyrimidine 5'-nucleotidase (P5N) was separated into two subclasses. P5N-I and P5N-II, by DEAE Bio-Gel A column chromatography. Their enzymological properties were studied using five normal subjects and five patients with different P5N deficiencies. Study of the normal subjects showed that P5N-I and P5N-II have distinctive properties, and(More)