Yoshio Yanagihara

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To derive blood flow dynamics from cine-angiograms (CAGs), we have developed an image-processing algorithm to determine a two-dimensional blood flow velocity map projected on CAGs. Each image data of CAG is divided into a set of overlapping blocks, and it is assumed that the contrast medium in each block moves only to its ‘adjacent blocks’ between two(More)
The authors proposed a novel color transfer method based on color gradation which may represent human impression. The method has two steps of color transfer with color gradation mainly to transfer hue values and with the color distribution of gradation mainly to transfer saturation values and lightness values. The experiments of substituting or exchanging(More)
We developed a method for an observation system of time-sequenced images of heart, vessels, and surrounding organs. The observation images are constructed using multi-sliced CT tomogram images by applying texture mapping technology, one of which is namely 3D-pseudo solid image. The generated images could be observed like as a solid modeled image and be(More)
In coronary cineangiography, both X-ray absorption and light scatter in the image intensifier tend to degrade image quality, and so affect the accuracy of densitometric measurement of vessel diameter. To investigate this problem, we compared the accuracy and precision of the densitometric method and the edge detection method in the automated detection of(More)
A new computerized method for analyzing biplane coronary arteriograms was proposed. The method extracted the vessels in an image, detected branching points, and identified vessel segments according to their anatomical names. The method was applied to a pair of orthogonal projection images acquired in the right anterior oblique and left anterior oblique(More)
The observation of movement of diaphragm is one of important methods for diagnosis of lung diseases. So, we have been developing an observation system which generates a movie of pseudo solid images using numerous sagittal and frontal MRI images and the movie on a flat panel monitor. And also the direction of the solid images can be changeable dynamically by(More)
For an observation system assisted for diagnosis of 3-D CT images consisting of time-sequenced multi slice tomograms, the refinement method to obtain the more precise region detection on which noise areas are reduced is proposed. The experimental results show that noise areas are reduced effectively. And also the system model refined by code refactoring is(More)
This study concerns methods of accurately measuring vessel diameters using coronary cineangiograms. Various edge detection filters are compared and a new method for determining the centerline of a vessel is developed. Vessel phantoms of different sizes are used to evaluate the precision and accuracy of an entropy filter, a combined first and second(More)