Showing papers by "Akihiro Sugimoto published in 2000"

A Linear Algorithm for Computing the Homography from Conics in Correspondence

Abstract: This paper presents a study, based on conic correspondences, on the relationship between two perspective images acquired by an uncalibrated camera. We show that for a pair of corresponding conics, the parameters representing the conics satisfy a linear constraint. To be more specific, the parameters that represent a conic in one image are transformed by a five-dimensional projective transformation to the parameters that represent the corresponding conic in another image. We also show that this transformation is expressed as the symmetric component of the tensor product of the transformation based on point/line correspondences and itself. In addition, we present a linear algorithm for uniquely determining the corresponding point-based transformation from a given conic-based transformation up to a scale factor. Accordingly, conic correspondences enable us to easily handle both points and lines in uncalibrated images of a planar object.

Influence of peripheral vascular occlusive disease on the morbidity and mortality of coronary artery bypass grafting.

Abstract: The impact of peripheral vascular occlusive disease (PVD) on outcome for patients who have undergone coronary artery bypass grafting (CABG) was assessed by comparing preoperative and intraoperative patient characteristics and outcome in 2 groups of patients who underwent CABG (patients with PVD, n=96; patients without PVD, n=593). Patients with PVD were significantly older (69±8.4 vs 63±8.7; p<0.0001), and had a higher incidence of diabetes mellitus (48% vs 32%; p<0.01), hypertension (62% vs 46%; p<0.01), preoperative cerebral infarction (26% vs 12%; p<0.001) and chronic renal dysfunction (11% vs 4.4%; p<0.01) than those without PVD. Postoperative morbidity and mortality were assessed, after those risk factors were adjusted, using multivariate logistic regression analysis. The perioperative myocardial infarction (PMI) rate and in-hospital mortality rate were significantly higher in patients with PVD than in patients without PVD (9.4% vs 3.0%; p=0.0108, 17% vs 2.7%; p=0.0003, respectively). The odds ratio of PMI and in-hospital mortality were 3.4 (95% confidence intervals (CI): 1.3-8.6) and 4.3 (95% CI: 2.0-9.5), respectively. Although the excess mortality rate was mainly the result of cardiac problems, such as low output syndrome or arrhythmia, in most of the cases, PVD, which may frequently prevent the use of the intraaortic balloon pump, also seemed to have a strong relation to postoperative morbidity and mortality.

[Efficacy of axillary-axillary bypass grafting for the subclavian artery disease].

Abstract: Axillary-axillary bypass procedure was performed in 5 patients (3: atherosclerosis, 1: rupture of aortic arch aneurysm, 1: trauma) with the total occlusion of the subclavian artery. All the operations were performed with 6 mm ringed expanded polytetrafluoroethylene under general anesthesia. Though several types of extrathoracic procedures such as carotid-subclavian bypass, subclavian-subclavian bypass and axillary-axillary bypass are introduced, the efficacy of axillary-axillary bypass procedure is greater ease of anatomic exposure with no concern of interfering with the carotid circulation. The type of bypass to be used in a given case will depend on the individual circumstances. We suggest that this procedure is minimally invasive as well as effective for subclavian artery occlusion depending on the case.

Multilinear relationships between the coordinates of corresponding image conics

Abstract: This paper presents a study, based on conic correspondences, on the relationship between multiple images acquired by uncalibrated cameras. Representing image conics as points in the five-dimensional projective space allows one to handle image conics in the same way as image points. We show that the coordinates of corresponding image conics satisfy the multilinear constraints, as shown in the case for points and lines. To be more specific, the coordinates of two corresponding image conics satisfy bilinear constraints. When a third image comes in, the coordinates of three corresponding image conics satisfy trilinear constraints. Moreover, these constraints are naturally extended to the case where more images are available.

Evaluation of right ventricular function by intraoperative transesophageal echocardiography for patients with left ventricular dysfunction

Abstract: We evaluated right and left ventricular function by intraoperative transesophageal echocardiography for the patients with left ventricular dysfunction (left ventricular ejection fraction (LVEF) < or = 40) who underwent isolated coronary artery bypass grafting (CABG). We divided these patients into two groups; group 1 who had difficulty of weaning from cardiopulmonary bypass due to hypotension (n = 8) and group 2 who did not have any difficulty of it (n = 17). Basement characteristics (age, gender, history of myocardial infarction, congestive heart failure, LVEF, severity of the right coronary artery disease) of both groups were not different significantly. Intraoperative characteristics (the number of distal anastomoses, duration of aortic cross-clamp and cardiopulmonary bypass, and bypass to the right coronary artery) were also not different between two groups. However, mean duration of ICU stay and in-hospital mortality were significantly longer and higher in group 1 than group 2. On the other hand, right ventricular systolic function was severely impaired, particularly postoperatively, in group 1 compared with group 2. Right and left ventricular systolic function of group 2 was fairly improved postoperatively. These results may indicate that right ventricular dysfunction is a potent predictor of postoperative morbidity and mortality for the patients with left ventricular dysfunction who undergo isolated CABG.