ABSTRACT
All image warping algorithms to date are image-independent, namely, relate only to the geometry of the image plane, ignoring the content of the image. We show that taking the image content into account yields elaborate warping schemes which may be used to enhance, sharpen and scale images. Sharpening the image is achieved by "squashing" the pixels in edge areas, and "stretching" the pixels in flat areas. Since image pixels are only moved, not modified, some drawbacks of classical linear filtering methods are avoided. We also lay the mathematical foundation for the use of an image-dependent warping scheme in traditional warping applications, such as distortion minimization.
ABSTRACT
A space-filling curve is a linear traversal of a discrete finite multidimensional space. In order for this traversal to be useful in many applications, the curve should preserve "locality". We quantify "locality" and bound the locality of multidimensional space-filling curves. Classic Hilbert space-filling curves come close to achieving optimal locality.
ABSTRACT
We evaluated the improvement in hemodynamic and left ventricular (LV) function in 15 patients with acute myocardial infarction and cardiogenic shock, who were treated with intraaortic balloon counterpulsation (IABP). They were studied by flow-directed right heart catheterization and nuclear angiography. IABP decreased LV end-diastolic volume from 134 to 114 ml and LV end-systolic volume from 100 to 72 ml. LV stroke volume increased from 34 to 42 ml and cardiac output from 3.0 to 3.6 L/min. Global LV ejection fraction increased from 27.6% to 36.1%, and this was due to improvement in regional ejection fraction in ischemic areas. Pulmonary capillary wedge pressure and pulmonary blood volume decreased. Right ventricular ejection fraction also increased significantly. IABP improved LV function in acute myocardial infarction.
