Abstract: The present invention is a siding panel and a method of making the siding panel. The siding panel comprises a planar portion extending the longitudinal length of the siding panel. The planar portion comprises a first edge and a second edge. The width from the first edge to the second edge is at least about 4.0 inches. The planar portion has a surface variance of less than about 0.05 inches relative to an imaginary straight line connecting the first edge and the second edge, and the radius curvature between the first edge and the second edge is at least about 85 inches.

Abstract: The present invention is a vinyl siding panel and a method of making the vinyl siding panel. The vinyl siding panel comprises a planar portion extending the longitudinal length of the vinyl siding panel. The planar portion comprises a first edge and a second edge. The width from the first edge to the second edge is at least about 4.0 inches. The planar portion has a surface variance of less than about 0.05 inches relative to an imaginary straight line connecting the first edge and the second edge, and the radius curvature between the first edge and the second edge is at least about 85 inches.

Abstract: To improve the reliability of the image or to selectively enhance parts of the image produced by way of a tomographic technique such as electrical impedance tomography (EIT), also known as applied potential tomography (APT), the method and apparatus of the invention provides that the electrical signal measurements be made over varying periods of time. The manner of variation can be related to the relative positions of drive and receive electrode pairs or to the output signal size, either as theoretically expected or as actually measured. The invention can be applied to serial or to parallel data collection techniques.

Abstract: In an APT method, the surface-contact electrodes are located in a closed loop or rosette array on one planar, or nominally planar, skin surface of a body to be investigated, and electrically connected to data acquisition and processing equipment. The invention also includes apparatus for carrying out this method, comprising an array of surface-contact electrodes (8), adapted to be applied to the skin of a body to be investigated, the electrodes (8) being arranged on a flexible carrier (10) in a closed loop, or rosette formation on one common plane, or nominal plane.

Abstract: A method of, and apparatus for, real-time imaging are described employing a plurality of contact electrodes (1) located for example around the thorax (2) with simultaneous measurement of potential between adjacent pairs of electrodes (1), digital demodulation of the potentials, and measurement and division of the drive current into the potential measurements before image reconstruction by the use of transputers (20, 22, 24 and 26).

Abstract: A method of determining the external shape of a body comprises placing a plurality of electrodes adjacent the surface at spaced intervals around the body, causing currents to flow in the body by applying an electrical potential between pairs of electrodes in turn, measuring potentials between other pairs of electrodes, relating the measured potentials to the distances between the corresponding points of current introduction and of potential measurement, and determining electrode positions consistent with these distances, which electrode positions define the external shape of the body.

Abstract: Tomographic images (I.sub.1 and I.sub.2) of a body are constructed by placing a plurality of surface electrodes (1 to 16) at spaced intervals on the body (M), causing currents to flow in the body, and measuring the potential between pairs of electrodes, calculating the potential in each case on the assumption that the body consists of one uniform medium, plotting the isopotentials corresponding to the calculated results to create a uniform image of the body, obtaining the ratio between the measured potential and the calculated potential in each case, and modifying the image in accordance with the respective ratios by increasing the impedance along an isopotential in proportion to a ratio greater than unity or decreasing the impedance in proportion to a ratio less than unity. The calculations of potentials and the obtaining of ratios are carried out using a computer and the plotting of the isopotentials is carried out by a visual display unit (VDU) and/or a print-out unit run off the computer.