Adjacent Data Points Research Articles

4729098 System and method employing nonlinear interpolation for the display of surface structures contained within the interior region of a solid body

A method and apparatus for displaying three dimensional surface images includes the utilization of a case table for rapid retrieval of surface approximation information. Eight cubically adjacent data points associated with a given voxel element are compared with a predetermined threshold value or range to generate an eight bit vector. This eight bit vector is employed to rapidly produce vector lists of approximating surfaces. A non-linear interpolation operation is performed so as to more closely approximate the desired surface and to provide more accurate representations of vectors normal to the desired surface. The accurate representation of these normal directions provides means for accurately representing shading information on a display screen. The method and apparatus of the present invention are particularly useful for the display of medical images both from X-ray generated data and from data generated from various other sources including magnetic resonance imaging and positron emission tomography. The present invention provides a means for rapid generation of three dimensional images so as to enable interactive use by medical practitioners.

4710876 System and method for the display of surface structures contained within the interior region of a solid body

A method and apparatus for displaying three dimensional surface images includes the utilization of a case table for rapid retrieval of surface approximation information. Eight cubically adjacent data points associated with a given voxel element are compared with a predetermined threshold value or range to generate an eight bit vector. This eight bit vector is employed to rapidly produce vector lists of approximating surfaces. An interpolation operation is performed so as to more closely approximate the desired surface and to provide more accurate representations of vectors normal to the desired surface. The accurate representation of these normal directions provides means for accurately representing shading information on a display screen. The method and apparatus of the present invention are particularly useful for the display of medical images both, from x-ray generated data and from data generated from various other sources including magnetic resonance imaging and positron emission tomography. The present invention provides a means for rapid generation of three dimensional images so as to enable interactive use by medical practitioners.

High precision deformation measurement by digital phase shifting holographic interferometry

A digital phase shifting technique capable of quantitatively determining the phase of holographic interferometric displacement fringes is presented. This technique uses computer control to take data and calculate surface deformation. The phase value at each detector point can be calculated by taking four successive intensity data frames with the reference phase shifted between each frame. The displacement fringe order number can be assigned by adding or subtracting 2π from a data point until the phase difference between adjacent data points is less than π. Experimental results show that this technique can precisely determine a fraction of a fringe with an accuracy of ±1°.

Software for interpolating and modelling unknown functions

Software has been developed for fitting a stochastic process model to multi-dimensional data. Applications include contouring, cross-section plotting and optimization. The behaviour of the variance and the gradient of the interpolating function in the near neighbourhood of closely adjacent data points has been investigated.

Long-term cerebral effects of small doses of x-irradiation in childhood as manifested in adult visual evoked responses.

In Israel between the years 1949 and 1960, approximately 20,000 children ranging from 1 to 15 years of age were irradiated for eradication of tinea capitis. Radiation to the cerebral hemipheres ranged up to 140 rads. Of those treated, now adults, 44 subjects were elected by stratified sampling for recording and analysis of visual evoked responses (VERs). A control group of 57 subjects similar in age and ethnic origin was chosen. Two occipital leads, a right and a left, were recorded by the international 10-20 system. Fifty responses to diffuse white-flash stimulation were averaged in each case. The first 256 msec (data points) of each VER were reduced to 77 variables by repeated averaging over three adjacent data points; these variables were then analyzed by several statistical methods. The analyses detected significant differences between the VER averages in study subjects compared with controls. These differences may reflect delayed, probably permanent functional damage to the central nervous system caused by small doses of x-radiation (XR) to immature normal human brain. The left hemispheres appeared to be more involved, consistent with the fact that these children received, on the average, more XR to the left side of the brain, as shown in simulated phantom models. This disparity is reflected in a greater degree of difference between the left VERs of the irradiated versus control group. The major differences between the VERs occurred in the first part of the secondary response and suggest possible subcortical involvement. The results strengthen previous evidence of potential hazards of XR in children.

Isotropic four-point interpolation

An efficient algorithm is given for constructing a smooth curve through an arbitrary sequence of data points. The method is local, using only four points at a time; isotropic, giving a result independent of the orientation of the curve relative to the underlying coordinate system; and applicable to curves in an arbitrary number of dimensions. It makes the direction of the curve at each data point that of a circle through that point and the two adjacent data points.