Method for representing digitized image data

A method for determining and displaying the coordinates of an initial curve passing through a set of initial Cartesian coordinate data points, and for determining the coordinates of at leas tone additional curve equidistant from the initial curve, comprising the steps of:

• (a) generating a two-dimensional field of image data by a non-intrusive cross-sectional image generating device;
• (b) selecting a set of initial data points represented in Cartesian coordinates from the image data;
• (c) converting the initial data points from Cartesian coordinates to polar coordinates such that all of the points lie in the upper quadrants of the polar coordinate system;
• (d) determining a set of cubic spline polynomials describing an initial curve passing through each of the converted initial data points;
• (e) calculating the polar coordinates of intermediate data points between the converted initial data points at a selectable resolution using the determined set of cubic spline polynomials;
• (e) calculating the slope of a perpendicular at selected ones of the calculated intermediate points;
• (g) at each of the selected ones of the calculated intermediate points, determining and storing the coordinates of additional data points a preset distance along a line having the calculated perpendicular slope, the additional data points defining at least one curve equidistant from the initial curve;
• (h) converting the calculated intermediate data points from polar coordinates to Cartesian coordinates;
• (i) displaying at least the converted intermediate data points and the initial data points on a display means as an apparent approximately continuous initial curve passing through the set of initial data points.

A method for selecting and displaying image data corresponding to the intersection of (1) the coordinates of a curve passing through a set of initial Cartesian coordinate data points input by a user, with (2) image data produced in a two-dimensional field by a non-intrusive cross-sectional image generating device, comprising the steps of:

• (a) generating at least one set of image data representing a two-dimensional field generated by a non-intrusive cross-sectional image generating device;
• (b) selecting a set of initial data points represented in Cartesian coordinates from at least one set of the image data;
• (c) converting the initial data points from Cartesian coordinates to polar coordinates such that all of the points lie in the upper quadrants of the polar coordinate system;
• (d) determining a set of cubic spline polynomials describing a curve passing through each of the converted initial data points;
• (e) calculating the polar coordinates of intermediate data points between the converted initial data points at a selectable resolution using the determined set of cubic spline polynomials;
• (f) converting the calculated intermediate data points from polar coordinates to Cartesian coordinates;
• (g) addressing at leas tone of the sets of image data by selected ones of the calculated intermediate data points and initial data points;
• (h) selecting the image data at each such address;
• and
• (i) displaying the selected image data on a display means as an apparent cross-sectional image.

A method for selecting and displaying image data corresponding to the intersection of (1) the coordinates of a curve equidistant to a set of initial Cartesian coordinate data points input by a user, with (2)image data produced in a two-dimensional field by a non-intrusive cross-sectional image generating device, comprising the steps of:

• (a) generating at least one set of image data representing a two-dimensional field generated by a non-intrusive cross-sectional image generating device;
• (b) selecting a set of initial data points represented in Cartesian coordinates from at least one set of the image data;
• (c) converting the initial data points from Cartesian coordinates to polar coordinates such that all of the points lie in the upper quadrants of the polar coordinate system;
• (d) determining a set of cubic spline polynomials describing an initial curve passing through each of the converted initial data points;
• (e) calculating the polar coordinates of intermediate data points between the converted initial data points at a selectable resolution using the determined set of cubic spline polynomials;
• (f) calculating the slope of a perpendicular at selected ones of the calculated intermediate points;
• (g) at each of the selected ones of the calculated intermediate points, determining the coordinates of additional data points a preset distance along a line having the calculated perpendicular slope, the additional data points defining at least one curve equidistant from the initial curve;
• (h) converting the determined additional data points defining at least one such equidistant curve from polar coordinates to Cartesian coordinates;
• (i) addressing at least one of the sets of image data by selected ones of the converted additional data points;
• (j) selecting the image data at each such address;
• and
• (k) displaying the selected image data on a display means as an apparent cross-sectional image.