Cartesian to polar coordinate transformation

An image-processing system for converting a Cartesian system of discrete data elements to a polar system of discrete data elements comprising:

• an input that receives a source array of discrete data elements indexed by Cartesian coordinates, each Cartesian element having a corresponding data value;
• and
• a processing subsystem comprising a processor and a memory, the processor operating under the control of a program stored in the memory to:
• divide each Cartesian element into subelements, each subelement indexed by its own Cartesian coordinates;
• designate one of the subelements as a polar system origin;
• define a polar system about said origin including an intersecting plurality of radial sector lines and a plurality of confocal arcs formed of said subelements, said sector lines and arcs defining boundaries of polar elements;
• for each subelement within the boundaries of a polar element, determine a subelement data value derived from the data value of the Cartesian element from which the subelement was divided;
• calculate a data value for each polar element based on the data values of the subelements within the boundaries of the polar element;
• and
• store each polar element data value in memory.

A method for converting a pixel image array arranged as a Cartesian system of discrete data elements to an image array arranged as a polar system of discrete data elements, each Cartesian element having a corresponding data value, comprising:

• sensing an image at a sensor comprising an array of pixels;
• storing said image in a memory as an array of discrete data elements indexed by Cartesian coordinates;
• dividing each Cartesian element into subelements;
• designating one of the subelements as a polar system origin;
• defining a polar system about said origin comprising an intersecting plurality of radial sector lines and a plurality of confocal arcs formed of said subelements, said sector lines and arcs defining boundaries of polar elements;
• for each subelement within the boundaries of a polar element, determining a subelement data value derived from the data value of the Cartesian element from which the subelement was divided;
• calculating a data value for each polar element based on the data values of the subelements within the boundaries of the polar element;
• and
• storing the polar element data values in memory.