Method and system for determining camera parameters from a long range gradient based on alignment differences in non-point image landmarks

A system, comprising:

• an image capturing device configured to generate a camera image;
• a memory arrangement configured to store the camera image, a synthetically generated planar template pattern that is a representation of a sporting field embedded on a surface, a 3D geometry of the surface, and a set of parameter values that models a perspective of the image capturing device;
• and
• a processor configured to warp the planar template pattern into the perspective of the image capturing device based on the set of parameter values to generate a warped template image,
• the processor configured to calculate a long range gradient of the planar template pattern,
• wherein the long range gradient of the planar template pattern is based on a calculation within a gradient window,
• the processor configured to generate an error image based on a comparison between the camera image and the warped template image,
• the processor configured to compute an adjusted set of parameter values to reduce an error associated with the error image, wherein the computing is based on the long range gradient.