Patent NZ-590921-A (NZ)
Title: Machine-readable form configuration and system and method for interpreting at least one user mark
Inventor: Pnevmatikakis Aristodemos
IPC: G06K9/20
Filed: 2009-07-29
Abstract: 590921 Disclosed is a system for detecting user marks. The system includes a camera, a processor mechanism in operative communication with the camera and at least one form (700). The form (700) includes thereon at least a first fiducial mark and a second fiducial mark such that the first fiducial mark comprises an outline portion and an interior portion. The outline portion of the first fiducial mark is sufficiently different from the interior portion of the first fiducial mark so as to result in the camera being capable of distinguishing between the outline portion and the interior portion. The second fiducial mark comprises an outline portion and an interior portion such that the outline portion of the second fiducial mark is sufficiently different from the interior portion of the second fiducial mark so as to result in the camera being capable of distinguishing between the outline portion and the interior portion. The form (700) is placed in a field of view of the camera. The camera and processor calculate a scale and orientation of the first fiducial mark based at least in part on the ratio of an area of the outline portion of the first fiducial mark and an interior area of the interior portion of the first fiducial mark and a first distance between the camera and the first fiducial mark. They then calculate a scale and orientation of the second fiducial mark based at least in part on the ratio of an area of the outline portion of the second fiducial mark and an interior area of the interior portion of the second fiducial mark and a second distance between the camera and the second fiducial mark. Finally, they calculate a distance between at least the first fiducial mark and the second fiducial mark with the processor mechanism in operative communication with the camera. This is done based at least in part upon the scale and the orientation of the first fiducial mark, and the scale and the orientation of the second fiducial mark. The processor detects at least a first user marking cell on the form (700) based at least in part upon the calculated distance between the first fiducial mark and the second fiducial mark, wherein the first user marking cell is bounded by at least one first indicium that is visible to the camera. The processor then calculates a displacement vector of the detected first user marking cell versus an ideal planar position of the detected first user marking cell and detects with the at least a second user marking cell on the form (700). The second user marking cell is bounded by at least one second indicium that is visible to the camera, and the second user marking cell is detected based at least in part upon the displacement vector of the detected first user marking cell. The processor determines evidence of at least a first user mark in the detected first user marking cell based at least in part upon a degree of brightness similarity between (a) at least a portion of the electronic image surrounding the at least one first indicium bounding the first user marking cell; and (b) at least a portion of the electronic image included inside the at least one first indicium bounding the first user marking cell. The processor then determines evidence of at least a second user mark in the detected second user marking cell based at least in part upon a degree of brightness similarity between (a) at least a portion of the electronic image surrounding the at least one second indicium bounding the second user marking cell; and (b) at least a portion of the electronic image included inside the at least one second indicium bounding the second user marking cell.