Perimeter Detection

A device comprising:

• a memory storing non-transient program code;
• and
• a processor configured to identify a colour block area, given an image and a user-provided origin point by executing the code to perform the steps of:
• a) scanning for border crossings in the image in a direction from a user-provided origin point;
• b) on finding a border crossing, tracing a path of the border such that the colour block area is on a predetermined side of the traced path;
• c) if the path encloses the origin point and is traced clockwise or counterclockwise according to the predetermined choice of keeping the colour block area to the right or left respectively, determining that the border is the perimeter for the colour block area;
• or if not, continuing to scan for border crossings in said direction;
• and
• d) if the border is determined to be the perimeter of the colour block area, scanning the image in the colour block area so as to detect further border crossings in the image.

A non-transitory computer readable storage medium having stored thereon computer readable instructions that, when executed at a computer system, cause the computer system to perform a method for identifying a colour block area in an image, the method comprising:

• a) scanning for border crossings in the image in a direction from a user-provided origin point;
• b) on finding a border crossing, tracing a path of the border such that the colour block area is on a predetermined side of the traced path;
• c) if the path encloses the origin point and is traced clockwise or counterclockwise according to the predetermined choice of keeping the colour block area to the right or left respectively, determining that the border is the perimeter for the colour block area;
• or if not, continuing to scan for border crossings in said direction;
• and
• d) if the border is determined to be the perimeter of the colour block area, scanning the image in the colour block area so as to detect further border crossings in the image.