Marker, method of detecting position and pose of marker, and computer program

A non-transitory computer-readable medium storing a computer program that causes a computer comprising one or more processors and being capable of communicating with a device including a camera to detect a marker, the computer program causing the computer to realize functions of:

• capturing external scenery with the camera;
• extracting the marker from an image of the captured external scenery, the marker comprising quadrilateral specifying elements that specify a quadrilateral shape;
• identifying, from the extracted marker, first and second identification elements that identify the marker, the first and second identification elements being within the quadrilateral shape, the first identification elements being present in a line of a first diagonal which is one of two diagonals of the specified quadrilateral shape, and the second identification elements being present in a line of a second diagonal which is the other diagonal of the two diagonals than the first diagonal;
• identifying a direction-identification element of the marker that identifies a direction of the extracted marker, the direction-identification element being other than the first and second identification elements, and a center of the direction-identification element overlapping neither of the first and second diagonals;
• and
• first calculating position and pose of the marker with respect to the camera based on the identified direction-identification element of the marker and the plurality of first and second identified identification elements,
• wherein the direction-identification element is located in one of four triangles defined by the quadrilateral specifying elements and an intersection of the first and second diagonals, no other direction-identification element is located on the other three triangles.