1. An augmented reality (AR) image processing method comprising: storing in a storage an image data of a CG object corresponding to an AR marker; causing a camera to capture from a first capturing position a first captured image of a first scene which includes the AR marker and surroundings of the AR marker; causing an AR marker recognition based first AR analyzer to obtain the first captured image, carry out an AR marker recognition process to find out an AR marker image from the first captured image and determine a position, posture, and scale of the AR marker image in a first view volume space defined in a first coordinate system of the first AR analyzer corresponding to the first captured image; causing the camera at a second position different from the first position to capture a second captured image of a second scene; causing a natural feature tracking based second AR analyzer to obtain the first captured image and data of the determined position, posture, and scale of the AR marker image in the first view volume space corresponding to the first captured image; causing the second AR analyzer to calculate a position, posture, and scale of the AR marker image in a second view volume space defined in a second coordinate system of the second AR analyzer corresponding to a current position, center axis direction and field of view of the camera, and carry out a natural feature tracking process between the first and the second captured images to determine a position, posture, and scale of the AR marker image in the second view volume space of the second AR analyzer, the second coordinate system being different from the first coordinate system; causing a CG rendering unit to read out the image data of the CG object corresponding to the AR marker from the storage, reproduce an image of the CG object corresponding to the calculated position, posture, and scale in the second view volume space and composite the image of the CG object with the second captured image of the camera; and causing a display unit to display the composite image.