Rating and advising for selection of augmented reality markers

For an augmented reality (AR) content creation system having a marker database, when a user requests this system to use a first sub-image of an image to update the marker database, this system computes a suitability score of the first sub-image for rating feature richness of the first sub-image and uniqueness thereof against existing markers in the marker database. When the suitability score is less than a threshold value, a second sub-image of the image having a suitability score not less than the threshold value and completely containing the first sub-image is searched. Then the second sub-image, the suitability score thereof and the suitability score of the first sub-image are substantially-immediately presented to the user for real-time suggesting the user to use the second sub-image instead of the first sub-image as a new marker in updating the marker database to increase feature richness or uniqueness of the new marker.