In order to be correctly recognized, images indexed in database must have a minimum size, e.g. for an A4 page size: 1000px height. Beyond a certain size, impact of the image resolution on recognition is zero.
This is why a PNG image of 5000px high and weighing 10MB will not be better recognized than a 2000px image weighing 1MB. We recommend uploading images weighing between 100KB and 1MB so as not to slow down the interface.
This is why we invite you to check the size and origin of the images before submitting them on the platform. Images from prepress or indesign streams are sometimes oversized. Web streams are perfectly suited for use in augmented reality.
Minimalist images will be poorly recognized by the mobile app. We advise you to upload a target image rich in details (varied shapes, angles, texts, etc.) and color contrasts.
Recommendation: 72dpi, RVB, 100KB to 1MB
The target proportion must preferably fit to the mobile screen dimension (i.e. higher than wide) so that mobile camera will capture the overall target during the augmented reality experience. If your image target is larger than high, then camera phone may see only a portion of the target, or users may be tempted to hold off from it to get a wider view; in that case it may be relevant to focus on a specific area of the Print target, and give mobile users clear instructions about what area should be aimed at (see example). You can use the recognition parameters to do that.