@DTS Engineer Thank you and you're totally right. Now I can get the entity displayed at the image anchor position and it looks great. The issue was caused by a plastic cover. I printed the image on a paper and put it into a transparent plastic cover. I would like to try it outdoor so I thought it would prevent it from dust and water. It turns out that the move actually caused some side-effect to the recognition (maybe it was due to the light reflection on the plastic cover). Once I remove it, image anchor recognition works perfectly.