Identifying position of marker in environment

A technique is described herein for determining the position of at least one previously-placed physical marker in a physical environment. In one approach, the technique detects the marker at plural vantage points in the environment, to yield plural instances of marker information. The technique then computes the position of the marker based on the plural instances of marker information collected at the plural vantage points. The technique may also provide a movement indicator that assists the user in moving to specified vantage points in the physical environment. The technique may use the identified position(s) of the marker(s) to accurately place virtual objects relative to real-world objects in a modified-reality world. 本文所描述的技术用于确定物理环境中的至少一个先前放置的物理标记的位置。在一种途径中，该技术在环境中的多个有利点处检测标记，以产生标记信息的多个实例。然后，该技术基于在多个有利点处收集的标记信息的多个实例计算标记的位置。该技术还可以提供移动指示器，该移动指示器帮助用户移动到物理环境中的指定有利点。该技术可以使用(一个或多个)标记的(一个或多个)标识的位置，以相对于现实世界对象将虚拟对象准确地放置在修改现实世界中。