This paper summarizes and compares techniques for detecting and identifying markers in the context of computer vision. Existing approaches use correlation, digital, or topological methods for marker identification. The comparison points out that all marker processing algorithms, which employ sophisticated digital codes are more robust and reliable. Existing bit representation schemes for these codes and marker designs are compared with each other. We illustrate in this context, why the marker processing algorithm introduced in [11] is the best performer regarding marker occlusion and minimal detectable pattern size. Keywords and phrases Marker identification, computer vision Digital Object Identifier 10.4230/OASIcs.VLUDS.2010.36