Marker Displacement Method Used in Vision-Based Tactile Sensors—From 2-D to 3-D: A Review

The vision-based tactile sensor has been proven to be a promising device for sensing tactile information. Among such sensors, the marker displacement method (MDM) is the most common method used in such sensors for representing and extracting contact information. It uses the position field and displacement field of a marker array to characterize the original tactile information and further achieves multimodal tactile perception through original information processing. This article is the first to classify MDM into three typical categories based on the dimensionality perspective: 2-D MDM, 2.5-D MDM, and 3-D MDM. A comparison study is presented with a focus on the principles, characteristics, applications, and distinctions of these three methods. The latest literature has also been researched as the arguments. Finally, a summary of these three categories is presented as a helpful reference.