1. A system, comprising: a projection device; and a computing device including, a first detection module to detect a first feature of a target image in a return image, wherein the return image is to be captured using a pattern slide fabricated according to a pattern image, a first designation module to designate a feature type of the first feature, including assigning a first letter to the first feature, a first association module to associate an index with the first letter, wherein the index is associated with the pattern slide, a horizontal position module to calculate a horizontal position in the pattern slide of the first feature, a vertical position module to calculate a vertical position in the pattern slide of the first feature, and a depth calculation module to calculate a depth of the first feature.