Investigative Ophthalmology & Visual Science,33:1263. 1992. [ARVO 1992; Sarasota, FL.]

It has recently been demonstrated that early vision is capable of recovering several properties of the three-dimensional world. We describe a series of visual search experiments showing that such recovery includes a completion process that allows for the interpretation of objects that are partially occluded. Search for easily-detectable line segments is made much more difficult when they can be interpreted as the visible parts of a line that has been occluded by a three-dimensional object. We describe some of the conditions under which this completion process takes place, such as its dependence on orientation, contrast, and spacing. We then show that fragments of three-dimensional objects can be completed in a similar way. These results extend what is known about rapid parallel scene interpretation -- in addition to assigning scene-based properties to image elements, early vision also constructs elements not present in the original image.