{"type":"ScholarlyArticle","title":"Is What You See What You Get?","authors":[{"name":"Anni R. Bruss","slug":"anni-r-bruss","given":"Anni R.","family":"Bruss","affiliation":""}],"abstract":"How much information about the shape of an object can be inferred from its image ? In particular, can the shape of an object b e reconstructed by measuring the light it reflects from points on its surface? These questions were raised by Horn (Ref.1) who formulated a set of conditio ns such that the image formation can be d e scribed in terms of a first order partial differential equation, the imag e irradiance equation. In general, animage irradiance equation has infinitely man y solutions. Thus constraints n e c e ssary to find a unique solution need to be identified. First we study the continuous image irradiance equation. We show how much about the shape of a s urface can be deduced from so called singular points. At these points the surface orientation is uniquely determined by the measured bri g htness. Then we investigate imag e s in which certain types of silhouettes, which we call b-silhouettes, can be det e cted. In particular we answer thefollowing question in the affirmative: Is there a set of constraints which assu r e that if an image irradiance equation has a solution, it is unique? To this end we postulate three constraints upon the image irradiance equation and prove that they are sufficient to uniquely reconstructthe surface from its image. Furthermore it is shown that any two of these constraints are insufficient to assure a unique solution to an image irradianceequation. Examples are given which illustrate the different issues. This work was done while the author was at the Artificial Intelligence Laborator y , Massachusetts Institute of Technology, Cambridge, MA 02139, U.S.A. This resear6h was supported in part by theAdvanced Research Projects Agency of theDepartment of Defense under contractnumber N00014-80-C-0505 and in part by the Office of Naval Research under contractnumber N00014-77-C-0389.","doi":null,"url":"https://ijcai.org/proceedings/1983/244","pdf":"https://ijcai.org/proceedings/1983/0244.pdf","markdown":"https://ijcai.org/proceedings/1983/244.md","bibtex":"https://ijcai.org/proceedings/1983/bibtex/244","volume":{"slug":"1983","title":"Proceedings of the Eighth International Joint Conference on Artificial Intelligence","short_title":"IJCAI 1983","url":"https://ijcai.org/proceedings/1983/","year":1983,"location":"Karlsruhe, West Germany","dates":"","editors":"Alan Bundy","isbn":"","publisher":"International Joint Conferences on Artificial Intelligence","doi_prefix":""},"section":"Vision","track":"Vision","number":244,"pages":{"first":1053,"last":1055},"keywords":[],"videos":[],"references":[],"license_note":"Copyright International Joint Conferences on Artificial Intelligence."}