This paper presents an improved technique for obtaining depth from focus and a new method for combining the results of stereo and focus to reduce the number of stereo matching errors. Potential sources of error in applying the focusing algorithm are identified by examining the local gray level variance of the image. Some regions are eliminated from further consideration, while in other areas the size, shape and orientation of the windows used in estimating focus quality are selected based on analysis of the local image content. Using this approach, depth values from focus may be obtained in more regions of the image than are obtained using earlier methods. The results of focus may then be incorporated directly into a stereo matching algorithm called LMA. Essentially, focus is used to add support to candidate stereo matches that are consistent with its results. This simple combination technique is shown to resolve the ambiguities of periodic regions in matching and to filter out incorrect matches, especially when a wide range of depth values is possible.

Date Published: 1 March 1990
PDF: 14 pages
Proc. SPIE 1198, Sensor Fusion II: Human and Machine Strategies, (1 March 1990); doi: 10.1117/12.969968

Published in SPIE Proceedings Vol. 1198:
Sensor Fusion II: Human and Machine Strategies
Paul S. Schenker, Editor(s)