What Does the Sky Tell Us about the Camera?
نویسندگان
چکیده
As the main observed illuminant outdoors, the sky is a rich source of information about the scene. However, it is yet to be fully explored in computer vision because its appearance depends on the sun position, weather conditions, photometric and geometric parameters of the camera, and the location of capture. In this paper, we propose the use of a physically-based sky model to analyze the information available within the visible portion of the sky, observed over time. By fitting this model to an image sequence, we show how to extract camera parameters such as the focal length, and the zenith and azimuth angles. In short, the sky serves as a geometric calibration target. Once the camera parameters are recovered, we show how to use the same model in two applications: 1) segmentation of the sky and cloud layers, and 2) data-driven sky matching across different image sequences based on a novel similarity measure defined on sky parameters. This measure, combined with a rich appearance database, allows us to model a wide range of sky conditions.
منابع مشابه
The Natural Rights of Children
What does libertarian theory, Murray Rothbard’s theory in particular, tell us about the rights of children? The two foundational principles of Rothbardian libertarianism are the sanctity of private property and the rule of non-aggression. Persons, including children, are “self-owners”. Yet children, at a young age, are not yet capable of functioning fully as “self-owners.” They must be cared fo...
متن کاملMistaking the Map for the Territory: What Society Does With Medicine; Comment on “Medicalisation and Overdiagnosis: What Society Does to Medicine”
Van Dijk et al describe how society’s influence on medicine drives both medicalisation and overdiagnosis, and allege that a major political and ethical concern regarding our increasingly interpreting the world through a biomedical lens is that it serves to individualise and depoliticize social problems. I argue that for medicalisation to serve this purpose, it would have to exclude the possibil...
متن کاملWhat does the residual income method tell us about housing affordability in Australia?
This bulletin is based on research conducted by Professor Terry Burke and Ms Liss Ralston at the AHURI UNSWUWS Research Centre, and Professor Michael Stone from the University of Massachusetts, USA. The project considered the policy implications of using a different measure for housing affordability— using the residual income rather than the income ratio method. What does the residual income me...
متن کاملImpact? What Three Years of Research Tell Us about Library Instruction
7 I keep returning to a question librarians in my line of work have asked ourselves many times during the course of our careers: " Are we having an impact with library instruction? " We can judge our success by talking to colleagues or hearing anecdotal feedback from our students after any library workshop. But what does the literature tell us? I decided to peruse issues of C&RL published over ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2008