A pot of gold: Rainbows as a calibration cue

Scott Workman, Radu Paul Mihail, Nathan Jacobs

Research output: Contribution to journalConference articlepeer-review

7 Scopus citations


Rainbows are a natural cue for calibrating outdoor imagery. While ephemeral, they provide unique calibration cues because they are centered exactly opposite the sun and have an outer radius of 42 degrees. In this work, we define the geometry of a rainbow and describe minimal sets of constraints that are sufficient for estimating camera calibration. We present both semi-automatic and fully automatic methods to calibrate a camera using an image of a rainbow. To demonstrate our methods, we have collected a large database of rainbow images and use these to evaluate calibration accuracy and to create an empirical model of rainbow appearance. We show how this model can be used to edit rainbow appearance in natural images and how rainbow geometry, in conjunction with a horizon line and capture time, provides an estimate of camera location. While we focus on rainbows, many of the geometric properties and algorithms we present also apply to other solar-refractive phenomena, such as parhelion, often called sun dogs, and the 22 degree solar halo.

Original languageEnglish
Pages (from-to)820-835
Number of pages16
JournalLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume8693 LNCS
Issue numberPART 5
StatePublished - 2014
Event13th European Conference on Computer Vision, ECCV 2014 - Zurich, Switzerland
Duration: Sep 6 2014Sep 12 2014

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Computer Science (all)


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