Measuring time-to-contact using active camera control

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations


In this paper we use a simple, active-camera model to estimate the time-to-contact (TTC) of a moving object. We estimate TTC by enforcing a "uniform scale" constraint on the moving object. By actively adjusting the focal length of the pinhole model, the projected object maintains a fixed image scale regardless of its motion. These adjustments on the ideal pinhole focal length are translated into changes of the actual zoom and focus settings of a real camera system. We obtain improvements over a fixed-camera approach because the scale adjustment (zoom) improves image divergence measurements. We show experimental results indicating that our active method can reduce errors over a larger distance range than fixed-camera methods of estimating time-to-contact.

Original languageEnglish
Title of host publicationComputer Analysis of Images and Patterns - 6th International Conference, CAIP 1995, Proceedings
EditorsVaclav Hlavac, Radim Sara
Number of pages6
StatePublished - 1995
Event6th International Conference on Computer Analysis of Images and Patterns, CAIP 1995 - Prague, Czech Republic
Duration: Sep 6 1995Sep 8 1995

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference6th International Conference on Computer Analysis of Images and Patterns, CAIP 1995
Country/TerritoryCzech Republic

Bibliographical note

Publisher Copyright:
© Springer-Verlag Berlin Heidelberg 1995.

ASJC Scopus subject areas

  • Theoretical Computer Science
  • General Computer Science


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