DOCSLIB.ORG

Biologically Motivated Modeling and Imitating the Chameleon's Vision

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Biologically Motivated Modeling and Imitating the Chameleon's Vision Biologically Motivated Modeling and Imitating the Chameleon's Vision System Ofir Avni Technion - Computer Science Department - M.Sc. Thesis MSC-2006-27 - 2006 Technion - Computer Science Department - M.Sc. Thesis MSC-2006-27 - 2006 Biologically Motivated Modeling and Imitating the Chameleon's Vision System Research Thesis Submitted in partial fulfillment of the requirements for the degree of Master of Science in Computer Science Ofir Avni Submitted to the Senate of the Technion|Israel Institute of Technology HESHVAN 5767 HAIFA NOVEMBER 2006 Technion - Computer Science Department - M.Sc. Thesis MSC-2006-27 - 2006 Technion - Computer Science Department - M.Sc. Thesis MSC-2006-27 - 2006 The research was done under the supervision of Assoc. Prof. Ehud Rivlin in the department of Computer Science I wish to thank my advisor, Assoc. Prof. Ehud Rivlin, for his guidance and support through my long research. I would also like to thank Prof. Gadi Katzir from the department of Biology in the university of Haifa, for his guidance in the biological aspects of this research. The support and guidance of Dr. Hector Rotstein and Dr. Francesco Borrelli on issues regarding control theory was also very valuable. I would also like to thank Shay Ohayon, which provided help on pose estimation, and the source code for his tracking system, which served as a basis for mine. The generous financial help of the Technion is gratefully acknowledged. Technion - Computer Science Department - M.Sc. Thesis MSC-2006-27 - 2006 Technion - Computer Science Department - M.Sc. Thesis MSC-2006-27 - 2006 Contents Abstract 1 1 Introduction 3 1.1 Biologically Motivated Approach . 3 1.2 Tracking the Eyes of the Chameleon . 4 1.3 The Chameleon as a Model . 4 1.4 Thesis Outline . 8 2 The Visual System of the Chameleon 11 3 Related Work 15 3.1 3D Pose Estimation . 15 3.2 Environment Visual Scanning . 18 3.3 Active Target Tracking . 20 4 Tracking the Eyes of the Chameleon 23 4.1 Tracking the Chameleon Head . 23 4.2 Tracking the Eyes . 34 4.3 Calibration of Multiple Cameras and Mirrors . 38 4.4 Experiments . 44 Technion - Computer Science Department - M.Sc. Thesis MSC-2006-27 - 2006 5 Scanning the Environment 47 6 Low Level Control - Smooth Pursuit and Saccade 53 6.1 Active Vision Model . 53 6.2 Smooth Pursuit Control . 56 6.3 Saccade Controller . 57 6.4 Switching between Smooth Pursuit and Saccade . 60 7 Simulations and Experiments 61 7.1 System Architecture . 61 7.2 Scanning Method Simulations . 62 7.3 Smooth Pursuit and Saccade Controllers: Experimental Validation . 66 8 Conclusions 69 References 75 Hebrew Abstract ix Technion - Computer Science Department - M.Sc. Thesis MSC-2006-27 - 2006 List of Figures 1.1 The robotic head and a chameleon head . 6 1.2 System architecture . 7 2.1 A map of the ganglion cells in the chameleon eye . 12 2.2 Comparison of Chameleon Eye with a Typical Lizard Eye . 13 2.3 Focus/De-focus Movements of the Chameleon Eyes . 14 4.1 Body, world and camera coordinates systems . 24 4.2 A chameleon with the artificial features attached to it . 31 4.3 The parameters of the appearance of a feature . 32 4.4 Pattern of a feature . 33 4.5 Eye Model . 34 4.6 Finding the direction of the eye by line-sphere intersection . 36 4.7 Difference image reveals the location of the eyelid . 37 4.8 Mirror as a virtual camera . 40 4.9 Experiments setup . 45 4.10 Results of tracking the eyes . 46 6.1 Pan-tilt model and coordinate systems . 54 6.2 System model . 56 6.3 Smooth Pursuit min-max MPC Controller . 58 Technion - Computer Science Department - M.Sc. Thesis MSC-2006-27 - 2006 6.4 Saccade controller for different horizons N . 59 7.1 Simulation setup for the 1D case . 63 7.2 Simulation results for the search method in 1D . 63 7.3 Simulation results for search method using four cameras . 65 7.4 Simulation results for search method in 2D . 65 7.5 Experimental results for tracking sinusoidal signal . 67 7.6 Experimental results for tracking a target with constant acceleration . 67 Technion - Computer Science Department - M.Sc. Thesis MSC-2006-27 - 2006 Abstract This thesis takes the biologically motivated approach with regard to the visual system of the chameleon. The chameleon has a unique visual system, in which the two eyes scan independently the environment. In the first part of this work, a complex and innovative computer vision system, which uses cameras and mirrors, is designed and implemented in order to track the direction of the eyes of chameleons. In this part the problem of pose estimation with multiple cameras and mirrors is formulated and solved. The problem is formulated as a minimization problem of the three-dimensional geometric errors given the location of features found in the image and their three-dimensional model. The direction of the eyes is found by founding the eyelid in the image, and based on a geometric model of the eye. Preliminary results from this part, which includes biological experiments, indicates that chameleons scan the environment using a \negative correlation" strategy. That is, when one eye scans forward, the other, with high probability, scans backwards. In the second part, a robotic system based on the chameleon visual system is con- structed. Based on the observation from the first part, a new method for visual scanning with a set of independent pan-tilt cameras is presented. The method combines information about the environment and a model for the motion of the target to perform optimal scan- ning based on stochastic dynamic programming. For the implementation, a model-based control strategy is developed that performs target tracking. A switching control, combining smooth pursuit and saccades, is proposed. Robust and Minimum-time Model Predictive Control (MPC) theory is used for the design of the control law. Finally, simulative and experimental validation of the approach is presented. The scanning algorithm was simulated in matlab, and the resulting scanning pattern has a remarkable resemblance to the scanning behavior of chameleons. The target tracking method was implemented in a real-time system of two cameras mounted on top of pan-tilt heads. Experimental results of tracking a target are presented. 1 Technion - Computer Science Department - M.Sc. Thesis MSC-2006-27 - 2006 Technion - Computer Science Department - M.Sc. Thesis MSC-2006-27 - 2006 Chapter 1 Introduction 1.1 Biologically Motivated Approach In Biologically Motivated Robotics, biologists and scientists are working together to create robotic systems that mimic biological behaviors. The benefits from this kind of work are mutual. Biologists, for instance, can test models for biological behaviors on a real, usually simplified, system. As models are tested on real systems new ideas and corrections to the models may rise, improving the understanding of biological behaviors. Scientists, on the other hand, may get from the biological behaviors new ideas on how to solve engineering problems. These new ideas have the advantage of a \working solution" as they are tested and improved on a daily basis in the course of evolution. In this dissertation, we follow the biologically motivated approach to investigate the visual system of the chameleon, or more specific, eye movements in the chameleon. The chameleon has interesting eye movements since the laterally positioned eyes are able to move independently, each over a wide range. The eyes perform saccadic movements - i.e. large and rapid reorientation of the eye from one direction to the other - thus enabling the chameleon to quickly scan its surrounding. This arrangement of the visual system raises questions like what is the correct way to scan the environment, and how it should be carried out. In this dissertation we will try to answer those questions. This work explores several fields which compose the biologically motivated research. In the first part, the advanced abilities of computer vision are used to conduct biological research. A computer-vision system is designed and implemented to track the eye move- ments of chameleons. Using this system, experiments, which are biological in nature, are 3 Technion - Computer Science Department - M.Sc. Thesis MSC-2006-27 - 2006 4 CHAPTER 1. INTRODUCTION performed. In the second part, based on inputs from the biological experiments, a model that describes the biological behavior is formed. Last, a robotic system is implemented that mimic the biological behavior. 1.2 Tracking the Eyes of the Chameleon Tracking the eyes of a chameleon can be considered as the estimation of the 3D pose of an articulated body, where the head of the chameleon is considered as a rigid body, and each of the two eyes has additional two degrees of freedom. There are numerous works dealing with estimating pose of articulated body, many of them in the context of tracking the human body. In [Drouin et al., 2003] for example, the authors track and estimate a skeletal model of a human body. The tracked person is dressed with a black outfit, and distinguishable markers are placed on the joints, which enables easier tracking of the joints. In [Nickels and Hutchinson, 2001] the authors present a model-based approach to track articulated bodies, where the kinematic model is known. In our system, the chameleon's head is marked with distinguishable features which help to identify the head's pose. The direction of each eye is found relative to the head. In order to find the direction of the eye, the eyelid is needed to be found. This brings a difficulty since the range of motion of each eye is large, and the eyelid will not always be visible using one camera.
Load more

Recommended publications
  • Reptilian Eyes and Orbital Structures
    REPTILIAN EYES AND ORBITAL STRUCTURES Jeanette Wyneken, PhD Florida Atlantic University, Dept. of Biological Sciences, 777 Glades Road, Boca Raton, FL 33431 USA ABSTRACT The anatomy of the reptilian eye is similar across species, generally, but the eyes of various taxa differ in details. The eyeball is formed of layers and has three chambers. Pupil shape differs among reptilian taxa with behavior. The retina’s photosensitive cells (rods and cones or all- cones) transmit signals to the optic nerve, which is an extension of the brain. Retinal sensitivity is increased by foveae in lizards and tuataras, while turtles and snakes have areas. The lens is soft and is shaped for accommodation by the ciliary muscles (lizards, turtles and crocodilians) or movement (snakes). All reptiles have eyelids, however some lizards have partially fused lids, while other lizards and all snakes have fused clear lids, the spectacle. Ocular glands lubricate the cornea in all species. Movements of the eyes are critical to preventing photoreceptor fatigue and loss of image recognition. INTRODUCTION TO THE REPTILIAN EYE Reptilian eyes are anatomically similar to those of other vertebrates in that the eyeball (= globe) is formed of layers, filled with fluid, and has a lens that focuses light on a retina. The eye is structured as a series of chambers. The anterior chamber is the fluid-filled space inside the eye between the iris and the cornea's innermost surface; the posterior chamber is a small space directly posterior to the iris, anterior to the lens, and bordered by the ciliary body or ciliary muscles. The anterior and posterior chambers are filled with aqueous humour.
    [Show full text]
  • The Diversity and Adaptive Evolution of Visual Photopigments in Reptiles Frontiers in Ecology and Evolution, 7: 352
    http://www.diva-portal.org This is the published version of a paper published in Frontiers in Ecology and Evolution. Citation for the original published paper (version of record): Katti, C., Stacey-Solis, M., Anahí Coronel-Rojas, N., Davies, W I. (2019) The Diversity and Adaptive Evolution of Visual Photopigments in Reptiles Frontiers in Ecology and Evolution, 7: 352 https://doi.org/10.3389/fevo.2019.00352 Access to the published version may require subscription. N.B. When citing this work, cite the original published paper. Permanent link to this version: http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-164181 REVIEW published: 19 September 2019 doi: 10.3389/fevo.2019.00352 The Diversity and Adaptive Evolution of Visual Photopigments in Reptiles Christiana Katti 1*, Micaela Stacey-Solis 1, Nicole Anahí Coronel-Rojas 1 and Wayne Iwan Lee Davies 2,3,4,5,6 1 Escuela de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador, 2 Center for Molecular Medicine, Umeå University, Umeå, Sweden, 3 Oceans Graduate School, University of Western Australia, Crawley, WA, Australia, 4 Oceans Institute, University of Western Australia, Crawley, WA, Australia, 5 School of Biological Sciences, University of Western Australia, Perth, WA, Australia, 6 Center for Ophthalmology and Visual Science, Lions Eye Institute, University of Western Australia, Perth, WA, Australia Reptiles are a highly diverse class that consists of snakes, geckos, iguanid lizards, and chameleons among others. Given their unique phylogenetic position in relation to both birds and mammals, reptiles are interesting animal models with which to decipher the evolution of vertebrate photopigments (opsin protein plus a light-sensitive retinal chromophore) and their contribution to vision.
    [Show full text]
  • Operator's Manual Chameleon Ultra™ and Chameleon Vision™ Diode
    Operator’s Manual Chameleon Ultra™ and Chameleon Vision™ Diode-Pumped Lasers 5100 Patrick Henry Drive Santa Clara, CA 95054 Chameleon Ultra & Chameleon Vision Operator’s Manual This document is copyrighted with all rights reserved. Under the copyright laws, this document may not be copied in whole or in part or reproduced in any other media without the express written permission of Coherent, Inc. Permitted copies must carry the same proprietary and copyright notices as were affixed to the original. This exception does not allow copies to be made for others, whether or not sold, but all the material purchased may be sold, given or loaned to another person. Under the law, copying includes translation into another language. Coherent, the Coherent Logo, Chameleon Ultra, Chameleon Vision, Verdi, PowerTrack, FAP-I and FieldMax are registered trademarks of Coherent, Inc. Every effort has been made to ensure that the data given in this document is accurate. The information, figures, tables, specifications, part numbers and schematics contained herein are subject to change without notice. Coherent makes no warranty or representation, either expressed or implied, with respect to this document. In no event will Coherent be liable for any direct, indirect, special, incidental or consequential damages resulting from any defects in its documentation. Technical Support In the United States: Should you experience any difficulties with your laser or need any technical information, visit our web site www.Coherent.com. Additional support can be obtained by contacting our Technical Support Hotline at 1-800-367-7890 (1-408-764-4557 outside the U.S.) or E-mail ([email protected]).
    [Show full text]
  • The Photopigment Content of the Teleost Pineal Organ
    The Photopigment Content of the Teleost Pineal Organ Stuart Neil Peirson UCL Department of Visual Science, Institute of Ophthalmology, University College London, University of London A thesis submitted to the University of London for the degree of Doctor of Philosophy (PhD) 2000 ProQuest Number: U643536 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest. ProQuest U643536 Published by ProQuest LLC(2016). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code. Microform Edition © ProQuest LLC. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 ABSTRACT Numerous studies have addressed the issue of the photopigment complement of the retinae of different vertebrate species. However, in most non-mammalian vertebrates, extraretinal photoreceptive sites also exist, of which the pineal complex is the most evident. The pineal organ of lower vertebrates contains photoreceptive cells, similar to the cones of the retina, and is thought to play an important role in the temporal organization of the animal, through both a neural output to the brain and the synthesis of the photoperiod-mediating hormone melatonin. The visual system of teleost fishes has been studied extensively, particularly in regard to its adaptations to different photic environments. Although several studies have addressed extraretinal photoreception in teleosts, little is known as to the exact nature of the photopigments found in the teleost pineal organ, in terms of the number of photopigments present, their spectral sensitivity and their relationship to the visual pigments of the retina.
    [Show full text]
  • Operator's Manual Chameleon Ultra™ and Chameleon Vision™ Diode-Pumped Lasers
    Operator’s Manual Chameleon Ultra™ and Chameleon Vision™ Diode-Pumped Lasers 5100 Patrick Henry Drive Santa Clara, CA 95054 Chameleon Ultra & Chameleon Vision Operator’s Manual This document is copyrighted with all rights reserved. Under the copyright laws, this document may not be copied in whole or in part or reproduced in any other media without the express written permission of Coherent, Inc. Permitted copies must carry the same proprietary and copyright notices as were affixed to the original. This exception does not allow copies to be made for others, whether or not sold, but all the material purchased may be sold, given or loaned to another person. Under the law, copying includes translation into another language. Coherent, the Coherent Logo, Chameleon Ultra, Chameleon Vision, Verdi, PowerTrack, FAP-I and FieldMax are registered trademarks of Coherent, Inc. Every effort has been made to ensure that the data given in this document is accurate. The information, figures, tables, specifications, part numbers and schematics contained herein are subject to change without notice. Coherent makes no warranty or representation, either expressed or implied, with respect to this document. In no event will Coherent be liable for any direct, indirect, special, incidental or consequential damages resulting from any defects in its documentation. Technical Support In the United States: Should you experience any difficulties with your laser or need any technical information, visit our web site www.Coherent.com. Additional support can be obtained by contacting our Technical Support Hotline at 1-800-367-7890 (1-408-764-4557 outside the U.S.) or E-mail ([email protected]).
    [Show full text]
  • Composition and Sustainability: Teaching for a Threatened Generation. Refiguring English Studies. INSTITUTION National Council of Teachers of English, Urbana, IL
    DOCUMENT RESUME ED 458 601 CS 217 721 AUTHOR Owens, Derek TITLE Composition and Sustainability: Teaching for a Threatened Generation. Refiguring English Studies. INSTITUTION National Council of Teachers of English, Urbana, IL. ISBN ISBN-0-8141-0037-6 ISSN ISSN-1073-9637 PUB DATE 2001-00-00 NOTE 274p. AVAILABLE FROM National Council of Teachers of English, 1111 W. Kenyon Road, Urbana, IL 61801-1096 (Stock No. 00376-1659; members, $23.95; nonmembers, $33.95) .Tel: 800-369-6283; Web site: http://www.ncte.org. PUB TYPE Guides Non-Classroom (055) Opinion Papers (120) EDRS PRICE MF01/PC11 Plus Postage. DESCRIPTORS Case Studies; *Classroom Techniques; *Curriculum Development; *English Curriculum; Futures (of Society); Higher Education; *Rhetoric; *Teacher Role; *Writing Instruction IDENTIFIERS *Sustainability; Writing Contexts ABSTRACT This book is intended to be a stimulus for educators who want to teach or plan curriculum with the long view in mind. The book states that although sustainability--meeting today's needs without jeopardizing the interests of future generations--has become a dominating force in diverse disciplines, it has yet to play a substantive role in English studies. It argues that, in light of worsening environmental crises and accelerating social injustices, there is a need to use sustainability as a way to structure courses and curricula, and that composition studies, with its inherent cross-disciplinarity and its unique function in students' academic lives, can play a key role in giving sustainability a central place in students' thinking and in the curriculum as a whole. Presenting his own classroom, the book's educator/author draws on student writing to articulate a pedagogy that gives students opportunities to think and write in three zones of inquiry: place, work, and future.
    [Show full text]
  • Selection for Social Signalling Drives the Evolution of Chameleon Colour Change
    PLoS BIOLOGY Selection for Social Signalling Drives the Evolution of Chameleon Colour Change Devi Stuart-Fox1,2*, Adnan Moussalli3,4 1 School of Animal, Plant, and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa, 2 Department of Zoology, The University of Melbourne, Melbourne, Australia, 3 School of Biological and Conservation Sciences, University of KwaZulu Natal, Pietermaritzburg, South Africa, 4 Department of Sciences, Museum Victoria, Melbourne, Australia Rapid colour change is a remarkable natural phenomenon that has evolved in several vertebrate and invertebrate lineages. The two principal explanations for the evolution of this adaptive strategy are (1) natural selection for crypsis (camouflage) against a range of different backgrounds and (2) selection for conspicuous social signals that maximise detectability to conspecifics, yet minimise exposure to predators because they are only briefly displayed. Here we show that evolutionary shifts in capacity for colour change in southern African dwarf chameleons (Bradypodion spp.) are associated with increasingly conspicuous signals used in male contests and courtship. To the chameleon visual system, species showing the most dramatic colour change display social signals that contrast most against the environmental background and amongst adjacent body regions. We found no evidence for the crypsis hypothesis, a finding reinforced by visual models of how both chameleons and their avian predators perceive chameleon colour variation. Instead, our results suggest that selection for conspicuous social signals drives the evolution of colour change in this system, supporting the view that transitory display traits should be under strong selection for signal detectability. Citation: Stuart-Fox D, Moussalli A (2008) Selection for social signalling drives the evolution of chameleon colour change.
    [Show full text]
  • Retinal Photoreceptor Fine Structure in Some Reptiles
    The Egyptian Journal of Hospital Medicine Vol., 17 :167 – 186 Dec.2004 I.S.S.N: 12084 1687 -2002 Retinal Photoreceptor Fine Structure in some reptiles Fairoze Khattab; Fahmy I. Khattab; Nagui Fares and Aman Zaki (Department of Zoology, Faculty of Science, Ain Shams University, Abbassia, Cairo, Egypt.) Abstract The structure of the photoreceptors of four different reptiles: the homed viper Cerastes cerastes (diurnal and nocturnal), the European Chameleo chameleon (diurnal), the gold skink Eumeces schneidrii (diurnal) and the Egyptian gecko, Tarentola annularis (nocturnal) has been investigated by light and electron microscopy. The photoreceptors of diurnal reptiles were mainly of the cone type and those of nocturnal were mainly rods. The ellipsoid region of both double rods in the nocturnals and large single cones in the species having both nocturnals and diurnal activity, consist of several mitochondria arranged in a remarkable radially gradient architecture which accommodates with the specific function of this region as a focusing device helping to condense light onto the outer segments. Moreover the principle cone of double cone and single cone of diurnal reptiles possessed a large oil droplet in the region between the inner segment and outer segment. This droplet is thought to play a role in filtering light and so doing enhanced contrast reduce glare and lessen chromatic aberration. It is worth to mention that the outer segment of rods in nocturnal reptiles approaches a length of approximately four folds the length of the inner segments of the same photoreceptors cells. This character is of a particular interest, since the outer segment is the site of photopigments and the increase in its length magnifies its ability of light and consequently accommodate with the night vision.
    [Show full text]
  • Rod Nuclear Architecture Determines Contrast Transmission of the Retina
    RESEARCH ARTICLE Rod nuclear architecture determines contrast transmission of the retina and behavioral sensitivity in mice Kaushikaram Subramanian1,2,3, Martin Weigert1,2,3, Oliver Borsch4, Heike Petzold1, Alfonso Garcia-Ulloa1, Eugene W Myers1,2,3,5, Marius Ader4, Irina Solovei6, Moritz Kreysing1,2,3* 1Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany; 2Center for Systems Biology Dresden, Dresden, Germany; 3Cluster of Excellence, Physics of Life, Technische Universita¨ t Dresden, Dresden, Germany; 4Center for Regenerative Therapies Dresden, Technische Universita¨ t Dresden, Dresden, Germany; 5Department of Computer Science, Technische Universita¨ t Dresden, Dresden, Germany; 6Biozentrum, Ludwig Maximilians Universita¨ t, Mu¨ nchen, Germany Abstract Rod photoreceptors of nocturnal mammals display a striking inversion of nuclear architecture, which has been proposed as an evolutionary adaptation to dark environments. However, the nature of visual benefits and the underlying mechanisms remains unclear. It is widely assumed that improvements in nocturnal vision would depend on maximization of photon capture at the expense of image detail. Here, we show that retinal optical quality improves 2-fold during terminal development, and that this enhancement is caused by nuclear inversion. We further demonstrate that improved retinal contrast transmission, rather than photon-budget or resolution, enhances scotopic contrast sensitivity by 18–27%, and improves motion detection capabilities up to 10-fold in dim environments.
    [Show full text]
  • Vision in Chameleons—A Model for Non-Mammalian Vertebrates
    Seminars in Cell and Developmental Biology xxx (xxxx) xxx–xxx Contents lists available at ScienceDirect Seminars in Cell & Developmental Biology journal homepage: www.elsevier.com/locate/semcdb Vision in chameleons—A model for non-mammalian vertebrates Hadas Ketter-Katza,b,1, Tidhar Lev-Aric,1, Gadi Katzird,* a Goldschleger Eye Institute, Sheba Medical Center, Tel-Hashomer, 52621, Israel b Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, 69978, Israel c Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30332, USA d Department of Evolutionary and Environmental Biology, University of Haifa, 199 Aba Khoushy Ave., Mount Carmel, Haifa, 3498838, Israel ARTICLE INFO ABSTRACT Keywords: Chameleons (Chamaeleonidae, Reptilia) are known for their extreme sensory and motor adaptations to arboreal Animal model life and insectivoury. They show most distinct sequences of visuo-motor patterns in threat avoidance and in Chameleon predation with prey capture being performed by tongue strikes that are unparalleled in vertebrates. Optical Vision adaptations result in retinal image enlargement and the unique capacity to determine target distance by ac- Visually-guided behaviour commodation cues. Ocular adaptations result in complex eye movements that are context dependent, not in- Eye dependent, as observed in threat avoidance and predation. In predation, evidence from the chameleons’ capacity Lateralisation Binocular independence to track multiple targets support the view that their eyes are under individual controls. Eye movements and body Conjugate movements are lateralised, with lateralisation being a function of many factors at the population, individual, and Threat avoidance specific-situation levels. Chameleons are considered a potentially important model for vision in non-mammalian Predatory strikes vertebrates.
    [Show full text]
  • The Biology of Chameleons
    The Biology of Chameleons 5490036_FM.indd 1 03/10/13 11:57 AM 5490036_FM.indd 2 03/10/13 11:57 AM The Biology of Chameleons Edited by KRYSTAL A. TOLLEY and ANTHONY HERREL UNIVERSITY OF CALIFORNIA PRESS Berkeley Los Angeles London 5490036_FM.indd 3 03/10/13 11:57 AM University of California Press, one of the most distinguished university presses in the United States, enriches lives around the world by advancing scholarship in the humanities, social sciences, and natural sciences. Its activities are supported by the UC Press Foundation and by philanthropic contributions from individuals and institutions. For more information, visit www.ucpress.edu. University of California Press Berkeley and Los Angeles, California University of California Press, Ltd. London, England © 2014 by The Regents of the University of California Library of Congress Cataloging-in-Publication Data The biology of chameleons / edited by Krystal Tolley and Anthony Herrel. pages cm. Includes bibliographical references and index. isbn 978-0-520-27605-5 (cloth : alk. paper) 1. Chameleons. I. Tolley, Krystal. II. Herrel, Anthony. QL666.L23b56 2013 597.95’6—dc23 2013026609 Manufactured in the United States of America 22 21 20 19 18 17 16 15 14 13 10 9 8 7 6 5 4 3 2 1 The paper used in this publication meets the minimum requirements of ansi/niso Z39.48-1992 (r 2002) (Permanence of Paper). 8 Cover illustration: Trioceros johnstoni from the Rwenzori Mountains, Uganda. Photo by Michele Menegon. 5490036_FM.indd 4 03/10/13 11:57 AM CONTENTS Contributors viii Foreword xi 1 Biology of the Chameleons: An Introduction 1 Krystal A.
    [Show full text]
  • Avian Visual Perception: Interocular and Intraocular Transfer and Head
    Avian visual perception: Interocular and intraocular transfer and head-bobbing behaviour in birds A Dissertation submitted for the Degree of “Philosphiae doctoris” (PhD) in Neuroscience at the International Graduate School of Neuroscience (IGSN) of the RUHR-UNIVERSITY BOCHUM by Laura Jiménez Ortega October 2005 Printed with permission of the International Graduate School of Neuroscience of the RUHR-UNIVERSITY BOCHUM First Referee: Prof. Dr. Nikolaus F. Troje Second Referee: Prof. Dr. Onur Güntürkün Third Referee: Prof. Dr. L. Huber (Wien) Date of the oral examination: 30-11-2005 Table of contents 1. GENERAL INTRODUCTION....................................................................................1 1.2 Intraocular and interocular transfer in pigeons ............................................................................................... 2 1.2.1 Intraocular transfer of information ......................................................................................................... 3 1.2.2 Interocular transfer of information.......................................................................................................... 5 1.2.3 Interim summary ....................................................................................................................................... 9 1.3 Visual asymmetries in birds.............................................................................................................................. 10 1.3.1 Right eye/left hemisphere dominances..................................................................................................
    [Show full text]