Enhancing the mirror image
Engineering Design, Machine Elements, Product Development
Final Report Abstract
Camera-monitor systems (CMS) are being installed in increasing numbers of cars and trucks, but there has been very little research on how they affect the perception of moving traffic. We have conducted such research to answer two questions. (1) When the camera position is not in the virtual eye-point, the image on the monitor differs from the image a rearview mirror would provide. Does the altered image affect our ability to judge approaching vehicles and should certain camera or monitor placements be avoided or recommended for safety reasons? Could it serve to minimize the blind spot? And what is the user acceptance of different camera positions? (2) Moving from an optical mirror to a CMS creates the opportunity to enhance the mirror image and improve on it, which car manufacturers have not (yet) done. For instance, information could be added or removed. The latter might make it easier to spot important information. Our first Work Package (WP1) dealt with question (1). We have investigated the effects of changing horizontal camera positions on the vehicle. The results show that positions at the back minimize the blind spot, but depending on how far back the camera is, important reference information about the own car may disappear from view. Quite surprisingly, although most drivers preferred the standard position of the camera at the place where the mirror used to be, performance was not affected at all by horizontal camera placement. Time-to-collision (TTC) estimates, velocity judgments, and last safe gap assessment remained robust. In contrast, the visibility of the own vehicle as a reference significantly improved perception. These findings rendered WP2 (looking at the interaction of camera position and monitor position changes) somewhat obsolete. The second question (2) was addressed by the experiments of WP3, in which we investigated how reducing the amount of environmental information displayed in the monitor image affects TTC estimation. Even with a significant reduction in visual depth cues, the TTC estimates were as accurate as when the environment was fully displayed. Astonishingly, the estimates did not even deteriorate when all background was removed and observers judged cars that were approaching in the void. This suggests strongly that it is possible to reduce the complexity of the display information without impairing performance. Moreover, when altering the mirror image with the use of input from a would-be acceleration sensor surveying the rearward traffic, we were able to compensate for the ubiquitous errors observers make when confronted with accelerating objects. We achieved this by altering the optical size of an approaching vehicle in the monitor image. These results constitute a proof of concept that it is possible to enhance the mirror image such as to compensate perceptual errors. The results of these experiments have been presented at various conferences and were published in three peer-reviewed papers. A fourth manuscript has been written up and will soon be submitted for publication.
Publications
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Implications of camera-monitor systems for rearward perception in an automotive environment [Talk]. German Summer School for Human Factors, Mainz, Germany
Wögerbauer, E. & Hecht, H.
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Mirror or camera? Acceptance and valuation of camera-monitor systems. Transportation Research Interdisciplinary Perspectives, 13, 100512.
Bernhard, Christoph & Hecht, Heiko
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Camera-monitor systems and rearward perception in automobiles [Poster]. German Summer School for Human Factors, Chemnitz, Germany
Wögerbauer, E.
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Camera–Monitor Systems as An Opportunity to Compensate for Perceptual Errors in Time-to-Contact Estimations. Vision, 7(4), 65.
Wögerbauer, Elisabeth Maria; Hecht, Heiko & Wessels, Marlene
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Kamera-Monitor-Systeme als Möglichkeit zur Kompensation von Wahrnehmungsfehlern bei der Kontaktzeitschätzung [Talk]. Doktorandenworkshop Verkehrspsychologie, Stuttgart, Germany
Wögerbauer, E.
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Less is more: Does information removal in the rear-view mirror improve time-to-contact estimation? [Poster]. Human Factors and Ergonomics Society Europe Chapter Annual Meeting, Liverpool, UK
Wögerbauer, E. & Hecht, H.
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The effect of horizontal camera position on time-to-contact estimation when using a camera-monitor system [Talk]. Tagung experimentell arbeitender Psycholog*innen, Trier, Germany
Wögerbauer, E. & Hecht, H.
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Time-to-contact estimation: Can one perceptual error be cured by another? [Poster]. European Conference on Visual Perception, Paphos, Cyprus
Wögerbauer, E., Wessels, M. & Hecht, H.
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Camera-monitor systems and driver performance: The role of horizontal camera position and the visibility of one’s own vehicle as a reference [Talk]. ADok, Heidelberg, Germany
Wögerbauer, E. & Hecht, H.
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Camera-monitor systems and driver performance: The role of horizontal camera position and the visibility of one’s own vehicle as a reference [Talk]. Doktorandenworkshop Verkehrspsychologie, Ulm, Germany
Wögerbauer, E. & Hecht, H.
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Camera-monitor systems: The effect of horizontal camera displacement on driver’s gap acceptance [Poster]. Human Factors and Ergonomics Society Europe Chapter Annual Meeting, Lübeck, Germany
Wögerbauer, E. & Hecht, H.
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Synthetic Displays and Their Potential for Driver Assistance Systems. Information, 15(4), 177.
Wögerbauer, Elisabeth Maria; Bernhard, Christoph & Hecht, Heiko
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Visual perception through camera-monitor systems. Inauguraldissertation zur Erlangung des akademischen Grades eines Dr. phil., vorgelegt dem Fachbereich 02 – Sozialwissenschaften, Medien und Sport der Johannes Gutenberg-Universität Mainz
Wögerbauer, E.
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Estimating camera position in camera-monitor systems: Effects of horizontal displacement and reference visibility [Poster]. Tagung experimentell arbeitender Psycholog*innen, Frankfurt am Main, Germany
Wögerbauer, E. & Hecht, H.
