Search

Owing to their large field of view, a catadioptric imaging system is widely used in several research areas, including robot navigation, surveillance, and three‐dimensional (3D) reconstruction. The modelling and calibration of these systems allow the accurate measurement of objects. This paper presents a calibration method for a panoramic 3D reconstruction system based on pattern projection composed of two modules. The first module, which contains a charged coupled device camera and a parabolic mirror allows the acquisition of catadioptric images. The second module is a catadioptric projection system made of a light projector and a parabolic mirror that generates a projected pattern over the target for reconstruction purposes. Both the modules are calibrated independently. The method achieves a reprojection error of 0.6 pixels in the camera module and 1.2 pixels in the catadioptric projection system. To evaluate the performance of the proposed method, the results show 3D reconstructions of multiple objects with tolerances around 1.3 mm. [ABSTRACT FROM AUTHOR]

Nonverbal communication is an intrinsic part in daily face-to-face meetings. A frequently observed behavior during social interactions is mirroring, in which one person tends to mimic the attitude of the counterpart. This paper shows that a computer vision system could be used to predict the perception of competence in dyadic interactions through the automatic detection of mirroring events. To prove our hypothesis, we developed: (1) A social assistant for mirroring detection, using a wearable device which includes a video camera and (2) an automatic classifier for the perception of competence, using the number of nodding gestures and mirroring events as predictors. For our study, we used a mixed-method approach in an experimental design where 48 participants acting as customers interacted with a confederated psychologist. We found that the number of nods or mirroring events has a significant influence on the perception of competence. Our results suggest that: (1) Customer mirroring is a better predictor than psychologist mirroring; (2) the number of psychologist's nods is a better predictor than the number of customer's nods; (3) except for the psychologist mirroring, the computer vision algorithm we used worked about equally well whether it was acquiring images from wearable smartglasses or fixed cameras. [ABSTRACT FROM PUBLISHER]

Copyright of Automatika: Journal for Control, Measurement, Electronics, Computing & Communications is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Computing advances and increased smartphone use gives technology system designers greater flexibility in exploiting computer vision to support visually impaired users. Understanding these users' needs will certainly provide insight for the development of improved usability of computing devices. [ABSTRACT FROM PUBLISHER]