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Type: Artigo de periódico
Title: A Method To Synchronise Video Cameras Using The Audio Band.
Author: Leite de Barros, Ricardo Machado
Guedes Russomanno, Tiago
Brenzikofer, René
Jovino Figueroa, Pascual
Abstract: This paper proposes and evaluates a novel method for synchronisation of video cameras using the audio band. The method consists in generating and transmitting an audio signal through radio frequency for receivers connected to the microphone input of the cameras and inserting the signal in the audio band. In a software environment, the phase differences among the video signals are calculated and used to interpolate the synchronous 2D projections of the trajectories. The validation of the method was based on: (1) Analysis of the phase difference changes as a function of time of two video signals. (2) Comparison between the values measured with an oscilloscope and by the proposed method. (3) Estimation of the improvement in the accuracy in the measurements of the distance between two markers mounted on a rigid body during movement applying the method. The results showed that the phase difference changes in time slowly (0.150 ms/min) and linearly, even when the same model of cameras are used. The values measured by the proposed method and by oscilloscope showed equivalence (R2=0.998), the root mean square of the difference between the measurements was 0.10 ms and the maximum difference found was 0.31 ms. Applying the new method, the accuracy of the 3D reconstruction had a statistically significant improvement. The accuracy, simplicity and wide applicability of the proposed method constitute the main contributions of this work.
Subject: Biomechanical Phenomena
Image Interpretation, Computer-assisted
Imaging, Three-dimensional
Information Storage And Retrieval
Signal Processing, Computer-assisted
Video Recording
Citation: Journal Of Biomechanics. v. 39, n. 4, p. 776-80, 2006.
Rights: fechado
Identifier DOI: 10.1016/j.jbiomech.2004.12.025
Date Issue: 2006
Appears in Collections:Unicamp - Artigos e Outros Documentos

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