Détection de différence de mise au point lors des prises de vues stéréoscopiques
OPEN ACCESS
Live-action stereoscopic content production requires a stereo rig with two cameras precisely matched and aligned. While most deviations from this perfect setup can be corrected either live or in post-production, a difference in the focus distance or focus range between the two cameras will lead to unrecoverable degradations of the stereoscopic footage. In this paper we detect focus mismatch between views of a stereoscopic pair in four steps. First, we compute a dense disparity map. Then, we use a measure to compare focus in both images. After this, we use robust statistics to find which images’ zones have a different focus. Finally, to give useful feedback, we show the results on the original images and give hints on how to solve the focus mismatch.
RÉSUMÉ
La production d’images stéréoscopiques nécessite un rig stéréoscopique avec deux caméras parfaitement synchronisées et alignées. La plupart des imprécisions de ce montage peuvent être corrigées en direct ou en post-production. Par contre, une différence de distance de mise au point ou de profondeur de champ entre les caméras produira des dégradations irrécupérables dans les images. Dans cet article nous détectons des différences de mise au point entre les deux vues d’une paire stéréoscopique en quatre étapes. D’abord nous calculons une carte de disparité dense. Ensuite nous mesurons la netteté dans chaque image et nous comparons ces mesures. Puis, avec des méthodes statistiques robustes, nous identifions les zones de l’image qui présentent des différences. Finalement, nous proposons une méthode de visualisation sur les images originales pour informer l’opérateur des problèmes, et lui donner des indices pour les résoudre.
stereoscopic cinema, socus mismatch, depth from focus, depth from defocus
MOTS-CLÉS
cinéma stéréoscopique, flou, netteté, distance de mise au point, depth from focus, depth from defocus
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