Optical flow estimation on image sequences with differently exposed frames

Optical flow (OF) methods are used to estimate dense motion information between consecutive frames in image sequences. In addition to the specific OF estimation method itself, the quality of the input image sequence is of crucial importance to the quality of the resulting flow estimates. For instance, lack of texture in image frames caused by saturation of the camera sensor during exposure can significantly deteriorate the performance. An approach to avoid this negative effect is to use different camera settings when capturing the individual frames. We provide a framework for OF estimation on such sequences that contain differently exposed frames. Information from multiple frames are combined into a total cost functional such that the lack of an active data term for saturated image areas is avoided. Experimental results demonstrate that using alternate camera settings to capture the full dynamic range of an underlying scene can clearly improve the quality of flow estimates. When saturation of image data is significant, the proposed methods show superior performance in terms of lower endpoint errors of the flow vectors compared to a set of baseline methods. Furthermore, we provide some qualitative examples of how and when our method should be used

BATUD: Blind Atmospheric TUrbulence Deconvolution

A new blind image deconvolution technique is developed for atmospheric turbulence deblurring. The originality of the proposed approach relies on an actual physical model, known as the Fried kernel, that quantifies the impact of the atmospheric turbulence on the optical resolution of images. While the original expression of the Fried kernel can seem cumbersome at first sight, we show that it can be reparameterized in a much simpler form. This simple expression allows us to efficiently embed this kernel in the proposed Blind Atmospheric TUrbulence Deconvolution (BATUD) algorithm. BATUD is an iterative algorithm that alternately performs deconvolution and estimates the Fried kernel by jointly relying on a Gaussian Mixture Model prior of natural image patches and controlling for the square Euclidean norm of the Fried kernel. Numerical experiments show that our proposed blind deconvolution algorithm behaves well in different simulated turbulence scenarios, as well as on real images. Not only BATUD outperforms state-of-the-art approaches used in atmospheric turbulence deconvolution in terms of image quality metrics, but is also faster

10411 Abstracts Collection -- Computational Video

From 10.10.2010 to 15.10.2010, the Dagstuhl Seminar 10411 ``Computational Video \u27\u27 was held in Schloss Dagstuhl~--~Leibniz Center for Informatics. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available

Schätzung dichter Korrespondenzfelder unter Verwendung mehrerer Bilder

Most optical flow algorithms assume pairs of images that are acquired with an ideal, short exposure time. We present two approaches, that use additional images of a scene to estimate highly accurate, dense correspondence fields. In our first approach we consider video sequences that are acquired with alternating exposure times so that a short-exposure image is followed by a long-exposure image that exhibits motion-blur. With the help of the two enframing short-exposure images, we can decipher not only the motion information encoded in the long-exposure image, but also estimate occlusion timings, which are a basis for artifact-free frame interpolation. In our second approach we consider the data modality of multi-view video sequences, as it commonly occurs, e.g., in stereoscopic video. As several images capture nearly the same data of a scene, this redundancy can be used to establish more robust and consistent correspondence fields than the consideration of two images permits.Die meisten Verfahren zur Schätzung des optischen Flusses verwenden zwei Bilder, die mit einer optimalen, kurzen Belichtungszeit aufgenommen wurden. Wir präsentieren zwei Methoden, die zusätzliche Bilder zur Schätzung von hochgenauen, dichten Korrespondenzfeldern verwenden. Die erste Methode betrachtet Videosequenzen, die mit alternierender Belichtungsdauer aufgenommen werden, so dass auf eine Kurzzeitbelichtung eine Langzeitbelichtung folgt, die Bewegungsunschärfe enthält. Mit der Hilfe von zwei benachbarten Kurzzeitbelichtungen können wir nicht nur die Bewegung schätzen, die in der Bewegungsunschärfe der Langzeitbelichtung verschlüsselt ist, sondern zusätzlich auch Verdeckungszeiten schätzen, die sich bei der Interpolation von Zwischenbildern als große Hilfe erweisen. Die zweite Methode betrachtet Videos, die eine Szene aus mehreren Ansichten aufzeichnen, wie z.B. Stereovideos. Dabei enthalten mehrere Bilder fast dieselbe Information über die Szene. Wir nutzen diese Redundanz aus, um konsistentere und robustere Bewegungsfelder zu bestimmen, als es mit zwei Bildern möglich ist

Dense Corresspondence Estimation for Image Interpolation

We evaluate the current state-of-the-art in dense correspondence estimation for the use in multi-image interpolation algorithms. The evaluation is carried out on three real-world scenes and one synthetic scene, each featuring varying challenges for dense correspondence estimation. The primary focus of our study is on the perceptual quality of the interpolation sequences created from the estimated flow fields. Perceptual plausibility is assessed by means of a psychophysical userstudy. Our results show that current state-of-the-art in dense correspondence estimation does not produce visually plausible interpolations.In diesem Bericht evaluieren wir den gegenwärtigen Stand der Technik in dichter Korrespondenzschätzung hinsichtlich der Eignung für die Nutzung in Algorithmen zur Zwischenbildsynthese. Die Auswertung erfolgt auf drei realen und einer synthetischen Szene mit variierenden Herausforderungen für Algorithmen zur Korrespondenzschätzung. Mittels einer perzeptuellen Benutzerstudie werten wir die wahrgenommene Qualität der interpolierten Bildsequenzen aus. Unsere Ergebnisse zeigen dass der gegenwärtige Stand der Technik in dichter Korrespondezschätzung nicht für die Zwischenbildsynthese geeignet ist

Algorithmen zur Korrespondenzschätzung und Bildinterpolation für die photorealistische Bildsynthese

Free-viewpoint video is a new form of visual medium that has received considerable attention in the last 10 years. Most systems reconstruct the geometry of the scene, thus restricting themselves to synchronized multi-view footage and Lambertian scenes. In this thesis we follow a different approach and describe contributions to a purely image-based end-to-end system operating on sparse, unsynchronized multi-view footage. In particular, we focus on dense correspondence estimation and synthesis of in-between views. In contrast to previous approaches, our correspondence estimation is specifically tailored to the needs of image interpolation; our multi-image interpolation technique advances the state-of-the-art by disposing the conventional blending step. Both algorithms are put to work in an image-based free-viewpoint video system and we demonstrate their applicability to space-time visual effects production as well as to stereoscopic content creation.3D-Video mit Blickpunktnavigation ist eine neues digitales Medium welchem die Forschung in den letzten 10 Jahren viel Aufmerksamkeit gewidmet hat. Die meisten Verfahren rekonstruieren dabei die Szenengeometrie und schränken sich somit auf Lambertsche Szenen und synchron aufgenommene Eingabedaten ein. In dieser Dissertation beschreiben wir Beiträge zu einem rein bild-basierten System welches auf unsynchronisierten Eingabevideos arbeitet. Unser Fokus liegt dabei auf der Schätzung dichter Korrespondenzkarten und auf der Synthese von Zwischenbildern. Im Gegensatz zu bisherigen Verfahren ist unser Ansatz der Korrespondenzschätzung auf die Bedürfnisse der Bilderinterpolation ausgerichtet; unsere Zwischenbildsynthese verzichtet auf das Überblenden der Eingabebilder zu Gunsten der Lösung eines Labelingproblems. Das resultierende System eignet sich sowohl zur Produktion räumlich-zeitlicher Spezialeffekte als auch zur Erzeugung stereoskopischer Videosequenzen

Fiscal year 1973 scientific and technical reports, articles, papers, and presentations

Formal NASA technical reports, papers published in technical journals, and presentations by MSFC personnel in FY73 are presented. Papers of MSFC contractors are also included