This section is intended to introduce the reader to various aspects of art, which may be related to various aspects of the present disclosure that are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
In spite of the numerous improvements made recently in this technological field, 3D rendering remains as the object of intensive researches, with many issues still unsolved. Acquisition systems of background art are usually composed of 3D camera rigs where the cameras are aligned horizontally (or considered as equivalent through the implementation of mirrors). As a consequence, only the horizontal disparity between the 3D views can be evaluated.
Some algorithms of view interpolation have been developed, especially to adjust the level of 3D. This interpolation is performed exclusively in the horizontal direction, as illustrated by FIG. 1. The input format required to perform this operation must include the horizontal disparity (or depth) of the view. This format can be for instance multi-view+depth: the left and right 3D views, and the disparity map coding the disparity per pixel between these views.
Philips/Dimenco proposed a format named “Layered Depth video—LDV” (cf. FIG. 2). This format includes a video view corresponding to a central camera, a depth map associated to this view, an occlusion layer and its depth map. This format is one of the input format of the Dimenco multi-view monitors. Thanks to this information, the monitor can interpolate peripheral views around the central view. These peripheral views correspond to the views, as they would be acquired by peripheral cameras, horizontally shifted (dotted line cameras in FIG. 2).
Some areas behind the foreground objects are occluded in the central view. These areas will be disoccluded by the peripheral view interpolation. These background areas are reconstructed thanks to the occlusion layer and its depth map. For instance, the view corresponding to the virtual left dotted line camera will be reconstructed with the background information at the left of the horse (FIG. 3).
The position range of the interpolated view (corresponding to a distance of the virtual camera from the central camera) depends on the amount of information in the occlusion layer. The more information available behind the foreground object, the further the interpolated view from the central view can be.
In this example of prior art, since only horizontal information are available, only horizontal view interpolation can be performed. Therefore, the 3D effect can only be satisfactory rendered if the eyes axis is horizontal.
It would hence be desirable to provide a method for 3D rendering, which shows improvements over the background art.