Jungjin Lee

Rich360: optimized spherical representation from structured panoramic camera arrays

This paper presents Rich360, a novel system for creating and viewing a 360° panoramic video obtained from multiple cameras placed on a structured rig. Rich360 provides an as-rich-as-possible 360° viewing experience by effectively resolving two issues that occur in the existing pipeline. First, a deformable spherical projection surface is utilized to minimize the parallax from multiple cameras. The surface is deformed spatio-temporally according to the depth constraints estimated from the overlapping video regions. This enables fast and efficient parallax-free stitching independent of the number of views. Next, a non-uniform spherical ray sampling is performed. The density of the sampling varies depending on the importance of the image region. Finally, for interactive viewing, the non-uniformly sampled video is mapped onto a uniform viewing sphere using a UV map. This approach can preserve the richness of the input videos when the resolution of the final 360° panoramic video is smaller than the overall resolution of the input videos, which is the case for most 360° panoramic videos. We show various results from Rich360 to demonstrate the richness of the output video and the advancement in the stitching results.

Video Panorama for 2D to 3D Conversion

Accurate depth estimation is a challenging, yet essential step in the conversion of a 2D image sequence to a 3D stereo sequence. We present a novel approach to construct a temporally coherent depth map for each image in a sequence. The quality of the estimated depth is high enough for the purpose of2D to 3D stereo conversion. Our approach first combines the video sequence into a panoramic image. A user can scribble on this single panoramic image to specify depth information. The depth is then propagated to the remainder of the panoramic image. This depth map is then remapped to the original sequence and used as the initial guess for each individual depth map in the sequence. Our approach greatly simplifies the required user interaction during the assignment of the depth and allows for relatively free camera movement during the generation of a panoramic image. We demonstrate the effectiveness of our method by showing stereo converted sequences with various camera motions.

High-Quality Depth Estimation Using an Exemplar 3D Model for Stereo Conversion

High-quality depth painting for each object in a scene is a challenging task in 2D to 3D stereo conversion. One way to accurately estimate the varying depth within the object in an image is to utilize existing 3D models. Automatic pose estimation approaches based on 2D-3D feature correspondences have been proposed to obtain depth from a given 3D model. However, when the 3D model is not identical to the target object, previous methods often produce erroneous depth in the vicinity of the silhouette of the object. This paper introduces a novel 3D model-based depth estimation method that effectively produces high-quality depth information for rigid objects in a stereo conversion workflow. Given an exemplar 3D model and user correspondences, our method generates detailed depth of an object by optimizing the initial depth obtained by the application of structural fitting and silhouette matching in the image domain. The final depth is accurate up to the given 3D model, while consistent with the image. Our method was applied to various image sequences containing objects with different appearances and varying poses. The experiments show that our method can generate plausible depth information that can be utilized for high-quality 2D to 3D stereo conversion.High-quality depth painting for each object in a scene is a challenging task in 2D to 3D stereo conversion. One way to accurately estimate the varying depth within the object in an image is to utilize existing 3D models. Automatic pose estimation approaches based on 2D-3D feature correspondences have been proposed to obtain depth from a given 3D model. However, when the 3D model is not identical to the target object, previous methods often produce erroneous depth in the vicinity of the silhouette of the object. This paper introduces a novel 3D model-based depth estimation method that effectively produces high-quality depth information for rigid objects in a stereo conversion workflow. Given an exemplar 3D model and user correspondences, our method generates detailed depth of an object by optimizing the initial depth obtained by the application of structural fitting and silhouette matching in the image domain. The final depth is accurate up to the given 3D model, while consistent with the image. Our method was applied to various image sequences containing objects with different appearances and varying poses. The experiments show that our method can generate plausible depth information that can be utilized for high-quality 2D to 3D stereo conversion.

Object Segmentation Ensuring Consistency Across Multi-Viewpoint Images

We present a hybrid approach that segments an object by using both color and depth information obtained from views captured from a low-cost RGBD camera and sparsely-located color cameras. Our system begins with generating dense depth information of each target image by using Structure from Motion and Joint Bilateral Upsampling. We formulate the multi-view object segmentation as the Markov Random Field energy optimization on the graph constructed from the superpixels. To ensure inter-view consistency of the segmentation results between color images that have too few color features, our local mapping method generates dense inter-view geometric correspondences by using the dense depth images. Finally, the pixel-based optimization step refines the boundaries of the results obtained from the superpixel-based binary segmentation. We evaluate the validity of our method under various capture conditions such as numbers of views, rotations, and distances between cameras. We compared our method with the state-of-the-art methods that use the standard multi-view datasets. The comparison verified that the proposed method works very efficiently especially in a sparse wide-baseline capture environment.

ScreenX: Public Immersive Theatres with Uniform Movie Viewing Experiences

This paper introduces ScreenX, which is a novel movie viewing platform that enables ordinary movie theatres to become multi-projection movie theatres. This enables the general public to enjoy immersive viewing experiences. The left and right side walls are used to form surrounding screens. This surrounding display environment delivers a strong sense of immersion in general movie viewing. However, naïve display of the content on the side walls results in the appearance of distorted images according to the location of the viewer. In addition, the different dimensions in width, height, and depth among theatres may lead to different viewing experiences. Therefore, for successful deployment of this novel platform, an approach to providing similar movie viewing experiences across target theatres is presented. The proposed image representation model ensures minimum average distortion of the images displayed on the side walls when viewed from different locations. Furthermore, the proposed model assists with determining the appropriate variation of the content according to the diverse viewing environments of different theatres. The theatre suitability estimation method excludes outlier theatres that have extraordinary dimensions. In addition, the content production guidelines indicate appropriate regions to place scene elements for the side wall, depending on their importance. The experiments demonstrate that the proposed method improves the movie viewing experiences in ScreenX theatres. Finally, ScreenX and the proposed techniques are discussed with regard to various aspects and the research issues that are relevant to this movie viewing platform are summarized.