A pupil function of aperture in image capturing systems is theoretically derived such that one can perfectly reconstruct all-in-focus image through linear filtering of the focal stack. The perfect reconstruction filters are also designed based on the derived pupil function. The designed filters are space-invariant; hence the presented method does not require region segmentation. Simulation results using synthetic scenes shows effectiveness of the derived pupil function and the filters.

Construction of large-scale virtual environment is gaining more attentions for its applications in virtual mall, virtual sightseeing, tele-presence, etc. This paper presents a framework for building a realistic virtual environment from geometry-based approach. We propose an algorithm to construct a realistic 3-D model from multi-view range data and multi-view texture images. The proposed method tries to adopt the result of region segmentation of range images in some phases of the modeling process. It is shown that the relations obtained from region segmentation are quite effective in improving the result of registration as well as mesh merging.

Wireless connections between computers and devices introduce a new problem called device migration, which is the dynamic switching of a connection between a computer and a device. This paper describes a new system called the Network Extended Device Management System (NextD), which enables users to continue using a device even if device migration occurs. NextD's functions are device tracking, remote device access, seamless switching, and providing services over network boundaries. The system supports many device types, including a human interface device (HID) and audio and voice devices over both wireless and wired connections. We have implemented NextD on Linux. Experimental results showed that NextD is capable of supporting HIDs, and audio and voice devices, and that its processing time for a device migration is sufficient enough for actual use.

This paper describes a method of free iris and focus image generation based on transformation integrating multiple differently focused images. First, we assume that objects are defocused by a geometrical blurring model. And we combine acquired images on certain imaging planes and spatial information of objects by using a convolution of a three-dimensional blur. Then, based on spatial frequency analysis of the blur, we design three-dimensional filters that generate free iris and focus images from the acquired images. The method enables us to generate not only an all-in-focus image corresponding to an ideal pin-hole iris but also various images, which would be acquired with virtual irises whose sizes are different from the original one. In order to generate a certain image by using multiple differently focused images, especially very many images, conventional methods usually analyze focused regions of each acquired image independently and construct a depth map. Then, based on the map, the regions are merged into a desired image with some effects. However, generally, it is so difficult to conduct such depth estimation robustly in all regions that these methods cannot prevent merged results from including visible artifacts, which decrease the quality of generated images awfully. In this paper, we propose a method of generating desired images directly and robustly from very many differently focused images without depth estimation. Simulations of image generation are performed utilizing synthetic images to study how certain parameters of the blur and the filter affect the quality of generated images. We also introduce pre-processing that corrects the size of acquired images and a simple method for estimating the parameter of the three-dimensional blur. Finally, we show experimental results of free iris and focus image generation from real images.

Focal stacks (FS) have attracted attention as an alternative representation of light field (LF). However, the problem of reconstructing LF from its FS is considered ill-posed. Although many regularization methods have been discussed, no method has been proposed to solve this problem perfectly. This paper showed that the LF can be perfectly reconstructed from the FS through a filter bank in theory for Lambertian scenes without occlusion if the camera aperture for acquiring the FS is a Cauchy function. The numerical simulation demonstrated that the filter bank allows perfect reconstruction of the LF.