KEYWORDS: Polarization, 3D image processing, Polarizers, Inspection, Digital cameras, Image processing, Target detection, Metals, Digital imaging, 3D displays
We propose an effective technique for optically detecting images of the inner hole-surface of a hole (hereafter, referred to as the hole-surface) using the polarization property of a 3D television (TV) monitor. The polarized light emitted by the TV monitor illuminates the hole-surfaces present in the test target placed on the screen of the monitor. When the polarizer placed in front of a camera lens is adjusted such that the camera captures a dark image for the transmitted light, only the highlighted hole-surfaces are visible in the captured image.
A two-step color demosaicing algorithm for Bayer-pattern mosaic images is presented. Missing primary colors are at first estimated by an asymmetric average interpolation, and then sharpness of the initial estimate is improved by an iterative procedure. The intensity variation along an edge is not always uniform along one direction and its opposite with respect to a target pixel to be interpolated. Spatially asymmetric averaging along an edge is hence introduced in this study, where less intensity variation is assumed to be of stronger significance in the sense of stable restoration for details. Also, we restrict ourselves to use short-kernel filters for sharpness recovery. Spatially-adaptive filtering is involved with color demosaicing and an optical system for image acquisition and color filter array (CFA) sampling are subjected to the spatio-temporal aperture effect. Hence it is unavoidable to produce a blurred restoration to some extent. In order to overcome these difficulties and to restore a sharp image, an iterative procedure is introduced. Experimental results have shown a favorable performance in terms of objective measures such as PSNR and CIELAB color difference and subjective visual appearances, especially in sharpness recovery.
There are growing needs for quick preview of video contents for the purpose of improving accessibility of video archives as well as reducing network traffics. In this paper, a storyboard that contains a user-specified number of keyframes is produced from a given video sequence. It is based on hierarchical cluster analysis of feature vectors that are derived from wavelet coefficients of video frames. Consistent use of extracted feature vectors is the key to avoid a repetition of computationally-intensive parsing of the same video sequence. Experimental results suggest that a significant reduction in computational time is gained by this strategy.
In this work, hierarchical motion compensated three-dimensional (3-D) filter banks for spatio-temporal multi-resoution analysis are presented as new tools for scalable video format control. For recent developments in scalable video coding, most of them are based on 3-D wavelet transform with motion compensation. To achieve the function of frame-rate and spatial resolution scalabilities, motion compensated temporal filtering (MCTF) through lifting wavelet transform currently attracts many researchers as an effective temporal decomposition tool. As previous works, we proposed single stage deinterlacer banks as novel 3-D filter banks. Unlike other filter banks, our proposed system is constructed in a way unique to multi-dimensional systems by using invertible deinterlacers, which we have proposed before. The single stage deinterlacer banks decompose a progressive video into two subband sequences of a half frame-rate in the progressive scanning manner. Even though the system handles interlaced videos as intermediate data, introducing a multistage decomposition is simply achieved because the output sequences have also the progressive format as like the input. Our proposed hierarchical deinterlacer banks are accompanied by 2-D discrete wavelet transforms (DWT) as spatial transforms. The multistage technique provides interlaced sequences as well as several reduced-rate progressive sequences while maintaining the reconstruction of the original full-resolution full-rate video sequence. We show that fine granular control of spatio-temporal resolution can be acchieved through the hierarchical process. Some experimental results show novel functions and the significance of the proposed filter banks.
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