Wavelet-based resolution enhancement methods improve the image resolution by estimating the high-frequency band information. In this paper, we propose a new resolution enhancement method using inter-subband correlation in which the sampling phase in DWT is considered. Interpolation filters are designed by analyzing correlations between subbands having different sampling phases in the lower level, and applied to the correlated subbands in the higher level. The filters are estimated under the assumption that correlations between two subbands in the higher level are similar to that in the lower level in DWT. The experimental results show that our proposed method outperforms the conventional interpolation methods including the other wavelet-based methods with respect to peak signal-to-noise-ratio (PSNR) as well as the subjective quality.
In brain magnetic resonance (MR) images, image segmentation and 3D visualization are very useful tools for the diagnosis of abnormalities. Segmentation of white matter (WM), gray matter (GM), and cerebrospinal fluid (CSF) is the basic process for 3D visualization of brain MR images. Of the many algorithms, the fuzzy c-means (FCM) technique has been widely used for segmentation of brain MR images. However, the FCM technique does not yield sufficient results under radio frequency (RF) nonuniformity. We propose a hierarchical FCM (HFCM), which provides good segmentation results under RF nonuniformity and does not require any parameter setting. We also generate Talairach templates of the brain that are deformed to 3D brain MR images. Using the deformed templates, only the cerebrum region is extracted from the 3D brain MR images. Then, the proposed HFCM partitions the cerebrum region into WM, GM, and CSF.
A multi‐screen environment provides a new opportunity for digital signage applications, where various irregularly shaped screens are employed as an effective means for advertisements and information. A formation method applicable to numerous irregularly shaped screens is proposed to provide a new perspective on digital signage applications. The crucial part of the proposed method comes from the geometric sensing of each screen and the formation of a virtual screen where geometrically aligned content extraction and encoding are employed for content transmission to each screen. In addition, a software‐based synchronization method for the proposed system is proposed to address the frame‐level synchronization between screens. The experimental results of the proposed method show an improved performance of the frame‐level synchronization, where the inconsistency between frames is not identified.
In the incoming amendment of H.264/AVC for scalable video coding (SVC), down and up-samplings in a spatial domain are incorporated for spatial scalability. A new twofold up-sampling method is proposed for SVC. The proposed up-sampling method is based on a combination of the forward and backward type-II discrete cosine transform (DCT). As the proposed up-sampling kernel has various symmetries for efficient computation, a fast algorithm of type-II DCT-based up-sampling method is also proposed. For further improvement of the up-sampling performance, an adaptive filtering method in the type-II DCT up-sampling is introduced, which applies different weighting parameters to DCT coefficients. Even as this adaptive method is applied, the up-sampling operation in the decoder has the same computational complexity as the fixed weighting method. The proposed adaptive up-sampling method shows a much improved PSNR in comparison with the recent H.264 SVC up-sampling method.
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