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We investigated the accuracy of estimated synchronization positions for audio digital watermarking using the Modified Patchwork Algorithm (MPA) on analog channels. We focused our efforts on synchronization since correct synchronization of DCT frames is crucial for watermark detection using this algorithm. We employed M-sequence synchronization patterns, and embedded this pattern as synchronization headers with the MPA watermark. The synchronization at the decoder was accomplished by detecting the maximum correlation between the detected sync pattern and the correct sync pattern. This synchronization was shown to be possible with embed frame length (EFL) of 32 samples and above with no perturbations. The accuracy degrades considerably with analog loop back. In addition, with modest levels of additive Gaussian noise and sample rate conversion in addition to analog loop back, robustness was shown for some samples, while for other samples, we were not able to detect synchronization for all trials tested.

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We have been investigating registration methods for improving digital subtraction angiography (DSA) images to extract blood vessels by reducing artifacts due to body motion, such as rotation, contraction, and dilation. In this paper, we propose a new and simple DSA registration algorithm with local distortion vectors to reduce artifacts. According to the results, the proposed method works well for vascular system around the nasal cavity and the orbit of the head and neck DSA images, which cannot be observed clearly by conventional methods. Additionally, we have applied the proposed method to abdominal and leg DSA images.

The risk of X-ray exposure will increase when applying the 3D-CT methods such as MDCT. To decrease this risk it is better to lower the dose-level of X-ray, but it reduces the resolution of obtained image and causes negative effect on imaging diagnosis. We think that 3D-filtering methods will recover the reduction. In order to obtain a better filtered result, 3D linear and non-linear filters are designed and applied to 80%, 60%, 40% and 20%-dose simulated low dose clinical MDCT images of abdomen with a tumor. Direct observation and 3D voxel value profile is extracted to evaluate the filtered results. Experimental results show both the filtering and the evaluating method perform well.