An accurate comparison of inter-individual 3D image datasets of brains requires warping techniques to reduce geometric variations. In this study we use a point-based method of warping with weighted sums of displacement vectors, which is extended by an optimization process. To improve the practicability of 3D warping, we investigate fast automatic procedures for determining landmarks. The combin...

BACKGROUND Partial volume effects in atrophied areas should be taken into account when interpreting brain perfusion single photon emission computed tomography (SPECT) images of neurodegenerative diseases. To evaluate both perfusion and atrophy using brain SPECT alone, we developed a new technique applying tensor-based morphometry (TBM) to SPECT. METHODS After linear spatial normalization of b...

We have developed a highly e cient, high delity approach for parallel volume rendering that is called permutation warping. Permutation warping may use any one pass lter kernel, an example of which is trilinear reconstruction, an advantage over the shear warp approach. This work discusses experiments in improving permutation warping using data dependent optimizations to make it more competitive ...

The main goal behind coordinate transformation (warping) of a Linear Time Invariant (LTI) system is to represent its signals in terms of new basis functions that better suit the application in hand. Unitary operators simplify the analysis considerably; therefore, they are used to derive the relations between variables in the original and warped domains. These relations show that an LTI system c...

This paper studies the effects of desynchronization attacks such as delay and warping on the performance of watermark detection systems. First, we quantify the connection between attack channel estimation accuracy and detection performance. Second, we show how to design watermarks that minimize probability of error of the detector. Evaluation of the optimal likelihood ratio test is often comput...

Spatially-varying, non-linear image warping has gained growing interest due to the appearance of image domain warping applications such as aspect ratio retargeting or stereo remapping/stereo-to-multiview conversion. In contrast to the more common global image warping, e.g., zoom or rotation, the image transformation is now a spatially-varying mapping that, in principle, enables arbitrary image ...

Conventional Time-Frequency and Time-Scale Representations are often too rigid to capture fine details of sound or musical signals. Adaptation of ideal time-frequency tilings is often desirable in order to represent the signal in terms of components that are meaningful from a physical or perceptual point of view. Remapping of the time and frequency axes by means of time and frequency warping ca...

This paper deals with the problem of non-uniform torsion in thin-walled elastic beams with asymmetric cross-section, removing the basic concept of a fixed center of twist, necessary in the Vlasov’s and Benscoter’s theories to obtain a warping stress field equivalent to zero. In this new torsion/flexure theory, despite of the classical ones, the warping function will punctually satisfy the first...

The accurate comparison of inter-individual 3D image brain datasets requires non-affine transformation techniques (warping) to reduce geometric variations. Constrained by the biological prerequisites we use in this study a landmark-based warping method with weighted sums of displacement vectors, which is enhanced by an optimization process. Furthermore, we investigate fast automatic procedures ...

We have developed a highly e cient, high delity approach for parallel volume rendering that is called permutation warping. Permutation warping may use any one pass lter kernel, an example of which is trilinear reconstruction, an advantage over the shear warp approach. This work discusses experiments in improving permutation warping using data dependent optimizations to make it more competitive ...