Correction of the effects of acoustic heterogeneity on thermoacoustic tomography using transmission ultrasound tomography

The effects of acoustic heterogeneities on thermoacoustic tomography (TAT) are examined and corrected. One assumption made in the existing reconstruction algorithms for thermoacoustic tomography is that biological tissue is acoustically homogeneous. In medical imaging applications, this assumption can cause blurring and distortion in the reconstructed images. This degradation of image quality can be compensated for by using an approximate distribution of the acoustic speed in the tissue. A method based on transmission ultrasound tomography, which is compatible with our thermoacoustic imaging setup, is developed to correct those effects. Experiments verify the validity of this method. The technique can be used to improve the image quality of thermoacoustic tomography

Associated production of a neutral top-Higgs with a heavy-quark pair in the \gamma\gamma collisions at ILC

We have studied the associated production processes of a neutral top-Higgs in the topcolor assisted technicolor model with a pair of heavy quarks in \gamma\gamma collisions at the International Linear Collider (ILC). We find that the cross section for t\bar{t}h_t in \gamma\gamma collisions is at the level of a few fb with the c.m. energy \sqrt{s}=1000 GeV, which is consistent with the results of the cross section of t\bar{t}H in the standard model and the cross section of t\bar{t}h in the minimal supersymmetric standard modeland the little Higgs models. It should be distinct that hundreds of to thousands of h_t per year can be produced at the ILC, this process of \gamma\gamma \to t\bar{t}h_t is really interesting in testing the standard model and searching the signs of technicolor.Comment: 4 pages, 4 figures, some references are adde

On the detection of systematic errors in terrestrial laser scanning data

Quality descriptions are parts of the key tasks of geodetic data processing. Systematic errors should be detected and avoided in order to insure the high quality standards required by structural monitoring. In this study, the iterative closest point (ICP) method was invested to detect systematic errors in two overlapping data sets. There are three steps to process the systematic errors: firstly, one of the data sets was transformed to a reference system by the introduction of the Gauss–Helmert (GH) model. Secondly, quadratic form estimation and segmentation methods are proposed to guarantee the overlapping data sets. Thirdly, the ICP method was employed for a finer registration and detecting the systematic errors. A case study was casted in which a dam surface in Germany was scanned by terrestrial laser scanning (TLS) technology. The results indicated that with the conjugation of ICP algorithm the accuracy of the data sets was improved approximately by 1.6 mm