C-arm cone-beam CT (CBCT) is an emerging tool for intraoperative imaging, but current embodiments exhibit modest soft-tissue imaging capability and are largely constrained to high-contrast imaging tasks. A major advance in image quality is facilitated by statistical iterative reconstruction techniques. This work adapts a general penalized likelihood (PL) reconstruction approach with variable pe...

The reconstruction of dynamic PET data is usually performed using filtered backprojection algorithms (FBP). This method is fast, robust, linear and yields reliable quantitative results. However, the use of FBP for low count data, such as dynamic PET data, generally results in poor visual image quality, exhibiting high noise, disturbing streak artifacts and low contrast. These signal-to-noise ra...

It has been observed that the variances in reconstructed images from stationary noisy projection data by fan-beam filtered backprojection (fFBP) algorithm with ramp in the filtering step and linear interpolation in the backprojection step are nonuniform across the field-of-view. This is believed to be caused by the distance-dependent 1/L2 factor in the fFBP reconstruction formula. Shift-variant...

It is shown that under certain conditions the filtered backprojection algorithm produces a computed tomographic reconstruction for which the statistical accuracy attainable in the amplitude estimation of large-area objects meets the general lower bound derived by Tretiak. In this sense, filtered backprojection is an optimum algorithm.

objective(s): in spect, the sinogram contains scatter and lack of attenuated counts that degrade the reconstructed image quality and quantity. many techniques for attenuation and scatter correction have been proposed. an acceptable method of correction is to incorporate effects into an iterative statistical reconstruction. here, we propose new maximum likelihood expectation maximization (mlem) ...

On reconstructing a volume, the exact reconstruction algorithm for spiral cone-beam CT accesses the memory many times while all the filtered projection data has to be arrived. This is quite a bottleneck for implementation. Normally, the filtered projection data is transferred frame by frame in serial. In this paper, a new backprojection algorithm is proposed. The algorithm uses data inside the ...

When using visual video features in an interactive video index environment, it is necessary to visualize the meaning and impact of features to people that are not image processing experts, such as video librarians. Projection of feature values on the original video data is an important method to visualize the relation between the feature and the video. We describe the characteristics of feature...

Oceanic microseisms are generated by the interaction of opposing ocean waves and subsequent coupling with the seabed, so microseisms should contain information on the ocean conditions that generated them. This leads to the possibility of using seismic records as a proxy for the ocean gravity wavefield. Here we investigate the P-wave component of microseisms, which has previously been linked to ...