C-arm images suffer from pose dependant distortion, which needs to be corrected for intra-operative quantitative 3D surgical guidance. Several distortion correction techniques have been proposed in the literature, the current state of art using a dense grid pattern rigidly attached to the detector. These methods become cumbersome for intra-operative use, such as 3D reconstruction, since the gri...

PURPOSE To implement geometrical and optical distortion correction methods for anterior segment Scheimpflug images obtained with a commercially available system (Pentacam, Oculus Optikgeräte GmbH). METHODS Ray tracing algorithms were implemented to obtain corrected ocular surface geometry from the original images captured by the Pentacam's CCD camera. As details of the optical layout were not...

For a given source distribution, we establish properties of the conditional density achieving the rate distortion function lower bound as the distortion parameter varies. In the limit as the distortion tolerated goes to zero, the conditional density achieving the rate distortion function lower bound becomes degenerate in the sense that the channel it defines becomes error-free. As the permitted...

In this article, we propose a CMOS active balun targeting high linearity up to voltage swing and over wide bandwidth for direct RF sampling applications. All the blocks of are derived using common highly linear building block (HLBB). The HLBB is designed an inverter with strong source degeneration. To increase further, its nonlinearity mechanisms analyzed in detail. A bootstrapping technique in...

0026-2714/$ see front matter 2010 Elsevier Ltd. A doi:10.1016/j.microrel.2010.09.033 ⇑ Corresponding author. Tel.: +91 11 24115580; fax E-mail addresses: [email protected] ( (R.S. Gupta). 1 Tel.: +91 11 24115580; fax: +91 11 24110606. In the work proposed, linearity performance of dual material gate (DMG) AlGaN/GaN HEMT has been analyzed and compared with the corresponding performance o...

BACKGROUND Quantification of myocardial blood flow requires knowledge of the amount of contrast agent in the myocardial tissue and the arterial input function (AIF) driving the delivery of this contrast agent. Accurate quantification is challenged by the lack of linearity between the measured signal and contrast agent concentration. This work characterizes sources of non-linearity and presents ...

Forward error correction (FEC) methods have been developed for packet loss resilience in application layer for real-time video transmission over communication networks. In this paper, an efficient packet loss resilience method is proposed using closed form solution for unequal FEC assignment based on a new packet distortion model. We first derive the packet distortion model by investigating the...

We demonstrate a significant anisotropic magnification distortion, found on an FEI Titan Krios microscope and affecting magnifications commonly used for data acquisition on a Gatan K2 Summit detector. We describe a program (mag_distortion_estimate) to automatically estimate anisotropic magnification distortion from a set of images of a standard gold shadowed diffraction grating. We also describ...

BACKGROUND Image distortion limits application of direct 3-T magnetic resonance imaging for stereotactic functional neurosurgery. OBJECTIVE To test the application of a method to correct and curtail image distortion of 3-T magnetic resonance images. METHODS We used a phantom head model mounted on a platform with the dimensions and features of a stereotactic frame. The phantom was scanned wi...