In situ X-ray beam imaging using an off-axis magnifying coded aperture camera system

An imaging model and an image reconstruction algorithm for a transparent X-ray beam imaging and position measuring instrument are presented. The instrument relies on a coded aperture camera to record magnified images of the footprint of the incident beam on a thin foil placed in the beam at an oblique angle. The imaging model represents the instrument as a linear system whose impulse response takes into account the image blur owing to the finite thickness of the foil, the shape and size of camera’s aperture and detector’s point-spread function. The image reconstruction algorithm first removes the image blur using the modelled impulse response function and then corrects for geometrical distortions caused by the foil tilt. The performance of the image reconstruction algorithm was tested in experiments at synchrotron radiation beamlines. The results show that the proposed imaging system produces images of the X-ray beam cross section with a quality comparable with images obtained using X-ray cameras that are exposed to the direct beam

Lossless Compression Methods for Real-Time Images

This paper proposes and implements two lossless methods, to compress real-time greyscale medical images, which are Huffman coding and a new lossless method called Reduced Lossless Compression Method (RLCM), both of which were tested when applying a random sample of greyscale medical images with a size of 256×256 pixels. Different factors were measured to check the compression method performances such as the compression time, the compressed image size, and the compression ratio (CR). The system is fully implemented on a field programmable gate array (FPGA) using a fully hardware based (no software driven processor) system architecture. A Terasic DE4 board was used as the main platform for implementing and testing the system using Quartus-II software and tools for design and debugging. The impact of compressing the image and carrying the compressed data through parallel lines is like the impact of compressed the same image inside a single core with a higher compression ratio, in this system between 7.5 and 126.8

Real-time Transceiver System Based on Rapid-I/O Protocol

With the all transceiver systems the transmission speed is the most critical factor. The main objective of this paper is to design a new reference model for the multi-link system that is used to carry images in a real-time system, with a high resolution at high transceiver speeds, between two applications over physical media. The new system, called Transceiver System based on Rapid-I/O protocol (TRIO), for both transmitter and receiver, based on eight parallel devices was placed at the bottom of the system architecture, at both transmitter and receiver. The transceiver system is designed as scalable system in which the system data rate increased when multiple lines connected in parallel are used to carry data between the transmitter and the receiver instead of using a single line. By transmitting the same packet of data, once over a single transceiver system and then over eight transceiver systems, ideally an eightfold improvement in bit-rate is expected. The TRIO is implemented on a field programmable gate array (FPGA) and a Terasic DE4 board will be used as the main platform for implementing and testing the embedded system, while Quartus-II software and tools are used to design and debug the embedded hardware system

Position and flux stabilization of X-ray beams produced by double-crystal monochromators for EXAFS scans at the titanium K

The simultaneous and active feedback stabilization of X-ray beam position and monochromatic beam flux during EXAFS scans at the titanium K-edge as produced by a double-crystal monochromator beamline is reported. The feedback is generated using two independent feedback loops using separate beam flux and position measurements. The flux is stabilized using a fast extremum-searching algorithm that is insensitive to changes in the synchrotron ring current and energy-dependent monochromator output. Corrections of beam height are made using an innovative transmissive beam position monitor instrument. The efficacy of the feedback stabilization method is demonstrated by comparing the measurements of EXAFS spectra on inhomogeneous diluted Ti-containing samples with and without feedback applied. © 2014 International Union of Crystallography