A method for sinogram data interpolation based on a sinusoidal pattern in computed tomography has been developed. Sampled sinograms were acquired based on angular interval scanning of 5<sup>o</sup>, 10<sup>o</sup>, and 20<sup>o</sup>. Then each resulted sinogram was interpolated following sinusoidal pattern to make a complete full scanning sinogram as if they were sampled at 1<sup>o</sup>. After that, a formal summation convolved filtered back projection was applied to each sinogram to yield a crosssectional image. This method was successfully interpolated limited number of projections data to obtained complete sinogram. It works for simple and homogenous object. However, for high variation of physical properties, e.g. linear attenuation coefficient values, this method needs more consideration on interpolation strategies to produce good image.
A quality performance indicator for digital x-ray micro-radiography system has been developed. It was used for nondestructive testing on microstructure object. A set of testing apparatus for image quality indicator (IQI) was developed from acrylic sheets that were cut carefully using laser cutting tool. These IQI apparatus imitated common standard such as step wedges, holes indicator, and lines/wires tester. The IQI step wedge was used to measure the relative x-ray penetration capability. The IQI holes indicator was used to measure the Modulation Transfer Function (MTF) of the imaging system and the IQI lines/wires tester was used for pixel calibration and image spatial resolution determination. From this experience, this simple, low cost, customized, quick made and accurate IQI set fulfilled the performance testing requirement procedure.
An x-ray micro-digital radiography (μ-DR) system has been developed at the Gadjah Mada University Indonesia. The μ- DR system was developed as an add-on unit on an x-ray Diffraction (XRD) system using one extra beam-port as its radiation source. A fluorescence screen encapsulated in a dark tube then coupled by a CCD camera was used as an imaging plate. The radiography objects were some sample clays for earthen or ceramic material of handicraft. The clays differ by particle size, namely: 40 mesh, 60 mesh, 80 mesh, and 100 mesh. The objects were put in front of the imaging plate and then they were exposed by x-ray beam. The image formed on the screen was captured by the CCD camera and then it was converted into digital microradiograph of a size of 720x576. Then, after noise suppression process and normalization procedure, the microradiograph were compared each other by considering particle size. This facility can be used as a non-destructive and testing material studies for examining the quality of earthen or ceramic handicraft.