Abstract.A tomogram is a technical term for a CT image. It is also called a slice because it corresponds to what the object being scanned would look like if it were sliced open along a plane. A CT slice corresponds to a certain thickness of the object being scanned. So, while a typical digital image is composed of pixels, a CT slice image is composed of voxels (volume elements). In the case of x-ray tomography, similar to x-ray Radiography, the quantity being imaged is the distribution of the attenuation coefficient μ(x) within the object of interest. The different is only on the technique to produce the tomogram. The image of x-ray radiography can be produced straight foward after exposed to x-ray, while the image of tomography produces by combination of radiography images in every angle of projection. A number of image reconstruction methods by converting x-ray attenuation data into a tomography image have been produced by researchers. In this work, Ramp filter in "filtered back projection" has been applied. The linear data acquired at each angular orientation are convolved with a specially designed filter and then back projected across a pixel field at the same angle. This paper describe the step of using Image J software to produce image reconstruction of x-ray tomography.

In a conventional single-energy X-ray imaging technique, the information obtained from the examined object are often not sufficient for precise characterization. Hence, this study was designed to assess whether the dual-energy imaging technique would be a good alternative to the conventional method and can be used to improve the output image. An electronic microcontroller was chosen as the sample due to its complex inner structure. It was scanned using the X-ray micro computed tomography (micro-CT) scanner at two different energy levels: 60kVp and 100kVp. Dual-energy image processing method was applied to the acquired image and the results were compared to the single-energy image in term of contrast and image quality. The combined information from dual-energy scan at 60kVp and 100kVp was able to visualize the sample’s internal structure (raised surface). By comparison, the single-energy imaging technique was only capable at producing shadow image. The resolution of the dual-energy image, however, was much lower due to the loss of data….

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Expectation Maximization Algorithm and the Exact Inversion Formula are two mathematical methods that have been developed for various computational applications, such as in medical imaging, nuclear industries, econometric and sociological studies, as well as chemical engineering industries. These image reconstruction methods are usually used to create the SPECT scan images. However, most of the improvement and development of the images are made by using a medical phantom, such as the human brain phantom. Here, in this paper the reconstruction of images by both algorithms are made by using a numerical phantom of laboratory scale bubble columns due to its wide application in the chemical reaction engineering studies. The results for both algorithms are compared, evaluated and discussed.