Reconstruction algorithms based on Feldkamp methodsIntroductionImage reconstruction from projection data has been the subject of numerous studies. This is an interesting field in general in digital image processing techniques, especially in biomedical imaging. It has been heavily developed and practically implemented in almost all modern tomographic modalities. Diagnostic imaging equipment such as CT scanner, MRI, 3D-4D ultrasound etc. have been widely used in developed countries. All recent 3D medical image reconstruction techniques create 3D images from series of 2D sections, which can be recorded by various equipment such as CT, MRI, ultrasound etc. Each type of scanner has its own characteristics due to the physical principles of image registration, for example CT scanner images are often parallel sections with high contrast, ultrasound scanner images are parallel or divergent sections with low contrast etc. The word tomography itself is composed of the two Greek words tomos (slice) and graphein (to draw). Computed tomography (CT) is a technique for imaging cross-sections of an object using a series of X-ray measurements taken from different angles around the object. Computed tomography (CT) has evolved into an indispensable imaging method in clinical routine. It was the first method to non-invasively acquire images of the interior of the human body that were not affected by the superposition of distinct anatomical structures. This is due to the projection of all information onto a two-dimensional imaging plane, thanks to which CT produces images with much higher contrast than conventional radiography. Interesting technical, anthropomorphic, forensic and archaeological studies have recently been conducted (Thomsen et al. 2003 ) as well as paleontologists...... half of the paper ...... a filter is needed to back-project the projection data which can be given by the formula:Where cos(β) is the weight & g(a) represent the filter kernel.3. The filtered back projection is then given by:Over the years, numerous modifications to the FDK algorithm have been developed to obtain even better results. The term “computed tomography” is historically connected to the development of computers, which have been successfully applied in the field of image reconstruction since the 1960s. A projection represents an average. It would be difficult to interpret the results, since averaging results in a significant reduction in contrast, compared to the contrast present in a slice. Conventional CT produces two-dimensional slices. However, CT becomes a three-dimensional imaging modality if consecutive sections are arranged as axial stacks.