IMAGE PROCESSING OF CONVENTIONAL X-RAY IMAGES 
Dr. Khalil I. Jassam, 
Researcher, The Institute of Islamic Medicine for Education and Research, Panama City, FL 
and Visiting Professor, Department of Surveying Engineering, University of Maine, Orono, ME 
USA, Commission No: VII 
ABSTRACT: 
The goal of this paper is to outline the procedure of obtaining sharper and more visible images from a 
rejected X-ray. This process will improve X-ray image quality and produce image data that is more 
effectively displayed for a later visual imaging diagnosis. Image processing enhances image contrast 
thus increasing image visibility, helping both physicians and radiologists to make more accurate 
diagnoses and to decrease the need to retake X-rays. This in turn reduces the risk of radiation 
exposure and increases economical benefits by lessening the number of rejected X-rays. Different 
spectral and spatial enhancement techniques were used both in the spatial and frequency domain. The 
obtained X-ray images are sharper, more visible and recognizable, and provide much more 
information. 
Key Words: X-ray Imaging, Image Processing, Medical Imaging. 
INTRODUCTION 
The discovery of X-rays revolutionized the diagnosis 
procedure, and its importance can not be overemphasized. 
Radiographic quality refers to both image visibility and 
recognizability. The visibility of the image is best when its 
density is sufficient, its noise is minimal, and its contrast is 
maximum. It is most recognizable when its geometry is 
maintained, which takes place when sharpness is 
maximized and image distortion and magnification are 
minimized. Several factors affect the image quality, some 
of which are the focal-spot size, milliampere-seconds, 
kilovoltage, field size limitation, patient status, contrast 
media, and film quality. Over the years the optimum 
parameters for a specific examination have been empirically 
determined by a large number of practitioners. 
Tremendous efforts have been invested in upgrading X-ray 
image quality. A variety of techniques were developed, 
which were mainly concerned with hardware improvement, 
but their effects were limited. In the last decade computed 
tomography (CT) was developed. This system represents 
the state of the art in modern X-ray imaging. The CT 
system has major advantages as well as disadvantages. It 
maximizes both image visibility and recognizability, and it 
has a better resolution when compared to the conventional 
X-ray. The main disadvantage of the CT system is that it is 
too expensive to buy and operate, and only major clinics 
can afford it. In addition, it is less safe due to higher 
radiation levels and more expensive to the patiants. For 
these reasons, the need for the conventional X-ray will 
continue for the next decade. 
This paper expands the use of image processing techniques 
to improve the quality of conventional X-ray images 
without hardware modification. The only additional 
hardware needed is a digitizing device and a personal 
computer. 
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BACKGROUND 
X-rays were discovered in 1895 by the German physicist 
Roentgen and were so named because their nature was 
unknown at the time. Unlike ordinary light, these rays are 
invisible, but they travel in straight lines and affect 
photographic film in the same way as light. On the other: 
hand, they were much more penetrating than light and 
could easily pass through the human body, wood and other 
"opaque" objects. We know today that X-rays are 
electromagnetic radiation of exactly the same nature as light 
but of very much shorter wavelength. The unit of 
measurement in the X-ray region is the angstrom (À), equal 
to 10 5cm. X-rays, used in diffraction, have wavelengths 
lying approximately between the range of 0.5 - 2.5 A, 
where the wavelength of visible light is on the order of 
6000 A. X-rays therefore occupy the region between 
gamma and ultraviolet rays in the electromagnetic spectrum 
(figure 1). 
The method employed to produce X-rays is essentially the 
same as that used at the time of its discovery. A beam of 
electrons accelerated by high voltage to a velocity 
approaching the speed of light is rapidly decelerated upon 
colliding with a heavy metal target. In the process of 
slowing down, X-ray photons are emitted; the emitted X- 
ray is then directed to the human body. The number of X- 
rays that interact with the patient depend upon the thickness 
and the composition of the various tissues. Diagnostic X- 
rays interact primarily by the photoelectric and Compton 
processes. Photoelectric interactions are the most 
important for image formation because of the strong 
dependence of the photoelectric effect on the atomic 
composition of the absorber and the absence of long-range 
secondary radiations. Compton interactions are generally 
detrimental in that the likelihood of their occurrence 
depends mainly on tissue density, and the scattered X-rays 
produced in Compton collisions have a high probability of 
escaping from the patient and crossing the image plane.