Abstract  The  principle  objective  of  image  enhancement  is  to  process  an  image  so  that  the  result  is  more  suitable  than  the  original  image  for  a  specific  application.  This  pap er  presents  a  novel  hybrid  method  for  enhancing  dig ital  X-Ray  radiograph  images  by  seeking  optimal  spatial  and  frequency  dom ain  image  enhancement  combinations.  The  selected  me thods  from  the  spatial  domain  include: negative  transform,  histogr am  equalization  and  power-law  transform.  Selected  e nhancement  methods  from  the  frequency  domain  include:  gaussian  low  and   high  pass  filters  and  butterworth  low  and  high  pass  filters.  Over  80  possible combinations have been tested, where some  of the combinations have yielded in an optimal enhancement compared to  the  original  image,  according  to  radiologist  subjec tive  assessments.  Medically,  the  proposed  methods  h ave  clarified  the  vascular  impression  in  hilar  regions  in  regular  X-r ay  images.  This  can  help  radiologists  in  diagnosing   vascular  pathology,  such  as  pulmonary  embolism  in  case  of  thrombus  that   has  been  logged  in  pulmonary  trunk,  which  will  appear  as  a  filling  defect. The proposed method resulted in more detail ed images hence, giving radiologists additional information about thoracic  cage details including clavicles, ribs, and costoch ondral junction.   

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[24] Zwirn G. and Akselrod S., A Histogram-Based Technique for Echocardiographic Image Enhancement, IEEE Journal of Computers in Cardiology , vol. 31, pp. 81-84, 2004. Yusuf Abu Sa'dah received his BSc degree in applied computer science from Philadelphia University, Jordan in 2004. In 2010, he obtained his master degree in computer science from Al-Balq'a Applied Univeristy, Jordan. Currently, he is working as a senior systems programmer in the IT Department of the Free Zones Corporation, Jordan. His research interests include digital image processing and algorithms. Nijad Al-Najdawi received his BSc degree in computer science from Mu tah University, Jordan in 1999. He obtained his MSc degree in multimedia and internet computing in 2003 and a PhD degree in machine vision and autonomous systems in 2006, from Loughborough University, UK. After which he joined Loughborough University as a research Associate (Post-Doc position) in the Electronic and Electrical Engineering Department. Currently, he is appointed as an assistant professo r at Al-Balqa Applied University, Jordan. His research interests include: image processing, video coding, objects tracking and recognition. Exploiting Hybrid Methods for Enhancing Digital X-Ray Images 35 Sara Tedmori received her BSc degree in computer science from the American University of Beirut, Lebanon. In 2003, she obtained her MSc degree in multimedia and internet computing from Loughborough University. In 2008, she received her engineering doctorate in computer science from Loughborough University, UK. Currently, she is appointed as an assistant profess or in the Computer Science Department at Princess Sumaya University of Technology, Jordan. Her research interests include: object tracking, image processin g, expertise locator, knowledge extraction, knowledge sharing, and privacy.