Introduction: In order to reduce patient setup error in treatment field, portal images with treatment beam (megavoltage x-ray) are widely used. These images are acquired by electronic portal imaging devices (EPID). However, portal images suffer from insufficient anatomical information, contrast, and spatial resolution, because of the fact that Compton scatter is the main photon...

abstractbackground: delivering the radiation dose to the target volume and minimizing the dose to normal tissues are the main objectives in radiotherapy. the aim of our study is to enhance the contrast of the portal image to increase the accuracy of delineation of the organs in the irradiation field.   methods: the software was written based on local enhancement of the pixel values in image mat...

 ABSTRACTBackground: Delivering the radiation dose to the target volume and minimizing the dose to normal tissues are the main objectives in radiotherapy. The aim of our study is to enhance the contrast of the portal image to increase the accuracy of delineation of the organs in the irradiation field.   Methods: The software was written based on local enhancement of the pixel values in image ma...

This paper presents a new automatic image enhancement method by modifying the gamma value of its individual pixels. Most of existing gamma correction methods apply a uniform gamma value across the image. Considering the fact that gamma variation for a single image is actually nonlinear, the proposed method locally estimates the gamma values in an image using support vector machine. First, a dat...

Image registration is a crucial step in most image processing tasks for which the final result is achieved from a combination of various resources. In general, the majority of registration methods consist of the following four steps: feature extraction, feature matching, transform modeling, and finally image resampling. As the accuracy of a registration process is highly dependent to the fe...

background: mammography is the primary imaging technique for detection and diagnosis of breast cancer; however, the contrast of a mammogram image is often poor, especially for dense and glandular tissues. in these cases the radiologist may miss some diagnostically important microcalcifications. in order to improve diagnosis of cancer correctly, image enhancement technology is often used to enha...

introduction one of the most important pre-processing steps in optical coherence tomography (oct) is reducing speckle noise, resulting from multiple scattering of tissues, which degrades the quality of oct images. materials and methods the present study focused on speckle noise reduction and edge detection techniques. statistical filters with different masks and noise variances were applied on ...

In this paper, a new approach is presented for improving image quality. It provides a new outlook on how to apply the enhancment methods on images. Image enhancement techniques may deal with the  illumination, resolution, or distribution of pixels values. Issues such as the illumination of the scene and reflectance of objects affect on image captures. Generally, the pixels value of an image is ...