نتایج جستجو برای: image contrast
تعداد نتایج: 743637 فیلتر نتایج به سال:
Background and purpose: Selection of suitable parameters for brain MRA requires accurate measures, because the image quality depends on the location of arteries, veins and also the velocity differences of blood, taking into account the low blood flow in small veins and arteries, use of paramagnetic contrast media is recommended. Hence, in present study, we investigated the imaging optimizatio...
Local binary pattern (LBP) operators, which measure the local contrast within a pixel's neighborhood, successfully applied to texture analysis, visual inspection, and image retrieval. In this paper, we recommend a semi blind and informed watermarking approach. The watermark has been built from the original image using Weber Law. The approach aims is to present a high robustness and imperceptibi...
INTRODUCTION The use of a pre-contrast reference image, referred to as a mask, to suppress background signal and improve output contrast-to-noise ratio (CNR) through subtraction is common in contrast-enhanced MR angiography. It is critical that this operation be performed to optimize output image quality. As has been previously reported [1-3] it is advantageous to use complex subtraction for th...
parameters that have to be measured in gel dosimetry. However, the resolution in gel is strongly dependant on gel composition. Selection of optimum method in dose response readout and proper values of parameters can result in noise reduction as well as improvement of contrast, and spatial resolution considerably. Materials and Methods: MAGICA polymer gel dosimeters were manufactured and irradia...
The efficiency and accuracy of the image semantic segmentation algorithm represent a trade-off relationship, loss tends to increase as model structure simplifies improve efficiency. Developing more efficient accurate algorithms requires methods complement them. In this study, we applied logarithmic-exponential mixture (LEM) function for gamma correction images segmentation. basic used in work w...
Background: Cone-beam computed tomography (CBCT) scanners for image-guided radiotherapy are in clinical use today, but there has been no consensus on uniform acceptance to verify the CBCT image quality yet. The present work proposed new methods to fully evaluate the performance of CBCT in its three-dimensional (3D) reconstruction space. Materials and Methods: Compared to the traditional methods...
chest radiography is a common diagnostic imaging test, which contains an enormous amount of information about a patient. however,its interpretation is highly challenging. the accuracy of the diagnostic process is greatly influenced by image processing algorithms;hence enhancement of the images is indispensable in order to improve visibility of the details. this paper aims at improving radiograp...
Contrast enhancement is very useful in medical image analysis that helps the physicians for disease diagnosis. The quality of medical images affects the analysis if the contrast of the images is poor. This paper presents method to enhance the contrast with improved CNR (contrast to noise ratio).
introduction: filtering can greatly affect the quality of clinical images. determining the best filter and the proper degree of smoothing can help to ensure the most accurate diagnosis. methods: forty five patient’s data aquired during brain phantom spect studies were reconstructed using filtered back-projection technique. the ramp, shepp-logan, cosine, hamming, hanning, butterworth, metz and w...
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