In this paper a new method for contrast enhancement based on the discrete cosine transform is discussed and implemented. The technique converts the image into DCT domain and the DCT coefficients are modified using proposed mask then the enhanced image is reconstructed using inverse DCT. The discrete cosine transform outperforms with better image quality and highest PSNR value for noiseless gray...

Image restoration and enhancement are important parts of digital image processing, belonging to the early visual image processing problems. Image pre-processing is the necessary preliminary work of image analysis, such as filtering to reduce image noise and to enhance the image edges. The image enhancement technique plays an important role in improving image quality and is good for image post-p...

sar (synthetic aperture radar) image enhancement and segmentation is purpose of this thesis. sar image segmentation is a primary step before steps such as classification and target recognition. the main obstacle in sar image segmentation is inherent speckle noise. speckle noise is a multiplicative and highly destructive noise which results to intensity inhomogeneity. hence common segmentation m...

We used a new method to measure the perceived quality of contrast-enhanced motion video. Patients with impaired vision (n=24) and normally sighted subjects (n=6) adjusted the level of MPEG-based enhancement of 8 videos (4 min each) drawn from 4 categories. They selected the level of enhancement that provided the preferred view of the videos, using a decreasing-step-size staircase procedure. Mos...

BACKGROUND AND PURPOSE The diagnostic yield of vertebrobasilar transcranial color-coded duplex ultrasonography (US) is often hampered by insufficient acoustic penetration, anatomic variations, and vessel tortousity. The purpose of this study was to evaluate the effect of echo enhancement on vertebrobasilar transcranial color-coded duplex US. METHODS In 23 consecutive patients (mean age, 61.0 ...

background the first commercial system for digital radiography was introduced in 1987, and it has evolved a great deal since then. currently, it is possible to enhance images in digital radiography. objectives the aim of this study is to evaluate the diagnostic accuracy of image enhancement in direct digital radiography as it relates to interproximal carries assessment. conclusions using these ...

Image scaling is the process of resizing a digital image, wherein an image is converted from one resolution/dimension to another resolution/dimension without losing the visual content. It has many terminologies in literature such as Image Interpolation, image re-sampling, digital zooming, image magnification or enhancement, etc [1] [2]. Image interpolation algorithms can be grouped in two categ...

Histogram equalization is one of the most popular techniques in image enhancement. However, due to the shifting of the mean brightness, the quality of the output image is deteriorated with great amount of information loss. This paper proposes a novel modification of the adaptive histogram equalization algorithm to improve its abilities in preserving information entropy, maintaining the mean bri...

Principle objective of image enhancement is to process an image so that result is more suitable than original image for specific application. Digital image enhancement techniques provide a multitude of choices for improving visual quality of an image. Artifacts, over enhancement and unnatural effects are produced by current contrast enhancement algorithms. The Content aware algorithm enhances t...

In this paper we attempt to generalize a sharpness enhancement technique for TV applications. Basically, the enhancement is accomplished by adding overshoot to luminance edges. However, the optimal amount of overshoot added for a high image quality depends on the local image statistics. For this purpose, four properties of the video signal are analysed locally by separate units and depending on...