سکینه اسدی امیری

دانشکده مهندسی کامپیوتر، دانشگاه شاهرود

[ 1 ] - بهبود عملکرد کدگذار پیشگو با تغییر چیدمان تصویر به کمک الگوریتم ژنتیک

روش‎های فشرده‎سازی تصویر را می‎توان به دو دسته با‎اتلاف و بی‎اتلاف تقسیم‎بندی نمود. کدگذار پیشگو مبنای بسیاری از روش‎های فشرده‌سازی بی‌ اتلاف تصویر است. این کدگذار با توجه به مقدار پیکسل‌های همسایه، مقداری را برای هر پیکسل از تصویر پیشگویی می‌نماید. تفاضل مقدار واقعی هر پیکسل از مقدار پیشگویی شده، مقدار خطا تلقی می‌شود و این مقادیر خطا کد می‌گردند. در این مقاله، روش پیش‌پردازشی پیشنهاد شده است ...

[ 2 ] - ارائه روشی برای پیش‎پردازش تصویر جهت بهبود عملکرد JPEG 2000 در فشرده‎سازی تصویر

دو گام اساسی در فشرده‎سازی تصویر به شیوه JPEG 2000 تبدیل موجک و کدگذار صفحات بیتی می‎باشند. در این روش ابتدا از تصویر تبدیل موجک گرفته می‎شود، سپس بسته به نرخ فشرده‎سازی مورد نظر، تعدادی از صفحات بیتی ضرایب تبدیل موجک از پرارزش‎ترین بیت تا بیت کم‎ارزش‎تر کد می‎گردند. پس از دستیابی به نرخ فشرده‎سازی مورد نظر، سایر صفحات کم‎ارزش‎تر ضرایب موجک حذف می‎گردند. در به‌کارگیری این روش، تصاویری که وضوح ک...

[ 3 ] - Image quality enhancement in digital panoramic radiograph

One of the most common positioning errors in panoramic radiography is palatoglossal air space above the apices of the root of maxillary teeth. It causes a radiolucency obscuring the apices of maxillary teeth. In the case of this positioning error, the imaging should be repeated. This causes the patient be exposed to radiation again. To avoid the repetition of exposing harmful X-rays to the pati...

[ 4 ] - بهسازی تصاویر با تکیه بر اطلاعات گاما

In this paper a new automatic method is presented to enhance the image brightness through gamma correction process. Most of current gamma correction methods apply a uniform gamma correction across the image. Considering the fact that gamma variation for a single image is actually nonlinear, the proposed method does the gamma correction in a local approach. Thus the method is able to estimate ap...

[ 5 ] - Image Enhancement Using an Adaptive Un-sharp Masking Method Considering the Gradient Variation

Technical limitations in image capturing usually impose defective, such as contrast degradation. There are different approaches to improve the contrast of an image. Among the exiting approaches, un-sharp masking is a popular method due to its simplicity in implementation and computation. There is an important parameter in un-sharp masking, named gain factor, which affects the quality of the enh...

[ 6 ] - Deblocking Joint Photographic Experts Group Compressed Images via Self-learning Sparse Representation

JPEG is one of the most widely used image compression method, but it causes annoying blocking artifacts at low bit-rates. Sparse representation is an efficient technique which can solve many inverse problems in image processing applications such as denoising and deblocking. In this paper, a post-processing method is proposed for reducing JPEG blocking effects via sparse representation. In this ...

[ 7 ] - Improving Dark Channel Prior for Single Image Dehazing

This paper proposes an improved dark channel prior for removing haze from images. Dark channel prior is an effective method for removing haze. Dark channel is an image in the same size as the hazy image which is obtained by dividing the RGB images into windows and for each window, the minimum of each R, G and B channels are calculated. Then again the minimum of these three values is calculated ...

[ 8 ] - Image Quality Enhancement Using Pixel Wise Gamma Correction

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...

[ 9 ] - Salt and Pepper Noise Removal using Pixon-based Segmentation and Adaptive Median Filter

Removing salt and pepper noise is an active research area in image processing. In this paper, a two-phase method is proposed for removing salt and pepper noise while preserving edges and fine details. In the first phase, noise candidate pixels are detected which are likely to be contaminated by noise. In the second phase, only noise candidate pixels are restored using adaptive median filter. In...

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