BACKGROUND To study the impact of image quality on quantitative measurements and the frequency of segmentation error with optical coherence tomography angiography (OCTA). METHODS Seventeen eyes of 10 healthy individuals were included in this study. OCTA was performed using a swept-source device (Triton, Topcon). Each subject underwent three scanning sessions 1-2 min apart; the first two scans...

The recent development of digital image acquisition technologies leads to better image quality, in terms of spatial resolution and sensitivity. Image quality is a characteristic of an image that measures the perceived image degradation. Several techniques and metrics are proposed which can be classified as Full-Reference (FR) method, No-Reference (NR) method and Reduced Reference (RR) method. I...

djendjen river is one of the largest rivers in the region of jijel (algeria). human activities such as urban discharges, industrial, agricultural, and livestock have significant effects on the quality of water. the present study attempts to evaluate the quality of water along the banks of the djendjen river at different sampling sites, using physico-chemical and bacteriological methods. the col...

In this paper we propose an image steganography technique which embeds secret data without making explicit modifications to the image. The proposed method simultaneously provides both imperceptibility and undetectability. We decompose image by contourlet transform and determine nonsmooth regions. Embedding data in these regions cause less degradation in image quality. Contourlet sub-bands are d...

We report experimental evidence and correction of defocus in full-field optical coherence tomography of biological samples owing to mismatch of the refractive index of biological tissues and water. Via a metric based on the image quality, we demonstrate that we are able to compensate this index-induced defocus and to recover a sharp image in depth.

We describe a general coding strategy leading to a family of universal image compression systems designed to give good performance in applications where the statistics of the source to be compressed are not available at design time or vary over time or space. The basic approach considered uses a two-stage structure in which the single source code of traditional image compression systems is repl...

This paper presents system development for quality evaluation of fish fillet using image processing. The proposed system consists of conveyer belt, Ultraviolet (UV) lamp, CCD Camera, electronic circuits, interface card and computer. K-means clustering and thresholding techniques are used for quality evaluation of fish fillet. The image segments are used to calculated area of fish fillet and fis...