In this study, we evaluated the image distortion of three magnetic resonance imaging (MRI) systems with magnetic field strengths of 0.4 T, 1.5 T and 3 T, during stereotactic irradiation of the brain. A quality assurance phantom for MRI image distortion in radiosurgery was used for these measurements of image distortion. Images were obtained from a 0.4-T MRI (APERTO Eterna, HITACHI), a 1.5-T MRI...

This thesis addresses authentication watermarking and compression of digital images under zero-distortion and maximum-per-sample-distortion constraints. In this context, a hierarchical authentication watermark is proposed for securely verifying the source and integrity of digital images and for determining altered image regions when the integrity verification fails. The proposed approach elimin...

Modern endoscopes offer physicians a wide-angle field of view (FOV) for minimally invasive therapies. However, the high level of barrel distortion may prevent accurate perception of image. Fortunately, this kind of distortion may be corrected by digital image processing. In this paper we investigate the chromatic aberrations in the barrel distortion of endoscopic images. In the past, chromatic ...

Today, many automobile companies and researchers have developed various safety systems to reduce fatalities by traffic accidents[1, 2]. In order to prevent traffic accidents by distracted driving, therefore, the proposed system presents the vehicle and pedestrian detection using a novel image representation called equi-height mosaicking system[3]. Furthermore, the proposed system additionally s...

In this paper, an effective image demosaicking algorithm, which is based on the correlation among the three primary colors, is proposed for mosaic image with Bayer color filter array (CFA). To reduce the distortion and improve the reconstruction quality, the proposed interpolation method makes full use of the brightness information and the edge information. We design several filters with size o...

A new approach to information hiding in binary images with the capabilities of hidden data authentication and image distortion reduction is proposed. The hidden information may be of any data form. Based on a new feature called surrounding edge count for measuring the structural randomness in an image block, pixel embeddability is defined from the viewpoint of minimizing image distortion. Accor...

A recent image quality measure, M-SVD, can express the quality of distorted images either numerically or graphically. Based on the Singular Value Decomposition (SVD), it consistently measures the distortion across different distortion types and within a given distortion type at different distortion levels. The SVD decomposes every real matrix into a product of three matrices A = USV, where U an...

A new image-based ghost correction technique is described for general interleaved EPI. This technique works reliably with both even- and odd-number interleaved EPI sequences. It estimates the phase distortions causing the ghosts as a general function of (x,y) even in the presence of a significant overlap of parent image and ghosts. If the phase distortion is assumed to be a function of x (frequ...

This paper presents a new technique for estimating and correcting the geometric distortion produced by common offthe-shelf lenses. The taks of recovering the three most important parameters modeling the lens distortion of a digital camera is formulated as a problem of image warping where the distorted image of a planar calibration plate taken by the camera has to be registered onto the virtual ...

It is a common problem, radial distortion of off-theshelf cameras, especially those low-cost ones and wide-angle ones. And the most direct method to judge whether radial distortion occurs in an image is the straightness of those lines in the image, for the straight line in the image should be straight in the ideal image under the pin-hole camera model. In this paper, we present a new line-based...