With the improvement of synthetic aperture radar (SAR) technology, larger areas are being imaged and the resolution of the images has increased. Larger images have to be transmitted and stored. Due to the limited storage and/or downlink capacity on the airplane or satellite, the volume of the data must be reduced. This makes compression of SAR images with minimal loss of information important. ...

We describe a new method for pairwise retinal image registration. The proposed method is unique in that the radial distortion due to image acquisition is corrected prior to the geometric transformation. Since the overlapping region is typically small in a retinal image pair, only a few correspondences are available, thus limiting the applicable model to an affine transform at best. To recover t...

We present a novel image resizing method which attempts to ensure that important local regions undergo a geometric similarity transformation, and at the same time, to preserve image edge structure. To accomplish this, we define handles to describe both local regions and image edges, and assign a weight for each handle based on an importance map for the source image. Inspired by conformal energy...

This paper presents the results of three psychophysical experiments designed to investigate the effects of spatial correlations and the disruption of global precedence on the visual fidelity of natural images. The first two experiments used a psychophysical scaling paradigm in which subjects placed distorted images along a linear, one-dimensional “distortion axis” where physical distance corres...

Block transform coding is widely used in image and video compression methods. Due to quantization error, there are blocking artifacts in the decoded image. This paper presents a pre-processing method, called pre-distortion, to reduce both the bitrate and blocking artifacts. The proposed algorithm is an iterative algorithm which reduces the blocking artifacts of the decoded image by introducing ...

The goal of steganography is to hide the existence of secret communication between the two parties. The message to be transmitted has no relationship to the cover image and the only role the cover image plays is that of a foreign message carrier. The content of the cover image has no value to the sender or the decoder. Non-native data embedding always introduces distortion. Ideally the distorti...

Magnetic Resonance (MR) image is a medical image technique required enormous data to be stored and transmitted for high quality diagnostic application. Various algorithms have been proposed to improve the performance of the compression scheme. In this paper we extended the commonly used algorithms to image compression and compared its performance. For an image compression technique, we have lin...

Radial lens distortion found in real, most notably off-the-shelf medium to wide angle optics can be quite severe. A-priori calibration remedies the problem, but requires access to the camera. Alternative approaches make use of correspondences in multiple images of a moving camera [3], relying on sufficiently overlapping views. Our paper fits in the category of techniques, where straight scene l...

BACKGROUND Storage issues and bandwidth over networks have led to a need to optimally compress medical imaging files while leaving clinical image quality uncompromised. METHODS To determine the range of clinically acceptable medical image compression across multiple modalities (CT, MR, and XR), we performed psychometric analysis of image distortion thresholds using physician readers and also ...

With the rising use of facial recognition systems in a range real-world scenarios and applications, attackers are also increasing their efforts, with number spoofing techniques emerging. As result, developing reliable spoof detection mechanism is critical. Active-based have been shown to be good at finding spoofs, but they problems, such as being intrusive, expensive, hard compute, not able use...