Spatial uniformity is one of the most important image quality attributes in visual experience of displays. In conventional researches, spatial uniformity was mostly measured with a radiometer and its quality was assessed with non-reference image quality metrics. Cameras are cheaper than radiometers and they can provide accurate relative measurements if they are carefully calibrated. In this pap...

This paper introduces a new way to correct the non-uniformity (NU) in uncooled infrared-type images. The main defect of these uncooled images is the lack of a column (resp. line) time-dependent cross-calibration, resulting in a strong column (resp. line) and time dependent noise. This problem can be considered as a 1D flicker of the columns inside each frame. Thus, classic movie deflickering al...

OBJECTIVE We sought to determine the best parameters for rapid performance of daily quality control testing of intrinsic uniformity and relative sensitivity for the single-head gamma-camera system in our nuclear medicine department. METHODS The effects of the following parameters on intrinsic uniformity were studied: gamma source activity, number of acquired counts for the flood image, source...

The correlation of adjacent pixels is one of the important parameters for measuring the distribution of adjacent pixels’ gray value. And it is widely used to evaluate the scrambling degree of digital image. Distribution figures are always plotted to show the relation of adjacent pixels’ gray value, but only subjective and qualitative analysis has been applied to explain the uniformity of dots i...

....................................................................................................................... iv INTRODUCTION ................................................................................................................ 1 CHAPTER 1 MAGNETIC RESONANCE INHOMOGENEITY CORRECTION................ 3 1.1 Magnetic Resonance Image Acquisition Process ............................

Unsupervised image segmentation aims to match low-level visual features with semantic-level representations without outer supervision. In this paper, we address the critical properties from view of feature alignments and uniformity for UISS models. We also make a comparison between image-wise representation learning. Based on analysis, argue that existing MI-based methods in suffer collapse. By...

This paper describes a method to enhance line structures in a gray level image. For this purpose, we blur the image using anisotropic gaussian filters along the directions of each line structures. In a line structure region the gradients of image gray levels have a uniform direction. To find such line structures, we evaluate the uniformity of the directions of the local gradients. Before this e...