In order to eliminate the fixed-pattern noise (FPN) in the output image of time-delay-integration CMOS image sensor (TDI-CIS), a FPN correction method based on gray value compensation is proposed. One hundred images are first captured under uniform illumination. Then, row FPN (RFPN) and column FPN (CFPN) are estimated based on the row-mean vector and column-mean vector of all collected images, ...

When several gray midtones are present, like a black and white photo, two values are no longer sufficient to encode all the possible gray intensities, and to each pixel must be associated a numerical value, proportional to the brightness of that point. Typical choices for these values fall in the ranges 0 31 or 0 255 (requiring respectively 4 and 8 bits for each pixel). This second kind of imag...

BACKGROUND AND PURPOSE Recent improvements in MR gradient technology allow significant increases in diffusion weighting without prohibitive signal-to-noise degradation. The purpose of our investigation was to establish normative references for the signal intensity characteristics and apparent diffusion coefficient values of the adult brain at high b values. METHODS Fifty adults underwent diff...

This paper proposed a new method of feature description for target recognition and matching. Firstly, a method of calculating the difference was defined. The gray value matrix of an image was converted to a difference value matrix. Then the difference value, shape, angle and other features of a region and the combined features between regions were described. Finally, the method was applied to i...

The extraction of curve skeletons from tubular networks is a necessary prerequisite for virtual endoscopy applications. We present an approach for curve skeleton extraction directly from gray value images that supersedes the need to deal with segmentations and skeletonizations. The approach uses properties of the Gradient Vector Flow to derive a tube-likeliness measure and a medialness measure....

Aim: The aim of this in vitro study was to evaluate imaging artifacts induced by Titanium, Zirconium, Titanium-Zirconium abutments in CT, MRI and CBCT imaging modalities.Methods: A 4×8mm titanium fixture was inserted in a dry human mandible. Titanium, Zirconium and Titanium–Zirconium abutments measuring 10.5 mm in height are located on the fixture, one by one. Each abutment was scan...

in this research, the coupling between non-gray radiation and separation convection flow in a duct is investigated numerically. distributions of absorption coefficients across the spectrum  are obtained from the hitran2008 database. the full-spectrum k-distribution method is used to deal with the non-gray part of the problem, while the gray radiation calculations are performed using the planck ...

A binary reflected Gray code (Gray code for short) is a one-to-one function G(i) of the integers 0 • i • 2 – 1 (for some pre-selected value of n) to binary numbers such that the binary number for G(i) and G(i+1) differ in exactly one bit. For example, with N = 3, the Gray codes (written in binary) are 000, 001, 011, 010, 110, 111, 101, 100. In this paper, we describe a dynamic programming algor...