“平坦峰”对象的分割

对于目标所占比例很小的图像,目标在直方图中退化成平坦峰。该文根据直方图的形状,提出了一种对具有平坦峰的图像的分割方法,在具体的医学图像应用中取得了较好的分割效果。     

基于数学形态学的免疫细胞图象分割

为了实现对免疫细胞图象的分析，首先要对该种图象进行正确分割，针对这一要求，提出了一种有效的免疫细胞图象分割方法，该方法是根据数学形态学的知识，利用直方图势池数来提取标记点，并将这些标记点作为种子点来对梯度图进行Watershed变换，进而实现了细胞图象的分割。该方法是一种谱信息与空间信息相结合的分割方法，根据实验结果和分析可见，该方法不仅解决了细胞在参数测量前的精确分割问题，同时，为水域分割的关键步骤－种子点的选取找到了一种有效而可靠的方法，实践表明，分割的结果与 目视感受相一致，且其分割速度及可重复性都达到了医学临床的要求。     

基于采样的直方图生成方法

根据一些工业图像的特点及实时分析的需要，提出了一种快速生成直方图的方法，该方法对图像数据进行列间采样，实现简单，速度很快，生成的直方图与物体真实的直方图相差无几，完全能够保证直方图的波峰，波谷信息，对两种方法的所需时间，生成的直方图的相关度以及采样前后图像的相关度作了对经，阐明了本方法的适用范围及局限。     

基于颜色特征的图像检索技术研究

在基于内容的图像检索中,颜色作为图像的一种重要视觉信息,已得到广泛应用.相对于图像的几何特征而言,颜色具有一定的稳定性,对缩放、平移、旋转具有相当强的鲁棒性.本文从颜色检索的几个关键技术入手,对颜色模型的选择与量化、颜色直方图以及相似性度量等方面进行了详细的讨论,最后,阐述了本技术的局限性和目前存在的问题.     

A reversible data hiding method without rounding based on Haar wavelet transform: NON-R

The techniques that allow to obtain hidden data and recover the image has recently been much sought after. The basic objective of the method provided in this study was to analyse coefficients of digital images achieved by wavelet transform in the frequency space, to hide data, and to recover original image without loss. Wavelet transform is an efficient method to find pixel coefficient characteristic of digital images. The proposed method (NON-R) hides data using shifted histogram high-frequency Haar coefficients without rounding into integer. Thus, both hidden data and cover image can be easily recovered. Reversibility is provided by retrieving the cover image after hiding into high-frequency wavelet coefficients and extracting the message from wavelet coefficients. Experimental results show that the NON-R has a better performance than its counterparts in terms of statistical and perceptual outcomes.     

Efficiency calibration of a HPGe detector in the [46.54–2000] keV energy range for the measurement of environmental samples

Here we describe a general method of calibrating the efficiency of a Ge γ-ray spectrometer. The method, which is based on the work of Quintana and Fernández (Appl. Radiat. Isot. 47 (1996) 911), can now be applied to many different experimental set-ups including both liquid and solid environmental samples. The method requires two different types of experimental inputs. Firstly, it requires measurements with radioactive sources emitting cascades of γ rays covering the energy range of interest. Secondly, it requires measurements with sources emitting isolated γ rays in order to provide coincidence-summing corrections. On this basis, we establish a general function to describe the energy dependence of the efficiency for the particular geometry and source matrix. The method has been applied to 11 different experimental arrangements to provide efficiency calibrations over the range 46.54–2000 keV with associated uncertainties ranging from 0.1% to 1.8%. This allows high precision measurements with environmental samples, which often have very low activities.     

安装助抽增液器前后抽油井载荷分析

依据油井载荷理论计算公式，对助抽增液器安装前后抽油杆的受力分布进行了计算分析，找出提高油井泵效、减小抽油杆偏磨、降低杆底部断脱和油管底部漏失的新途径。     

An ADC histogram test based on small-amplitude waves

This paper deals with a new method improving the static test for analogue-to-digital converters. The method is based on a histogram procedure using as test signals small-amplitude triangular waves superimposed on suitable constant offset values. The histogram is built over the converter fullscale by varying the offset step by step systematically. A small amplitude and a reduced time slope in comparison to the converter range and slew rate, respectively, lead to static test conditions. This procedure allows inexpensive function generators to be used and the test duration to be dramatically reduced. Experimental results of tests aimed at validating, characterizing, and comparing the proposed method on two different converter architectures are presented.     

Error in the estimation of transition voltages with the standard histogram test of ADCs

In this paper we address the use of overdrive in the standard histogram test of analog to digital converters. The error in the estimation of the transition voltages due to the presence of additive noise is calculated and expressions for the minimum amount of overdrive required are presented. A comparison with previously published work is carried out.     

基于嵌入式零树小波编码直方图图像检索

图像和视频应用的快速增长，使得根据图像和视频内容进行查询的技术变得越来越重要，人们提出了许多基于像素域或压缩域的图像检索技术，因为多媒体数据库通常具有相当大的数据量，所以基于像素域图像检索技术的计算复杂度相当大，因此，许多文献提出更快的基于压缩域的图像检索技术，本文提出一种改进的基于嵌入式零树小波编码直方图的图像检索技术，特征提取综合考虑图像的颜色，纹理，频率和空间信息，所有的特征可以在压缩过程中自动得到，图像检索的过程就是匹配待检索图像和来自数据库的侯选图像的索引，实验证明这种方法具有好的检索性能。