Video microscopic image processing facilitates the evaluation of light microscopic autoradiography at high magnification

Light microscopic autoradiographs of H-thymidine labelled unstained semithin sections of Xenopus laevis embryonic nuclei were examined with conventional Nomarski differential interference contrast, phase-contrast and video microscopy. Whereas at low magnification it was possible to obtain a photograph of the nuclear structure and the silver grains in one focal plain, at high magnification, with small depths of focus, a satisfactory image was not attainable. Therefore, we stored the images of the two different focus levels with a digital image processing system and combined both images by an arithmetic operation. This video microscopic technique allows the use of high magnification light microscopy with oil immersion objectives and the application of additional electronic contrast enhancing methods for an adequate and rapid analysis of light microscopic autoradiographs.     

基于硬盘的视频实时存储方法的研究

数字图像的实时存储是视频判读的基础,经常使用模拟录像机把视频信息记录在磁带上,由于磁带录像机的分辨率不高,影响判读的精度.本文针对数字图像的特点,提出了一种新型的、基于计算机硬盘的视频存储方法,其目的是简化判读系统的结构,提高判读的精度.它利用了数据压缩原理,对视频信号进行实时、无失真的压缩,再把压缩后的数据进行存盘,实现了视频图像实时存储.试验表明,用此方法可以完成512×512的视频图像的实时存储,且结构简单,方法实用,是一新型的视频存储方法.     

目标运动轨迹匹配式的红外-可见光视频自动配准

为实现精确的红外-可见光视频序列的自动配准,提出了一种新的基于目标轨迹线匹配的配准方法。首先,利用运动目标检测技术提取目标前景,并由基于相关滤波器(KCF)的多目标跟踪算法对每个前景顶点进行跟踪,进而获取每个目标的运动轨迹。此后,为每条轨迹线建立归一化运动方向描述子与归一化运动幅度描述子,通过时序分析、方向描述子匹配及幅值描述子匹配建立分步约束的匹配机制,完成轨迹线匹配工作。最后,采用迭代更新的方式获取最佳全局配准矩阵,实现对异源视频的配准。在LITIV数据库上的9组视频上进行测试验证,实验的结果表明:本文配准算法的重叠率误差一般小于0.2,接近或已超过手动的Ground-Truth矩阵。通过充分利用目标的运动信息,该算法实现了精确的红外-可见光图像序列配准。     

Microcomputer system for ion microscopy digital imaging and processing

Analytical ion microscopy is a powerful tool for biological tissue analysis as it allows direct chemical distribution imaging, even at low element concentrations. A microcomputer based digital imaging system achieving acquisition at low light level is presented. It includes a high sensitivity video camera connected to a specialized image processor subsystem. Acquired images consist of 512 times 512 pixels with 8 bits accuracy. Real-time image processing software has been implemented so that image processing may be performed on-line. Image processing software allows off-line image manipulation and correlation for biological interpretation of elemental mapping images. System capabilities are illustrated by a study of stable and radio iodine mapping in rat thyroid tissue.     

Laser scanning phase modulation microscope

We describe the concept and first implementation of an innovative new instrument for quantitative light microscopy. Currently, it provides selective imaging of optical path differences due to birefringence; with further development, it is also possible to selectively image several optical properties, including refractive path differences, optical rotation, and linear and circular dichroism, all with diffraction-limited resolution. An image consists of a 512×512 element array, with each pixel displaying one of 256 grey levels, linearly proportional to the specific optical property being observed. Additionally, conventional brightfield and polarized light microscopy are available, with the accompanying advantages of laser scanning and digital image processing. The microscope consists of three subsystems, representing three distinct technologies. The laser scanning subsystem moves a focused, microspot across the specimen; the output of a photodetector is an electric signal corresponding to a scanned image. The image display subsystem digitizes this signal and displays it as an image on a video monitor. When used in conjunction with a phase modulation feedback loop, the image formed is of the specimen's birefringent retardation or other selected optical property. The digitized images are also available for computer enhancement.     

Digital image tiles: a method for the processing of large sections

Segmentation of large areas of light microscopic slides into N by N fields, and each of these fields into M digital image tiles, allows the scanning, storage and digital processing of large images. Any of the original N² fields or composites of M adjacent tiles can be recalled to the video display for analysis. Developed procedures for use on a microscope equipped with a precision scanning stage allow registration of the image coordinates (X-Y) for any original or composite field and the alignment of one of these fields along the depth (Z) axis by means of external, machined fiducial marks in serial sections. To facilitate work whenever unavoidable, we have incorporated methods for digital image panning and zooming (changes of magnification) and discuss their use and implications.     

基于形态学边缘匹配的数字稳像方法

在一些实际应用场合,摄像机设备的震动是造成视频序列失稳的重要原因,为此提出了一种基于形态学边缘匹配的数字稳像方法,该方法首先利用形态学方法提取视频图像边缘,然后利用当前帧子块与参考帧子块的边缘进行特征匹配,以确定当前帧子块相对于参考帧的局部运动矢量,同时对得到的局部运动矢量进行分析判决,以确定该局部运动矢量是否为真正的抖动偏移量,消除视频帧本身因存在局部运动目标、低对比度、纹理区域等因素对全局运动矢量估计的影响,最后通过判别确认的局部运动矢量确定全局运动矢量并进行运动补偿,实现数字稳像。仿真实验表明该方法稳像精度较高,复杂度低,实际应用稳像效果良好,可应用于因摄像头平移震动等因素造成视频序列失稳。     

Colour display of video information in scanning electron microscopy: Principles and applications to physics,geology, soil science,biology, and medicine

From a colourimetric point of view, colour has two independent aspects: brightness and chromaticity. In black and white images, all elements are of the same chromaticity and can be distinguished only by brightness contrast. In the colour image, elements of the same brightness can be discriminated by chromaticity (colour) contrast. Generally, colour image elements can be discriminated both by brightness and by chromaticity. As the human eye can distinguish a number of hues two orders of magnitude larger than the number of grey levels, it is safe to say that the colour image is much more informative than the black and white image. There are some peculiarities of the colour image and methods of its formation in SEM. Two principles of image formation are used. The first consists of the formation of a real colour image in the cathodoluminescence mode. In this case the colour of an image element is determined by the spectrum of the luminescence emission excited in the corresponding point of an object by the electron beam. The second principle is that of colour coding (quasicolour, pseudocolour), when a video signal in colour (either digital or analog) corresponds to a video signal (amplitude, frequency, phase, etc.) produced by any mode in the scanning electron microscope. We present a review of the methods of colour display of video information in scanning electron microscopy and their applications to physics, geology, soil science, biology, and medicine.     

Video-enhanced microscopy with a computer frame memory

Video-enhanced microscopy combined with the use of a computer frame memory extends considerably the useful range of our video enhanced contrast (AVEC) methods for polarizing, double-beam interference and differential interference contrast microscopy. Increased visual contrast is achieved by two stages of amplifications: the first optical, by using high bias retardation settings, and the second electronic. These steps are followed by a reduction of background brightness by means of a clamp voltage applied to a DC restoration circuit of the video camera. One of the limitations of the AVEC method alone is the inevitable appearance under high gain conditions of a pattern of mottle due to inaccessible dirt and defects in the lenses even of high quality. This limitation has been circumvented by storing the mottle pattern in the frame memory (frame store) and continuously subtracting it from each succeeding frame to clear the image. A major gain in image quality has resulted. In polarizing microscopy, the frame memory can be used also to subtract the image at one compensator setting from that at the equivalent setting of opposite sign, thus removing from the final image not only most of the mottle pattern but also the contrast due to the bright-field contrast. In the polarizing microscope, these manipulations of the raw video image make it possible to observe and measure the birefringence of various organelles and elements such as microtubules, intermediate filaments and bundles of as few as a half dozen actin filaments. Since scattered light is also removed from the image, features hidden from view in the unprocessed image become visible. In differential interference microscopy, the AVEC method makes visible (i.e. detectable) many linear elements and particles that are an order of magnitude smaller than the resolution limit and not visible in the optical image. Such features are inflated by diffraction, however, to Airy disk size.     

改进的基于雾气理论的视频去雾

为了进一步提高有雾视频的可用性,提出了一种改进的基于雾气理论的视频去雾方法。该方法以雾气理论为基础,利用暗原色先验知识以及Retinex方法和图像融合的方式,将从视频背景图像求取的大气光值和介质传播图应用于视频的所有帧以便去除雾气。从主观定性评价、客观定量评价和运算速度3个方面对视频去雾效果进行了评价。结果表明,对分辨率为480×640的视频,本文方法的运算速度为5.45frame/s,不仅获得了较快的处理速度且能有效避免复原视频中出现颜色跳变的现象。由于本文采用区间估计的方式对大气光值进行估计,同时利用图像复原和图像增强的方法求取介质传播图,因此,复原视频的清晰度和对比度比典型的视频去雾方法有所提高,颜色效果也比较好。     

Analog enhancement of videomicroscope images

A simple, inexpensive technique for enhancing the contrast and resolution of videomicroscope images has been developed. The system has manual controls for gain and pedestal (black level) which permit expansion of low contrast images to the full white-to-black video range. Analog delay-line based circuits are used to sharpen the edges and enhance fine details in the image. These circuits also produce an effective increase in the information content of the image by selectively amplifying low amplitude, high frequency components of the video signal. When live, unstained cells were examined at high magnifications, cytoplasmic structures which were only faintly visible in the unenhanced image became clear. The images of fluorescent objects appear in pseudo-relief, which improves visibility even in the presence of background fluorescence. The system enhances images by performing signal processing functions that otherwise require expensive digital image processing equipment.     

结合图像内容匹配的机器人视觉导航定位与全局地图构建系统

为了解决机器人室内定位时的绑架问题和相似物体的干扰,设计了一种具有图像内容匹配功能的视觉系统,从而使机器人能有效提取关键帧序列构建室内全局地图并实现自主定位。考虑影响图像内容匹配的主要干扰是机器人视角和位移造成的图像畸变,本文通过对室内物体的图像畸变建模与特征分析,设计了一种图像内容匹配方法。该方法以图像重叠区提取、基于子块分解匹配的重叠区重建两部分为核心,可将待匹配的两帧图像畸变调整为一致后再进行内容匹配并准确解算它们的相似度。其能有效利用各个房间内不同的景物和布局信息来消除相似物体的影响,从机器人学习环境时采集的视频中提取空间间距大且重叠相连的关键帧序列建立整栋建筑内部的全局导航地图。机器人工作时,实时视觉的图像内容与地图关键帧序列匹配,提取出与每个时刻视觉图像最相似的关键帧对机器人实施定位。在由3个房间和2条走廊组成的实验区进行了实验测试,结果表明:机器人可有效消除相似物体的干扰,绑架发生时仍可通过与全局地图匹配实施准确自主定位,匹配准确率≥93%,定位精度误差(RMSE)0.5m。     

基于PCI总线的数字视频键控图像叠加卡的设计

设计了用于虚拟演播室的PCI总线数字视频键控图像叠加卡。该卡能实时完成背景数字视频和前景图像视频的实时叠加，并可通过alpha键控制前景视频和背景视频的叠加比例，也可单独输出前景视线或背景视频。键控技术作为理论基础被扼要阐述。详细讨论了PCI总线数字视频键控图像叠加卡的基本结构、数字视频编辑码的方法。系统时序发生和叠加处理的基本原理。给出了编制和调试开发SAA7146多媒体桥的内核级WDM（Win 32 Driver Model）设备驱动程序的方法和步骤。     

便携式仪表数字图像采集与处理技术

随着USB摄像头技术的普及、嵌入式技术的迅速发展以及数字图像处理技术的成熟完善,以往依托计算机进行数字图像处理的诸多仪器和设备可实现便携化。用摄像头采集数字图像,通过USB接口输入嵌入式开发板中实现各种数字图像处理算法如去噪声、图像分割、边缘检测、图像匹配及图像代数运算等算法,处理结果从LCD显示屏显示,这样就构成了一个便携式系统。     

A focusing algorithm for high magnification cell imaging

An algorithm to produce a uniformly focused image in digital acquisition of high magnification light microscopy images is presented. In very high magnification microscopic imaging the specimen surface cannot be considered ideally flat so that capturing a single image frame is usually not sufficient to capture an image that is focused everywhere. An image formation model for light microscopic images is presented, and based on this model an algorithm to construct a uniformly focused image is presented. The algorithm requires that multiple frames of the image at different focal planes be processed to combine their information to obtain an estimated of the desired image which is more completely focused than any of the individual frames. Experimental results show that the proposed algorithm is very effective in approximating the desired image in high magnification microscopic imaging and highly robust comparing to the gradient method.     

Computer-based determination of size and shape in living cells

Measurement of cell volume in living epithelial cells has become an important technique in studies of membrane transport processes that function in cell volume regulation. Planimetry of video images of optical sections enables the measurement of the cross sectional area of each section. Cell volume is calculated from the measured area of each section and the known focus displacements. In the past the measurement of cross section area has been done by manual positioning of a cursor superimposed on the video image. Each experiment generates approximately 200 images in which two or more cells may be analysed. We have developed a computer-based method that uses one image as a template, and allows automated area determination of successive images by template matching and digital image processing. This new method is comparable to the older method in speed and accuracy, but requires much less effort from the experimenter.     

Landmarks in biological light microscopy

The pioneering seventeenth-century work of Hooke (using the compound microscope) and Leeuwenhoek (using the simple microscope) was followed in the eighteenth century by a period of comparative stagnation until the early nineteenth-century work of Lister (who evolved the principle of aplanatic focal points in lens design). The founding of the Microscopical Society of London in 1839 reflected the increasing importance of the microscope as a scientific instrument and its involvement in specimen preparation techniques, cell theory and bacteriology is described. The pursuit of increased resolving power—in particular the development of apochromatic lenses by Abbe and Zeiss and enhanced contrast techniques—polarized fight, u.v. microscopy, u.v. absorption and fluorescence, phase contrast and the differential interference contrast techniques, etc., are discussed. The story of microscopy in the twentieth century is one of interlocking discoveries and advances and the techniques of epi-illumination in scanning fluorescence microscopy, video acquisition and analyses of images in digital form and confocal scanning microscopy are surveyed. It is concluded that these techniques have opened up whole new areas for the future development of light microscopy.     

一种基于基元匹配的立体图像修复算法

针对立体图像修复中直接采用二维图像修复算法所导致的深度信息修复效果欠佳的问题,提出一种基于基元匹配的立体图像修复算法.通过在立体图像左右视图间进行基元匹配,求得各个像素对应目标的深度信息;然后通过平滑深度求得缺损区域的深度数据;最后通过立体图像成像公式计算出左视图中用于填补右视图缺损区域的对应像素点坐标.通过与Criminisi算法进行对比实验,结果表明,对于多幅缺损的立体图像,该算法均取得了较好的修复效果.     

Image analysis of particle dispersions in microscopy images of cryo-sectioned sausages

Two feature extraction methods, the three-dimensional (3-D) local box-counting method and the area distribution method, are presented to describe the fat dispersion pattern on digital microscopy images of cryo-sectioned sausages. Both methods calculate whole arrays of variables for each microscopy image. The 3-D box-counting method calculates scale dependent (local) dimensions. This is in contrast to common fractal methods, which are univariate. Principal component analysis (PCA) was used to show that different sausages yield different fat dispersion patterns. Partial least square regression (PLS) shows that there is a correlation between the variables gained with both methods and the fat content.     

基于分区灰度投影的稳像算法在卫星装配中的应用

针对传统电子稳像算法无法快速有效地消除视频图像随机抖动的问题,采用一种基于分区灰度投影的稳像算法,以确保机器人系统能够输出稳定连贯的卫星装配画面。对前后两帧视频图像进行划分并删除对比度低的子区域,利用间隔投影和互相关运算获取局部运动分量,通过基于平均误差门限的迭代步骤筛选后剩余的局部运动分量求解全局运动矢量;若判定存在低频扫描分量,还需对多帧图像的全局运动矢量作均值滤波处理。实验结果表明：基于分区灰度投影的稳像算法相比传统灰度投影法,在低对比度的自然场景图像和模拟装配图像中的稳像精确度分别提升119.1%和55.8%;同时执行时间只有块匹配算法的0.5%。能够有效消除随机抖动,快速输出稳定连贯的视频画面,保证机器人系统顺利完成卫星的地面装配工作。