共查询到20条相似文献，搜索用时 15 毫秒
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牙科X光片在牙科疾病的诊断治疗中越来越重要。牙齿X光片机不像光学相机可以聚焦,常受低对比度和噪声的影响,很难直接借此识别疾病特征,常常需要对图片进行增强处理,故主要探讨一些适用于电子病例的牙科X光图像增强算法。算法主要有直方图均衡化、限制对比度自适应直方图均衡化、锐化中值滤波自适应直方图均衡化和改进的对比度自适应直方图均衡化方法。通过对这些算法处理后的牙科X光片图像的均方根误差(RMSE)、图像信噪比(SNR)和改善对比度指数(CII)以及视觉效果进行比较,发现用改进的对比度自适应直方图均衡化方法处理所得图像的均方根误差、改善对比度指数最小,图像信噪比最大,图像视觉效果清晰。 相似文献
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An exponential contrast stretching (ECS) technique is developed to reduce the charging effects on scanning electron microscope images. Compared to some of the conventional histogram equalization methods, such as bi‐histogram equalization and recursive mean‐separate histogram equalization, the proposed ECS method yields better image compensation. Diode sample chips with insulating and conductive surfaces are used as test samples to evaluate the efficiency of the developed algorithm. The algorithm is implemented in software with a frame grabber card, forming the front‐end video capture element. 相似文献
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彩色遥感图像的亮度直方图局部线性化增强 总被引：1，自引：0，他引：1
针对遥感图像能量低的实际问题,提出了一种亮度直方图局部线性化图像增强方法来提高彩色遥感图像的可视效果。首先,对RGB模型描述的彩色遥感图像进行HSI变换,以有效分离H、S和I分量;其次,对亮度I分量进行传统的直方图均衡化,得到均衡化灰度映射曲线;然后,将图像梯度作为目标函数,求出最优的线性化折点位置,对灰度低端动态范围映射曲线进行线性化处理,得到局部线性化的灰度映射曲线;最后利用新的灰度映射曲线对图像进行增强处理。Himawari-8真彩色图像增强实验结果表明,经亮度直方图局部线性化增强后,像素平均梯度由73提高到了147,较传统的RGB域直方图均衡化的123及HSI域直方图均衡化的134高;图像信息熵由5.87提高到6.63,全部优于传统的RGB域直方图均衡化和HSI域直方图均衡化。本文方法有效地改善了彩色遥感图像的可视效果,提高了图像对不同目标的辨识能力。 相似文献
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A conventional global contrast enhancement is difficult to apply in various images because image quality and contrast enhancement are dependent on image characteristics largely.And a local contrast enhancement not only causes a washed-out effect,but also blocks.To solve these drawbacks,this paper derives an optimal global equalization function with variable size block based local contrast enhancement.The optimal equalization function makes it possible to get a good quality image through the global contrast enhancement.The variable size block segmentation is firstly executed using intensity differences as a measure of similarity.In the second step,the optimal global equalization function is obtained from the enhanced contrast image having variable size blocks.Conformed experiments have showed that the proposed algorithm produces a visually comfortable result image. 相似文献
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This paper presents the development and implementation of a real‐time dynamic range compensation system for scanning electron microscope (SEM) imaging applications. Compared with conventional automatic brightness contrast compensators that are based on the average image or pixel intensity level, the proposed system utilizes histogram‐profiling techniques to compensate continuously the dynamic range of the processed video signal. The algorithms are implemented in software with a frame grabber card forming the front‐end video capture element. The proposed technique yields better image compensation compared with conventional methods. 相似文献
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Zhenyu HU;Qi CHEN;Daqi ZHU 《光学精密工程》2022,30(17):2133-2146
This study proposes an underwater enhancement algorithm based on color balance and multi-scale fusion to address the color deviation, detail blur, and low contrast of underwater images caused by water absorbing and scattered light. A color balance method was used to correct color. Then, the color-corrected image was converted from the RGB space to Lab space, and the L-channel was processed with the contrast limited adaptive histogram equalization method to enhance the contrast. Subsequently, the image was converted back to the RGB space. Finally, the multi-scale fusion method was used to fuse the color-corrected image with the contrast-enhanced image according to weight maps. After image enhancement, the enhancement effect of the proposed algorithm was compared with that of other algorithms in terms of visual effect and image quality evaluations. Experiments show that the proposed algorithm can remove color deviation of an underwater image, as well as improve its clarity and contrast. Compared with the original image, the entropy, UIQM, and UCIQE of the processed image increase by at least 5.2%, 1.25 times, and 30.8%, respectively, thereby proving that the proposed algorithm can effectively improve the visual quality of underwater images. 相似文献
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针对图像获取过程中外界光照的非均匀性会使图像存在阴影区和高亮区,从而丢失图像细节的问题,本文结合偏微分理论,提出了基于直方图均衡化的偏微分图像增强方法。该方法首先将图像变换到梯度域,通过梯度场的变换得到新的梯度函数;然后应用最小二乘原理,对梯度场中变换后的图像进行重建以增强图像的纹理细节,表现原本不清楚的细节信息。另外,针对光照的不均匀特性,结合直方图均衡化,提出反均衡变换来增强图像的亮度和对比度。提出的算法采用有限差分法将图像离散化,并与热方程相结合,其计算简单,运行速度快,具有较强的灵活性和较广的应用范围。采用VisiualC++编程,对于大小为512pixel×512pixel的图像的处理时间为35ms,达到了视频实时增强显示要求。 相似文献
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A. ENTWISTLE 《Journal of microscopy》2004,214(3):272-286
A means for improving the contrast in the images produced from digital light micrographs is described that requires no intervention by the experimenter: zero‐order, scaling, tonally independent, moderated histogram equalization. It is based upon histogram equalization, which often results in digital light micrographs that contain regions that appear to be saturated, negatively biased or very grainy. Here a non‐decreasing monotonic function is introduced into the process, which moderates the changes in contrast that are generated. This method is highly effective for all three of the main types of contrast found in digital light micrography: bright objects viewed against a dark background, e.g. fluorescence and dark‐ground or dark‐field image data sets; bright and dark objects sets against a grey background, e.g. image data sets collected with phase or Nomarski differential interference contrast optics; and darker objects set against a light background, e.g. views of absorbing specimens. Moreover, it is demonstrated that there is a single fixed moderating function, whose actions are independent of the number of elements of image data, which works well with all types of digital light micrographs, including multimodal or multidimensional image data sets. The use of this fixed function is very robust as the appearance of the final image is not altered discernibly when it is applied repeatedly to an image data set. Consequently, moderated histogram equalization can be applied to digital light micrographs as a push‐button solution, thereby eliminating biases that those undertaking the processing might have introduced during manual processing. Finally, moderated histogram equalization yields a mapping function and so, through the use of look‐up tables, indexes or palettes, the information present in the original data file can be preserved while an image with the improved contrast is displayed on the monitor screen. 相似文献
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为了使电机机械部件按照标准要求运行、满足自动化生产需求,提出一种应用红外图像识别技术的电机滑模变结构同步控制方法。利用光学系统、扫描器、探测器和制冷机等设备,组成热成像系统,采集目标具体信息,通过空间域增强和灰度均衡操作,增强图像整体画质和均匀灰度值,利用 Laplacian 算子锐化图像边缘,丰富细节信息,保护图像背景,将静止坐标系变换为旋转坐标系,结合电机的电压、定子磁链与转矩方程,构建电机运动数学模型;针对滑膜同步控制器,预留图像传输接口,将图像信息转变为电信号,选取切换函数,设置函数切换、状态变量和等效 3 种控制规律,结合不同目标实际情况,完成滑膜变结构同步控制。仿真结果表明,该算法能够获得更多目标信息,提供丰富的控制依据,提高了电机滑模变结构同步控制过程的精准度和稳定性。 相似文献
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二维扫描共焦显微镜的研究 总被引：4，自引：1，他引：3
从光学系统、机械扫描、光电转换、数据采集、计算机控制、三维重建等几大方面详细地介绍了研制的二维扫描共焦显微镜 ,并对其应用前景进行了预测。 相似文献
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传统红外图像增强方法由于未考虑人眼视觉特性而存在\"超区间值\",故极易丢失图像细节。本文结合对数图像处理（LIP）理论,提出了基于参数化对数模型（PLIP）的平台直方图均衡图像增强方法。该方法首先将图像变换为灰度色调函数;然后应用PLIP模型对变换后的图像进行重建,结合平台直方图均衡化来增强图像的对比度和细节信息,并利用图像评价函数（EMEE）与信息熵（En）确定模型的参数值。最后,研制了算法硬件平台,分别用中波和长波红外成像系统对算法进行了实验验证。实验结果显示：该方法对不同场景的图像均可取得很好的增强效果,图像的EMEE值比传统的平台直方图均衡算法提高至少5倍以上,对改善图像质量和视觉效果具有实用价值。 相似文献
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射线图像增强技术仿真研究 总被引：1，自引：0，他引：1
陈燕 《机械工程与自动化》2012,(2):56-57,60
图像增强在生物医学、无损检测、卫星遥感等领域得到广泛应用。对于低对比度射线图像而言,局部图像的反差较小是其特点。针对这一特点,将全局自适应均衡与局部动态增强相结合,通过增强倍数进行局部动态调整以适合各种对比度增强的要求。仿真结果表明,该算法能有效提高低对比度射线图像的整体对比度并同时突出细节。在实际应用中,对于其他成像技术的处理也有很好的参考价值。 相似文献
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The quantification of fluorescent emission from biological specimens can only be carried out in cellular regions where the relationship between fluorophore concentration and fluorescent emission is linear. Using a confocal scanning laser microscope, we show that quantification of fluorescent emission from biological samples labelled with fluorescein and fluorescein analogues mounted in a viscous medium can be readily achieved. Where the distribution of fluorophore is highly localized, for example in cells labelled for immunofluorescence analysis, we demonstrate that analysis of fluorescence depolarization can identify regions in which fluorophore concentration exceeds the range in which the relationship to fluorescent emission is linear. We also demonstrate that, under the conditions examined, depth-dependent effects, fading and quenching are either small enough to be ignored or can be corrected for mathematically when quantifying fluorescent emission. 相似文献
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The protein organization within focal adhesions has been studied by state‐of‐the‐art super resolution methods because of its thin structure, well below diffraction limit. However, to achieve high axial resolution, most of the current approaches rely on either sophisticated optics or diligent sample preparation, limiting their application. In this report we present a phasor‐based method that can be applied to fluorescent samples to determine the precise axial position of proteins using a conventional confocal microscope. We demonstrate that with about 4,000 photon counts collected along a z‐scan, axial localization precision close to 10 nm is achievable. We show that, with within 10 nm, the axial location of paxillin, FAK, and talin is similar at focal adhesion sites, while F‐actin shows a sharp increase in height towards the cell center. We further demonstrated the live imaging capability of this method. With the advantage of simple data acquisition and no special instrument requirement, this approach could have wide dissemination and application potentials. Microsc. Res. Tech., 76:1070–1078, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
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M.M. DYKAS K. PODDAR S.L. YOONG V. VISWANATHAN S. MATHEW A. PATRA S. SAHA G. PASTORIN T. VENKATESAN 《Journal of microscopy》2018,269(1):14-22
Carbon nanotubes (CNTs) have become an important nano entity for biomedical applications. Conventional methods of their imaging, often cannot be applied in biological samples due to an inadequate spatial resolution or poor contrast between the CNTs and the biological sample. Here we report a unique and effective detection method, which uses differences in conductivities of carbon nanotubes and HeLa cells. The technique involves the use of a helium ion microscope to image the sample with the surface charging artefacts created by the He+ and neutralised by electron flood gun. This enables us to obtain a few nanometre resolution images of CNTs in HeLa Cells with high contrast, which was achieved by tailoring the He+ fluence. Charging artefacts can be efficiently removed for conductive CNTs by a low amount of electrons, the fluence of which is not adequate to discharge the cell surface, resulting in high image contrast. Thus, this technique enables rapid detection of any conducting nano structures on insulating cellular background even in large fields of view and fine spatial resolution. The technique demonstrated has wider applications for researchers seeking enhanced contrast and high‐resolution imaging of any conducting entity in a biological matrix – a commonly encountered issue of importance in drug delivery, tissue engineering and toxicological studies. 相似文献
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Fluorescent emission and fluorophore concentration are only linearly related below particular concentrations of fluorophore. Theoretically, analysis of fluorescent polarization might allow identification of situations in which local concentrations of fluorophore are above the range of linear response. Using a confocal scanning laser microscope, we demonstrate that progressive depolarization of fluorescent emission from fluorescein and fluorescein analogues occurs over the concentration range where linearity is lost. Critically, depolarization of emission is first seen at concentrations of fluorophore slightly below those at which linearity is lost. Thus, polarization analysis can be used to determine whether the local concentration of fluorophore is such that quantitative analysis can be carried out. 相似文献
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Oliver Trepte 《Scanning》1995,17(3):171-174
An optical spectrometer for the visible range has been developed for the confocal scanning laser microscope (CSLM) Phoibos 1000. The spectrometer records information from a single point or a user-defined region within the microscope specimen. A prism disperses the spectral components of the recorded light over a linear CCD photodiode array with 256 elements. A regulated cooling unit cools the diode array, thereby reducing the detector dark current to a level, which allows integration times of up to 60 s. The spectral resolving power, λ/Δλ, ranges from 400 at λ = 375 nm to 100 at λ = 700 nm. Since the entrance aperture of the spectrometer has the same diameter as the detector aperture of the CSLM, the three-dimensional spatial resolution for spectrometer readings is equivalent to that of conventional confocal scanning, that is, down to 0.2 μm lateral and 0.8 μm axial resolution with an N.A.=1.3 objective. 相似文献
