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基于CCD的航空相机自动检焦系统 总被引:1,自引:0,他引:1
要使航空相机获得高质量的图像,必须保证镜头的焦距和实际成像面的位置符合技术要求。提出了一种自动检测航空相机焦距和是否离焦(实际成像面的位置是否在焦深范围内)的系统,论述了系统的工作原理、硬件组成和软件设计。该系统采用平行光管产生检焦信息,利用CCD摄像头作光电转换器件接收图像,采用重心法处理数据,由光电线位移传感器和光栅数显表共同作用实现摄像头轴向的精确平移,从而能够确定相机的最佳成像位置和图像尺寸。最佳图像位置用来判断是否离焦,最佳图像尺寸用来计算焦距。使用该系统对航空相机镜头焦距的检测准确率达到99.87%、是否离焦的判断与试飞结果完全相同。 相似文献
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提出一种异形热态锻件几何尺寸测量方法。基于线激光器、CCD和伺服系统构建线激光扫描测量系统,通过提取图像上被锻件表面轮廓调制的激光条纹二维信息,经过坐标变换及点云三维重构得到锻件三维尺寸信息。针对被测异形锻件形貌特征,建立基于摄像机运动的扫描测量模型,并提出一种基于棋盘参考平面的摄像机光心轨迹求解方法。根据平面上特征点在CCD图像不同帧中的坐标拟合摄像机的运动轨迹,结合扫描测量模型实现对异形锻件完整轮廓尺寸的测量。通过实验对封头进行扫描测量,得到球冠部分截面测量直径误差小于4 mm,满足热态锻件测量要求,验证了该方法的可行性。 相似文献
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目的为了提高生产线上生物芯片点样质量检测的精度与效率,研究基于图像处理和卷积神经网络的算法,判断某生物芯片点样质量是否合格,并检测点样合格的生物芯片上的点样点半径。方法采用CCD相机获取生物芯片点样后的图像,通过图像预处理,利用canny边缘检测和圆的拟合等图像处理方法,得到点样点的几何信息,进而计算出点样点半径。同时提出基于卷积神经网络的点样质量检测方法,通过区域建议网络提取点样点卷积特征,引入分割全连接层来训练检测模型,通过离线训练来验证获得模型的最佳参数。结果和手动测量结果进行对比发现,半径误差不超过±0.1 mm,点样质量检测准确率为91.1%,单个生物芯片检测时间总和不超过1.6s。结论所提出的方法能够满足生产线上产品检测准确性和实时性的要求。 相似文献
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基于曲面主曲率的人耳结构特征提取方法 总被引:1,自引:1,他引:0
针对人耳识别问题,提出了一种自动提取人耳解剖学结构特征点的方法.首先对包含耳廓区域的侧脸图像进行预处理消除噪声和毛刺现象;然后把2D灰度侧脸图像看作是一个曲面,则利用曲面上位于边缘处的灰度变化较大,因此该位置的曲率就会大于周围灰度变化平坦位置处的曲率的性质,求曲面的最大主曲率和最小主曲率;最后通过自动阈值分割对两幅曲率图像进行阚值化,并进行融合得到耳廓解剖学特征边缘信息.实验表明,用该方法提取的结构特征边缘曲线光滑、连通性好,不受光照强度变化的影响,满足下一步识别的要求. 相似文献
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Measurement of absorption and reduced-scattering optical coefficients a and s is possible when a steady-state backscattered image is used on a sample surface. A new method for processing the backscattered image, acquired with a CCD, has been developed. The image is integrated to decrease sensitivity to noise. The resulting curve is defined as the integral reflectance. The curve is then fitted with a relaxation model to evaluate a and s . We have validated the method with calibrated scattering and absorption phantoms. The integral reflectance method is then applied to measurements of the a and s coefficients of human skin in vivo . 相似文献
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为减少或避开地球表面稠密大气层对可见光、红外辐射背景以及减少地面杂电波的严重干扰,从空中直接摄取与精密跟踪测量动态目标的光辐射及电波特性具有十分重要意义。国外机载,弹工及星载等先进测量手段皆采取了避开大气层的测量模式,本文设计了一种适用于飞机吊仓使用的TV跟踪测量系统,特别是从地面上直接遥控空中机载TV测量设备,采用双镜头双视场共用一个CCD接收器件进行二档大变双视场自动变焦技术以便能获取高清晰度 相似文献
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A method for recording digital holograms on an image intensifier coupled with a CCD sensor is presented. The advantage of the image intensifier is that it can be gated (electronic shutter action produced by controlling of the image intensifier's photocathode voltage). This allows us to record holograms with a short exposure time. Two holograms of an object submitted to dynamical displacements (e.g., vibrations) are recorded by two short exposures. The phase of the wave front recorded at different times is calculated from the recorded intensity by use of a digital Fourier-transform method. By comparison of the phases recorded it is possible to get the displacement of the object during a short interval. Experimental results are presented, and the problems related to the noise and to the spatial resolution are discussed. 相似文献
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A novel measuring system based on a single CCD camera and two laser projectors to record images and perform three-dimensional measurement of a distant object is proposed here. Because of the alignment of the laser beams which form in parallel with the optical axis of the CCD camera, projected spots will appear on the same scan line in a CCD image. As a result processing of a single scan line rather than the whole image is only required to identify the projected spots in the CCD image. Complex computation of video signals of the whole image via either pattern recognition or image analysis methods is therefore circumvented. On the basic of an established relationship between the distance and pixel counts between the projected spots in the CCD image, the proposed system not only measures the distance from a distant object but also the length of two arbitrarily designated points on the object. To provide better accuracy, intrinsic parameters of the CCD camera are taken into consideration in the measurement. Furthermore, the effect of laser diffusion is also proved to be irrelevant to the measuring accuracy here. Experimental results have demonstrated that the proposed measuring method is capable of yielding accurate results of three-dimensional measurement for a distant object in a very responsive way. 相似文献
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Xiao Tang Pierre L’Hostis Yu Xiao 《Journal of research of the National Institute of Standards and Technology》2000,105(4):565-569
An auto-focusing method in a digital image system is demonstrated that uses a standard deviation of pixel gray levels as a feedback signal. In this system, an optical microscope and a charge coupled device (CCD) camera are used to create clear pit images of optical discs. A dynamic focusing scheme is designed in the system-control software, which is able to eliminate environmental disturbances and other noises so that a fast and stable focus can be achieved. The method shows an excellent focusing accuracy. The performance and possible applications of this method are discussed. The test results for optical discs are given in this paper. 相似文献
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Measurement of phase objects by simple means 总被引:1,自引:0,他引:1
Massig JH 《Applied optics》1999,38(19):4103-4105
A printed fringe pattern is imaged by a CCD camera, whereas a phase object is placed in the ray path for imaging. The ray deflections distort the image of the pattern and are measured by evaluation of the image with the Fourier transform method. 相似文献