共查询到20条相似文献,搜索用时 62 毫秒
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According to non-rigid medical image registration, new method of classification registration is proposed. First, Feature points are extracted based on SIFT (Scale Invariant Feature Transform) from reference images and floating images to match feature points. And the coarse registration is performed using the least square method. Then the precise registration is achieved using the optical flow model algorithm. SIFT algorithm is based on local image features that are with good scale, rotation and illumination invariance. Optical flow algorithm does not extract features and use the image gray information directly, and its registration speed is faster. The both algorithms are complementary. SIFT algorithm is used for improving the convergence speed of optical flow algorithm, and optical flow algorithm makes the registration result more accurate. The experimental results prove that the algorithm can improve the accuracy of the non-rigid medical image registration and enhance the convergence speed. Therefore, the algorithm has some advantages in the image registration. 相似文献
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基于光流的运动小目标检测算法 总被引:2,自引:0,他引:2
运动目标的检测是目标识别与跟踪的关键技术之一。光流技术是一种以物体的运动特征来检测目标的方法,它的提出为运动小目标的检测开辟了新的空间。在一个搜索跟踪系统中使用光流技术检测和跟踪空中小目标,目标大概为5~10个像素,而且背景复杂,相机抖动,普通分割算法无法得到小目标。在目标的运动明显异于背景的情况下,通过利用基于光流的目标检测算法来检测出小目标,同时运用高斯金字塔模型,提高算法的运算速度。试验结果表明提出的基于光流的检测算法在背景运动的红外图像中取得了较好的效果。 相似文献
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Lei Yang Qingyuan Li Xiaowei Song Wenjing Cai Chunping Hou Zixiang Xiong 《Entropy (Basel, Switzerland)》2021,23(7)
This paper proposes an improved stereo matching algorithm for vehicle speed measurement system based on spatial and temporal image fusion (STIF). Firstly, the matching point pairs in the license plate area with obviously abnormal distance to the camera are roughly removed according to the characteristic of license plate specification. Secondly, more mismatching point pairs are finely removed according to local neighborhood consistency constraint (LNCC). Thirdly, the optimum speed measurement point pairs are selected for successive stereo frame pairs by STIF of binocular stereo video, so that the 3D points corresponding to the matching point pairs for speed measurement in the successive stereo frame pairs are in the same position on the real vehicle, which can significantly improve the vehicle speed measurement accuracy. LNCC and STIF can be used not only for license plate, but also for vehicle logo, light, mirror etc. Experimental results demonstrate that the vehicle speed measurement system with the proposed LNCC+STIF stereo matching algorithm can significantly outperform the state-of-the-art system in accuracy. 相似文献
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为了提高汽车夜间行驶安全性能,设计并实现了一套基于红外图像处理的夜视安全系统。使用被动式红外相机对车辆和行人进行红外成像以得到车辆前方行人和车辆的准确位置;测距必须确定对象的形心,对红外图像的灰度值进行判定区分行人和车辆,对行人使用中值空域滤波方法进行降噪,对车辆使用db4小波进行预处理,然后使用基于图像边缘的图像分割方法进行图像分割,使用最大类间方差评估确定分割结果,再进行区域提取得到形心坐标;使用小孔成像模型计算形心与本车的距离,提取本车速度、加速度参数计算理论碰撞时间,当理论碰撞时间小于时间阈值时进行声光告警,从而实现实时预警。系统使用DIR-384-P红外相机,系统算法使用PFGA实现,测试结果表明,经过标校和加固后,系统与目标存在5米距离时,车辆测距的误差率达到2.74%,行人测距的误差率低于3.9%,具有一定的实际应用价值。 相似文献
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为了准确、快速的在动态场景中对运动车辆进行检测,提出一种基于特征点光流聚类的车辆检测方法。该方法取Harris角点为特征量,通过对特征点做光流提取来剔除一些没有运动的干扰角点,然后再通过模糊U邻域(FUNN)聚类算法剔除噪音、孤立点和不感兴趣样本并实现前景和背景的分离,最后通过设定阈值判断前景目标是否是车辆。实验结果证明在复杂的动态场景中该算法具有更高的车辆识别率。 相似文献
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The paper discusses mainly how to check the defects such as fiber-stacking fiber-cut and fiber-uneven with an improved method in the process of fiber optic gyroscope coil winding. In the paper, it is aimed at the gray level image of optic fiber coil winding to get binary image using mathematical morphology and to get optic fiber position image using the improved moving target detection algorithm, on the base of the optic fiber position image, to figure out the relative position of adjacent optic fiber. Through the value of the relative position of adjacent optic fiber, the status of optic fiber winding can be estimated. Experimental results show that the entire image processing and defect detection method can effectively distinguish the defects in the process of optical fiber coil winding. 相似文献
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基于几何代数的彩色光流场计算 总被引:4,自引:0,他引:4
提出了一种新的基于几何代数的彩色光流场计算方法.从新的角度出发讨论了运用几何代数的概念来解决彩色图像序列的可行性和简便性.在几何代数域内对彩色图像序列用多重矢量表示,证明了彩色光流场分析时进行约束条件时的测量问题,通过多重矢量而非多通道的图像处理方法来表示图像连续特性,从而扩大了测量范围;然后依据物体色彩在运动过程中保持不变的原理,在几何代数域内推导了彩色图像序列的光流约束方程及其解法.结果表明,该算法能够显著提高各种情况下的彩色光流场计算能力. 相似文献
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A field prototype of a laser-based non-intrusive vehicle detection system has been developed for the measurement of delineations of moving vehicles on the highway. This prototype is based on our previous research on the principle of the measurement. The detection system uses two laser lines that are projected onto the ground as probes. The reflected light is collected and focused onto a photodiode array by an optical system. Vehicle presence is detected based on the absence of reflected laser light. By placing two identical laser/sensor pairs at a known distance apart, the speed of both the front and rear of a vehicle can be calculated based on the times when each sensor is triggered. The detector data are acquired and processed by a real-time system to obtain speed, acceleration, and length of a detected vehicle. The travel time of a vehicle can be acquired by detecting a vehicle at the beginning of a link and re-identifying the same vehicle at the end of the link. Several tests have been done with the field prototype system on the highway. The testing results show that the system can obtain the accuracy of measurement necessary to distinguish between moving vehicles on the highway. This article describes the design and implementation of each functional component of an advanced version of the field prototype system. 相似文献
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针对现有动态背景下运动目标检测算法的不足,提出一种基于光流场分析的运动目标检测算法.首先根据前背景在光流梯度幅值和光流矢量方向上的差异确定目标的大致边界,然后通过点在多边形内部原理获得边界内部的稀疏像素点,最后以超像素为节点,利用混合高斯模型拟合的表观信息和超像素的时空邻域关系构建马尔可夫随机场模型的能量函数,并通过使目标函数能量最小化得到最终的运动目标检测结果.该算法不需要任何先验假设,能够同时处理动态背景和静态背景两种情况.多组实验结果表明,本文算法在检测的准确性和处理速度上均优于现有算法. 相似文献
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针对光电跟踪系统中实时提取运动目标脱靶量的应用需求,设计了一种基于灰度直方图的Mean-shift 图像跟踪算法,对算法中目标模型与候选模型的建立进行了改进,抑制了背景像素对目标跟踪产生的影响。算法在系统上位机Visual C+ + 6.0平台上实现,当光电跟踪系统捕获到运动目标后,利用Mean-shift图像跟踪算法跟踪运动目标,并实时将运动目标脱靶量作为伺服控制系统的输入信号,驱动跟踪器跟踪目标。实验结果表明:设计的算法可以实时、准确、有效地跟踪运动目标,使稳定后的脱靶量换算得到的角偏差量控制在30"之内。 相似文献
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基于光学菲涅耳衍射的"盲数字水印"技术 总被引:3,自引:0,他引:3
基于光学菲涅耳衍射,设计了一种新的“盲数字水印”计算方法。水印图像通过离散菲涅耳衍射变换成一复矩阵,将此复矩阵的实部和虚部分开,分别嵌入到宿主图像的不同位置中。通过将水印嵌入点的宿主图像的像素值更改为其近邻像素值的均值,而实现“盲水印”的提取。数值计算结果表明:该水印计算法对像素变换攻击具有很强的鲁棒性,如图像亮度、对比度和灰度曲线的调整;能抵抗JPEG有损压缩、剪切和噪声污染攻击;能抵抗对图像的重采样攻击,可从显示屏幕拷贝的图像中提取水印。由于该方法为使用者提供了灵活的水印嵌入方式和双重密钥的选取,以及提取水印不需要原始图像数据,因而使该方法具有很高的安全性和实用价值。 相似文献
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环境感知是无人车夜间行驶中的一项关键任务,提出一种改进的YOLOv3网络,以实现夜间对无人车获取的红外图像中行人、车辆的检测,将判断周边车辆的行驶方向问题转化为预测车辆位置的角度大小问题,并与深度估计信息进行融合对周边车辆行驶的距离和速度作出判断,从而实现夜间无人车对周边车辆行驶意图的感知。该网络具有端到端的优点,能实现整张图像作为网络的输入,直接在输出层回归检测目标的边界框位置、所属的类别和车辆的角度预测结果,并和深度估计信息融合得到周边车辆的距离和速度信息。实验结果表明,使用改进的YOLOv3网络对夜间无人车获取的红外图像进行目标检测的时间为0.04 s/帧,角度和速度预测效果较好,准确性和实时性达到了实际应用要求。 相似文献
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基于最大模糊熵和遗传算法的图像分割 总被引:3,自引:0,他引:3
为了分割照度不均匀的网格图像,提出了一种基于最大模糊熵和遗传算法的阈值分割方法。基于模糊集合理论,根据像素灰度值把原始图像中的像素分为黑和亮两个模糊集,利用最大模糊熵准则确定模糊区间的范围,寻找模糊参数的最优组合,实现图像分割。由于穷举法搜索模糊参数的最优组合存在计算复杂度高、占用存储空间大等缺点,因此采用了遗传算法确定最优阈值。为了验证该方法的有效性,对其进行了图像分割实验,并与最大类间方差法、迭代法和一维最大熵法进行了比较。实验结果表明,该方法能够自动、有效地选取阈值,分割效果优于其它三种算法,并能保留原始图像的主要特征。 相似文献
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在光学精密测量中,相移干涉法应用广泛。常用的相移器件容易出现相移误差,采用等步距相位提取算法会产生测量误差。基于最小二乘的迭代相位提取算法可以有效消除该类相位提取误差,提高测量精度,但是其迭代过程运行时间长,效率低。提出了一种基于选择采样的迭代相位提取算法,先对干涉图像进行等间隔抽样,降低计算量;再根据对比度滤除干涉图像中低质量像素点,防止误差增大,进行最小二乘迭代求解相位。仿真实验对算法进行了分析和验证,在抽样间隔为2时的选择采样方法与所有像素点全部代入计算相比,运行时间从6.687 s降为0.725 s,均方根误差仅为0.032 9。实验结果证明:选择采样的迭代相位提取算法运算时间短、误差小,非常适合高速相移干涉测量应用。 相似文献
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Ru-Chao Tan Tong Lei Qing-Min Zhao Li-Hua Gong Zhi-Hong Zhou 《International Journal of Theoretical Physics》2016,55(12):5368-5384
To improve the slow processing speed of the classical image encryption algorithms and enhance the security of the private color images, a new quantum color image encryption algorithm based on a hyper-chaotic system is proposed, in which the sequences generated by the Chen’s hyper-chaotic system are scrambled and diffused with three components of the original color image. Sequentially, the quantum Fourier transform is exploited to fulfill the encryption. Numerical simulations show that the presented quantum color image encryption algorithm possesses large key space to resist illegal attacks, sensitive dependence on initial keys, uniform distribution of gray values for the encrypted image and weak correlation between two adjacent pixels in the cipher-image. 相似文献