共查询到20条相似文献,搜索用时 156 毫秒
1.
字符识别中的畸变字符校正算法研究 总被引:1,自引:0,他引:1
文章提出了一种基于模板匹配的畸变字符识别算法。该算法可以自动校正由于柱面透视投影所引起的畸变字符图像,显著提高柱面字符识别的正确率。然后对校正后的图像进行字符定位,最终通过模板匹配算法对字符做出判决。试验结果表明,畸变字符校正算法有效地提高了算法对于圆柱面上字符的识别能力,在测试中取得了良好的效果。 相似文献
2.
短焦距大视角镜头会造成图像的径向畸变。在阐述了镜头畸变原理的基础上,结合对鱼眼图像经度校正算法的分析,提出一种基于经纬映射的径向畸变图像快速校正算法。该算法首先建立畸变图像球面坐标定位模型,确定畸变中心;再对各经纬度像素坐标映射,进行源图像与目标图像的空间坐标转换;最后利用双线性插值算法进行灰度重采样,完成畸变图像的校正。利用MATLAB软件进行了实验,结果表明,该算法能够以较低运算复杂度实现对短焦距大视角镜头畸变图像的快速校正,得到较好的校正效果,可用于针对精度要求不高、不具备参数标定条件的场合。 相似文献
3.
4.
本文提出了基于全局收敛线性搜索的内窥镜图像桶形畸变的校正方法。方法假定畸变为圆对称形式,并利用多项式映射将畸变图像从畸变图像空间映射到校正图像空间。根据内窥镜成像特性以及基于全局收敛的线性搜索法来确定畸变图像中心和多项式系数。采用非线性回归对校正图像进行补偿。试验结果证实,该方法校正效果好、响应速度快、满足需要定量分析的图像处理的要求。 相似文献
5.
大视场角的鱼眼镜头在成像时由于不同视场垂轴放大率不同,从而产生畸变使最终成像弯曲变形,这为识别和测量等应用带来了不便。针对传统经度校正方法的不足,将算法改进为双向经度鱼眼图像快速校正算法。通过对鱼眼图像有效区域进行划分,并对不同区域内的畸变点在横、纵两个方向上分别建立校正模型,确定畸变图像与理想图像之间坐标映射关系,求取校正坐标的位置。最后对图像进行非线性拉伸,改善图像中心与边缘放大率不同而产生的"膨胀感",获得符合人眼视觉习惯的图像。运用Matlab对3组图像进行校正实验,结果表明,该算法能快速有效地对鱼眼图像进行畸变校正。 相似文献
6.
7.
8.
实弹射击是部队的基础军事训练项目。现有报靶系统中基于计算机视觉的弹孔识别定位系统由于具有快速、精确、安全、人员成本低等优点而被广泛应用到该项目中。然而,计算机视觉系统处理的图像通常受镜头加工工艺以及相机轴向与被测对象所在平面不垂直的影响,导致被测对象的图像产生畸变,最终会给弹孔坐标位置的精准定位带来误差。为了提高基于计算机视觉的自动报靶系统的报靶精度,提出一种基于卷积神经网络的畸变校正算法,只需一张胸环靶面的模板图像即可模拟出大量训练数据集。训练完成后,输入一张畸变图片就可以得到该图片的畸变参数,并利用该参数完成对图像的畸变校正。与传统校正算法的对比结果表明,该算法校正效果较好,有利于提升基于计算机视觉的自动报靶系统的报靶精度。 相似文献
9.
10.
在皮肤反射式共聚焦显微成像过程中,针对MEMS振镜二维扫描引起的共聚焦图像畸变,开展了光束偏转理论分析,得出了投影面扫描图像的具体形状表征,理论畸变图像与真实畸变图像一致,明确了畸变机理,提出一种有效的畸变校正算法,实现对图像二维畸变的校正。首先记录原始光栅畸变图像,然后基于Hessian矩阵提取光栅中心线,拾取特征点并设置基准参考线,通过基于最小二乘法的7次多项式插值法标定二维方向像素畸变校正量,采用加权平均法填补间隙像素灰度值,最终实现图像畸变校正。利用网格畸变测试靶实验得出7次多项式插值后的校正决定系数最高、均方根误差值最低,整幅512行图像在7次多项式插值后最优行数占379行,比例为74%,通过残差分析,二维方向上残差最大为4个像素,最小为0个像素,平均为1.15个像素,校正结果较为精确。皮肤在体实时成像实验显示,图像畸变校正后组织结构特征更加真实准确,表明这种校正算法有效可行,有助于皮肤疾病的准确诊断。 相似文献
11.
Park J.H. Jang I.H. Kim N.C. 《Vision, Image and Signal Processing, IEE Proceedings -》2005,152(6):668-676
An efficient algorithm for rotational skew correction of business card images acquired in a PDA (personal digital assistant) camera is presented. The proposed method is composed of four parts: block adaptive binarisation (BAB), stripe generation, skew angle calculation and image rotation. In BAB, an input image is binarised block by block so as to lessen the effects of irregular illumination and shadow over the input image. In stripe generation, character string clusters are generated merging adjacent characters and their strings, and then only clusters useful for skew angle calculation are output as stripes. In skew angle calculation, the direction angles of the stripes are calculated using their central moments and then the skew angle of the input image is determined averaging the direction angles. In image rotation, the input image is rotated by the skew angle. Experimental results show that the proposed method yields root mean square error of 0.44/spl deg/ for test images of several types of business cards acquired by a PDA under various surrounding conditions. 相似文献
12.
该文针对机载双站SAR收、发系统分置的特点,首先建立了接收机静止模式下双站SAR的回波信号模型,然后分析该模式下几何特点、距离徙动及距离徙动差和方位向调频率的变化情况,接着讨论距离多谱勒域距离向调频率的变化情况,并提出了方位向调频率扰动函数的解析表达式,在此基础上结合单站的CS算法实现接收机静止的双站SAR数据聚焦,并对应用此成像算法所得扭曲聚焦图像进行几何校正处理。仿真实验验证了该文提出的方法的正确性和在接收机静止模式下应用此算法处理大测绘带成像的可行性。 相似文献
13.
V. A. Cherepenin A. V. Kokoshkin V. A. Korotkov K. V. Korotkov E. P. Novichikhin 《Journal of Communications Technology and Electronics》2018,63(3):212-219
A method for compensating the influence of unknown side lobes of a distorting instrument function on the quality of image recovery is proposed. A processing algorithm, based on the knowledge of the main lobe of the instrument function and its spectrum together with a universal reference spectrum, is used to compensate the contribution of the unknown side lobes to the spectrum of the distorted image. The stability of the method to the noise inherent in the improved images and various forms of distorting instrument functions is analyzed. High efficiency of the method of compensation is demonstrated in the cases in which the total contribution from the unknown side lobes to the resulting brightness of the distorted image significantly (four-fold) exceeds the contribution from the main lobe. 相似文献
14.
Image quality is an important challenge in image processing. The quality measures should be designed in the direction where the correlation between the mathematical evaluation and subjective evaluation is high. We propose a new image quality assessment relying on block-based singular vectors. The corresponded distorted blocks are projected onto the singular vector matrices of the original blocks. These projection coefficients are the main quality attribute. The algorithm is further developed into the reduced reference method. Eigenvectors of the covariance matrix of all original blocks are used as the constant basis to compute the projecting coefficients of all original and distorted blocks. Simulation results on different databases with various distortion types and comparison to state-of-the-art methods show the proposed method in most cases gives the best correlation with human evaluation. 相似文献
15.
A novel technique that uses boundary interpolation to correct geometric distortion and shading artifacts present in images of printed materials is presented. Unlike existing techniques, our algorithm can simultaneously correct a variety of geometric distortions, including skew, fold distortion, binder curl, and combinations of these. In addition, the same interpolation framework can be used to estimate the intrinsic illumination component of the distorted image to correct shading artifacts. We detail our algorithm for geometric and shading correction and demonstrate its usefulness on real-world and synthetic data. 相似文献
16.
虹膜识别中图像采集的研究 总被引:2,自引:2,他引:0
介绍了图像采集中的自动调焦方法,并给出了一种基于图像灰度处理的自动调焦判别函数--锐度判别函数,在此算法的基础上设计开发了虹膜识别的图像采集系统.实验证明,用此方法采集的虹膜图像纹理清晰,提高了系统的有效率. 相似文献
17.
V. N. Karnaukhov M. G. Mozerov 《Journal of Communications Technology and Electronics》2016,61(12):1426-1431
In this study, an original method for restoration of multispectral images by means of gradient reconstruction is proposed. The method uses a simple relationship between the gradient at the neighboring points in the distorted image and the gradient at distant points in the initial image. The result of restoration by the proposed algorithm excels the result obtained by the standard method based on the Wiener filtering. A new method for estimation of the parameters of the distorting motion-blur operator is also proposed. In this case, the blurred image is considered as a superposition of M shifted original images, and the autocorrelation convolution of the distorted image can be represented as a linear combination of M 2 mutual convolutions of several identical shifted images. Thus, the autocorrelation function of the distorted image is a straight line passing through the center, and the direction of this line and its length coincides with the parameters of the distorting operator. As compared to the best present-day algorithms, the proposed method exhibits higher accuracy of parameter estimation. In addition, computation of parameters with the use of this method takes much less time than with the use of popular estimation algorithms based on the Radon transform. 相似文献
18.
19.
为了提高图像的可调焦范围,以往的自适应清晰度自动调焦算法对深度和轻度离焦图像采取了不同的评价方式,却未给出明确的图像离焦深浅度判定方法,进而影响了算法的可行性。为解决该问题,从Sobel算子出发来提取图像边缘,并通过阈值选择出阶跃边缘,从而利用阶跃边缘宽度来判别图像离焦程度。经实验分析,该方法可以无参考地判断单张图像的清晰度。与SMD、Laplace等方法相比,它具有与场景无关的优势。不同场景的相同清晰度图片的边缘宽度标准差仅为0.0676。此外,边缘宽度的大小与图像离焦程度成正相关,证明了该方法的有效性。本文算法的判定准确率达到了86.8%,与高频和算法、基于无参考结构清晰度的算法相比具有一定优势。 相似文献