共查询到20条相似文献,搜索用时 62 毫秒
1.
鉴于利用彩色视觉装置进行在线测量是颜色测量在工业应用发展的趋势,而光源的光谱分布和相机响应函数与人眼的光谱响应曲线的不一致会严重影响测量的精确性,在人工D65光源和LED阵列光源照明下,利用相同的工业相机获取校正图片,采用多项式回归方法在与设备无关空间sRGB和CIEL*a*b*空间进行校正。实验结果显示在校正前平均色差分别为27.68E和16.09E,人工D65光源照明下获取的图片色差较小,校正后不同光源下获取图片的色度趋于一致,分别为2.56E和2.39E。采用sRGB颜色空间,在校正精度、校正步骤、图片显示等方面都要优于CIEL*a*b*空间。以一幅拍摄的实际图片校正为例,显示了色度校正对彩色装置的重要性。 相似文献
2.
3.
4.
基于感知颜色空间的灰度图像伪彩色编码 总被引:12,自引:3,他引:9
提出了一种基于感知颜色空间的灰度图像伪彩色编码的新方法。首先建立了灰度级和色调、饱和度和亮度等与人的感知颜色特征之间的函数关系。然后通过感知颜色空间到RGB空间的矩阵变换 ,得到相应的RGB值。最后将其分别送入彩色显示器的红、绿、蓝枪即可得到伪彩色图像。建立了相应的数学模型 ,给出了分析和实验结果 ,并对如何获得符合人们视觉习惯的伪彩色图像等问题进行了讨论。根据不同的实际需要 ,可以方便地建立灰度级与颜色的色调、饱和度与亮度的不同对应关系 ,使产生的伪彩色图像符合人们的感知习惯。用该方法得到的伪彩色是近似均匀的 ,即在不同的灰度级上 ,相邻两灰度级对应的色差近似相等 相似文献
5.
牛顿对光与颜色的研究 总被引:1,自引:0,他引:1
详细叙述了牛顿在1665-1675年间对光和颜色的研究过程,阐明牛顿从原来看到光谱带有五种颜色到认为光谱带有七种颜色的转变,论述了这种转变的原因 相似文献
6.
7.
采用光学积分原理设计的光电色度仪器,由于其结构简单、测量速度快、成本低等优点已被广泛地应用在产品的色度检验控制过程中。基于微型颜色传感器的颜色测量仪器也属于光电色度类仪器,由于它不能完全模拟标准色度观察者和标准光源,即不能完全满足卢瑟(Luther)条件,所以其测量值RGB与三刺激值XYZ并不相等,且存在非线性关系。讨论了采用BP神经网络进行微型颜色传感器颜色特性校正的方法,其优点是对仪器的匹配滤色片要求较低,只要在测量软件中增加训练好的校正网络程序,就可以获得准确的颜色三刺激值。 相似文献
8.
等腰三角形结构光编码的面形测量误差分析 总被引:2,自引:1,他引:2
对具有等腰三角形齿结构的线性结构光编码的三维面形测量技术(LCP)进行了误差分析,推导了由于随机电噪声、相移误差带来的测量误差,并利用计算机系统仿真研究了量化误差、光学系统误差等对测量结果的影响,且对理论分析的结果进行了验证。 相似文献
9.
系统研究了两步相移数字全息干涉术中相移误差引起的波前再现误差的计算和校正方法. 基于衍射物光相位分布的随机性和振幅相位的相互独立性原理,介绍了相移数字全息中物光波前再现误差的表达形式,推导出步长为π/2的两步算法中物光重建误差的表达式. 通过进一步分析这一重建误差的结构和特点,结合物光表达式,给出了自动校正相移误差引起的波前重建误差的校正方法. 该方法无需增加测量,在未知相移误差大小的情况下,只对标准两步相移算法恢复的物光复振幅进行处理就可以实现对物光振幅和相位的同时校正. 计算机模拟结果表明,校正后可将
关键词:
相移干涉术
数字全息
物光重建
误差校正 相似文献
10.
一种多视点视频自动颜色校正系统 总被引:1,自引:0,他引:1
针对多视点视频系统中视点间图像颜色不一致的问题,提出了一种多视点视频自动颜色校正系统。通过求取目标图像和源图像间的颜色校正矩阵,判断其是否满足全局校正的要求;对不满足要求的图像,通过图像分割和K-L变换(Karhunen-Loeve transform),建立起目标图像和源图像中各分割区域间的局部映射关系,并通过感兴趣区域匹配,来实现对源图像的校正,最后通过视频跟踪技术实现对视频图像的校正。以标准的多视点测试图像集为例,通过将新方法与直方图匹配、全局一维线性校正算法等进行比较,表明新方法能消除匹配失真的影响,且具有较好的颜色校正效果。研究结果表明该系统可以很好地揭示图像间的颜色变化关系,并且具有很好的内容自适应性,是一种有效的多视点视频图像系统颜色校正方法。 相似文献
11.
12.
为提升线结构光传感器的标定效率与精度,设计了一种集成自背光可调节位姿的平面棋盘格-同心圆互补线结构光标定系统。该系统基于同心圆圆心的真实投影位置与投影椭圆圆心位置的几何关系,建立非线性优化偏心误差补偿模型,精确得到透射投影下圆心偏心误差补偿位置。该方法与传统标定方法对比降低重投影误差84.7%,有效解决了圆形标志物偏心误差补偿的高精度标定难题。通过将相机坐标系下过光心、光条中心线的平面与靶标平面结合,多次获取空间交线的坐标信息增加特征点,并使用最小二乘法拟合光平面方程,解决了因特征点少从而平面拟合标定精度较低的问题。在复杂环境下重复实验测得大尺寸砂轮外径误差均值为0.005 1 mm,结果表明该标定系统具有一定的准确性和简便实用性。 相似文献
13.
14.
15.
为了建立物体的整体三维模型,在一般线结构光三维视觉系统结构的基础上,提出了一种三维视觉扫描方式———被动模式。这种模式是基于摄像机不动,使物体旋转,实现对物体的全方位扫描,解决了物体三维模型周视扫描的问题。给出了物体旋转轴心坐标的标定方法和物体的三维重建过程。 相似文献
16.
17.
Decoding is a challenging and complex problem in a coded structured light system. In this paper, a robust pattern decoding method is proposed for the shape-coded structured light in which the pattern is designed as grid shape with embedded geometrical shapes. In our decoding method, advancements are made at three steps. First, a multi-template feature detection algorithm is introduced to detect the feature point which is the intersection of each two orthogonal grid-lines. Second, pattern element identification is modelled as a supervised classification problem and the deep neural network technique is applied for the accurate classification of pattern elements. Before that, a training dataset is established, which contains a mass of pattern elements with various blurring and distortions. Third, an error correction mechanism based on epipolar constraint, coplanarity constraint and topological constraint is presented to reduce the false matches. In the experiments, several complex objects including human hand are chosen to test the accuracy and robustness of the proposed method. The experimental results show that our decoding method not only has high decoding accuracy, but also owns strong robustness to surface color and complex textures. 相似文献
18.
K. Szelag G. Maczkowski R. Gierwialo A. Gebarska R. Sitnik 《Opto-Electronics Review》2017,25(4):326-336
This paper introduces a new comprehensive procedure for both geometric and colour calibration of structured light system. In order to perform both geometric and colour calibration procedure, a new calibration artifact is proposed. The intrinsic and extrinsic parameters of projector and camera are estimated by using an extended pinhole camera model with a tangential and radial distortion. Camera image plane coordinates are obtained by extracting features from images of a calibration artifact. Projector image plane coordinates are calculated on the basis of continuous phase maps obtained from a fringe pattern phase reconstruction procedure. In order to stereo calibrate camera-projector system, pairs of corresponding image plane points are calculated with subpixel accuracy. In addition, one of three pattern views is used in colour calibration. RGB values of a colour field pattern detected by camera and their reference values are compared. This comparison leads to derivation of a colour transformation matrix. The performance of the proposed method is tested by measuring plane, sphere and distance reference. Also 360 degrees complex object 3D model from a set of measurements is obtained. Residual mean errors for all tests performed are calculated. 相似文献
19.
Three-dimensional profile measurement of the blade based on surface structured light 总被引:3,自引:0,他引:3
As the blade must have precise size and accurate shape, three-dimensional profile measurement of the blade is very important. In this paper, three-dimensional profile measurement method of the blade based on surface structured light is proposed. A new phase unwrapping method is also proposed. This encoding method combined coding fringe pattern with the four-step phase-shifting method, the coding information is embedded into the phase, which can be used to determine fringe order for absolute phase retrieval. The encoding method is simple and easy to implement, so the phase unwrapping of the blade can be quickly perform. The experimental and simulation results show that the method can achieve a high precision, high speed and low cost three-dimensional profile measurement of the blade. 相似文献
20.
Structured light illumination (SLI) systems are well-established optical inspection techniques for noncontact 3D surface measurements. A common technique is multi-frequency sinusoidal SLI that obtains the phase map at various fringe periods in order to estimate the absolute phase, and hence, the 3D surface information. Nevertheless, multi-frequency SLI systems employ multiple measurement planes (e.g. four phase shifted frames) to obtain the phase at a given fringe period. It is therefore an age old challenge to obtain the absolute surface information using fewer measurement frames. Grey level (GL) coding techniques have been developed as an attempt to reduce the number of planes needed, because a spatio-temporal GL sequence employing p discrete grey-levels and m frames has the potential to unwrap up to pm fringes. Nevertheless, one major disadvantage of GL based SLI techniques is that there are often errors near the border of each stripe, because an ideal stepwise intensity change cannot be measured. If the step-change in intensity is a single discrete grey-level unit, this problem can usually be overcome by applying an appropriate threshold. However, severe errors occur if the intensity change at the border of the stripe exceeds several discrete grey-level units. In this work, an optimum GL based technique is presented that generates a series of projection patterns with a minimal gradient in the intensity. It is shown that when using this technique, the errors near the border of the stripes can be significantly reduced. This improvement is achieved with the choice generated patterns, and does not involve additional hardware or special post-processing techniques. The performance of that method is validated using both simulations and experiments. The reported technique is generic, works with an arbitrary number of frames, and can employ an arbitrary number of grey-levels. 相似文献