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Calibration plays an important part in the structured light system. It used to be regarded as time-consuming, expensive and hard to implement. In this paper, we introduce a novel and fast method to calibrate the structured light system by using the camera to control the projector to “capture” images. Firstly, we projected just six trapezoidal grayscale pattern to establish the corresponding pixel between the camera and the projector, then we converted the camera image to its corresponding projector image. Thus the structured light system can be easy controlled by the camera calibration. Experiments showed that the present calibration method is fast, easy and accurate. 相似文献
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An array illuminator is a device/optical system that splits an incoming beam of light into an array of many light spots/beams. It is useful in logic systems and in optical digital computing or in switching systems to energize arrays of components such as logic gates, optically bistable devices and electro-optic modulators. Array illuminators working in white light are interesting because they do not suffer from coherent noise and yield better signal-to-noise ratio. We propose configurations for array illuminator based on Fresnel diffraction and working under white light illumination conditions. Performance evaluation of the illuminators is also undertaken and the results of investigation are reported. 相似文献
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A new method for obtaining color rainbow holograms of 3D scenes using single wavelength laser is proposed and implemented by combining integral photography, computer graphics and rainbow holography. In the method, three integral photography (IP) images whose colors correspond to three primary colors are calculated by simulating integral photography, and exported on the film. By illuminating the IP images with diffused coherent beam from the opposite side, three images of the 3D scene are reproduced and overlapped on a particular image plane by the three linear micro-lens arrays. The linear micro-lens arrays can be regarded as the slits. A color rainbow hologram can be created after a single exposure by interfering the reproduced 3D images and the reference beam. Furthermore, we demonstrate experimentally the new method for a simple case and the results can be generalized in integral photography. 相似文献
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A phase-stepping lateral shearing Sagnac interferometer for wavefront measurement is described. Phase shifting is implemented using a polarisation modulator operating on the wavelength independent Pancharatnam's phase allowing accurate measurement of phase maps even with broadband light. We demonstrate the interferometer by measuring a range of different wavefront shapes using both laser and white light. 相似文献
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以正硅酸乙酯作为前驱体,利用碱催化方式制备了SiO2溶胶,采用提拉法在K9基片上镀制SiO2单层薄膜,分别用热处理、紫外辐射处理、氨水加六甲基二硅胺烷气氛处理和酸碱复合膜4种后处理法对膜层进行处理,采用分光光度计、红外光谱、扫描探针显微镜、静滴接触角测量仪、椭偏仪等分析了薄膜的特性,通过真空环境加速污染实验对处理前后的膜层进行抗污染能力对比,结果表明:在碱性SiO2膜层上加镀一层酸性SiO2膜的复合膜层整体透过率仍保持在99%以上,疏水角达到128°,膜层真空抗污染能力大大加强。 相似文献
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介绍了基于光学干涉原理的图像分割理论算法。在计算机上模拟一个均匀相干光源、一个滤波器和一个接收屏。选择强度 相位的转换曲线,将输入图像的强度信息转化成伪相位信息,并显示在滤波器上。利用光源照明滤波器上的相位图,在接收屏上得到其干涉条纹。再通过选择阈值对干涉图进行分割得到二值图,从而实现输入图像的边缘分割。计算结果表明,该方法得到的图像轮廓,与Sobel 算子效果相当。与实验结果对比分析可得,改善硬件并实现良好的分割效果的关键在于:控制光源的相干长度,或增大液晶的点阵间隔,并利用CCD相机和计算机相连,对干涉图进行二值化。 相似文献
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针对现存的大多图像增强算法增强的图像可见性丢失问题,提出了一种基于BIRCH聚类加速的彩色图像增强算法;首先,通过BIRCH聚类加速确定数据库中与输入图像直方图相似度最高的图像来提取图像特征;然后,选择最小欧氏距离的特征值进行图像融合以获取目标图像;最后,增强图像通过目标图像直方图规范化和后期处理获得;大量图像融合实验结果验证了算法的有效性,该算法扩展了图像增强的类别,解决了增强过程中可能出现的可见性丢失问题,使图像增强的适应性更强;另外,EM、CII和SSIM评估指标的结果表明该算法明显改善了增强效果。 相似文献
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We propose two approaches to encrypt color images based on interference and virtual optics. In the first method, a color image is first decomposed into three independent channels, i.e., red, green and blue. Each channel of the input image is encrypted into two random phase-only masks based on interference. In the second method, a color image is first converted into an image matrix and a color map, and only the image matrix is encrypted into random-phase masks based on interference. After the phase masks are retrieved, a concept based on virtual optics is further applied to enhance the security level. Numerical simulations are demonstrated to show the feasibility and effectiveness of the proposed methods. 相似文献
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在时域中求解得到,光路中存在色散介质的情况下,白光双光束干涉光强度.由此证明了:用白光干涉法测量得到的是白光在色散介质中的群折射率,而并非相关报道中认为的折射率;讨论了介质厚度及色散对于涉条纹的可见度和干涉条纹显现时动镜移动范围的影响.上述结论得到了实验验证. 相似文献
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An enhanced asymmetric cryptosystem for color image is proposed by using equal modulus decomposition (EMD) in the gyrator transform domains. In this scheme, the EMD is performed to create the effective trapdoor one-way function. Moreover, to enhance the security of the cryptosystem, the Baker mapping is considered and utilized for scrambling the RGB components of the color image. The parameters in the Baker mapping and gyrator transform can be served as the extra keys of the entire cryptosystem. Various types of attacks are considered in the robustness analysis experiments. Some numerical simulations are made to verify the validity and capability of the proposed color encryption algorithm. 相似文献
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提出一种新的虚拟光学加密方法,该方法分3个步骤将两幅图像隐藏于3个随机相位板中。将两幅图像分别作为相位和幅度信息隐藏于一个复数场中,利用随机相位板作为参考光,并采用数字全息术将该复数场转换成平稳随机白噪声,利用干涉加密原理进一步将此白噪声储存于2个随机相位板中,从而将两幅图像信息隐藏于3个纯随机相位板中。该方法原理简单,无需进行迭代操作。计算机模拟结果显示:任何一个密钥错误,均无法得到原始图像的任何信息。同时,解密过程对系统中距离及波长等参数非常敏感,较大地提升了系统的安全性。 相似文献
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The phase error and its periodic behavior caused by the partial intensity saturation of fringe patterns in the digital projection grating phase-shifting profilometry are studied. A saturation coefficient K is defined to describe the saturation degree of the fringe patterns projected on a measured object. The distribution of the phase error is analyzed through a simulation method. Moreover, a novel phase-recovering algorithm is studied to resolve the phase error issue introduced by the partial saturated fringe patterns. The real phase can be recovered by the unsaturated intensity values. A series of results corresponding to different degrees of saturation defined by K are given to prove the validity of the proposed algorithm. 相似文献
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Color image watermarking has become essential and important copyright protection or authentication scheme. It is noted that most of the existing color image watermarking algorithms are performed only in the single domain (spatial domain or frequency domain), and not to integrate these merits of the different domains. By utilizing the generating principle and distribution feature of the direct current (DC) coefficient, a novel blind watermarking algorithm is proposed for color host images in this paper. Firstly, the Y luminance of host image is divided into 8 × 8 sub-blocks and the DC coefficients of each block are directly calculated in the spatial domain without DCT transform. Secondly, according to the watermark information and the quantization step, the DC coefficients are calculated and their increments are further utilized to modify directly the values of all pixels in the spatial domain instead of the DCT domain to embed watermark. When watermark extraction, only the watermarked image and the quantization step are needed in the spatial domain. Experimental results show that the proposed method not only can resist both traditional signal processing attacks and geometric attacks, but also has more efficient in computational complexity. Comparisons also demonstrate the advantages of the method. 相似文献