共查询到20条相似文献,搜索用时 140 毫秒
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与点扫描方式相比,面曝光选区激光熔化因具有成形效率高、残余应力水平低等优势,而成为极具发展前景的新一代选区激光熔化增材制造技术的发展方向。利用波长为915 nm的二极管连续激光器作为光源,结合电寻址反射式纯相位液晶空间光调制器,搭建了新一代面曝光选区激光熔化增材制造原理装置平台。获得了“○”形样式的面光斑曝光,基于光敏纸和低熔点金属粉末材料进行面曝光熔化成形并获得了样品,实现了面曝光选区激光熔化的原理性实验验证。 相似文献
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基于空间光调制器的多层图像的构建与可视化 总被引:1,自引:0,他引:1
为解决实时直观地观察多层再现图像的问题,提出利用发光材料实现其可视化.针对由沿光轴方向的二维图层组成的空间图像,利用高效、快速的三维Gerchberg-Saxton算法,得到位相型计算全息图,并通过计算机进行了数字模拟再现.阐述了三维Gerchberg-Saxton算法的流程,并搭建了基于液晶空间光调制器的位相全息图光学再现与可视化光路.利用液晶空间光调制器的灰度-位相曲线把计算全息图转换为灰度图,加载在液晶空间光调制器上,再现出高质量的三维光场,同时利用量子点材料的荧光特性实现了图像的可视化.实验结果表明,光学再现与计算机模拟结果较吻合.该技术在医学、军事、三维显示、微加工以及显微技术等领域有重要应用价值. 相似文献
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为解决实时直观地观察多层再现图像的问题,提出利用发光材料实现其可视化.针对由沿光轴方向的二维图层组成的空间图像,利用高效、快速的三维Gerchberg-Saxton算法,得到位相型计算全息图,并通过计算机进行了数字模拟再现.阐述了三维Gerchberg-Saxton算法的流程,并搭建了基于液晶空间光调制器的位相全息图光学再现与可视化光路.利用液晶空间光调制器的灰度-位相曲线把计算全息图转换为灰度图,加载在液晶空间光调制器上,再现出高质量的三维光场,同时利用量子点材料的荧光特性实现了图像的可视化.实验结果表明,光学再现与计算机模拟结果较吻合.该技术在医学、军事、三维显示、微加工以及显微技术等领域有重要应用价值. 相似文献
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基于液晶空间光调制器的空间滤波实验 总被引:1,自引:0,他引:1
空间滤波实验可以实现对输入物体的频谱分析及图像的边缘增强、噪声消除等各种图像处理。液晶空间光调制器可以作为衍射波面变换器件来使用。在空间滤波实验系统的滤波面上放置了液晶空间光调制器,并用CCD数码相机进行输出图像的观察和记录,分别给出了低通滤波、高通滤波、方向滤波等的仿真实验结果。该实验实现了输入数字物体的实时改变,并能够实时观察采用不同空间滤波器对输出像的影响。 相似文献
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为了在低照度条件下获取目标的彩色图像,提高夜间对目标的识别能力,提出了基于四波段图像融合的彩色夜视方法.采用F-P滤光片设计出了透射中心在三基色光中心波长及近红外波段的四波段滤光片,在各个透射区域的平均透射率均达90%以上;将四波段滤光片设计成圆形滤色轮结构,用分光计测得了各波段滤光片的光谱透射性;对加入滤光片后的系统信噪比进行了分析和计算,分析结果表明加入滤光片不会引入噪声,计算结果表明加入蓝色、绿色、红色和近红外波段滤光片的成像系统的信噪比分别是原来单色微光夜视系统信噪比的19.59%、38.45%、47.28%和46.70%.借助国产超二代像增强器在微光实验室进行了四波段图像采集及彩色图像融合实验,实验时光照度分别为1×10~(-3)lx和1×10~(-1)lx,对获取的图像质量进行了评价.结果表明:在照度为1×10~(-3)lx时,融合的彩色图像在均值、方差和熵这三项指标上均优于过滤后的蓝色和绿色的单色图像,且由于彩色图像中利用了近红外图像进行增强,使得彩色图像亮度更高,颜色分辨性更好;在照度为1×10~(-1)lx时,融合后的彩色图像的信息熵比红、绿、蓝三种基色图像的大,彩色图像携带的信息量更大.本文的研究对彩色夜视成像系统的设计和研发具有借鉴和指导意义. 相似文献
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复杂结构件由于有效厚度差异大和成像系统动态范围受限, 单一能量下的投影数据信息不完整, 常用CT重建算法及不完全数据重建算法无法在数据缺失严重的情况, 有效实现复杂结构件的CT重建. 为此论文提出基于对数解调的递变能量CT成像方法. 该方法在分析直接高动态CT成像所存在问题的基础上, 提出利用对数变换压缩递变能量投影序列动态范围, 并利用现有的基于图像灰度一致性的融合方法, 计算融合加权系数, 再经常规重建算法实现复杂构件的CT成像. 论文并以某复杂仪表为对象, 进行实验, 相比传统的固定能量成像方式, CT信息完整, 质量高. 从而说明论文所提出的方法, 能够实现CT系统动态范围的扩展, 实现复杂结构件的高动态CT成像. 相似文献
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This paper presents a novel structured light approach for the 3D reconstruction of specular surface. The binary shifting strip is adopted as structured light pattern instead of conventional sinusoidal pattern. Based on the framework of conventional High Dynamic Range (HDR) imaging technique, an efficient means is first introduced to estimate the camera response function. And then, dynamic range of the generated radiance map is compressed in the gradient domain by introducing an attenuation function. Subject to the change of lighting conditions caused by projecting different structured light patterns, the structure light image with middle exposure level is selected as the reference image and used for the slight adjustment of the primary fused image. Finally, the regenerated structured light images with well exposing condition are used for 3D reconstruction of the specular surface. To evaluate performance of the method, some stainless stamping parts with strong reflectivity are used for the experiments. And the results showed that, different specular targets with various shapes can be precisely reconstructed by the proposed method. 相似文献
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高速分幅成像系统中多路图像性能不一致的校正方法研究 总被引:4,自引:2,他引:2
针对用于获取具有时间分辨能力的序列图像的高速分幅相机而言,其图像处理主要包括了图形的几何形变校正、图形位置配准、一幅图像中各像元响应的平场校正及各幅图像响应一致性的校正等内容,不仅要解决每幅图像本身的问题,还要解决各幅图像间的形态对比的问题。通过对这些处理目的所涉及的方法逐一进行进一步的研究,所获得的处理方法用于实际图像的处理获得了比较好的效果,大幅度提高了图像间的相关度和一致性,为解决多路成像系统图像性能不一致的现象提供了有效的方法,达到了实际应用的水平。 相似文献
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Iman Heidarpour Shahrezaei Morteza Kazerooni Mohsen Fallah 《Waves in Random and Complex Media》2017,27(1):47-66
In this paper, synthetic aperture radar raw data generation of complex target terrain based on inverse equalized hybrid-domain processing technique is proposed. Firstly, the basic synthetic aperture radar (SAR) echo model is derived via spectral analysis of extended chirp scaling. Then, the inverse equalized extended chirp scaling algorithm (ECSA) procedure is applied directly step by step to a real input SAR image in order to generate the raw data of the reference SAR image. The whole raw data generation (RDG) procedure only consists of Inverse Equalized ECSA (IEECSA) without integral equation and computation complexity, which means easier implementation and higher efficiency. By applying the resulted RDG into different image formation algorithms (IFAs), not only the final images are reconstructed but also the resulted RDG is evaluated in practice. Finally, valid image quality assessment techniques are implemented on the reconstructed images. The simulations not only confirm the validity of the proposed RDG method based on inverse equalized hybrid-domain technique but also evaluate the quality metrics of reconstructed images as a method of reliability assurance. 相似文献
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Restoration of TDI camera images with motion distortion and blur 总被引:1,自引:0,他引:1
Jiagu Wu Zhenzhen Zheng Huajun Feng Zhihai Xu qi Li Yueting Chen 《Optics & Laser Technology》2010,42(8):1198-1203
Platform movement during exposure of imaging system severely degrades image quality. In the case of Time delay and integration (TDI) camera, abnormal movements cause not only image blur but also distortion, for image Point Spread Function (PSF) is space-variant. In this paper, we present a motion degradation model of TDI image, and provide a method to restore such degraded image. While a TDI camera is imaging, it outputs images row by row (or line by line) along the scanning axis, and our method processes in the same track. We firstly calculate the space-invariant PSF of each row using the movement information of the TDI camera. Then, we substitute pixels of the row and the ones of their neighbor rows together with the PSF into standard Richardson–Lucy algorithm. By deconvoluting we get the restored pixels of the row. The same operations are executed for all rows of the degraded TDI image. Finally, a restored image can be reconstructed from those restored rows. Both simulated and experimental results prove the effectiveness of our method. 相似文献
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A new method based upon data driven tool, principal component analysis (PCA), for fingerprint enhancement is proposed in this paper. PCA is a very useful statistical technique that has found application in many different fields like image compression, face recognition and is commonly used for finding patterns in data of high dimension. In the proposed method, the input image is first decomposed into directional images using decimation free Directional Filter Bank (DDFB). Then these directional images are normalized. A data driven technique PCA is applied to these normalized directional fingerprint images, which gives the PCA filtered images. These are basically directional images. Then these directional images are reconstructed into one image which is the enhanced one. Simulation results are included illustrating the capability of the proposed method. 相似文献