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摘要:为了实现高像质相机低成本、小型化的需求,本文提出了一种大视场简单光学系统的光学-算法协同设计方法,并通过图像复原算法校正简单光学系统的残余像差。首先,针对大视场光学系统,对空间变化的交叉通道去卷积算法进行改进,加入倍率色差校正,使图像复原算法可显著去除色差的影响。然后,在光学设计过程中,放开色差的约束,并专注优化绿色通道的像质,使其成像锐利,在后期交叉通道去卷积算法中有助于红、蓝两通道图像复原。利用该方法设计了一个由两片同种材料的镜片构成的大视场简单光学系统。系统焦距为50 mm,全视场为46°, F数为5.6,探测器分辨率为1 000万像素。实验结果表明:本文设计的两片镜、大视场简单光学系统的成像质量可媲美三片式库克镜头,明显优于纯图像复原的结果。本文方法实现了大视场简单光学系统的设计,并能够通过系统最终获得高分辨率、高像质图像。Abstract:In order to meet requirements of the low cost and miniaturization of high-quality cameras, an optical/algorithmic co-design method for a large-field simple optical system is proposed. The residual aberrations of this simple optical system are corrected using an image restoration algorithm. Firstly, spatially varying cross-channel deconvolution is improved for large-field optical systems, wherein correction of lateral chromatic aberrations is introduced so that they can be significantly removed through the image restoration algorithm. Then, when designing the optical system, the constraints of chromatic aberrations are removed and we concentrate on optimizing the quality of the green channel to make the image sharp, which will help the restoration of images in the red and the blue channels in later cross-channel deconvolution. Using this method, a large-field simple optical system with two lenses of the same material is designed. The focal length of the system is 50 mm, the full field is 46 degrees, the Fnumber is 5.6 and the resolution of the sensor is 10 mega pixels. Experimental results indicate that the image quality of the proposed simple large-field optical system is comparable to that when using a Cooke triplet lens and is better than that when using pure image restoration algorithms. Our proposed method succeeds as a simple large-field optical system and can obtain high-resolution and high-quality images.
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表 1简单光学系统的镜头参数
Table 1.Lens data of the simple optical system
Surface Radius Thickness Glass Semi-Aperture Object Infinity Infinity 1 7.872 8 1.71 HK9L_CDGM 6.30 2 6.582 4 5.57 5.38 stop Infinity 4.28 4.28 4 -33.333 4 10.00 HK9L_CDGM 6.28 5 -13.943 6 56.45 9.10 Image Infinity 0 20.21 表 2BRISQUE评价结果对比
Table 2.Comparison of BRISQUE scores
Flowers Campus Ground truth 17.079 6 21.843 0 Krishnanet al. 51.551 5 49.697 0 Heideet al. 44.991 0 44.785 0 Ours 30.548 2 39.275 0 Cooke lens 29.490 0 36.888 0 表 3NIQE评价结果对比
Table 3.Comparison of NIQE scores
Flowers Campus Ground truth 3.238 0 3.333 8 Krishnanet al. 6.612 2 6.527 4 Heideet al. 6.059 0 5.825 9 Ours 4.838 0 4.577 5 Cooke lens 4.200 0 4.413 1 -
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