梯度方向一致性约束下的多级低照度图像超分辨率重建模型  

Super⁃resolution reconstruction model of multilevel low⁃illumination image under constraint of gradient direction consistency

作　　者：赵雪静 李仁伟[1] ZHAO Xuejing;LI Renwei(North University of China,Taiyuan 030000,China)

机构地区：[1]中北大学,山西太原030000

出　　处：《现代电子技术》2022年第23期55-59,共5页Modern Electronics Technique

摘　　要：低照度图像受不同方向梯度的影响,造成其重建时的失真程度较高。为此,构建梯度方向一致性约束下的多级低照度图像超分辨率重建模型。使用鲁棒映射方法去除灰度梯度波动影响,计算定点水平方向梯度,基于图像横向梯度分析结果分离出图像中的灰度梯度。利用相邻正交方向梯度值合成水平、垂直方向梯度值,并将其作为辅助指标进行自适应调整,通过最小化模型拟合误差来约束,重建图像轮廓线。采用非均匀插补强化技术,保持图像原有色彩,引入色彩恢复因子,避免出现彩色图像色彩不平衡和失真问题。使用多尺度梯度主方向一致性约束处理方式,构建反射成分投影矩阵,重建低分辨率图像块。由实验结果可知,该模型主观测试结果是重建的图像清晰,客观测试结果是峰值信噪比最大值为21.3 dB,结构相似度最大值为93%,感知质量最大值为13.5 pi,图像失真程度小。The low⁃illumination image is affected by gradient in different directions,which results in a high distortion degree in the image reconstruction.Therefore,a super⁃resolution reconstructed model of multilevel low⁃illumination image under the constraint of gradient direction consistency is constructed.The robust mapping method is used to remove the influence of gray gradient fluctuation.The fixed point horizontal gradient is calculated.The gray gradient in the image is separated based on the analysis results of image transverse gradient.The gradient values in the horizontal and vertical directions are synthesized by the adjacent orthogonal direction gradient values,which are used as auxiliary indicators for adaptive adjustment.The image contour is reconstructed and constrained by minimizing the model fitting error.The non⁃uniform interpolation enhancement technology is adopted to maintain the original color of the image.The color restoration factor is introduced to avoid the color imbalance and distortion of the color image.With the multi⁃scale gradient principal direction consistency constraint processing method,the reflection component projection matrix is constructed to reconstruct low resolution image blocks.The experimental results show that the subjective test result of the model is that its reconstructed image is clear,and the objective test result is that its maximum peak signal to noise ratio(PSNR)is 21.3 dB,its maximum structure similarity is 93%,its maximum perceived quality is 13.5 pi,and its image distortion degree is small.

关 键 词：梯度方向一致性 多级低照度图像 超分辨率 图像失真程度 图像重建 灰度梯度 

分 类 号：TN911.73-34[电子电信—通信与信息系统] TP391[电子电信—信息与通信工程]