基于乘数交替方向法的系统图像退化恢复方法

针对一般正则化方法不能有效解决非线性成像和高动态成像的系统退化恢复问题,提出一种非线性图像恢复方法,该方法利用乘数交替方向法解决双边全变差(bilateral total variation,BTV)模型的正则化项不平滑问题.建立包含复原图像的非线性最小二乘数据拟合项和BTV正则化项的目标函数;对目标函数进行优化;构建一套有效的乘数交替方向法(multiplier alternating direction method,MADM)求解提出的模型.利用峰值信噪比(peak signalto noise ratio,PSNR)和结构相似性度量(structural similarity index measurement,SSIM)评估图像恢复结果.对于非线性成像系统退化,提出的方法在PSNR和SSIM方面比基于TV(total variation)模型的方法分别提高4.5％和4.1％.对于高动态的成像退化问题,提出的方法获得的恢复图像PSNR值可达61.89 dB,相比其他方法,至少提高了2.9％.此外,该方法的运行时间也至少节省了26％,具有较高的计算效率.

An image restoration method for degradation of imaging system based on multipliers alternating direction method

As common regularization cannot solve image restoration effectively in the cases of nonlinear imaging and high dynamic imaging, a nonlinear image restoration method is proposed, and in which multiplier alternating direction method is used to solve the non-smooth regularization problem in bilateral total variation (BTV) model. Firstly, the objective function that includes term of BTV regularization and term of nonlinear least squares fitting is created. Then, the objective function is optimized. Finally, an effective multiplier alternating direction method (MADM) is proposed to solve the proposed model. Peak signal to noise ratio (PSNR) and structural similarity index metric (SSIM) are applied to assessing the results of image restoration. For degradation of nonlinear imaging system, PSNR and SSIM of the proposed method is 4. 5% and 4. 1% more than that of other methods based on TV model respectively. For degradation of high dynamic imaging system, PSNR of the restored image can get 61. 89 dB in the proposed method, which is 2. 9% more than that of other algorithms. Meanwhile, the running time is reduced by at least 26% , with efficiency computation.