PMD(photonic mixer device)相机是一款基于TOF(time-of-flight)技术的3维成像系统,在获得2维灰度图像的基础上,能够同时捕捉距离图像和幅度图像。但它的主要缺点是分辨率低,并存在较大的随机噪声。针对此问题,结合PMD相机幅度信息和双边滤波器的特点,提出一种改进的非连续自适应马尔科夫随机场(DAMRF)模型的超分辨率重建方法,该模型引入调制信号幅度A的平方作为可信度,将其作为权值对传统DAMRF模型中能量函数的距离项进行自适应加权,从而增加距离图像每个像素点在平滑过程中的权值。该方法不仅提高了距离图像的空间分辨率,又能有效地对距离图像进行滤波去噪,同时也增强了距离图像的边缘信息,较好地保持了图像边缘的连续性。实验结果表明,该方法的重建结果优于传统DAMRF模型的超分辨率方法,获得重建图像的信噪比(SNR)和均方根误差(RMSE)都有较好的改善,重建图像的视觉效果也得到一定的提高。

A PMD (photonic mixer device) camera is a three-dimensional imaging system based on the TOF (time-of-flight) technology.While obtaining the two-dimensional gray image,this camera can capture a range image and an amplitude image at the same time.However,the main drawbacks of the camera are the low resolution and random noise.According to this problem,we combine the amplitude information of the PMD camera and a bilateral filter.An improved discontinuity adaptive Markov random field (DAMRF) model is introduced by a combination of super-resolution reconstruction methods,which introduces the square of the modulating signal amplitude A as confidence.Then this method will use it as the weight to carry on an adaptive weight for the distance items of the energy function of the traditional DAMRF model,so it increases the weights of the range image pixel in the process of smoothing.This method not only increases the spatial resolution of the range images,but also effectively filters and de-noises the range image.At the same time,it enhances the marginal information of the range image,and better maintains the continuity of the image edges.The experimental results demonstrate that the reconstruction result of this method is superior to that of the traditional DAMRF model.The method obtains a better improvement in the reconstructed image signal to noise ratio (SNR) and root mean square error (RMSE),and improves the visual effects of the reconstructed image.