Restoration Method of Sootiness Mural Images Based on Dark Channel Prior and Retinex by Bilateral Filter

Abstract

Environmental changes and human activities can cause serious degradation of murals, where sootiness is one of the most common problems of ancient Chinese indoor murals. In order to improve the visual quality of the murals, a restoration method is proposed for sootiness murals based on dark channel prior and Retinex by bilateral filter using hyperspectral imaging technology. First, radiometric correction and denoising through band clipping and minimum noise fraction rotation forward and inverse transform were applied to the hyperspectral data of the sootiness mural to produce its denoised reflectance image. Second, a near-infrared band was selected from the reflectance image and combined with the green and blue visible bands to synthesize a pseudo color image for the subsequent sootiness removal processing. The near-infrared band is selected because it is better penetrating the sootiness layer to a certain extent comparing to other bands. Third, the sootiness covered on the pseudo color image was preliminarily removed by using the method of dark channel prior and by adjusting the brightness of the image. Finally, the Retinex by bilateral filter was performed on the image to get the final restored image, where the sootiness was removed. The results show that the proposed method can effectively reduce the influence of sootiness on the mural image and improve its visual quality. It can also be used to reveal the original appearance of the mural to reasonable extent.

Application of hyperspectral imaging technology to digitally protect murals in the Qutan temple

“…Fig. 2 The overall workflow [30]. The step of data preprocessing is performed by the hyperspectral image acquisition software provided by the instrument producer and the ENVI.…”

Computer-Aided Virtual Restoration of Frescoes Based on Intelligent Generation of Line Drawings

“…e World Computer Graphics Conference held in the United States in July 1994 had a large proportion of computer art content and a special edition of selected computer art works [15]. eoretical research on computer art covers various aspects: the nature of computer art creation and its social functions, the impact of computer technology on artistic functions and forms, and the roles of computer engineers, commercial artists, and academic artists in creation; however, there are still no mature conclusions.…”