Weighted Nuclear Norm Minimization Based Tongue Specular Reflection Removal

Zhenchao Cui,Kuanquan Wang,Naimin Li,Dongyu Zhang,Wangmeng Zuo,Hongzhi Zhang

doi:10.1155/2015/979415

Zhenchao Cui, Kuanquan Wang + Show 4 more

Open Access

https://doi.org/10.1155/2015/979415

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Abstract

In computational tongue diagnosis, specular reflection is generally inevitable in tongue image acquisition, which has adverse impact on the feature extraction and tends to degrade the diagnosis performance. In this paper, we proposed a two-stage (i.e., the detection and inpainting pipeline) approach to address this issue: (i) by considering both highlight reflection and subreflection areas, a superpixel-based segmentation method was adopted for the detection of the specular reflection areas; (ii) by extending the weighted nuclear norm minimization (WNNM) model, a nonlocal inpainting method is proposed for specular reflection removal. Experimental results on synthetic and real images show that the proposed method is accurate in detecting the specular reflection areas and is effective in restoring tongue image with more natural texture information of tongue body.

Highlights

In traditional Chinese medicine (TCM), the practitioners observe the color, shape, texture, and coating characteristics of tongue to evaluate the healthy condition of a person
We proposed a two-stage approach to address this issue: (i) by considering both highlight reflection and subreflection areas, a superpixel-based segmentation method was adopted for the detection of the specular reflection areas; (ii) by extending the weighted nuclear norm minimization (WNNM) model, a nonlocal inpainting method is proposed for specular reflection removal
This paper focused on the tongue image specular reflections removal, whose contributions are of twofold: (i) detection of highlight reflection and subreflection areas, and (ii) WNNM-based inpainting

Summary

Introduction

In traditional Chinese medicine (TCM), the practitioners observe the color, shape, texture, and coating characteristics of tongue to evaluate the healthy condition of a person. Bilinear interpolation [20] and totalvariation- (TV-) based methods [21] were applied for inpainting the tongue specular reflection regions These methods, only considered the local smoothness of the image and were not effective when the reflection areas are large. We adopted the detection and inpainting pipeline and proposed a novel method for the removal of specular reflection areas in tongue image. This paper focused on the tongue image specular reflections removal, whose contributions are of twofold: (i) detection of highlight reflection and subreflection areas, and (ii) WNNM-based inpainting. Compared with other inpainting approaches, our method can obtain more natural textures information of tongue, especially for large reflection area, which could promote both the PSNR value and the visual effect of the restored tongue image.

Tongue Image Specular Reflection Detection

The WNNM-Based Nonlocal Inpainting Method

Experimental Results

Conclusion