# Robust Chromatic Adaptation Based Color Correction Technology for Underwater Images  
[PERSON]  
1 School of Mechanical Engineering, Shenyang Jianzhu University, Shenyang 110168, China; [EMAIL_ADDRESS] (X.Y.); [EMAIL_ADDRESS] (C.Y.); [EMAIL_ADDRESS] (Z.Z.); [EMAIL_ADDRESS] (Y.L.); [EMAIL_ADDRESS] (W.L.); [EMAIL_ADDRESS] (D.W.)  
[PERSON]  
1 School of Mechanical Engineering, Shenyang Jianzhu University, Shenyang 110168, China; [EMAIL_ADDRESS] (X.Y.); [EMAIL_ADDRESS] (C.Y.); [EMAIL_ADDRESS] (Z.Z.); [EMAIL_ADDRESS] (Y.L.); [EMAIL_ADDRESS] (W.L.); [EMAIL_ADDRESS] (D.W.)  
[PERSON]  
1 School of Mechanical Engineering, Shenyang Jianzhu University, Shenyang 110168, China; [EMAIL_ADDRESS] (X.Y.); [EMAIL_ADDRESS] (C.Y.); [EMAIL_ADDRESS] (Z.Z.); [EMAIL_ADDRESS] (Y.L.); [EMAIL_ADDRESS] (W.L.); [EMAIL_ADDRESS] (D.W.)  
[PERSON]  
1 School of Mechanical Engineering, Shenyang Jianzhu University, Shenyang 110168, China; [EMAIL_ADDRESS] (X.Y.); [EMAIL_ADDRESS] (C.Y.); [EMAIL_ADDRESS] (Z.Z.); [EMAIL_ADDRESS] (Y.L.); [EMAIL_ADDRESS] (W.L.); [EMAIL_ADDRESS] (D.W.)  
[PERSON]  
1 School of Mechanical Engineering, Shenyang Jianzhu University, Shenyang 110168, China; [EMAIL_ADDRESS] (Y.L.); [EMAIL_ADDRESS] (C.Y.); [EMAIL_ADDRESS] (Z.Z.); [EMAIL_ADDRESS] (Y.L.); [EMAIL_ADDRESS] (W.L.); [EMAIL_ADDRESS] (D.W.)  
[PERSON]  
1 School of Mechanical Engineering, Shenyang Jianzhu University, Shenyang 110168, China; [EMAIL_ADDRESS] (X.Y.); [EMAIL_ADDRESS] (C.Y.); [EMAIL_ADDRESS] (Z.Z.); [EMAIL_ADDRESS] (Y.L.); [EMAIL_ADDRESS] (W.L.); [EMAIL_ADDRESS] (D.W.)  
[PERSON]  
2 State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016, China; [EMAIL_ADDRESS] (Correspondence: [EMAIL_ADDRESS] 2 Most of the underwater image restoration and enhancement methods try to correct the color cast and enhance the contrast simultaneously. The color correction methods are used casually and there is no specialized comprehensive comparison between different color correction methods on underwater images. This paper focuses on the color correction of underwater images with the assumption that sunlight is the only light source. Color cast is generated due to the variation of light attenuation, which is caused by absorption and scattering, in different wavelengths [9]. To be exact, during the light propagation in the water medium, color cast is formed in two processes. One is the light travels downward before reaching the scene and the other is the light travels to the camera after reflected by the scene [7; 13]. Since the object of interest called foreground is usually closer to the camera than the background, the color cast of the foreground formed in the second process is generally little. The color cast formed in the first process is dominant, especially for the images captured in deep water. Without considering the color cast formed in the second process, it looks like that an underwater image is captured with the scene illuminated by an unknown light source. Using a sunlight-like light source instead will make the underwater images look natural.  
Chromatic adaptation is a study of change in the photoreceptive sensitivity of the human visual system under various viewing conditions, such as illumination [14]. The chromatic adaptation mechanism tries to eliminate the effect of the illuminant and has been widely applied in many fields [15; 16; 17; 18]. In this paper, a chromatic adaptation based color correction method is proposed for underwater images and a comparison between this method and several conventional methods [18; 19; 20; 21; 22] is drawn. Example results obtained by the proposed method can be seen in Figure 1.  
The contributions of this paper are as follows. First, a simple yet effective and robust color correction method for underwater images is proposed. Second, a comprehensive comparison between several typical white balance and color correction methods on underwater images is drawn. Third, several key issues to be concerned in the color correction of underwater images are discussed.