Image and Signal Processing Methods

Variational contrast enhancement guided by global and local contrast measurements for single-image defogging

[+] Author Affiliations
Li Zhou, Du-Yan Bi, Lin-Yuan He

Air Force Engineering University, Aerospace Engineering College, Communication and Navigation Lab, No. 1 Ba Ling Road, Shan Xi Province, Ba Qiao District, Xi’an 710038, China

J. Appl. Remote Sens. 9(1), 095049 (Oct 06, 2015). doi:10.1117/1.JRS.9.095049
History: Received April 20, 2015; Accepted September 2, 2015
Text Size: A A A

Abstract.  The visibility of images captured in foggy conditions is impaired severely by a decrease in the contrasts of objects and veiling with a characteristic gray hue, which may limit the performance of visual applications out of doors. Contrast enhancement together with color restoration is a challenging mission for conventional fog-removal methods, as the degrading effect of fog is largely dependent on scene depth information. Nowadays, people change their minds by establishing a variational framework for contrast enhancement based on a physically based analytical model, unexpectedly resulting in color distortion, dark-patch distortion, or fuzzy features of local regions. Unlike previous work, our method treats an atmospheric veil as a scattering disturbance and formulates a foggy image as an energy functional minimization to estimate direct attenuation, originating from the work of image denoising. In addition to a global contrast measurement based on a total variation norm, an additional local measurement is designed in that optimal problem for the purpose of digging out more local details as well as suppressing dark-patch distortion. Moreover, we estimate the airlight precisely by maximization with a geometric constraint and a natural image prior in order to protect the faithfulness of the scene color. With the estimated direct attenuation and airlight, the fog-free image can be restored. Finally, our method is tested on several benchmark and realistic images evaluated by two assessment approaches. The experimental results imply that our proposed method works well compared with the state-of-the-art defogging methods.

Figures in this Article
© 2015 Society of Photo-Optical Instrumentation Engineers

Citation

Li Zhou ; Du-Yan Bi and Lin-Yuan He
"Variational contrast enhancement guided by global and local contrast measurements for single-image defogging", J. Appl. Remote Sens. 9(1), 095049 (Oct 06, 2015). ; http://dx.doi.org/10.1117/1.JRS.9.095049


Tables

Access This Article
Sign in or Create a personal account to Buy this article ($20 for members, $25 for non-members).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging & repositioning the boxes below.

Related Book Chapters

Topic Collections

Advertisement
  • Don't have an account?
  • Subscribe to the SPIE Digital Library
  • Create a FREE account to sign up for Digital Library content alerts and gain access to institutional subscriptions remotely.
Access This Article
Sign in or Create a personal account to Buy this article ($20 for members, $25 for non-members).
Access This Proceeding
Sign in or Create a personal account to Buy this article ($15 for members, $18 for non-members).
Access This Chapter

Access to SPIE eBooks is limited to subscribing institutions and is not available as part of a personal subscription. Print or electronic versions of individual SPIE books may be purchased via SPIE.org.