Fast Image Dehazing Method Based on Linear Transformation

ABSTRACT:

Images captured in hazy or foggy weather conditions are seriously degraded by the scattering of atmospheric particles, which directly influences the performance of outdoor computer vision systems. In this paper, a fast algorithm for single image dehazing is proposed based on linear transformation by assuming that a linear relationship exists in the minimum channel between the hazy image and the haze-free image. First, the principle of linear transformation is analyzed. Accordingly, the method of estimating a medium transmission map is detailed and the weakening strategies are introduced to solve the problem of the brightest areas of distortion. To accurately estimate the atmospheric light, an additional channel method is proposed based on quad-tree subdivision. In this method, average grays and gradients in the region are employed as assessment criteria. Finally, the haze-free image is obtained using the atmospheric scattering model. Numerous experimental results show that this algorithm can clearly and naturally recover the image, especially at the edges of sudden changes in the depth of field. It can thus achieve a good effect for single image dehazing. Furthermore, the algorithmic time complexity is a linear function of the image size. This has obvious advantages in running time by guaranteeing a balance between the running speed and the processing effect.

EXISTING SYSTEM:

• They proposed a simple but powerful color attenuation prior for haze removal from a single input hazy image.

• By creating a linear model for modeling the scene depth of the hazy image under this novel prior and learning the parameters of the model with a supervised learning method, the depth information can be well recovered.

• With the depth map of the hazy image, they can easily estimate the transmission and restore the scene radiance via the atmospheric scattering model, and thus effectively remove the haze from a single image.

DISADVANTAGES OF EXISTING SYSTEM:

• Existing dehazing methods can achieve good results on a single image, the high computation limits their applications in real-time systems.

PROPOSED SYSTEM:

• In this method, the transmission map is estimated using a linear transformation model which has less computational complexity, and the atmospheric light is obtained with an additional channel method based on a max-median filter by using the ratio of grays and gradients in the region.

• With those information, we can easily get the haze-free image through the atmospheric scattering model.

ADVANTAGES OF PROPOSED SYSTEM:

• In this method, the estimation of the transmission map is based on a linear model that includes only linear operations without any exponential operations or sample training. Therefore, it is easy to realize and has less computational complexity.

SYSTEM REQUIREMENTS:

HARDWARE REQUIREMENTS:

• System           : Pentium Dual Core.

• Hard Disk      : 120 GB.

• Monitor          : 15’’ LED

• Input Devices : Keyboard, Mouse

• Ram                : 1GB.

SOFTWARE REQUIREMENTS:

• Operating system : Windows 7.

• Coding Language : MATLAB

• Tool                      : MATLAB R2013A

REFERENCE:

Wencheng Wang, Xiaohui Yuan, Member, IEEE, Xiaojin Wu and Yunlong Liu, “Fast Image Dehazing Method Based on Linear Transformation”, IEEE Transactions on Multimedia, 2017.