27. Improved Local Adaptive Image Enhancement Algorithm Based on Lee Algorithm

Experiments indicate that Lee algorithm is sensitive to noise in image enhancement, which means that the details of texture and noises will be enhanced simultaneously. Therefore, an improved adaptive local image enhancement algorithm based on Lee algorithm is proposed in the paper to reduce the negative impact of the noises. Firstly, traditional Lee algorithm is employed to improve the image brightness and enhance the image details. Then, logarithmic transformation is applied to make the image more consistent with human vision mechanism. Finally, double platform threshold based on histogram equalization is used to overcome the disadvantage that the targets and details occupying less pixels become blurred and lost due to pixel-level merging, while the background and noise are enhanced excessively by setting the threshold of the double platform. Verification experiments demonstrate that the improved algorithm can enhance image local contrast and adaptively adjust image dynamic range effectively, regardless of the impact of noises to avoid excessive enhancement.