Research on Automatic Dodging Method for Road Surface Line Array Images

Abstract

Line scan cameras are widely used to acquire pavement images due to their imaging characteristics and low price, but the acquired pavement line array images often have uneven brightness. To eliminate the impact of image greyscale unevenness on subsequent processing, an automatic dodging method is proposed based on mask dodging algorithm. The main idea of the method is to chuck the images into sub-blocks with the approximate greyscale change degree by introducing the cumulative slope conception. The rules to determine the filter size and the parameters required to adjust the sub-block are self-adaptive. The contrast stretching method is improved to make it more suitable for pavement images. The method is compared with other classical dodging algorithms, and the results show that the proposed automatic dodging method is better than others intuitively and quantitatively. The image length has no significant influence on it. Moreover, the crack segmentation results indicate that the proposed dodging method is effective for line array images, and a more accuracy crack segmentation could be achieved if the images preprocessed by the proposed dodging methods.