Vision-based detection of container lock holes using a modified local sliding window method

Abstract

Container yards have been facing the increase of freight volume. In order to improve the efficiency of container handling, automatic stations have been established in many terminals. However, current container handling still needs a manual operation to locate container lock holes. Hence, it is inefficient and potential to risk workers’ health under long working hours. This paper presented a hybrid machine vision method to automatically recognize and locate container lock holes. The proposed method extracted the top area of the container from the multiple container areas, and then presented a new modified local sliding window to detect the keyhole region. The algorithm learned the histograms of oriented gradients (HOG) features using a multi-class support vector machine (SVM). Finally, the holes were located using direct least square fitting of ellipses. We carried an experiment under various weather and light conditions including nights and rainy days. The results showed that both the recognition and location accuracy outperformed the state-of-the-art results.