基于快速ACE算法的视觉里程计图像增强方法

为提高同时定位与地图构建(simultaneous localization and mapping, SLAM)在室内定位的不同场景下的鲁棒性,应对室内场景纹理少,光线差等极端环境的挑战。通过利用改进快速自动彩色增强(automatic color enhancement, ACE)图像增强技术,优化定向FAST和旋转BRIEF(oriented FAST and rotated briEF,ORB)特征点法的前端视觉里程计。同时将原始图像数据、限制对比度自适应直方图均衡(contrast limited adaptive histogram equalization, CLAHE)增强后、单尺度Retinex(single scale retinex, SSR)增强后,改进快速ACE增强后图像数据应用于楼梯间,地下停车场等不同现实场景中做基于图像质量和特征提取匹配两方面对比实验。实验结果表明,改进快速ACE增强后图像质量其他算法,并且视觉里程计(visual odometry, VO)应用该算法增强后提取到的特征点数量增幅达到倍数级,极端环境下匹配数量增幅在7%～25%,鲁棒性提高。

Image enhancement method of visual odometer based on fast ACE algorithm

In order to improve the robustness of simultaneous localization and mapping (SLAM) in different indoor scenes and deal with the challenges in extreme environments such as less texture and poor light. The visual odometry based on ORB algorithm is improved by using the improved fast automatic color enhancement (ACE) image enhancement technique. At the same time, the original image data, the image data enhanced by contrast limited adaptive histogram equalization (CLAHE), single scale retinex ( SSR), and the improved fast ACE were applied to different real scenes, such as stairwells, subterranean parking lots, and two comparison experiments based on image quality and feature extraction matching are done. The experimental results show that the quality of the image enhanced by the improved fast ACE is better than the other algorithms. After enhancement, the number of feature points of visual odometry (VO) is increased by a multiple order, the matching number is increased by 7% ~ 25% in extreme environments, and the robustness is improved.