Improved Daytime Detection of Pavement Markings with Machine Vision Cameras

Automotive machine vision camera systems commonly rely on edge detection schemes to locate pavement markings. These enable robust operation of advanced driver assistance system (ADAS) functions such as lane departure warning and lane keeping systems, well as autonomous driving functions. Edge detection algorithms commonly detect first-order gradients in pixel intensity, and binarize images so only pixels with gradients above a threshold value are retained. In this paper, the authors demonstrate that by increasing the luminance of a pavement marking over a range of illumination conditions, and by placing a contrast stripe adjacent to that pavement marking that has low luminance values under different illumination conditions, it is possible to increase both the Weber contrast of a marking and a representative contrast gradient based on a Sobel operator. A contrast stripe adjacent to a white marking reduces the dependence of the Sobel contrast gradient on illumination levels, and also enables higher Sobel contrast gradient values even for darker(e.g. soiled, aged) markings. If illumination and luminance of the markings result in a Weber contrast greater than ~4, the Sobel contrast gradient is relatively constant. The authors further demonstrate that widths of both pavement marking and contrast stripe may be selected for a given camera field-of-view, focal length, sensor size, and pixel density to optimize the pixel luminance values and gradients. They anticipate that appropriately sized pavement markings for a desired viewing distance with appropriate absolute luminance values and gradients will enable more robust lane detection.

• Supplemental Notes:
  • This paper was sponsored by TRB committee AHB50 Standing Committee on Traffic Control Devices.
• Authors:
  • Whitney, Jordan
  • Hedblom, Thomas
  • Clear, Susannah
• Conference:
  • Transportation Research Board 97th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2018-1-7 to 2018-1-11
• Date: 2018

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; Photos; References; Tables;
• Pagination: 19p

Subject/Index Terms

• TRT Terms: Daylight; Driver support systems; Edge detection; Luminance; Machine vision; Road markings
• Subject Areas: Highways; Materials; Pavements;

Filing Info

• Accession Number: 01661613
• Record Type: Publication
• Report/Paper Numbers: 18-05478
• Files: TRIS, TRB, ATRI
• Created Date: Feb 28 2018 5:00PM