Surface Imaging System (SIS)

The Surface Imaging System (SIS) is a high-resolution pavement imaging system recording images for crack detection image analysis. The SIS records the road pavement surface while travelling at normal traffic speed using line-scan technology.

While recording, the pavement is illuminated with a highly efficient flashing diode lamp configuration overruling any shadow cast due to the sun. The system can be operated as a standalone system or synchronized with other equipment.

Continuous undistorted image

To obtain sharp images an array of high-power flashing LED’s is used. For every 1mm the vehicle moves (depending on the resolution), the LED light makes a flash with a strength many times stronger than the sunlight, which removes shadows cast due to the sun.

The camera is triggered simultaneous and each line from the camera is added to the previous lines to make up one long continuous image. This eliminates the overlap algorithms that combines standard single frames.

The continuous image is stored on a computer, tagged with time and distance identifying the precise position for each part of the image.


  • Continuous undistorted image of the road surface, exported to user defined image sizes.
  • Based on best image sensors on the market.
  • Homogeneous illumination with less than +-5 DN variation over entire image width, i.e. no lines/areas with brighter or darker illumination.
  • Independent of sunlight, i.e. no shadow casts, from e.g. road signs or bridges.
  • Include Greenwood Engineering’s own LED based lamps for strong image illumination, several times stronger than sunlight.
  • Typical configuration: 4-meter-wide image with a resolution of 1mm pixel size.
  • Driving speed as high as undisturbed traffic.