Effect of external illumination on camera images

Object detection

Adding an external illumination will not improve objects detection. As explained in the article How does the Pickit 3D camera work?, our cameras are based on the structured light principle. For this to work, the structured light pattern needs to be the most present light source in the scene. If additional light is added to the scene, this can interfere with the known pattern. This interference can lead to worse 3D data.

The M and L cameras work with structured infrared light. So only other infrared light sources interfere with these cameras, the most common one being direct sunlight.

The M-HD and L-HD cameras works with structured visible light. To be less dependent on changing lighting conditions, these cameras use a strong projector. Because of this, typical changing lighting conditions in an office or factory don’t have much influence on the camera. Still, direct sunlight and bright spotlights can cause interference.

Note

When the color filter is used, the same recommendations mentioned below for calibration also apply.

Calibration

Detecting the calibration plate uses the color image. The following recommendations on external illumination sources help to improve the quality of plate detections, and therefore of the calibration process:

  • For non-HD, we need a uniform and diffuse external light source.

  • For HD, we don’t need additional light sources. It’s even recommended to reduce the external illumination, at least when the distance between the camera and the markers plate is larger than 1.5 m.