General purpose lighting technique.
The illuminator is mounted directly on the sensor and illuminates any object in front of it. A ring light provides diffused lighting over a small area.

• Advantages: provides correct lighting also for small objects.
  Reduces shadows on images with protrusions. Centres the light on the image.

• Disadvantages: with large objects, the corners of the image may lose brightness, creating a halo of black pixels along the external image edge. With highly reflective objects, the image may contain a circular glare of reflected light.