Automated traffic control systems require good quality pictures to allow a relevant identification of the vehicle, particularly concerning road infrigement.

Relevant pictures usually demand three ingredients :
- An Identifiable background and car body, if possible with colours (except, of course, for IR pictures),
- The driver's face and
- Last but not least, the licence plate number, with enough precision to allow treatment by an Automated Licence Plate Recognition (ALPR) system.

Using a flash illuminator is essential to obtain a well-exposed backgrounds, and capture driver's face inspite of losses through the cars' windscreen (example here). Nevertheless, retro-reflecting parts, such as licence plates, redirect the major part of the light to its source. When the flash is placed close to the camera, licence plates often appear over-exposed on pictures, and are illegible by ALPR systems.

Lumix's optical splitting filter overcome this trouble. When fixed in front of a camera lens, the splitting filter duplicates the original frame, creating a "ghost picture" 4 f-stops less exposed than the main picture.

The drawing above shows how a beam of light coming from the subject to the camera is split into a main and a secondary subdued beam :
- The major part of the light is captured by the camera CCD or CMOS (symbolized in yellow lines on the drawing) as a main picture ;
- A part of the light is redirected (green lines on the drawing). The resulting picture (named "ghost picture") is approximately 6° next to the original one, and is less exposed ; even if the whole picture is duplicated, only the shiny parts stand out, the rest fading away in the more exposed main picture.

On the very same picture, shiny parts like licence plates appear twice, but only the licence plate created by the splitting filter is well-exposed, and can be identified by ALPR systems.

Lumix's splitting filter is patent pending.

Lumix's Splitting Filter sales area is restricted.