For example, if the photometric limiting distance of an automotive headlamp is 10 m, it is possible to reduce the measuring distance to less than one meter by using the KMP system. Depending on the light source being measured, the optical imaging system and the detectable angle range, the measuring distance can be even further reduced. The resulting necessary construction space is very compact.
KMP
compact measuring station
The KMP system allows an indirect measurement of LID (luminous intensity distribution) via an additional optical imaging system. This optical imaging system shortens the photometric limit distance of the light source because the light is projected in the focus plane of the optical system. At the position of the focus plane a reflective wall is installed.
All parallel emitted light beams are imaged at one point. This happens to the entire parallel beams at the same angle. Therefore each measurement point on the reflective wall can be associated with a viewing angle of the light source.
If the spatial resolution of the reflective wall and the geometric and photometric relations between the light source (in spherical coordinates) and the reflective wall (in camera coordinates) are well known, then the luminous intensity distribution can be calculated from the luminance image.
To minimise stray light effects, diffuse and low reflective apertures and material with special surface properties are used.
