scope:

The basic task of imaging luminance measurement devices (ILMDs) is to measure (the projection of) the spatial luminance distribution of (self-radiating) extended sources and illuminated surfaces. In literature, different terms may be found to describe the same device such as: multi-channel luminance meter, luminance mapper, array (or matrix) luminance meter, video photometer, CCD luminance meter, luminance camera or spatial luminance profile device.

Compared with a traditional spot luminance measurement device (LMD) the user of an ILMD measures a luminance image containing not only one spatially averaged luminance measurement value of the object for one direction. An ILMD samples an object by many measurement points. In addition, information about the surrounding of the object is obtained. It is therefore possible to evaluate a luminance image in different ways, e.g. using different regions and illustrating these regions directly on a displayed image. An example is given in Figures 1-3.

Due to their properties, ILMDs are used for a wide range of applications including the characterization of displays, near-field goniophotometry, or visibility and lighting studies of complex scenes. Their advantages are clearly:

• temporal synchronized measurement of a large number of measurement points;

• direct spatial identification of the measurement object (documentation);

• arbitrary geometrical shape of multiple measurement fields and complex evaluations (e.g. luminance-based evaluation shapes).

The objective of this document is to

• give clear definitions for the individual characteristics which can be used f or evaluating the performance of ILMDs;

• recommend methods for the characterization and the calibration of these devices;

• provide a guideline for the selection and correct use of these measurement devices .