Illumination device and illumination process with automatic shading compensation

An illumination device for illuminating a surface, the illumination device comprising:

• a light source set comprising several light sources;
• a distance measuring arrangement comprising several spaced-apart distance meters;
• and
• a signal-processing control unit,
• wherein the illumination device has an optical center axis and is configured to achieve a maximum total illuminance on the illuminated surface in a maximum area,
• wherein each of the light sources of the light source set has a respective light axis and is configured to generate a respective light field on the illuminated surface, wherein the light source has a maximum achievable individual illuminance of the generated light field,
• wherein the maximum individual illuminance of each of the light sources of the light source set can be set independently of the respective maximum individual illuminance of the or each of the other light sources to a value which lies between zero and the maximum achievable individual illuminance of this light source,
• wherein the control unit is configured to capture respective predetermined information for each light source of the light source set,
• wherein the captured or capturable information includes the respective maximum achievable individual illuminance of each light source and the respective position and/or orientation of the light axis of each light source relative to the optical center axis of the illumination device,
• wherein each distance meter of the distance measuring arrangement has a respective measuring direction pointing towards the illuminated surface and is configured to measure a respective distance between itself and a light-scattering object,
• wherein the control unit is configured to set the respective current individual illuminance of each light source of the set of light sources to a value,
• wherein the control unit is further configured to capture an illuminance specification that specifies a target value for the maximum total illuminance which the illumination device should generate,
• wherein the control unit is further configured, depending on a signal from the distance measuring arrangement, to determine whether a shading event has occurred, the shading event comprising an event during which at least one object is located between the illumination device and the illuminated surface, after determining that a shading event has occurred, to determine a shading area, which shading area includes an area on the illuminated surface which is completely or at least partially shaded by the object, and to search, depending on the determined shading area, for at least one light source of the light source set suitable for shading compensation,
• wherein a light source suitable for shading compensation is a light source:
• that is currently being operated with a value for the maximum individual illuminance that is lower than the maximum achievable individual illuminance of the light source;
• that is not shaded at all or at least not completely shaded;
• and that has its light axis intersecting the illuminated surface in the determined shading area,
• wherein the control unit is further configured to compensate for shading when at least one light source suitable for shading compensation is found,
• wherein the control unit is further configured, depending on the captured illuminance specification and depending on the captured information about the light sources of the light source set, to determine a subset with at least one suitable light source and to calculate for each light source of the selected subset a respective target value for the maximum individual illuminance,
• wherein the target value for each light source in the determined subset is greater than a current value of the maximum individual illuminance of this light source, and
• wherein the control unit is further configured to effect that this light source actually achieves the calculated target value for the maximum individual illuminance,
• wherein two objectives in calculating the target values for the maximum individual illuminances of the light sources of the subset are that the position of the maximum area relative to the optical center axis remains unchanged and the actual value of the maximum total illuminance that the illumination device currently achieves in the maximum area is equal to the captured illuminance specification.