System for sensing light exposure of a user

A lighting control system for ensuring a predetermined light exposure, comprising:

• a light exposure sensing system including:
• at least one wearable device;
• at least two light receivers oriented towards different directions orthogonal to each other and configured to receive light from the different directions, the light receivers being arranged on the at least one wearable device, and
• a control unit configured to determine light intensities received from the at least two light receivers,
• wherein the control unit is further configured to determine a ratio of daylight to artificial light (X/Y) based on the light intensities received from the at least two light receivers and based on the relation
• X/Y={(1/f)*S2−S1}/{(1/f)*(S1−S2)},
• wherein a highest light intensity of the light intensities received from the at least two light receivers is denoted as S1, a lowest light intensity of the light intensities received from the at least two light receivers is denoted as S2, and f is an illuminance ratio of vertical to horizontal illuminance from the artificial light, and wherein the control unit is further configured to determine a directional illuminance of a user using a ratio of the light intensities received from the at least two light receivers, or an average or a weighted average of the light intensities received from the at least two light receivers;
• at least one lighting system;
• and
• a central control unit, configured to use the determined directional illuminance, which is received from the light exposure sensing system, as a feedback parameter to control the at least one lighting system.

A method for sensing light exposure of a user using at least two light receivers arranged in different directions on at least one wearable device, the method comprising:

• receiving light from the different directions by the at least two light receivers,
• wherein a ratio of daylight to artificial light is determined based on the light intensities of the light received from the different directions by the at least two light receivers and based on the relation
• X/Y={(1/f)*S2−S1}/{(1/f)*(S1−S2)},
• wherein the highest light intensity of the light intensities of the light received by the at least two light receivers is denoted as S1, the lowest light intensity of the light intensities of the light received by the at least two light receivers is denoted as S2, and f is an illuminance ratio of vertical to horizontal illuminance from the artificial light.