Excess light detection for greenhouse illumination

Industrial scale greenhouses have, during the last decade, reached a high level of automation. However, the illumination is in general still controlled manually. One key factor in controlling the illumination in greenhouses is to detect how well the light energy is used for photosynthesis. Whereas too dim light means reduced production, too strong light is harmful for plants. The focus here is on finding a robust method for remote sensing of decreases in photosynthetic yield, suitable for closed loop control of the lighting in greenhouses.