Fig. 2From: Sensor-based phenotyping of above-ground plant-pathogen interactionssource of illumination or on the opposite side of the samplePhysical paths of electromagnetic radiation in biological samples and their detection using non-invasive sensors. Passive (ambient light) or active radiation can be used to illuminate or excite the sample. Radiation can be reflected, transmitted, scattered, absorbed and re-emitted by the sample to varying degrees. The characteristic radiation can then be measured with sensors positioned on the side of the Back to article page