To carry out multispectral measurements, the photographic shooting setup requires proper lighting and the presence of radiometric and exposure metering references.
The radiometric references used for the calibration of the images are divided into a chessboard of colors (Target or ColorChecker), available in various formats and sizes depending on the designated application field and the size of the subject to be photographed; each notch of the Target is previously measured in the laboratory with certified instrumentation.
For the calibration of transparent surfaces, transparent Targets have been developed; whose notches are previously measured in the laboratory with certified instrumentation.
The exposure references, instead, are necessary to balance the exposure and compensate for any variations in lighting. In this case, the materials used are reference whites and/or a white reference polymer.