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As reflections are one of our major problems when taking images from the drone, its important to conduct some tests to find the best camera setting to reduce the reflections to a minimum. One major problem which bring reflections into the detection algorithms and human vision is that there is no contrast at these areas anymore. Its like a nonlinearity which limits the information around these areas.

Even if the image is darker afterwards, we can increase the brightness / black white adjust the image afterwards. The decrease in the colordynamics range is not so important for us as nonlinearitys.

The informationdensity can be interpreted as entropy of a image. The higher the entropy of a image, the more information is in the image. As we are also interested in the informationdensity in the area of reflections or bright spots, we should also have a look at the entropy per area.

Tests including polarizationfilters will also be analyzed here.

• use pi camera v2
• use pistill programm:
• test different settings regarding exposure :
  • ex: exposure mode (auto, sports, beach)
  • ev: exposure compensation (-10 … 10)
• measurments
  • Shannon entropy: To check overall entropy
  • Local Entropy: Area based entropy
• Testscripts:

Setup: