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• Set max camera height ~1.7 meters above pot top ->

• set focus according to the color checker at aperture=F4 ->

• Increase flash power + increase F-number to around 10.

• Set exposure time to 250 uS.

• Modify aperture up or down until an appropriate exposure level is reached.

• if too much light, increase aperture to f/11 or f/12

• as f number increase, image quality generally increases but as it get too high image quality decreases

• The camera should stay at 170 +- 5 cm

• only moving up as plant grow taller

• generally don’t want images to be too bright because you risk over exposure with flowers or wet pots

• only thing that changes would be the height of the camera (z-axis) in the upward 20cm direction. The camera should only move up with the increase height of plants

• adjust strobe delay 50, 100, 150, 200 while the exposure time stays at a constant 100

  • if it’s darker 50, decrease to 25, then if it’s still darker we stay at 0 and move exposure back to 250

• use a second color checker card at pot level to confirm that images are in focus with above adjustments

• what if the small color checker is not in focus?

  • increase the f-number to 13 and the flash power to full power

    • if images are too underexposed, can increase

  • increasing exposure

  • Maybe we need to increase the F-number then, and increase the exposure time slightly. As well as the flash power

  what if the image is still dark at f/10?

  • getting f number closer to 12/13 is more ideal

    • depth of field will likely increase ~25%

• if the small color checker chart is still out of focus, we can adjust the gain

Color correction

• Long term color correction should be done in RawTherapee using a DNG file

• find the corresponding RGB values in RawTherapee using the color picker and “change foreground” tool and use the value for whatever matrix calculation tool (plantcv)

Gamma correction:

https://stackoverflow.com/questions/71734861/opencv-python-lut-for-16bit-image (quick and easy gamma correction, not ideal for longterm workflows)

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