Cube
Period
—
Where the green is counted
the dish, found in each photocounted as green plant
Coverage is the share of the dish that is green plant. In each photo the dish is
found first (its agar reads warmer than the card and foil around it), so a nudged
camera still measures its dish, and the boards, foil and card are never counted.
The photo is then white-balanced on the dish itself, so neither the lights' colour
nor the agar's tint reads as plant, and a pixel counts when it is green
(…): brown seed coats, orange roots and pale agar don't. Measured a few times a
day while the lights are on — a frame shot in the dark measures the
darkness. Read the rate, not just the level, and check the thumbnail against
the number.